This patient presents with clinical features that are indicative of a right middle/lower lobe pneumonia. Considering her past medical history of a stroke and the specific location of the chest signs, it is highly probable that she is suffering from aspiration pneumonia.

The two-level PE Wells score has been simplified to determine the likelihood of a pulmonary embolism (PE) into two outcomes: likely or unlikely. A score of over 4 indicates that a PE is likely, while a score of 4 points or less indicates that a PE is unlikely.

The allocation of points is as follows:

– Clinical symptoms and signs of deep vein thrombosis (DVT) = 3 points
– An alternative diagnosis that is less likely than a PE = 3 points
– Heart rate greater than 100 = 1.5 points
– Immobilization for more than 3 days or recent surgery within 4 weeks = 1.5 points
– Previous history of DVT or PE = 1.5 points
– Presence of haemoptysis = 1 point
– Malignancy (currently on treatment, treated in the last 6 months, or palliative care) = 1 point.

The risk of primary spontaneous pneumothorax is associated with smoking tobacco and increases as the duration of exposure and daily consumption rise. The changes caused by smoking in the small airways may contribute to the development of local emphysema, leading to the formation of bullae. In this case, the patient does not have any clinical features or significant risk factors for the other conditions mentioned. Therefore, primary spontaneous pneumothorax is the most probable diagnosis.

The duration of submersion is the most crucial factor in predicting the outcome of drowning incidents. If the submersion time is less than 10 minutes, it is considered a positive indicator for prognosis, while if it exceeds 25 minutes, it is considered a negative indicator. There are other factors that are associated with higher rates of illness and death, such as a low Glasgow Coma Score, absence of pupillary response, pH imbalance (acidosis), and low blood pressure (hypotension). However, it is important to note that these prognostic factors have not been consistently validated in studies and cannot reliably predict the outcome of drowning incidents.

Further Reading:

Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid. It can be classified as cold-water or warm-water drowning. Risk factors for drowning include young age and male sex. Drowning impairs lung function and gas exchange, leading to hypoxemia and acidosis. It also causes cardiovascular instability, which contributes to metabolic acidosis and cell death.

When someone is submerged or immersed, they will voluntarily hold their breath to prevent aspiration of water. However, continued breath holding causes progressive hypoxia and hypercapnia, leading to acidosis. Eventually, the respiratory center sends signals to the respiratory muscles, forcing the individual to take an involuntary breath and allowing water to be aspirated into the lungs. Water entering the lungs stimulates a reflex laryngospasm that prevents further penetration of water. Aspirated water can cause significant hypoxia and damage to the alveoli, leading to acute respiratory distress syndrome (ARDS).

Complications of drowning include cardiac ischemia and infarction, infection with waterborne pathogens, hypothermia, neurological damage, rhabdomyolysis, acute tubular necrosis, and disseminated intravascular coagulation (DIC).

In children, the diving reflex helps reduce hypoxic injury during submersion. It causes apnea, bradycardia, and peripheral vasoconstriction, reducing cardiac output and myocardial oxygen demand while maintaining perfusion of the brain and vital organs.

Associated injuries with drowning include head and cervical spine injuries in patients rescued from shallow water. Investigations for drowning include arterial blood gases, chest X-ray, ECG and cardiac monitoring, core temperature measurement, and blood and sputum cultures if secondary infection is suspected.

Management of drowning involves extricating the patient from water in a horizontal position with spinal precautions if possible. Cardiovascular considerations should be taken into account when removing patients from water to prevent hypotension and circulatory collapse. Airway management, supplemental oxygen, and ventilation strategies are important in maintaining oxygenation and preventing further lung injury. Correcting hypotension, electrolyte disturbances, and hypothermia is also necessary. Attempting to drain water from the lungs is ineffective.

Patients without associated physical injury who are asymptomatic and have no evidence of respiratory compromise after six hours can be safely discharged home. Ventilation strategies aim to maintain oxygenation while minimizing ventilator-associated lung injury.

Mycoplasma pneumoniae infection does not have a connection with infective endocarditis. However, it is associated with various extra-pulmonary complications. These include skin conditions such as erythema multiforme and Stevens-Johnson syndrome. In the central nervous system, it can lead to Guillain-Barre syndrome, meningitis, encephalitis, optic neuritis, cerebellar ataxia, and cranial nerve palsies. Gastrointestinal symptoms may include anorexia, nausea, diarrhea, hepatitis, and pancreatitis. Hematological complications can manifest as cold agglutinins, hemolytic anemia, thrombocytopenia, and disseminated intravascular coagulation. Mycoplasma pneumoniae infection can also cause pericarditis and myocarditis. Rheumatic symptoms such as arthralgia and arthritides may occur, and acute glomerulonephritis can affect the kidneys.

The typical range for lactate levels in the body is 0.5-2.2 mmol/L, according to most UK trusts. However, it is important to mention that the RCEM sepsis guides consider a lactate level above 2 mmol/L to be abnormal.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

Whooping cough is a respiratory infection caused by the bacteria Bordetella pertussis. It is highly contagious and spreads to about 90% of close household contacts. Public Health England (PHE) has identified two priority groups for managing whooping cough contacts. Group 1 includes infants under one year who have received less than three doses of the pertussis vaccine and are at risk of severe infection. Group 2 includes pregnant women at 32 weeks or more, healthcare workers dealing with infants and pregnant women, individuals working with unvaccinated infants under 4 months old, and individuals living with unvaccinated infants under 4 months old.

According to current guidelines, antibiotic prophylaxis with a macrolide antibiotic like erythromycin should only be given to close contacts if the following criteria are met: the index case has had symptoms within the past 21 days and there is a close contact in one of the priority groups. If both criteria are met, all contacts, regardless of age and vaccination status, should be offered chemoprophylaxis. In this case, the mother falls into group 2, so the recommended action is to provide chemoprophylaxis to all household contacts, including the mother, father, and brother. Additionally, those who receive chemoprophylaxis should also consider immunization or a booster dose based on their current vaccination status.

Croup, also known as laryngo-tracheo-bronchitis, is typically caused by the parainfluenza virus. Other viruses such as rhinovirus, influenza, and respiratory syncytial viruses can also be responsible. Before the onset of stridor, there is often a mild cold-like illness that lasts for 1-2 days. Symptoms usually reach their peak within 1-3 days, with the cough often being more troublesome at night. A milder cough may persist for another 7-10 days.

A distinctive feature of croup is a barking cough, but it does not indicate the severity of the condition. To reduce airway swelling, dexamethasone and prednisolone are commonly prescribed. If a child is experiencing vomiting, nebulized budesonide can be used as an alternative. However, it is important to note that steroids do not shorten the duration of the illness. In severe cases, nebulized adrenaline can be administered.

Hospitalization for croup is uncommon and typically reserved for children who are experiencing worsening respiratory distress or showing signs of drowsiness or agitation.

This patient’s medical history and physical examination findings are indicative of a diagnosis of asbestosis. Additionally, the patient exhibits characteristics consistent with interstitial lung disease that has developed as a result of the asbestosis.

Exposure to asbestos was prevalent in various professions, particularly during the 1970s and earlier. Occupations commonly associated with asbestos exposure include shipyard workers, builders, miners, and pipefitters.

It is important to consider the possibility of mesothelioma in individuals who have been exposed to asbestos. This should be suspected if the patient presents with constitutional symptoms such as weight loss, fatigue, and loss of appetite, along with the presence of thickening of the pleura and/or accumulation of fluid in the pleural space.

This patient presents with symptoms and signs that are consistent with an atypical pneumonia, most likely caused by an infection with Mycoplasma pneumoniae. The clinical features of Mycoplasma pneumoniae infection include a flu-like illness that precedes respiratory symptoms, along with fever, myalgia, headache, diarrhea, and cough (initially dry but often becoming productive). Focal chest signs typically develop later in the course of the illness.

Mycoplasma pneumoniae infection is commonly associated with the development of erythema multiforme, a rash characterized by multiple red lesions on the limbs that evolve into target lesions a few days after the rash appears. Additionally, this infection can also cause Steven-Johnson syndrome. It is worth noting that haemolytic anaemia with cold agglutinins can complicate Mycoplasma pneumoniae infections, providing further evidence for the diagnosis.

The recommended first-line antibiotic for treating this case would be a macrolide, such as clarithromycin. Doxycycline can also be used but is generally considered a second-line option.

The recommended daily oral dose for adults is 900 mg, which should be taken in 2-3 divided doses. For severe asthma or COPD, the initial intravenous dose is 5 mg/kg and should be administered over 10-20 minutes. This can be followed by a continuous infusion of 0.5 mg/kg/hour. In the case of a 50 kg individual, the appropriate infusion rate would be 25 mg/hour. It is important to note that the therapeutic range for aminophylline is narrow, ranging from 10-20 microgram/ml. Therefore, it is beneficial to estimate the plasma concentration of aminophylline during long-term treatment.

Whooping cough, also known as pertussis, is a respiratory infection caused by the bacteria Bordetella pertussis. It is transmitted through respiratory droplets and has an incubation period of about 7-21 days. This highly contagious disease can be passed on to around 90% of close household contacts.

To prevent the spread of whooping cough, Public Health England advises that children with the illness should stay away from school, nursery, or childminders for 48 hours after starting antibiotic treatment. If no antibiotic treatment is given, they should be kept away for 21 days from the onset of the illness. It’s important to note that even after treatment, non-infectious coughing may persist for several weeks.

For more information on how to control infections in schools and other childcare settings, you can refer to the guidance provided by Public Health England.

This patient has come in with worsening shortness of breath and coughing up blood. They have a long history of smoking, and the likely diagnosis is superior vena cava obstruction caused by a primary bronchial tumor.

The typical symptoms of superior vena cava obstruction include breathlessness, chest pain, swelling in the neck, face, and arms, dilated veins and telangiectasia on the arms, neck, and chest wall, facial flushing, stridor due to laryngeal edema, and cyanosis.

Given the severity of the symptoms, this man needs to be urgently referred and admitted to the hospital. To provide immediate relief, his head should be elevated and he should be given supplemental oxygen. Corticosteroids and diuretics may also be administered. Further investigation through CT scanning is necessary, and radiotherapy may be recommended as a treatment option.

The typical pH range for blood is 7.35-7.45. The blood gases indicate a condition called respiratory acidosis, which is partially corrected by metabolic processes. This condition may also be referred to as type 2 respiratory failure, characterized by low oxygen levels and high carbon dioxide levels in the blood.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

This patient is displaying symptoms of life-threatening asthma, and the only available option for treatment with the correct dosage is an aminophylline loading dose.

The signs of acute severe asthma in adults include a peak expiratory flow (PEF) of 33-50% of the best or predicted value, a respiratory rate of over 25 breaths per minute, a heart rate of over 110 beats per minute, and an inability to complete sentences in one breath.

On the other hand, life-threatening asthma is characterized by a PEF of less than 33% of the best or predicted value, a blood oxygen saturation level (SpO2) below 92%, a partial pressure of oxygen (PaO2) below 8 kPA, a normal partial pressure of carbon dioxide (PaCO2) within the range of 4.6-6.0 kPa, a silent chest, cyanosis, poor respiratory effort, exhaustion, altered consciousness, and hypotension.

The recommended drug doses for adult acute asthma are as follows: 5 mg of salbutamol delivered through an oxygen-driven nebulizer, 500 mcg of ipratropium bromide via an oxygen-driven nebulizer, 40-50 mg of prednisolone taken orally, 100 mg of hydrocortisone administered intravenously, and 1.2-2 g of magnesium sulfate given intravenously over a period of 20 minutes. Intravenous salbutamol may be considered (250 mcg administered slowly) only when inhaled therapy is not possible, such as in a patient receiving bag-mask ventilation.

According to the current ALS guidelines, IV aminophylline can be considered in cases of severe or life-threatening asthma, following consultation with a senior medical professional. If used, a loading dose of 5 mg/kg should be administered over 20 minutes, followed by a continuous infusion of 500-700 mcg/kg/hour. It is important to maintain serum theophylline levels below 20 mcg/ml to prevent toxicity.

For more information, please refer to the BTS/SIGN Guideline on the Management of Asthma.

Whooping cough, also known as pertussis, is a respiratory infection caused by the bacteria Bordetella pertussis. It is transmitted through respiratory droplets and has an incubation period of approximately 7-21 days. This highly contagious disease can be transmitted to about 90% of close household contacts.

The clinical course of whooping cough can be divided into two stages. The first stage, known as the catarrhal stage, resembles a mild respiratory infection with symptoms such as low-grade fever and a runny nose. Although a cough may be present, it is usually mild and not as severe as in the next stage. The catarrhal stage typically lasts for about a week.

The second stage, called the paroxysmal stage, is when the characteristic paroxysmal cough develops as the catarrhal symptoms begin to subside. During this stage, coughing occurs in spasms, often preceded by an inspiratory whoop and followed by a series of rapid expiratory coughs. Other symptoms may include vomiting, subconjunctival hemorrhages, and petechiae. Patients generally feel well between spasms, and there are usually no abnormal chest findings. This stage can last up to 3 months, with a gradual recovery during this period. The later stages are sometimes referred to as the convalescent stage.

Complications of whooping cough can include secondary pneumonia, rib fractures, pneumothorax, herniae, syncopal episodes, encephalopathy, and seizures.

To diagnose whooping cough, nasopharyngeal swabs can be cultured in a medium called Bordet-Gengou agar, which contains blood, potato extract, glycerol, and an antibiotic to isolate Bordetella pertussis.

Although antibiotics do not alter the clinical course of the infection, they can reduce the period of infectiousness and help prevent further spread.

The BTS guidelines for managing acute asthma in children over the age of 2 recommend the following approaches:

Bronchodilator therapy is the first-line treatment for acute asthma. Inhaled β agonists are preferred, and a pmDI + spacer is the recommended option for children with mild to moderate asthma. It is important to individualize drug dosing based on the severity of the condition and adjust it according to the patient’s response. If initial β agonist treatment does not alleviate symptoms, ipratropium bromide can be added to the nebulized β2 agonist solution. In cases where children with a short duration of acute severe asthma symptoms have an oxygen saturation level below 92%, it is advisable to consider adding 150 mg of magnesium sulfate to each nebulized salbutamol and ipratropium within the first hour.

Long-acting β2 agonists should be discontinued if short-acting β2 agonists are required more frequently than every four hours.

Steroid therapy should be initiated early in the treatment of acute asthma attacks. For children aged 2-5 years, a dose of 20 mg prednisolone is recommended, while children over the age of 5 should receive a dose of 30-40 mg. Children already on maintenance steroid tablets should receive 2 mg/kg prednisolone, up to a maximum dose of 60 mg. If a child vomits after taking the initial dose of prednisolone, the dose should be repeated. In cases where a child is unable to retain orally ingested medication, intravenous steroids should be considered. Typically, treatment with oral steroids for up to three days is sufficient, but the duration of the course should be adjusted based on the time needed for recovery. Tapering is not necessary unless the course of steroids exceeds 14 days.

In cases where initial inhaled therapy does not yield a response in severe asthma attacks, the early addition of a single bolus dose of intravenous salbutamol (15 micrograms/kg over 10 minutes) should be considered. Aminophylline is not recommended for children with mild to moderate acute asthma, but it may be considered for those with severe or life-threatening asthma that is unresponsive to maximum doses of bronchodilators and steroids. The use of IV magnesium sulfate as a treatment for acute asthma in children is considered safe, although its role in management is not yet fully established.

This patient exhibits signs of potentially life-threatening asthma. In adults, acute severe asthma is characterized by a peak expiratory flow (PEF) of 33-50% of the best or predicted value, a respiratory rate exceeding 25 breaths per minute, a heart rate over 110 beats per minute, and an inability to complete sentences in one breath. On the other hand, life-threatening asthma is indicated by a PEF below 33% of the best or predicted value, a blood oxygen saturation (SpO2) below 92%, a partial pressure of oxygen (PaO2) below 8 kPA, a normal partial pressure of carbon dioxide (PaCO2) within the range of 4.6-6.0 kPa, a silent chest, cyanosis, poor respiratory effort, exhaustion, altered consciousness, and hypotension.

To address acute asthma in adults, the recommended drug doses include administering 5 mg of salbutamol through an oxygen-driven nebulizer, delivering 500 mcg of ipratropium bromide via an oxygen-driven nebulizer, providing 40-50 mg of prednisolone orally, administering 100 mg of hydrocortisone intravenously, and infusing 1.2-2 g of magnesium sulfate intravenously over a period of 20 minutes.

According to the current Advanced Life Support (ALS) guidelines, it is advisable to seek senior advice before considering the use of intravenous aminophylline in cases of severe or life-threatening asthma. If used, a loading dose of 5 mg/kg should be given over 20 minutes, followed by a continuous infusion of 500-700 mcg/kg/hour. To prevent toxicity, it is important to maintain serum theophylline levels below 20 mcg/ml.

In situations where inhaled therapy is not feasible, intravenous salbutamol can be considered, with a slow administration of 250 mcg. However, it should only be used when a patient is receiving bag-mask ventilation.

It is worth noting that there is currently no evidence supporting the use of leukotriene receptor antagonists, such as montelukast, or Heliox in the management of acute severe or life-threatening asthma.

Ipratropium bromide is a medication that falls under the category of antimuscarinic drugs. It is commonly used to manage acute asthma and chronic obstructive pulmonary disease (COPD). While it can provide short-term relief for chronic asthma, it is generally recommended to use short-acting β2 agonists as they act more quickly and are preferred.

According to the guidelines set by the British Thoracic Society (BTS), nebulized ipratropium bromide (0.5 mg every 4-6 hours) can be added to β2 agonist treatment for patients with acute severe or life-threatening asthma, or those who do not respond well to initial β2 agonist therapy.

For mild cases of chronic obstructive pulmonary disease, aerosol inhalation of ipratropium can be used for short-term relief, as long as the patient is not already using a long-acting antimuscarinic drug like tiotropium. The maximum effect of ipratropium occurs within 30-60 minutes after use, and its bronchodilating effects can last for 3-6 hours. Typically, treatment with ipratropium is recommended three times a day to maintain bronchodilation.

The most common side effect of ipratropium bromide is dry mouth. Other potential side effects include constipation, cough, paroxysmal bronchospasm, headache, nausea, and palpitations. It is important to note that ipratropium can cause urinary retention in patients with prostatic hyperplasia and bladder outflow obstruction. Additionally, it can trigger acute closed-angle glaucoma in susceptible patients.

For more information on the management of asthma, it is recommended to refer to the BTS/SIGN Guideline on the Management of Asthma.

This man is experiencing an acute asthma episode. His initial peak flow is 55% of his best, indicating a moderate exacerbation. In such cases, it is recommended to administer steroids, specifically a dose of prednisolone 40-50 mg orally.

Chest X-rays are not routinely performed to investigate acute asthma. However, they should be considered in certain situations, including suspected pneumomediastinum, consolidation, life-threatening asthma, inadequate response to treatment, and the need for ventilation.

Nebulised ipratropium bromide is only added to treatment with nebulised salbutamol in patients with acute severe or life-threatening asthma, or those who do not respond well to salbutamol therapy. Therefore, it is not necessary in this particular case.

While it may be reasonable to prescribe an antihistamine for a patient with a history of worsening hay fever, it should not be prioritized over treatment with steroids.

Bronchiolitis is a common respiratory infection that primarily affects infants. It typically occurs between the ages of 3-6 months and is most prevalent during the winter months from November to March. The main culprit behind bronchiolitis is the respiratory syncytial virus, accounting for about 70% of cases. However, other viruses like parainfluenza, influenza, adenovirus, coronavirus, and rhinovirus can also cause this infection.

The clinical presentation of bronchiolitis usually starts with symptoms resembling a common cold, which last for the first 2-3 days. Infants may experience poor feeding, rapid breathing (tachypnoea), nasal flaring, and grunting. Chest wall recessions, bilateral fine crepitations, and wheezing may also be observed. In severe cases, apnoea, a temporary cessation of breathing, can occur.

Bronchiolitis is a self-limiting illness, meaning it resolves on its own over time. Therefore, treatment mainly focuses on supportive care. However, infants with oxygen saturations below 92% may require oxygen administration. If an infant is unable to maintain oral intake or hydration, nasogastric feeding should be considered. Nasal suction is recommended to clear secretions in infants experiencing respiratory distress due to nasal blockage.

It is important to note that there is no evidence supporting the use of antivirals (such as ribavirin), antibiotics, beta 2 agonists, anticholinergics, or corticosteroids in the management of bronchiolitis. These interventions are not recommended for this condition.

This man is experiencing an acute episode of asthma. His initial peak flow measurement is 46% of his best, indicating a severe exacerbation. According to the BTS guidelines, acute asthma can be classified as moderate, acute severe, life-threatening, or near-fatal.

Moderate asthma is characterized by increasing symptoms and a peak expiratory flow rate (PEFR) between 50-75% of the individual’s best or predicted value. There are no signs of acute severe asthma in this case.

Acute severe asthma is identified by any one of the following criteria: a PEFR between 33-50% of the best or predicted value, a respiratory rate exceeding 25 breaths per minute, a heart rate over 110 beats per minute, or the inability to complete sentences in one breath.

Life-threatening asthma is indicated by any one of the following: a PEFR below 33% of the best or predicted value, oxygen saturation (SpO2) below 92%, arterial oxygen pressure (PaO2) below 8 kPa, normal arterial carbon dioxide pressure (PaCO2) between 4.6-6.0 kPa, a silent chest, cyanosis, poor respiratory effort, arrhythmia, exhaustion, altered conscious level, or hypotension.

Near-fatal asthma is characterized by elevated PaCO2 levels and/or the need for mechanical ventilation with increased inflation pressures.

Lung protective ventilation is a strategy that involves using smaller amounts of air during each breath (low tidal volumes) and restricting the maximum pressure applied during inhalation (plateau pressure). This approach also allows for a certain level of increased carbon dioxide levels in the body (hypercapnia).

Further Reading:

Mechanical ventilation is the use of artificial means to assist or replace spontaneous breathing. It can be invasive, involving instrumentation inside the trachea, or non-invasive, where there is no instrumentation of the trachea. Non-invasive mechanical ventilation (NIV) in the emergency department typically refers to the use of CPAP or BiPAP.

CPAP, or continuous positive airways pressure, involves delivering air or oxygen through a tight-fitting face mask to maintain a continuous positive pressure throughout the patient’s respiratory cycle. This helps maintain small airway patency, improves oxygenation, decreases airway resistance, and reduces the work of breathing. CPAP is mainly used for acute cardiogenic pulmonary edema.

BiPAP, or biphasic positive airways pressure, also provides positive airway pressure but with variations during the respiratory cycle. The pressure is higher during inspiration than expiration, generating a tidal volume that assists ventilation. BiPAP is mainly indicated for type 2 respiratory failure in patients with COPD who are already on maximal medical therapy.

The pressure settings for CPAP typically start at 5 cmH2O and can be increased to a maximum of 15 cmH2O. For BiPAP, the starting pressure for expiratory pressure (EPAP) or positive end-expiratory pressure (PEEP) is 3-5 cmH2O, while the starting pressure for inspiratory pressure (IPAP) is 10-15 cmH2O. These pressures can be titrated up if there is persisting hypoxia or acidosis.

In terms of lung protective ventilation, low tidal volumes of 5-8 ml/kg are used to prevent atelectasis and reduce the risk of lung injury. Inspiratory pressures (plateau pressure) should be kept below 30 cm of water, and permissible hypercapnia may be allowed. However, there are contraindications to lung protective ventilation, such as unacceptable levels of hypercapnia, acidosis, and hypoxemia.

Overall, mechanical ventilation, whether invasive or non-invasive, is used in various respiratory and non-respiratory conditions to support or replace spontaneous breathing and improve oxygenation and ventilation.

Whooping cough is a respiratory infection caused by the bacteria Bordetella pertussis. It is highly contagious and can be transmitted to about 90% of close household contacts. The Health Protection Agency has identified two priority groups for public health action in managing whooping cough contacts.

Group 1 consists of individuals who are at a higher risk of severe or complicated infection. This includes infants under one year old who have received less than three doses of the pertussis vaccine.

Group 2 consists of individuals who are at a higher risk of transmitting the infection to those in Group 1. This includes pregnant women who are at or beyond 32 weeks of gestation, healthcare workers who work with infants and pregnant women, individuals who work with infants too young to be vaccinated (under 4 months old), and individuals who share a household with infants too young to be vaccinated.

According to current guidance, antibiotic prophylaxis with a macrolide antibiotic, like erythromycin, should only be offered to close contacts if two criteria are met. First, the index case (the person with whooping cough) must have developed symptoms within the past 21 days. Second, there must be a close contact in one of the two priority groups.

If both criteria are met, all contacts, regardless of their vaccination status and age, should be offered chemoprophylaxis. In this case, the mother is in Group 2, so the current recommendation is that all household contacts, including the mother, father, and brother, should receive chemoprophylaxis.

Additionally, immunization or a booster dose should be considered for those who have been offered chemoprophylaxis, depending on their current vaccination status.

When determining the initial EPAP and IPAP pressure settings for this patient, it is important to consider their specific needs and condition. In general, the EPAP pressure should be set between 3-5 cmH2O, which helps to maintain positive pressure in the airways during exhalation, preventing them from collapsing. This can improve oxygenation and reduce the work of breathing.

The IPAP pressure, on the other hand, should be set between 10-15 cmH2O. This higher pressure during inhalation helps to overcome any resistance in the airways and ensures adequate ventilation. It also assists in improving the patient’s tidal volume and reducing carbon dioxide levels.

Therefore, the recommended initial EPAP and IPAP pressure settings for this patient would be EPAP 3-5 cmH2O / IPAP 10-15 cmH2O. These settings provide a balance between maintaining airway patency during exhalation and ensuring sufficient ventilation during inhalation. However, it is important to regularly assess the patient’s response to therapy and adjust the settings as needed to optimize their respiratory function.

Further Reading:

Mechanical ventilation is the use of artificial means to assist or replace spontaneous breathing. It can be invasive, involving instrumentation inside the trachea, or non-invasive, where there is no instrumentation of the trachea. Non-invasive mechanical ventilation (NIV) in the emergency department typically refers to the use of CPAP or BiPAP.

CPAP, or continuous positive airways pressure, involves delivering air or oxygen through a tight-fitting face mask to maintain a continuous positive pressure throughout the patient’s respiratory cycle. This helps maintain small airway patency, improves oxygenation, decreases airway resistance, and reduces the work of breathing. CPAP is mainly used for acute cardiogenic pulmonary edema.

BiPAP, or biphasic positive airways pressure, also provides positive airway pressure but with variations during the respiratory cycle. The pressure is higher during inspiration than expiration, generating a tidal volume that assists ventilation. BiPAP is mainly indicated for type 2 respiratory failure in patients with COPD who are already on maximal medical therapy.

The pressure settings for CPAP typically start at 5 cmH2O and can be increased to a maximum of 15 cmH2O. For BiPAP, the starting pressure for expiratory pressure (EPAP) or positive end-expiratory pressure (PEEP) is 3-5 cmH2O, while the starting pressure for inspiratory pressure (IPAP) is 10-15 cmH2O. These pressures can be titrated up if there is persisting hypoxia or acidosis.

In terms of lung protective ventilation, low tidal volumes of 5-8 ml/kg are used to prevent atelectasis and reduce the risk of lung injury. Inspiratory pressures (plateau pressure) should be kept below 30 cm of water, and permissible hypercapnia may be allowed. However, there are contraindications to lung protective ventilation, such as unacceptable levels of hypercapnia, acidosis, and hypoxemia.

Overall, mechanical ventilation, whether invasive or non-invasive, is used in various respiratory and non-respiratory conditions to support or replace spontaneous breathing and improve oxygenation and ventilation.

Bronchiolitis is a common respiratory infection that primarily affects infants. It typically occurs between the ages of 3-6 months and is most prevalent during the winter months from November to March. The main culprit behind bronchiolitis is the respiratory syncytial virus, accounting for about 70% of cases. However, other viruses like parainfluenza, influenza, adenovirus, coronavirus, and rhinovirus can also cause this infection.

The clinical presentation of bronchiolitis usually starts with symptoms resembling a common cold, which last for the first 2-3 days. Infants may experience poor feeding, rapid breathing (tachypnoea), nasal flaring, and grunting. Chest wall recessions, bilateral fine crepitations, and wheezing may also be observed. In severe cases, apnoea, a temporary cessation of breathing, can occur.

Bronchiolitis is a self-limiting illness, meaning it resolves on its own over time. Therefore, treatment mainly focuses on supportive care. However, infants with oxygen saturations below 92% may require oxygen administration. If an infant is unable to maintain oral intake or hydration, nasogastric feeding should be considered. Nasal suction is recommended to clear secretions in infants experiencing respiratory distress due to nasal blockage.

It is important to note that there is no evidence supporting the use of antivirals (such as ribavirin), antibiotics, beta 2 agonists, anticholinergics, or corticosteroids in the management of bronchiolitis. These interventions are not recommended for this condition.

The recommended daily oral dose for adults is 900 mg, which should be taken in 2-3 divided doses. For severe asthma or COPD, the initial intravenous dose is 5 mg/kg and should be administered over 10-20 minutes. This can be followed by a continuous infusion of 0.5 mg/kg/hour. In the case of a patient weighing 60 kg, the appropriate loading dose would be 300 mg. It is important to note that the therapeutic range for aminophylline is narrow, ranging from 10-20 microgram/ml. Therefore, it is beneficial to estimate the plasma concentration of aminophylline during long-term treatment.

Respiratory acidosis occurs when the respiratory system is unable to effectively remove carbon dioxide from the body, leading to an increase in acidity. This is often seen in cases of opioid overdose, where respiratory depression can occur. In respiratory acidosis, the bicarbonate levels may rise as the body’s metabolic system tries to compensate for the increased acidity.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

The PaO2/FiO2 ratio is a measurement used to determine the severity of Acute Respiratory Distress Syndrome (ARDS). It is calculated by dividing the arterial oxygen partial pressure (PaO2) by the fraction of inspired oxygen (FiO2). However, it is important to note that this calculation should only be done when the patient is receiving a minimum positive end-expiratory pressure (PEEP) of 5 cm water. The resulting ratio is then used to classify the severity of ARDS, with specific thresholds provided below.

Further Reading:

ARDS is a severe form of lung injury that occurs in patients with a predisposing risk factor. It is characterized by the onset of respiratory symptoms within 7 days of a known clinical insult, bilateral opacities on chest X-ray, and respiratory failure that cannot be fully explained by cardiac failure or fluid overload. Hypoxemia is also present, as indicated by a specific threshold of the PaO2/FiO2 ratio measured with a minimum requirement of positive end-expiratory pressure (PEEP) ≥5 cm H2O. The severity of ARDS is classified based on the PaO2/FiO2 ratio, with mild, moderate, and severe categories.

Lung protective ventilation is a set of measures aimed at reducing lung damage that may occur as a result of mechanical ventilation. Mechanical ventilation can cause lung damage through various mechanisms, including high air pressure exerted on lung tissues (barotrauma), over distending the lung (volutrauma), repeated opening and closing of lung units (atelectrauma), and the release of inflammatory mediators that can induce lung injury (biotrauma). These mechanisms collectively contribute to ventilator-induced lung injury (VILI).

The key components of lung protective ventilation include using low tidal volumes (5-8 ml/kg), maintaining inspiratory pressures (plateau pressure) below 30 cm of water, and allowing for permissible hypercapnia. However, there are some contraindications to lung protective ventilation, such as an unacceptable level of hypercapnia, acidosis, and hypoxemia. These factors need to be carefully considered when implementing lung protective ventilation strategies in patients with ARDS.

This patient’s clinical presentation is consistent with a diagnosis of idiopathic pulmonary fibrosis. The typical symptoms of idiopathic pulmonary fibrosis include a dry cough, progressive breathlessness, arthralgia and muscle pain, finger clubbing (seen in 50% of cases), cyanosis, fine end-expiratory bibasal crepitations, and right heart failure and cor pulmonale in later stages.

Finger clubbing, which is prominent in this patient, can also be caused by bronchiectasis and tuberculosis. However, these conditions would not result in a raised FEV1/FVC ratio, which is a characteristic feature of a restrictive lung disorder.

In restrictive lung disease, the FEV1/FVC ratio is typically normal, around 70% predicted, while the FVC is reduced to less than 80% predicted. Both the FVC and FEV1 are generally reduced in this condition. The ratio can also be elevated if the FVC is reduced to a greater extent.

It is important to note that smoking is a risk factor for developing idiopathic pulmonary fibrosis, particularly in individuals with a history of smoking greater than 20 pack-years.

The recommended daily oral dose for adults is 900 mg, which should be taken in 2-3 divided doses. For severe asthma or COPD, the initial intravenous dose is 5 mg/kg and should be administered over 10-20 minutes. This can be followed by a continuous infusion of 0.5 mg/kg/hour. In the case of a patient weighing 50 kg, the appropriate loading dose would be 250 mg. It is important to note that the therapeutic range for aminophylline is narrow, ranging from 10-20 microgram/ml. Therefore, it is beneficial to estimate the plasma concentration of aminophylline during long-term treatment.

The diving reflex occurs when the face comes into contact with cold water, leading to apnoea, bradycardia, and peripheral vasoconstriction. This response helps decrease the workload on the heart, lower oxygen demand in the heart muscle, and ensure adequate blood flow to the brain and vital organs. The trigeminal nerve (CN V) is responsible for transmitting sensory information, while the vagus nerve (CN X) primarily controls the motor response. This reflex is more prominent in young children and is believed to contribute to their improved survival rates in prolonged submersion in cold water.

Further Reading:

Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid. It can be classified as cold-water or warm-water drowning. Risk factors for drowning include young age and male sex. Drowning impairs lung function and gas exchange, leading to hypoxemia and acidosis. It also causes cardiovascular instability, which contributes to metabolic acidosis and cell death.

When someone is submerged or immersed, they will voluntarily hold their breath to prevent aspiration of water. However, continued breath holding causes progressive hypoxia and hypercapnia, leading to acidosis. Eventually, the respiratory center sends signals to the respiratory muscles, forcing the individual to take an involuntary breath and allowing water to be aspirated into the lungs. Water entering the lungs stimulates a reflex laryngospasm that prevents further penetration of water. Aspirated water can cause significant hypoxia and damage to the alveoli, leading to acute respiratory distress syndrome (ARDS).

Complications of drowning include cardiac ischemia and infarction, infection with waterborne pathogens, hypothermia, neurological damage, rhabdomyolysis, acute tubular necrosis, and disseminated intravascular coagulation (DIC).

In children, the diving reflex helps reduce hypoxic injury during submersion. It causes apnea, bradycardia, and peripheral vasoconstriction, reducing cardiac output and myocardial oxygen demand while maintaining perfusion of the brain and vital organs.

Associated injuries with drowning include head and cervical spine injuries in patients rescued from shallow water. Investigations for drowning include arterial blood gases, chest X-ray, ECG and cardiac monitoring, core temperature measurement, and blood and sputum cultures if secondary infection is suspected.

Management of drowning involves extricating the patient from water in a horizontal position with spinal precautions if possible. Cardiovascular considerations should be taken into account when removing patients from water to prevent hypotension and circulatory collapse. Airway management, supplemental oxygen, and ventilation strategies are important in maintaining oxygenation and preventing further lung injury. Correcting hypotension, electrolyte disturbances, and hypothermia is also necessary. Attempting to drain water from the lungs is ineffective.

Patients without associated physical injury who are asymptomatic and have no evidence of respiratory compromise after six hours can be safely discharged home. Ventilation strategies aim to maintain oxygenation while minimizing ventilator-associated lung injury.

The most probable diagnosis in this situation is Goodpasture’s syndrome, a rare autoimmune vasculitic disorder characterized by three main symptoms: pulmonary hemorrhage, glomerulonephritis, and the presence of anti-glomerular basement membrane (Anti-GBM) antibodies. Goodpasture’s syndrome is more prevalent in men, particularly in smokers. It is also associated with HLA-B7 and HLA-DRw2.

The clinical manifestations of Goodpasture’s syndrome include constitutional symptoms like fever, fatigue, nausea, and weight loss. Patients may also experience hemoptysis or pulmonary hemorrhage, chest pain, breathlessness, and inspiratory crackles at the lung bases. Anemia due to bleeding within the lungs, arthralgia, rapidly progressive glomerulonephritis, hematuria, hypertension, and rarely hepatosplenomegaly may also be present.

Blood tests will reveal iron deficiency anemia, an elevated white cell count, and renal impairment. Elisa for Anti-GBM antibodies is highly sensitive and specific, but it is not widely available. Approximately 30% of patients may also have circulating antineutrophilic cytoplasmic antibodies (ANCAs), although these are not specific for Goodpasture’s syndrome and can be found in other conditions such as Wegener’s granulomatosis, which also cause renal impairment and pulmonary hemorrhage.

Diagnosis is typically confirmed through a renal biopsy, which can detect the presence of anti-GBM antibodies. This would be the most appropriate investigation to confirm the diagnosis in this case.

The management of Goodpasture’s syndrome involves a combination of plasmapheresis to remove circulating antibodies and the use of corticosteroids or cyclophosphamide.

This individual, who has been smoking for a long time, is likely to have squamous cell carcinoma of the lung located at the right apex. This particular type of cancer is causing Pancoast’s syndrome. Pancoast’s syndrome typically presents with rib erosion, leading to severe shoulder pain, as well as Horner’s syndrome due to the infiltration of the lower part of the brachial plexus. Additionally, there may be hoarseness of the voice and a ‘bovine cough’ due to a concurrent recurrent laryngeal nerve palsy.

The classic description of Horner’s syndrome includes the following clinical features on the same side as the tumor: miosis (constricted pupil), ptosis (drooping eyelid), anhidrosis (lack of sweating), and enophthalmos (sunken appearance of the eye). A chest X-ray would be able to detect the presence of the apical tumor and confirm the diagnosis.

Klebsiella pneumoniae is commonly observed in individuals who are dependent on alcohol. It is more prevalent in men compared to women and typically manifests after the age of 40.

The clinical manifestations of this condition include fevers and rigors, pleuritic chest pain, purulent sputum, and haemoptysis, which occurs more frequently than with other bacterial pneumonias. Klebsiella pneumoniae tends to affect the upper lobes of the lungs and often leads to the formation of cavitating lesions.

While Staphylococcus aureus can also cause cavitation, it usually affects multiple lobes and is not limited to the upper lobes. Other potential causes of cavitating pneumonia include Pseudomonas aeruginosa, Mycobacterium tuberculosis, and, although rare, Legionella pneumophila.

This patient is likely to have pigeon fancier’s lung, which is a type of extrinsic allergic alveolitis (EAA) caused by chronic exposure to avian antigens found in bird droppings. This condition leads to hypersensitivity pneumonitis and the formation of granulomas in the lungs.

While his presentation could also be consistent with idiopathic pulmonary fibrosis, the fact that he keeps and races pigeons makes EAA more likely in this case.

EAA can manifest as either an acute or chronic condition. The acute form typically presents with flu-like symptoms such as fever, cough, chest tightness, and breathlessness occurring 4 to 6 hours after exposure.

The clinical features of chronic pigeon fancier’s lung include a productive cough, progressive breathlessness, weight loss, anorexia, fatigue, and malaise.

Other forms of EAA include farmer’s lung (caused by exposure to Saccharopolyspora rectivirgula from wet hay), malt-worker’s lung (caused by exposure to Aspergillus clavatus from moldy malt), cheese-worker’s lung (caused by exposure to Penicillium casei from moldy cheese), chemical worker’s lung (caused by exposure to trimetallic anhydride, diisocyanate, and methylene diisocyanate), mushroom worker’s lung (caused by exposure to thermophilic actinomycetes in mushroom compost), and hot tub lung (caused by exposure to Mycobacterium avium from poorly maintained hot tubs).

This presentation strongly suggests a diagnosis of whooping cough, which is an infection of the upper respiratory tract caused by the bacteria Bordetella pertussis. The disease is highly contagious and is transmitted through respiratory droplets. The incubation period is typically 7-21 days, and it is estimated that about 90% of close household contacts will become infected.

The clinical course of whooping cough can be divided into two stages. The first stage, known as the catarrhal stage, is similar to a mild respiratory infection with symptoms such as low-grade fever and a runny nose. A cough may be present, but it is usually mild compared to the second stage. This phase typically lasts about a week.

The second stage, called the paroxysmal stage, is characterized by the development of a distinctive cough. The coughing occurs in spasms, often preceded by an inspiratory whoop sound. These spasms are followed by a series of rapid, hacking coughs. Patients may experience vomiting and may develop subconjunctival hemorrhages and petechiae. Between spasms, patients generally feel well and there are usually no abnormal chest findings. This stage can last up to 3 months, with a gradual recovery over this period. The later stages of this phase are sometimes referred to as the convalescent stage.

Complications of whooping cough can include secondary pneumonia, rib fractures, pneumothorax, hernias, syncopal episodes, encephalopathy, and seizures.

Public Health England (PHE) provides recommendations for testing for whooping cough based on the age of the patient, time since onset of illness, and severity of presentation. For infants under 12 months of age, hospitalised patients should undergo PCR testing, while non-hospitalised patients within two weeks of onset should be tested using culture of a nasopharyngeal swab or aspirate. Non-hospitalised patients presenting over two weeks after onset should be investigated with serology for anti-pertussis toxin IgG antibody levels.

For children over 12 months of age and adults, patients within two weeks of onset should be tested using culture of a nasopharyngeal swab or aspirate. Patients aged 5 to 16 who have not received the vaccine within the last year and present over two weeks after onset should have oral fluid testing for anti-pertussis toxin IgG antibody levels.

Croup, also known as laryngo-tracheo-bronchitis, is typically caused by the parainfluenza virus. Other viruses such as rhinovirus, influenza, and respiratory syncytial viruses can also be responsible. Before the onset of stridor, there is often a mild cold-like illness that lasts for 1-2 days. Symptoms usually reach their peak within 1-3 days, with the cough often being more troublesome at night. A milder cough may persist for another 7-10 days.

A distinctive feature of croup is a barking cough, but it does not indicate the severity of the condition. To reduce airway swelling, dexamethasone and prednisolone are commonly prescribed. If a child is experiencing vomiting, nebulized budesonide can be used as an alternative. However, it is important to note that steroids do not shorten the duration of the illness. In severe cases, nebulized adrenaline can be administered.

Hospitalization for croup is uncommon and typically reserved for children who are experiencing worsening respiratory distress or showing signs of drowsiness or agitation.

Bronchiolitis is a short-term infection of the lower respiratory tract that primarily affects infants aged 2 to 6 months. It is commonly caused by a viral infection, with respiratory syncytial virus (RSV) being the most prevalent culprit. RSV infections are most prevalent during the winter months, typically occurring between November and March. In the UK, bronchiolitis is the leading cause of hospitalization among infants.

The typical symptoms of bronchiolitis include fever, difficulty breathing, coughing, poor feeding, irritability, apnoeas (more common in very young infants), and wheezing or fine inspiratory crackles. To confirm the diagnosis, a nasopharyngeal aspirate can be taken for RSV rapid testing. This test is useful in preventing unnecessary further testing and facilitating the isolation of the affected infant.

Most infants with acute bronchiolitis experience a mild, self-limiting illness that does not require hospitalization. Treatment primarily focuses on supportive measures, such as ensuring adequate fluid and nutritional intake and controlling the infant’s temperature. The illness typically lasts for 7 to 10 days.

However, hospital referral and admission are recommended in certain cases, including poor feeding (less than 50% of usual intake over the past 24 hours), lethargy, a history of apnoea, a respiratory rate exceeding 70 breaths per minute, nasal flaring or grunting, severe chest wall recession, cyanosis, oxygen saturations below 90% for children aged 6 weeks and over, and oxygen saturations below 92% for babies under 6 weeks or those with underlying health conditions.

If hospitalization is necessary, treatment involves supportive measures, supplemental oxygen, and nasogastric feeding as needed. There is limited or no evidence supporting the use of antibiotics, antivirals, bronchodilators, corticosteroids, hypertonic saline, or adrenaline nebulizers in the management of bronchiolitis.

Lung protective ventilation involves several important elements, with low tidal volumes being a crucial component. Specifically, using tidal volumes of 5-8 ml/kg is recommended to minimize the risk of lung injury. Additionally, it is important to maintain inspiratory pressures, also known as plateau pressure, below 30 cm of water to further protect the lungs. Lastly, permissible hypercapnia, or allowing for higher levels of carbon dioxide in the blood, is another key aspect of lung protective ventilation.

Further Reading:

ARDS is a severe form of lung injury that occurs in patients with a predisposing risk factor. It is characterized by the onset of respiratory symptoms within 7 days of a known clinical insult, bilateral opacities on chest X-ray, and respiratory failure that cannot be fully explained by cardiac failure or fluid overload. Hypoxemia is also present, as indicated by a specific threshold of the PaO2/FiO2 ratio measured with a minimum requirement of positive end-expiratory pressure (PEEP) ≥5 cm H2O. The severity of ARDS is classified based on the PaO2/FiO2 ratio, with mild, moderate, and severe categories.

Lung protective ventilation is a set of measures aimed at reducing lung damage that may occur as a result of mechanical ventilation. Mechanical ventilation can cause lung damage through various mechanisms, including high air pressure exerted on lung tissues (barotrauma), over distending the lung (volutrauma), repeated opening and closing of lung units (atelectrauma), and the release of inflammatory mediators that can induce lung injury (biotrauma). These mechanisms collectively contribute to ventilator-induced lung injury (VILI).

The key components of lung protective ventilation include using low tidal volumes (5-8 ml/kg), maintaining inspiratory pressures (plateau pressure) below 30 cm of water, and allowing for permissible hypercapnia. However, there are some contraindications to lung protective ventilation, such as an unacceptable level of hypercapnia, acidosis, and hypoxemia. These factors need to be carefully considered when implementing lung protective ventilation strategies in patients with ARDS.

This question discusses the prioritization of patient care, specifically focusing on the initial management of acutely unwell patients. The sequence followed in such cases is known as ‘ABCDE’, which stands for airway, breathing, circulation, disability, and exposure. It is crucial to call for help as soon as possible, as the patient’s condition may deteriorate rapidly. If a patient’s consciousness level is dropping, urgent assistance is required, and it is unlikely that you will be able to handle the situation independently.

While waiting for the resuscitation team to arrive, you will be occupied with managing the patient. Therefore, it is not appropriate to make a phone call to the Emergency Department consultant for advice. Although the Emergency Department nurses may be helpful, it is essential to call the resuscitation team first. Continuing to handle the situation alone, regardless of the patient’s clinical condition, indicates a failure to recognize the need for assistance in this scenario.

Before starting BiPAP, it is important for patients with COPD to have already started maximum medical therapy. This includes receiving supplemental oxygen, using nebulizers with salbutamol and ipratropium, taking steroids and antibiotics if necessary, and potentially receiving IV bronchodilators. Additionally, patients should meet the blood gas requirements of having a pH level below 7.35 and a pCO2 level above 6 Kpa. Another criteria for initiating NIV is having a respiratory rate higher than 23.

Further Reading:

Mechanical ventilation is the use of artificial means to assist or replace spontaneous breathing. It can be invasive, involving instrumentation inside the trachea, or non-invasive, where there is no instrumentation of the trachea. Non-invasive mechanical ventilation (NIV) in the emergency department typically refers to the use of CPAP or BiPAP.

CPAP, or continuous positive airways pressure, involves delivering air or oxygen through a tight-fitting face mask to maintain a continuous positive pressure throughout the patient’s respiratory cycle. This helps maintain small airway patency, improves oxygenation, decreases airway resistance, and reduces the work of breathing. CPAP is mainly used for acute cardiogenic pulmonary edema.

BiPAP, or biphasic positive airways pressure, also provides positive airway pressure but with variations during the respiratory cycle. The pressure is higher during inspiration than expiration, generating a tidal volume that assists ventilation. BiPAP is mainly indicated for type 2 respiratory failure in patients with COPD who are already on maximal medical therapy.

The pressure settings for CPAP typically start at 5 cmH2O and can be increased to a maximum of 15 cmH2O. For BiPAP, the starting pressure for expiratory pressure (EPAP) or positive end-expiratory pressure (PEEP) is 3-5 cmH2O, while the starting pressure for inspiratory pressure (IPAP) is 10-15 cmH2O. These pressures can be titrated up if there is persisting hypoxia or acidosis.

In terms of lung protective ventilation, low tidal volumes of 5-8 ml/kg are used to prevent atelectasis and reduce the risk of lung injury. Inspiratory pressures (plateau pressure) should be kept below 30 cm of water, and permissible hypercapnia may be allowed. However, there are contraindications to lung protective ventilation, such as unacceptable levels of hypercapnia, acidosis, and hypoxemia.

Overall, mechanical ventilation, whether invasive or non-invasive, is used in various respiratory and non-respiratory conditions to support or replace spontaneous breathing and improve oxygenation and ventilation.

COHb is a measure used to evaluate the presence of carbon monoxide poisoning in individuals who are in good health. hHb refers to deoxygenated haemoglobin.

Further Reading:

Methaemoglobinaemia is a condition where haemoglobin is oxidised from Fe2+ to Fe3+. This process is normally regulated by NADH methaemoglobin reductase, which transfers electrons from NADH to methaemoglobin, converting it back to haemoglobin. In healthy individuals, methaemoglobin levels are typically less than 1% of total haemoglobin. However, an increase in methaemoglobin can lead to tissue hypoxia as Fe3+ cannot bind oxygen effectively.

Methaemoglobinaemia can be congenital or acquired. Congenital causes include haemoglobin chain variants (HbM, HbH) and NADH methaemoglobin reductase deficiency. Acquired causes can be due to exposure to certain drugs or chemicals, such as sulphonamides, local anaesthetics (especially prilocaine), nitrates, chloroquine, dapsone, primaquine, and phenytoin. Aniline dyes are also known to cause methaemoglobinaemia.

Clinical features of methaemoglobinaemia include slate grey cyanosis (blue to grey skin coloration), chocolate blood or chocolate cyanosis (brown color of blood), dyspnoea, low SpO2 on pulse oximetry (which often does not improve with supplemental oxygen), and normal PaO2 on arterial blood gas (ABG) but low SaO2. Patients may tolerate hypoxia better than expected. Severe cases can present with acidosis, arrhythmias, seizures, and coma.

Diagnosis of methaemoglobinaemia is made by directly measuring the level of methaemoglobin using a co-oximeter, which is present in most modern blood gas analysers. Other investigations, such as a full blood count (FBC), electrocardiogram (ECG), chest X-ray (CXR), and beta-human chorionic gonadotropin (bHCG) levels (in pregnancy), may be done to assess the extent of the condition and rule out other contributing factors.

Active treatment is required if the methaemoglobin level is above 30% or if it is below 30% but the patient is symptomatic or shows evidence of tissue hypoxia. Treatment involves maintaining the airway and delivering high-flow oxygen, removing the causative agents, treating toxidromes and consider giving IV dextrose 5%.

Bronchiolitis is a short-term infection of the lower respiratory tract that primarily affects infants aged 2 to 6 months. It is commonly caused by a viral infection, with respiratory syncytial virus (RSV) being the most prevalent culprit. RSV infections are most prevalent during the winter months, typically occurring between November and March. In the UK, bronchiolitis is the leading cause of hospitalization among infants.

The typical symptoms of bronchiolitis include fever, difficulty breathing, coughing, poor feeding, irritability, apnoeas (more common in very young infants), and wheezing or fine inspiratory crackles. To confirm the diagnosis, a nasopharyngeal aspirate can be taken for RSV rapid testing. This test is useful in preventing unnecessary further testing and facilitating the isolation of the affected infant.

Most infants with acute bronchiolitis experience a mild, self-limiting illness that does not require hospitalization. Treatment primarily focuses on supportive measures, such as ensuring adequate fluid and nutritional intake and controlling the infant’s temperature. The illness typically lasts for 7 to 10 days.

However, hospital referral and admission are recommended in certain cases, including poor feeding (less than 50% of usual intake over the past 24 hours), lethargy, a history of apnoea, a respiratory rate exceeding 70 breaths per minute, nasal flaring or grunting, severe chest wall recession, cyanosis, oxygen saturations below 90% for children aged 6 weeks and over, and oxygen saturations below 92% for babies under 6 weeks or those with underlying health conditions.

If hospitalization is necessary, treatment involves supportive measures, supplemental oxygen, and nasogastric feeding as needed. There is limited or no evidence supporting the use of antibiotics, antivirals, bronchodilators, corticosteroids, hypertonic saline, or adrenaline nebulizers in the management of bronchiolitis.

Based on the provided information, it is highly probable that this patient is suffering from chronic obstructive pulmonary disease (COPD). This conclusion is supported by several factors. Firstly, the patient has a history of chronic productive cough and wheezing, which are common symptoms of COPD. Additionally, the patient has a long-term smoking history, which is a major risk factor for developing this condition.

Furthermore, the patient’s raised packed cell volume (PCV) is likely a result of chronic hypoxemia, a common complication of COPD. This indicates that the patient’s body is trying to compensate for the low oxygen levels in their blood.

Moreover, the chest X-ray reveals evidence of hyperinflation, which is a characteristic finding in patients with COPD. This suggests that the patient’s lungs are overinflated and not functioning optimally.

Lastly, the arterial blood gas analysis shows hypoxemia, indicating that the patient has low levels of oxygen in their blood. This is another significant finding that aligns with a diagnosis of COPD.

In summary, based on the patient’s history, smoking habits, raised PCV, chest X-ray findings, and arterial blood gas results, it is highly likely that they have COPD.

This patient has a history of worsening breathlessness and lung function tests that show a pattern of restrictive lung disease. In restrictive lung disease, the ratio of FEV1 to FVC is usually normal, around 70% predicted, but the FVC is reduced to less than 80% predicted. Both the FVC and FEV1 can be reduced in this condition. The ratio can also be higher if the FVC is reduced to a greater extent. Out of the options provided, only idiopathic pulmonary fibrosis can cause a restrictive lung disease pattern. Smoking is a risk factor for developing idiopathic pulmonary fibrosis, especially if the person has smoked more than 20 packs of cigarettes per year.

An anion gap greater than 11 is considered high when using modern ion-selective electrode analyzers. This indicates a condition known as high anion gap acidosis. The anion gap can be calculated using the equation: ([Na+] + [K+]) – ([Cl-] + [HCO3-]). In this particular case, the calculation results in a value of 30.4 mmol/l. Anion gaps greater than 11 are considered high.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

This patient is displaying symptoms and signs that are consistent with an atypical pneumonia, most likely caused by an infection from Mycoplasma pneumoniae. The clinical features commonly associated with Mycoplasma pneumoniae infection include a flu-like illness that occurs before respiratory symptoms, fever, myalgia, headache, diarrhea, and cough (initially dry but often becoming productive). Focal chest signs typically develop later in the course of the illness. It is worth noting that Mycoplasma pneumoniae is frequently linked to the development of erythema multiforme and can also be a cause of Steven-Johnson syndrome. The rash associated with erythema multiforme is characterized by multiple red lesions on the limbs that develop into target lesions a few days after the rash first appears.

Based on the clinical features of this individual, it is highly likely that they have pulmonary fibrosis. The key to determining the correct diagnosis is to differentiate between extrinsic allergic alveolitis (EAA) and idiopathic pulmonary fibrosis (IPF), also known as cryptogenic fibrosing alveolitis (CFA).

In this case, the gentleman does not have any occupational risk factors for EAA and exhibits digital clubbing. While clubbing is not commonly seen in EAA, it is a frequent occurrence in IPF. Therefore, based on these factors, IPF is the more probable diagnosis.

Spirometry results in IPF can either be normal or show a restrictive pattern, whereas an obstructive pattern would be expected in COPD. The history and clinical features presented do not align with the other diagnoses mentioned in this question.

In order to achieve satisfactory bronchodilation, most individuals require a plasma theophylline concentration of 10-20 mg/litre (55-110 micromol/litre). However, it is possible for a lower concentration to still be effective. Adverse effects can occur within the range of 10-20 mg/litre, and their frequency and severity increase when concentrations exceed 20 mg/litre.

To measure plasma theophylline concentration, a blood sample should be taken five days after starting oral treatment and at least three days after any dose adjustment. For modified-release preparations, the blood sample should typically be taken 4-6 hours after an oral dose (specific sampling times may vary, so it is advisable to consult local guidelines). If aminophylline is administered intravenously, a blood sample should be taken 4-6 hours after initiating treatment.

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

The BTS guidelines for managing acute asthma in adults provide the following recommendations:

Oxygen:
– It is important to give supplementary oxygen to all patients with acute severe asthma who have low levels of oxygen in their blood (hypoxemia). The goal is to maintain a blood oxygen saturation level (SpO2) between 94-98%. Even if pulse oximetry is not available, oxygen should still be administered.

β2 agonists therapy:
– High-dose inhaled β2 agonists should be used as the first-line treatment for patients with acute asthma. It is important to administer these medications as early as possible.
– Intravenous β2 agonists should be reserved for patients who cannot reliably use inhaled therapy.
– For patients with life-threatening asthma symptoms, nebulized β2 agonists driven by oxygen are recommended.
– In cases of severe asthma that does not respond well to an initial dose of β2 agonist, continuous nebulization with an appropriate nebulizer may be considered.

Ipratropium bromide:
– Nebulized ipratropium bromide (0.5 mg every 4-6 hours) should be added to β2 agonist treatment for patients with acute severe or life-threatening asthma, or those who do not respond well to initial β2 agonist therapy.

Steroid therapy:
– Steroids should be given in adequate doses for all cases of acute asthma attacks.
– Prednisolone should be continued at a dose of 40-50 mg daily for at least five days or until the patient recovers.

Other therapies:
– Nebulized magnesium is not recommended for the treatment of acute asthma in adults.
– A single dose of intravenous magnesium sulfate may be considered for patients with acute severe asthma (peak expiratory flow rate <50% of the best or predicted value) who do not respond well to inhaled bronchodilator therapy. However, this should only be done after consulting with senior medical staff.
– Routine prescription of antibiotics is not necessary for patients with acute asthma.

For more information, please refer to the BTS/SIGN Guideline on the Management of Asthma.

According to the brit-thoracic guidelines, if a patient with COPD continues to experience respiratory acidosis even after receiving standard medical therapy for one hour, it is recommended to consider using non-invasive ventilation (NIV). This is especially important if the patient’s hypoxia and hypercapnia are worsening despite the initial treatment.

Further Reading:

Arterial blood gases (ABG) are an important diagnostic tool used to assess a patient’s acid-base status and respiratory function. When obtaining an ABG sample, it is crucial to prioritize safety measures to minimize the risk of infection and harm to the patient. This includes performing hand hygiene before and after the procedure, wearing gloves and protective equipment, disinfecting the puncture site with alcohol, using safety needles when available, and properly disposing of equipment in sharps bins and contaminated waste bins.

To reduce the risk of harm to the patient, it is important to test for collateral circulation using the modified Allen test for radial artery puncture. Additionally, it is essential to inquire about any occlusive vascular conditions or anticoagulation therapy that may affect the procedure. The puncture site should be checked for signs of infection, injury, or previous surgery. After the test, pressure should be applied to the puncture site or the patient should be advised to apply pressure for at least 5 minutes to prevent bleeding.

Interpreting ABG results requires a systematic approach. The core set of results obtained from a blood gas analyser includes the partial pressures of oxygen and carbon dioxide, pH, bicarbonate concentration, and base excess. These values are used to assess the patient’s acid-base status.

The pH value indicates whether the patient is in acidosis, alkalosis, or within the normal range. A pH less than 7.35 indicates acidosis, while a pH greater than 7.45 indicates alkalosis.

The respiratory system is assessed by looking at the partial pressure of carbon dioxide (pCO2). An elevated pCO2 contributes to acidosis, while a low pCO2 contributes to alkalosis.

The metabolic aspect is assessed by looking at the bicarbonate (HCO3-) level and the base excess. A high bicarbonate concentration and base excess indicate alkalosis, while a low bicarbonate concentration and base excess indicate acidosis.

Analyzing the pCO2 and base excess values can help determine the primary disturbance and whether compensation is occurring. For example, a respiratory acidosis (elevated pCO2) may be accompanied by metabolic alkalosis (elevated base excess) as a compensatory response.

The anion gap is another important parameter that can help determine the cause of acidosis. It is calculated by subtracting the sum of chloride and bicarbonate from the sum of sodium and potassium.

The CURB criteria, also referred to as the CURB-65 criteria, is a clinical prediction rule that has been scientifically proven to predict mortality in cases of community-acquired pneumonia. These criteria consist of five factors: confusion of new onset (AMTS <8), urea level greater than 7 mmol/l, respiratory rate exceeding 30 per minute, blood pressure below 90 mmHg systolic or 60 mmHg diastolic, and age over 65 years. Based on the score obtained from these criteria, the risk level can be determined. A score of 0-1 indicates a low-risk situation, where outpatient treatment is recommended. A score of 2-3 suggests a moderate risk, and either inpatient treatment or an ambulatory care pathway is recommended. A score of 4-5 indicates a high risk, requiring hospitalization and potentially critical care involvement.

Bronchiolitis is a respiratory infection that primarily affects infants aged 2 to 6 months. It is typically caused by a viral infection, with respiratory syncytial virus (RSV) being the most common culprit. RSV infections are most prevalent during the winter months, from November to March. In fact, bronchiolitis is the leading cause of hospitalization among infants in the UK.

The symptoms of bronchiolitis include poor feeding (consuming less than 50% of their usual intake in the past 24 hours), lethargy, a history of apnea, a respiratory rate exceeding 70 breaths per minute, nasal flaring or grunting, severe chest wall recession, cyanosis (bluish discoloration of the skin), and low oxygen saturation levels. For children aged 6 weeks and older, oxygen saturation levels below 90% indicate a need for medical attention. For babies under 6 weeks or those with underlying health conditions, oxygen saturation levels below 92% require medical attention.

To confirm the diagnosis of bronchiolitis, a nasopharyngeal aspirate can be taken for rapid testing of RSV. This test is useful in preventing unnecessary further testing and allows for the isolation of the infected infant.

Most infants with bronchiolitis experience a mild, self-limiting illness that does not require hospitalization. Treatment primarily focuses on supportive measures, such as ensuring adequate fluid and nutritional intake and controlling the infant’s temperature. The illness typically lasts for 7 to 10 days.

However, hospital referral and admission are recommended in cases of poor feeding, lethargy, a history of apnea, a respiratory rate exceeding 70 breaths per minute, nasal flaring or grunting, severe chest wall recession, cyanosis, and oxygen saturation levels below 94%. If hospitalization is necessary, treatment involves supportive measures, supplemental oxygen, and nasogastric feeding as needed. There is limited or no evidence supporting the use of antibiotics, antivirals, bronchodilators, corticosteroids, hypertonic saline, or adrenaline nebulizers for the treatment of bronchiolitis.

Based on the clinical history and examination, it strongly indicates that the patient has developed a pulmonary embolism due to a deep vein thrombosis in his right leg.

The symptoms commonly associated with a pulmonary embolism include shortness of breath, pleuritic chest pain, coughing, and/or coughing up blood. These symptoms may also suggest the presence of a deep vein thrombosis. Other clinical features that may be observed are rapid breathing and heart rate, fever, and in severe cases, signs of systemic shock, a gallop heart rhythm, and increased jugular venous pressure.

This patient is displaying symptoms and signs that are consistent with community-acquired pneumonia (CAP). The most common cause of CAP in an adult patient who is otherwise in good health is Streptococcus pneumoniae.

When it comes to treating community-acquired pneumonia, the first-line antibiotic of choice is amoxicillin. According to the NICE guidelines, patients who are allergic to penicillin should be prescribed a macrolide (such as clarithromycin) or a tetracycline (such as doxycycline).

For more information, you can refer to the NICE guidelines on the diagnosis and management of pneumonia in adults.

This patient exhibits signs of potentially life-threatening asthma. In adults, acute severe asthma is characterized by a peak expiratory flow (PEF) of 33-50% of the best or predicted value, a respiratory rate exceeding 25 breaths per minute, a heart rate over 110 beats per minute, and an inability to complete sentences in one breath. On the other hand, life-threatening asthma is indicated by a PEF below 33% of the best or predicted value, a blood oxygen saturation (SpO2) below 92%, a partial pressure of oxygen (PaO2) below 8 kPA, a normal partial pressure of carbon dioxide (PaCO2) within the range of 4.6-6.0 kPa, a silent chest, cyanosis, poor respiratory effort, exhaustion, altered consciousness, and hypotension.

To address acute asthma in adults, the recommended drug doses include administering 5 mg of salbutamol through an oxygen-driven nebulizer, delivering 500 mcg of ipratropium bromide via an oxygen-driven nebulizer, providing 40-50 mg of prednisolone orally, administering 100 mg of hydrocortisone intravenously, and infusing 1.2-2 g of magnesium sulfate intravenously over a period of 20 minutes.

According to the current Advanced Life Support (ALS) guidelines, it is advisable to seek senior advice before considering the use of intravenous aminophylline in cases of severe or life-threatening asthma. If used, a loading dose of 5 mg/kg should be given over 20 minutes, followed by a continuous infusion of 500-700 mcg/kg/hour. To prevent toxicity, it is important to maintain serum theophylline levels below 20 mcg/ml.

In situations where inhaled therapy is not feasible, intravenous salbutamol can be considered, with a slow administration of 250 mcg. However, it should only be used when a patient is receiving bag-mask ventilation.

It is worth noting that there is currently no evidence supporting the use of leukotriene receptor antagonists, such as montelukast, or Heliox in the management of acute severe or life-threatening asthma.

For further information, please refer to the BTS/SIGN Guideline on the Management of Asthma.

Legionella pneumophila is a type of Gram-negative bacterium that can be found in natural water supplies and soil. It is responsible for causing Legionnaires’ disease, a serious illness. Outbreaks of this disease have been associated with poorly maintained air conditioning systems, whirlpool spas, and hot tubs. In the past, there have been instances of Legionnaires’ disease outbreaks on cruise ships due to inadequate maintenance of air conditioning and shower units.

The pneumonic form of Legionnaires’ disease presents with certain clinical features. Initially, there may be a mild flu-like prodrome lasting for 1-3 days. A persistent cough, which is usually non-productive and occurs in approximately 90% of cases, is also common. Other symptoms include pleuritic chest pain, haemoptysis, headache, nausea, vomiting, diarrhoea, and anorexia. Additionally, some individuals may experience a condition called syndrome of inappropriate antidiuretic hormone secretion (SIADH), which can lead to hyponatraemia.

It is important to note that infections caused by Legionella pneumophila are resistant to amoxicillin. However, they can be effectively treated with macrolide antibiotics like erythromycin or quinolones such as ciprofloxacin. Tetracyclines, including doxycycline, can also be used for treatment.

The recommended drug doses for adult acute asthma are as follows:

– Salbutamol: Administer 5 mg using an oxygen-driven nebulizer.
– Ipratropium bromide: Deliver 500 mcg via an oxygen-driven nebulizer.
– Prednisolone: Take orally at a dose of 40-50 mg.
– Hydrocortisone: Administer 100 mg intravenously.
– Magnesium sulphate: Infuse 1.2-2 g intravenously over a period of 20 minutes.

Terbutaline can be used as an alternative to salbutamol, with a dose of 10 mg via an oxygen-driven nebulizer. Intravenous salbutamol may be considered (250 mcg IV slowly) only when inhaled therapy is not possible, such as when a patient is receiving bag-mask ventilation.

According to the current ALS guidelines, IV aminophylline may be considered in severe or life-threatening asthma, following senior advice. If used, a loading dose of 5 mg/kg should be given over 20 minutes, followed by an infusion of 500-700 mcg/kg/hour. It is important to maintain serum theophylline levels below 20 mcg/ml to prevent toxicity.

For more information, please refer to the BTS/SIGN Guideline on the Management of Asthma.