Chest X-rays are not typically recommended as a routine investigation for acute asthma. However, they may be necessary in specific situations. These situations include suspected pneumomediastinum or consolidation, as well as cases of life-threatening asthma. Additionally, if a patient fails to respond adequately to treatment or requires ventilation, a chest X-ray may be performed. It is important to note that these circumstances warrant the use of chest X-rays, but they are not routinely indicated for the investigation of acute asthma.

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.

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).

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.

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.

Legionella pneumophila, a Gram-negative bacterium, 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.

The pneumonic form of Legionnaires’ disease presents with specific clinical features. Initially, there may be a mild flu-like prodrome lasting for 1-3 days. A non-productive cough, occurring in approximately 90% of cases, is also common. Pleuritic chest pain, haemoptysis, headache, nausea, vomiting, diarrhoea, and anorexia are other symptoms that may be experienced.

Fortunately, Legionella pneumophila infections can be effectively treated with macrolide antibiotics like erythromycin, or quinolones such as ciprofloxacin. Tetracyclines, including doxycycline, can also be used as a treatment option.

While the majority of Legionnaires’ disease cases are caused by Legionella pneumophila, there are several other species of Legionella that have been identified. One such species is Legionella longbeachae, which is less commonly encountered. It is primarily found in soil and potting compost and has been associated with outbreaks of Pontiac fever, a milder variant of Legionnaires’ disease that does not primarily affect the respiratory system.

Currently, there is no evidence to support the use of nebulised magnesium sulphate in the treatment of adults with asthma. For adults experiencing acute asthma, the recommended drug doses are as follows:

– Salbutamol: 5 mg administered through an oxygen-driven nebuliser.
– Ipratropium bromide: 500 mcg delivered via an oxygen-driven nebuliser.
– Prednisolone: 40-50 mg taken orally.
– Hydrocortisone: 100 mg administered intravenously.
– Magnesium sulphate: 1.2-2 g 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 when a patient is receiving bag-mask ventilation.

According to the current ALS guidelines, IV aminophylline can be considered in cases of 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.

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.

Whispering pectoriloquy is a phenomenon that occurs when there is lung consolidation. It is characterized by an amplified and clearer sound of whispering that can be heard when using a stethoscope to listen to the affected areas of the lungs. To conduct the test, patients are usually instructed to whisper the phrase ninety-nine.

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.

The British Thoracic Society (BTS) advises that chest drains should be inserted within the safe triangle to minimize the risk of harm to underlying structures and prevent damage to muscle and breast tissue, which can result in unsightly scarring. The safe triangle is defined by the base of the axilla, the lateral border of the latissimus dorsi, the lateral border of the pectoralis major, and the 5th intercostal space.

There are several potential complications associated with the insertion of small-bore chest drains. These include puncture of the intercostal artery, accidental perforation of organs due to over-introduction of the dilator into the chest cavity, hospital-acquired pleural infection caused by a non-aseptic technique, inadequate stay suture that may lead to the chest tube falling out, and tube blockage, which may occur more frequently compared to larger bore Argyle drains.

For more information on this topic, please refer to the British Thoracic Society pleural disease guidelines.

Arterial blood gas (ABG) interpretation is crucial in evaluating a patient’s respiratory gas exchange and acid-base balance. While the normal values on an ABG may slightly vary between analysers, they generally fall within the following ranges: pH of 7.35 – 7.45, pO2 of 10 – 14 kPa, PCO2 of 4.5 – 6 kPa, HCO3- of 22 – 26 mmol/l, and base excess of -2 – 2 mmol/l.

In this particular case, the patient’s medical history raises concerns about a potential diagnosis of pulmonary embolism. The relevant ABG findings are as follows: significant hypoxia (indicating type 1 respiratory failure), elevated pH (alkalaemia), low PCO2, and normal bicarbonate levels. These findings suggest that the patient is experiencing primary respiratory alkalosis.

By analyzing the ABG results, healthcare professionals can gain valuable insights into a patient’s respiratory function and acid-base status, aiding in the diagnosis and management of various conditions.

Q fever is a highly contagious infection caused by Coxiella burnetii, which can be transmitted from animals to humans. It is commonly observed as an occupational disease among individuals working in farming, slaughterhouses, and animal research. Approximately 50% of cases do not show any symptoms, while those who are affected often experience flu-like symptoms such as headache, fever, muscle pain, diarrhea, nausea, and vomiting.

In some cases, patients may develop an atypical pneumonia characterized by a dry cough and minimal chest signs. Q fever can also lead to hepatitis and enlargement of the liver (hepatomegaly), although jaundice is not commonly observed. Typical blood test results for Q fever include an elevated white cell count (30-40%), ALT/AST levels that are usually 2-3 times higher than normal, increased ALP levels (70%), reduced sodium levels (30%), and reactive thrombocytosis.

It is important to check patients for heart murmurs and signs of valve disease, as these conditions increase the risk of developing infective endocarditis. Treatment for Q fever typically involves a two-week course of doxycycline.

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 BTS guidelines for acute asthma in children recommend administering oral steroids early in the treatment of asthma attacks. It is advised to give a dose of 20 mg prednisolone for children aged 2–5 years and a dose of 30–40 mg for children over 5 years old. If a child is already taking maintenance steroid tablets, they should receive 2 mg/kg prednisolone, up to a maximum dose of 60 mg. If a child vomits after taking the medication, the dose of prednisolone should be repeated. In cases where a child is unable to keep down orally ingested medication, intravenous steroids should be considered. Typically, treatment for up to three days is sufficient, but the duration of the course should be adjusted based on the time needed for recovery. Tapering off the medication is not necessary unless the steroid course exceeds 14 days. For more information, refer to the BTS/SIGN Guideline on the Management of Asthma.

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.

According to the current NICE guidelines on febrile illness in children under the age of 5, there are certain symptoms and signs that may indicate the presence of pneumonia. These include tachypnoea, which is a rapid breathing rate. For infants aged 0-5 months, a respiratory rate (RR) of over 60 breaths per minute is considered suggestive of pneumonia. For infants aged 6-12 months, an RR of over 50 breaths per minute is indicative, and for children older than 12 months, an RR of over 40 breaths per minute may suggest pneumonia.

Other signs that may point towards pneumonia include crackles in the chest, nasal flaring, chest indrawing, and cyanosis. Crackles are abnormal sounds heard during breathing, while nasal flaring refers to the widening of the nostrils during breathing. Chest indrawing is the inward movement of the chest wall during inhalation, and cyanosis is the bluish discoloration of the skin or mucous membranes due to inadequate oxygen supply.

Additionally, a low oxygen saturation level of less than 95% while breathing air is also considered suggestive of pneumonia. These guidelines can be found in more detail in the NICE guidelines on the assessment and initial management of fever in children under 5, as well as the NICE Clinical Knowledge Summary on the management of feverish children.

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.

Psittacosis is a type of infection that can be transmitted from animals to humans, caused by a bacterium called Chlamydia psittaci. It is most commonly seen in people who own domestic birds, as well as those who work in pet shops or zoos. The typical symptoms of psittacosis include pneumonia that is acquired within the community, along with flu-like symptoms. Many patients also experience severe headaches and sensitivity to light. Enlargement of the spleen is a common finding in about two-thirds of individuals with this infection.

Infected individuals often develop a rash on their face, known as Horder’s spots, which appear as reddish macules. In some cases, erythema nodosum and erythema multiforme may also occur. The recommended treatment for psittacosis is a course of tetracycline or doxycycline for a period of 2-3 weeks.

On the other hand, rose spots are typically observed in cases of typhoid fever. These spots have a similar appearance to Horder’s spots but are usually found on the trunk rather than the face. Erythema marginatum is a pale red rash seen in rheumatic fever, while malar flush, also known as ‘mitral facies’, refers to the reddish discoloration of the cheeks commonly seen in individuals with mitral stenosis. Lastly, erythema chronicum migrans is the distinctive rash seen in Lyme disease, characterized by a circular rash with a central ‘bulls-eye’ appearance that spreads outward from the site of a tick bite.

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.

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.

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.

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.

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.

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.

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.

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, 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.

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.

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.