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.

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 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.

The typical range for the partial pressure of carbon dioxide (pCO2) is 4.4-6.4 kilopascals (kPa). In terms of arterial blood gas (ABG) results, the normal range for pO2 (partial pressure of oxygen) is 10-14.4 kPa or 70-100 millimeters of mercury (mmHg). The normal range for pCO2 is 4.4-6.4 kPa or 35-45 mmHg. Additionally, the normal range for bicarbonate levels is 23-28 millimoles per liter (mmol/L).

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.

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’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 clinical history and examination strongly suggest that the patient has a pulmonary embolism caused by a deep vein thrombosis in his right leg.

The typical symptoms of a pulmonary embolism include shortness of breath, chest pain that worsens with breathing, coughing, and/or coughing up blood. There may also be symptoms indicating the presence of a deep vein thrombosis. Other signs include rapid breathing and heart rate, fever, and in severe cases, signs of shock, an abnormal heart rhythm, and increased pressure in the jugular veins.

Given the patient’s high probability Wells score, it is recommended that an immediate CT pulmonary angiogram (CPTA) be performed. This test is considered the most reliable method for diagnosing a pulmonary embolism. A d-dimer test would not provide any additional benefit in this case. While a chest X-ray and ECG may provide useful information, they alone cannot confirm the diagnosis.

For patients who have an allergy to contrast media, renal impairment, or are at high risk from radiation exposure, a ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) scan or a V/Q planar scan can be offered as an alternative to CTPA.

In cases of mixed acidosis, both the respiratory and metabolic systems play a role in causing the low pH levels. This means that the patient’s acidotic state is a result of both low bicarbonate levels in the metabolic system and high levels of CO2 in the respiratory system.

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.

SCUBA divers face the potential danger of developing pulmonary barotrauma, which can lead to conditions like arterial gas embolism (AGE) or pneumothorax. Based on the patient’s diving history and clinical symptoms, it is highly likely that they are experiencing a left-sided pneumothorax caused by barotrauma. To confirm the presence of pneumothorax, a chest X-ray is usually performed, unless the patient shows signs of tension pneumothorax. In such cases, immediate decompression is necessary, which can be achieved by inserting a chest tube.

Further Reading:

Decompression illness (DCI) is a term that encompasses both decompression sickness (DCS) and arterial gas embolism (AGE). When diving underwater, the increasing pressure causes gases to become more soluble and reduces the size of gas bubbles. As a diver ascends, nitrogen can come out of solution and form gas bubbles, leading to decompression sickness or the bends. Boyle’s and Henry’s gas laws help explain the changes in gases during changing pressure.

Henry’s law states that the amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas. Divers often use atmospheres (ATM) as a measure of pressure, with 1 ATM being the pressure at sea level. Boyle’s law states that the volume of gas is inversely proportional to the pressure. As pressure increases, volume decreases.

Decompression sickness occurs when nitrogen comes out of solution as a diver ascends. The evolved gas can physically damage tissue by stretching or tearing it as bubbles expand, or by provoking an inflammatory response. Joints and spinal nervous tissue are commonly affected. Symptoms of primary damage usually appear immediately or soon after a dive, while secondary damage may present hours or days later.

Arterial gas embolism occurs when nitrogen bubbles escape into the arterial circulation and cause distal ischemia. The consequences depend on where the embolism lodges, ranging from tissue ischemia to stroke if it lodges in the cerebral arterial circulation. Mechanisms for distal embolism include pulmonary barotrauma, right to left shunt, and pulmonary filter overload.

Clinical features of decompression illness vary, but symptoms often appear within six hours of a dive. These can include joint pain, neurological symptoms, chest pain or breathing difficulties, rash, vestibular problems, and constitutional symptoms. Factors that increase the risk of DCI include diving at greater depth, longer duration, multiple dives close together, problems with ascent, closed rebreather circuits, flying shortly after diving, exercise shortly after diving, dehydration, and alcohol use.

Diagnosis of DCI is clinical, and investigations depend on the presentation. All patients should receive high flow oxygen, and a low threshold for ordering a chest X-ray should be maintained. Hydration is important, and IV fluids may be necessary. Definitive treatment is recompression therapy in a hyperbaric oxygen chamber, which should be arranged as soon as possible. Entonox should not be given, as it will increase the pressure effect in air spaces.

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.

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 patient presents with a medical history and physical examination findings that are consistent with a diagnosis of Löfgren’s syndrome, which is a specific subtype of sarcoidosis. This syndrome is most commonly observed in women in their 30s and 40s, and it is more prevalent among individuals of Nordic and Irish descent.

Löfgren’s syndrome is typically characterized by a triad of clinical features, including bilateral hilar lymphadenopathy seen on chest X-ray, erythema nodosum, and arthralgia, with a particular emphasis on ankle involvement. Additionally, other symptoms commonly associated with sarcoidosis may also be present, such as a dry cough, breathlessness, fever, night sweats, malaise, weight loss, Achilles tendonitis, and uveitis.

In order to further evaluate this patient’s condition, it is recommended to refer them to a respiratory specialist for additional investigations. These investigations may include measuring the serum calcium level, as it may be elevated, and assessing the serum angiotensin-converting enzyme (ACE) level, which may also be elevated. A high-resolution CT scan can be performed to assess the extent of involvement and identify specific lymph nodes for potential biopsy. If there are any atypical features, a lymph node biopsy may be necessary. Lung function tests can be conducted to evaluate the patient’s vital capacity, and an MRI scan of the ankles may also be considered.

Fortunately, the prognosis for Löfgren’s syndrome is generally very good, and it is considered a self-limiting and benign condition. The patient can expect to recover within a timeframe of six months to two years.

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.

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 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.

Non-invasive ventilation is recommended for patients with hypercapnia and acidosis. Respiratory acidosis, indicated by a pH level below 7.35, is a strong indication for the use of BiPAP. However, patients with a pH level of 7.25 or lower may not respond well to non-invasive ventilation and should be considered for intensive care unit (ITU) treatment. Another criterion for the use of BiPAP is hypercapnia, which is characterized by an arterial pCO2 level greater than 6.0 KPa.

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.

Based on the clinical history and examination, it strongly indicates that the patient may have a pulmonary embolism caused by a deep vein thrombosis in his right leg. To confirm this, it is recommended that he undergoes a CT pulmonary angiogram and doppler ultrasound scan of his right leg.

The typical symptoms of a pulmonary embolism include shortness of breath, pleuritic chest pain, coughing, and/or coughing up blood. Additionally, there may be symptoms suggesting the presence of a deep vein thrombosis. Other signs to look out for 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 man is experiencing an acute asthma episode. His initial peak flow is 55% of his best, indicating a moderate 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.

Intercostal artery laceration during the insertion of a chest drain is a potentially life-threatening complication. Although rare, it occurs more frequently than other complications mentioned. To minimize the risk of damage to underlying structures and unsightly scarring, the British Thoracic Society (BTS) recommends inserting chest drains within the safe triangle. This 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.

Possible complications associated with the insertion of small-bore chest drains include puncture of the intercostal artery, organ perforation due to over-introduction of the dilator into the chest cavity, hospital-acquired pleural infection from non-aseptic techniques, inadequate stay suture leading to the chest tube falling out, and tube blockage, which may be more common with smaller bore Argyle drains.

When using an intercostal approach, it is important to place the chest drain closer to the superior border of the rib below in the intercostal space. This positioning helps avoid injury to the intercostal neurovascular bundle located under the costal groove of the rib above.

For more information, 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.

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.

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.

When rescuing drowning patients, it is important to extricate them from the water in a horizontal position whenever possible. This is because the pressure of the water on the body when submerged increases the flow of blood back to the heart, which in turn increases cardiac output. However, when the patient is removed from the water, this pressure effect is lost, which can lead to a sudden drop in blood pressure and circulatory collapse due to the loss of peripheral resistance and pooling of blood in the veins. By extricating the patient in a horizontal position, we can help counteract this effect.

It is worth noting that the amount of water in the lungs after drowning is typically small, usually less than 4 milliliters per kilogram of body weight. Therefore, attempting to drain the water from the lungs is ineffective and not recommended.

In cases of fresh water drowning, pneumonia may occur due to unusual pathogens such as aeromonas spp, burkholderia pseudomallei, chromobacterium spp, pseudomonas species, and leptospirosis.

If the patient experiences bronchospasm, nebulized bronchodilators can be used as a treatment.

To prevent secondary brain injury, it is important to prevent hyperthermia. This can be achieved by maintaining the patient’s core body temperature below 36 degrees Celsius during the rewarming process.

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.

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.

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.

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.

Psittacosis is a type of infection that can be transmitted from animals to humans, known as a zoonotic infection. It is caused by a bacterium called Chlamydia psittaci. This infection is most commonly seen in people who own domestic birds, but it can also affect those who work in pet shops or zoos.

The typical presentation of psittacosis includes symptoms similar to those of pneumonia that is acquired within the community. People may experience flu-like symptoms along with severe headaches and sensitivity to light. In about two-thirds of patients, an enlargement of the spleen, known as splenomegaly, can be observed.

Infected individuals often develop a reddish rash with flat spots on their face, known as Horder’s spots. Additionally, they may experience skin conditions such as erythema nodosum or erythema multiforme.

The recommended treatment for psittacosis is a course of tetracycline or doxycycline, which should be taken for a period of 2-3 weeks.

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.

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.

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.