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.

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

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

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

This child’s medical history and chest X-ray findings are indicative of an inhaled foreign object. Upon careful examination, it is evident that the left lung appears more transparent than the right lung, and the foreign body is lodged in the left tracheobronchial tree.

Airway foreign bodies in children can be life-threatening, and it is important to consider this diagnosis when young children experience unexplained difficulty breathing and wheezing. Unfortunately, there is often a delay in diagnosing this condition.

Foreign objects typically get stuck in the right tracheobronchial tree because the right main bronchus is wider, shorter, and more vertically positioned compared to the left main bronchus. However, they can become lodged anywhere in the tracheobronchial tree.

While there is often a history of choking prior to the symptoms, this is not always the case. Any history of running with objects in the mouth or being in close proximity to small objects that can be placed in the mouth can provide important clues. In the absence of a choking history, clinical features may include paroxysmal coughing, unexplained difficulty breathing, changes in voice, poor appetite, irritability, decreased breath sounds on one side, and localized wheezing.

To aid in diagnosis, a chest X-ray should be taken during expiration as it can accentuate any differences between the two lungs. The following findings may be observed: the normal lung may appear smaller and denser than the affected lung, the affected lung may appear excessively transparent and overinflated, and a radio-opaque foreign object may be visible. However, it is important to note that approximately 35% of patients may have a normal chest X-ray.

Bronchoscopy is considered the gold-standard test for diagnosing tracheobronchial foreign bodies. This procedure not only confirms the presence of a foreign object but also allows for potential retrieval.

Possible complications of this condition include pneumonia, atelectasis (collapsed lung), bronchospasm (constriction of the airways), pneumothorax (collapsed lung due to air leakage), broncho-oesophageal fistula (abnormal connection between the bronchial tubes and the esophagus), and bronchiectasis (permanent dilation of the bronchial tubes).

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.

In patients with COPD and type 2 respiratory failure, the desired range for oxygen saturation while receiving BiPAP is typically 88-92%.

Maintaining oxygen saturation within this range is crucial for individuals with COPD as it helps strike a balance between providing enough oxygen to meet the body’s needs and avoiding the risk of oxygen toxicity. Oxygen saturation levels below 88% may indicate inadequate oxygenation, while levels above 92% may lead to oxygen toxicity and other complications.

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.

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

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

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

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

The allocation of points is as follows:

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

The BTS guidelines categorize acute asthma into four classifications: moderate, acute severe, life-threatening, and near-fatal.

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

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 determined by any one of the following indicators: a PEFR below 33% of the best or predicted value, a blood oxygen saturation level (SpO2) below 92%, a partial pressure of oxygen (PaO2) below 8 kilopascals (kPa), a normal partial pressure of carbon dioxide (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.

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.

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

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