One of the diagnostic criteria for ARDS is the presence of hypoxemia. Other criteria include the onset of symptoms within 7 days of a clinical insult or new/worsening respiratory symptoms, bilateral opacities on chest X-ray that cannot be fully explained by other conditions, and respiratory failure that cannot be fully attributed to cardiac failure or fluid overload.

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.

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.

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.

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.

This patient is displaying symptoms and signs that are consistent with an atypical pneumonia, most likely caused by an infection from Mycoplasma pneumoniae. The clinical features of Mycoplasma pneumoniae infection typically 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 may develop later in the illness. Interestingly, the X-ray features of the pneumonia are often more noticeable than the severity of the chest symptoms.

Treatment for Mycoplasma pneumoniae infection can involve the use of macrolides, such as clarithromycin, or tetracyclines, such as doxycycline. The recommended minimum treatment period is 10-14 days, making clarithromycin a preferable option over doxycycline in this particular case.

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

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

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

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

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

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.

A pleural effusion refers to the accumulation of excess fluid in the pleural cavity, which is the fluid-filled space between the parietal and visceral pleura. Normally, this cavity contains about 5-10 ml of lubricating fluid that allows the pleurae to slide over each other and helps the lungs fill with air as the thorax expands. However, when there is too much fluid in the pleural cavity, it hinders breathing by limiting lung expansion.

Percutaneous pleural aspiration is commonly performed for two main reasons: to investigate pleural effusion and to provide relief from breathlessness caused by pleural effusion. According to the guidelines from the British Thoracic Society (BTS), pleural aspiration should be reserved for the investigation of unilateral exudative pleural effusions. It should not be done if unilateral or bilateral transudative effusion is suspected, unless there are atypical features or a lack of response to therapy. In urgent cases where respiratory distress is caused by pleural effusion, pleural aspiration can also be used to quickly decompress the pleural space.

During the procedure, the patient is typically seated upright with a pillow supporting their arms and head. It is important for the patient not to lean too far forward, as this increases the risk of injury to the liver and spleen. The conventional site for aspiration is in the mid-scapular line at the back (approximately 10 cm to the side of the spine), one or two spaces below the upper level of the fluid. To avoid damaging the intercostal nerves and vessels that run just below the rib, the needle should be inserted just above the upper border of the chosen rib.

The qCSI Score, also known as the Quick COVID-19 Severity Index, is a tool that can predict the risk of critical respiratory illness in patients who are admitted from the emergency department with COVID-19. This score takes into consideration three criteria: respiratory rate, pulse oximetry, and oxygen flow rate. By assessing these factors, the qCSI Score can provide an estimation of the 24-hour risk of severe respiratory complications in these patients.

On the other hand, the qSOFA Score is a different tool that is used to identify high-risk patients for in-hospital mortality when there is a suspicion of infection, particularly in cases of sepsis. However, it is important to note that the qSOFA Score is not specifically designed for use in the setting of febrile neutropenia.

Another scoring system, known as the CURB-65 Score, is utilized to estimate the mortality risk associated with community-acquired pneumonia. This score helps healthcare professionals determine whether a patient should receive inpatient or outpatient treatment based on their likelihood of experiencing adverse outcomes.

Lastly, the SCAP Score is a scoring system that predicts the risk of adverse outcomes in patients with community-acquired pneumonia who present to the emergency department. By assessing various clinical factors, this score can provide valuable information to healthcare providers regarding the potential severity of the illness and the need for further intervention.

In addition to these scores, there is also the MASCC Risk Index Score, which is specifically used in the context of cancer patients receiving supportive care. This score helps assess the risk of complications in this vulnerable population and aids in making informed decisions regarding their treatment and management.