Egyptian Board Thoracic Diseases key terms

The volume of air moved into or out of the lungs during one normal, quiet breath. Measured in millilitres and typically 6–8 mL/kg of predicted body weight in adults.

The volume of gas remaining in the lungs at the end of a passive expiration. It reflects the balance between outward chest wall recoil and inward elastic lung recoil.

The change in lung volume produced by a unit change in transpulmonary pressure, expressed in mL/cmH2O. Low compliance means stiff lungs needing more pressure for the same inflation.

A test measuring how readily carbon monoxide crosses the alveolar–capillary membrane. A low value suggests emphysema, interstitial disease, anaemia or pulmonary vascular disease rather than airway obstruction alone.

A forced breathing manoeuvre recording exhaled volume against time. It yields FEV1, FVC and the FEV1/FVC ratio, the core measurements for diagnosing and grading airflow obstruction.

The change in FEV1 measured before and after inhaling a short-acting beta-2 agonist. An increase of 12% and 200 mL supports asthma, while a blunted response is more typical of COPD.

The extent to which asthma symptoms, reliever use, night waking and activity limitation are minimised, assessed over the previous four weeks. Poor control signals need to step up or review inhaler technique and adherence.

The highest flow rate achieved during a forced expiration from full inspiration. Cheap and portable, it supports home monitoring and diurnal variability assessment in asthma.

Retention of excess gas in the lungs after full exhalation, reflected by a raised residual volume or residual volume to total lung capacity ratio. It worsens breathlessness and dynamic hyperinflation during exercise.

Positive alveolar pressure remaining at end-expiration when exhalation is incomplete, common in obstructive disease or with short expiratory times. It raises work of breathing and can cause hypotension and barotrauma.

The plateau pressure minus the applied positive end-expiratory pressure. It estimates the cyclic stress on lung tissue and higher values are linked with ventilator-induced injury.

A strategy using low tidal volumes (about 6 mL/kg predicted body weight), limited plateau pressure and adequate PEEP to reduce ventilator-induced lung injury in acute respiratory distress syndrome.

The airway pressure measured during an end-inspiratory pause, reflecting alveolar pressure when flow has ceased. It guides safe limits during mechanical ventilation.

Placing a ventilated patient face down for prolonged periods to improve oxygenation and survival in moderate-to-severe acute respiratory distress syndrome, mainly by recruiting dorsal lung regions.

A transient increase in airway pressure intended to reopen collapsed alveoli. Evidence of lasting benefit is limited and it carries risks of hypotension and barotrauma.

Support delivered through a mask or nasal interface without an artificial airway. It reduces intubation and mortality in acute hypercapnic exacerbations of COPD.

An abnormally high arterial partial pressure of carbon dioxide, usually above 45 mmHg. It arises from alveolar hypoventilation, ventilation–perfusion mismatch or increased dead space.

The portion of tidal volume that does not participate in gas exchange, including anatomical airway volume and alveoli that are ventilated but not perfused.

Inequality between the air reaching alveoli and the blood perfusing them. It is the commonest cause of hypoxaemia in lung disease and explains why oxygen helps most such patients.

Blood passing through the lungs without contacting ventilated alveoli, so it stays deoxygenated. Shunt causes hypoxaemia that responds poorly to supplemental oxygen.

The physiological adjustment of carbon dioxide or bicarbonate to limit pH change from a primary respiratory or metabolic disorder. It is assessed with the arterial blood gas and bicarbonate level.

Type 2 respiratory failure with a PaCO2 above 50 mmHg and hypoxaemia, caused by alveolar hypoventilation due to pump failure, obstructive disease or neuromuscular weakness.

Tuberculosis resistant to at least rifampicin and isoniazid, the two most potent first-line drugs. Treatment is longer, uses second-line agents and requires specialist supervision.

Directly observed treatment, short-course: a tuberculosis control strategy in which a trained observer watches the patient swallow each dose, with standardised regimens and monitoring.

Infection with tuberculosis bacilli without active disease, detected by a tuberculin skin test or interferon-gamma release assay. Preventive treatment reduces later progression to active tuberculosis.

Microscopic examination of stained sputum for acid-fast bacilli. It is rapid and cheap but less sensitive than culture or molecular testing, especially in HIV co-infection.

A score using confusion, urea, respiratory rate, blood pressure and age 65 or older to stratify pneumonia severity and guide site of care decisions.

A progressive fibrosing interstitial lung disease of unknown cause with a usual interstitial pneumonia pattern on imaging or histology. Antifibrotic drugs slow decline but do not reverse scarring.

Thin-slice CT imaging of the lungs used to characterise interstitial patterns, bronchiectasis and nodules. It is central to diagnosing fibrotic lung disease and assessing its pattern.

Clustered cystic airspaces with thick walls in the subpleural lung, usually showing a basal and peripheral distribution. It marks established fibrosis and is a hallmark of usual interstitial pneumonia.

The total volume forcibly exhaled after a maximal inspiration. Serial FVC is used to track functional decline in fibrotic and neuromuscular disease.

Asthma caused or worsened by workplace exposure to sensitising or irritant agents. Diagnosis relies on temporal relation to work, serial peak flow records and specific challenge testing.

Lung disease caused by inhaling and retaining mineral dusts such as silica, coal or asbestos. Fibrosis and impaired gas exchange develop after years of cumulative exposure.

Repeated upper airway collapse during sleep causing apnoeas, hypopnoeas and oxygen desaturation. It produces daytime sleepiness and raises cardiovascular risk.

The number of apnoeas and hypopnoeas per hour of sleep, from polysomnography or home testing. It grades sleep apnoea severity and guides treatment decisions.

A device delivering steady positive pressure through a mask to splint the upper airway open during sleep. It is first-line therapy for obstructive sleep apnoea and needs adherence monitoring.

Occlusion of pulmonary arteries by thrombus, usually from deep veins of the legs. It causes dyspnoea, chest pain and hypoxaemia and is risk-stratified to guide anticoagulation or thrombolysis.

A clinical prediction rule estimating the pretest probability of pulmonary embolism from features such as signs of deep vein thrombosis, tachycardia, immobilisation and alternative diagnoses.

A fibrin degradation product raised when clot formation and breakdown occur. A negative result in low-probability patients helps exclude pulmonary embolism; it is not specific.

Fluid in the pleural space caused by cancer, most often lung cancer or mesothelioma. It usually indicates advanced disease and is managed with drainage, pleurodesis or an indwelling catheter.

Three pleural fluid measurements separating exudates from transudates: protein ratio, lactate dehydrogenase ratio and fluid LDH level. Exudates meet at least one criterion.

Needle drainage of pleural fluid for diagnosis or symptom relief. Ultrasound guidance improves safety by locating fluid and avoiding the lung and diaphragm.

Clinical decision-making that integrates the best available research evidence, clinician expertise and patient values. It requires appraising study design, bias and applicability to the individual patient.

A study allocating participants randomly to interventions to balance confounders and support causal inference. Randomisation, allocation concealment and blinding limit systematic error.

The number of patients who must receive an intervention for one additional person to benefit. It is the reciprocal of the absolute risk reduction and expresses clinical impact.

A patient's voluntary agreement to a procedure or research participation after receiving adequate information about purpose, risks, benefits and alternatives, and confirming the patient's understanding and capacity.

Principles governing studies involving humans, including respect for persons, beneficence, non-maleficence and justice. Ethics committee approval and ongoing oversight are required before recruitment.