Respiratory and Thoracic Emergencies
Oxygenation, ventilation, and the failing airway
Candidates must separate oxygenation failure (hypoxemia) from ventilation failure (hypercapnia) and recognize when each needs escalation. Know the signs of impending airway loss: stridor, drooling, muffled voice, tripod positioning, and silent chest in severe asthma. Stridor is an upper airway sign and is a late, ominous finding. Rapid sequence intubation preparation, bag-mask ventilation, and rescue devices are examinable, as is the rule that a patient who can be oxygenated and ventilated by bag-mask should not be paralyzed before a plan for rescue exists.
Specific emergencies
Asthma: prolonged expiration, wheeze, accessory muscle use; treat with bronchodilators, steroids, and magnesium in severe cases; a normal or rising carbon dioxide in a visibly exhausted asthmatic signals imminent failure. COPD exacerbation: controlled oxygen targeting adequate saturation, bronchodilators, steroids, noninvasive ventilation for acidosis. Pulmonary embolism: risk factors, sudden dyspnea, pleuritic pain, tachycardia; massive PE with hypotension may need thrombolysis. Pneumothorax: absent breath sounds, hyperresonance, tracheal deviation away from the affected side in tension; needle decompression precedes imaging. Pulmonary edema: crackles, frothy sputum, orthopnea; noninvasive ventilation and nitrates when pressure is adequate.
Traps in questions
- Do not wait for a chest radiograph in suspected tension pneumothorax.
- A "quiet" asthmatic is deteriorating, not improving.
- High-flow oxygen in a COPD patient is not automatically wrong when the patient is hypoxemic; titrate to target rather than withholding.
- Epiglottitis and croup both cause stridor, but the adult with drooling and fever needs airway readiness, not a tongue blade examination.
Rule of thumb
If ventilation is failing despite oxygen, the next step is assisted ventilation, not a higher oxygen percentage. Worked example: a 24-year-old asthmatic with a silent chest, drowsiness, and rising carbon dioxide requires immediate bag-mask assistance and airway escalation alongside continuous bronchodilator therapy.