Respiratory and Thoracic Emergencies
Core concepts
Asthma and COPD exacerbations hinge on recognizing impending respiratory failure: a silent chest, exhaustion, altered mentation, or a normal-to-rising PaCO2 in a tachypneic asthmatic means the patient is tiring. Treat with continuous albuterol, ipratropium, systemic steroids, and magnesium; noninvasive ventilation helps COPD acidosis but is used cautiously in asthma. In COPD, titrate oxygen to SpO2 88–92% and start NIV early when pH is below 7.35. Pulmonary embolism: use pretest probability (Wells), PERC to avoid testing in very low-risk patients, and age-adjusted D-dimer; CT pulmonary angiography confirms. Massive PE with hypotension gets systemic thrombolysis or catheter-directed therapy. Tension pneumothorax demands immediate needle decompression (second intercostal space midclavicular or fourth–fifth anterior axillary) followed by tube thoracostomy - never wait for imaging in an unstable patient. Pneumonia is risk-stratified with CURB-65 or the pneumonia severity index to decide admission. ARDS is defined by Berlin criteria (bilateral opacities, P/F ratio ≤300 on PEEP ≥5, non-cardiogenic). NIV fails in agitated, vomiting, or unprotected-airway patients.
Traps
The silent chest sounds better but is worse. Pulse oximetry reads normal in carbon monoxide poisoning, severe anemia, and methemoglobinemia. A clear chest radiograph does not exclude PE or early pneumonia. In a ventilated patient who suddenly desaturates and becomes hypotensive, think tension pneumothorax first.
Rule of thumb
For the crashing intubated patient, run DOPES: Displacement, Obstruction, Pneumothorax, Equipment failure, Stacking. Intervene before you image.