Pulmonary air embolism

Pulmonary air embolism is a well-known consequence of surgery, trauma, divi ng, and aviation. This article reviews the physiological effects, means of detection and methods of prevention and treatment of pulmonary air embolism . The primary physiological effects are elevated pulmonary artery pressures , increased ventilation-perfusion inhomogeneity, and right ventricular fail ure. The degree of physiological impairment depends on the volume of gas en trained, the rate of entrainment, the type of gas entrained, and the positi on of the patient when the embolism occurs. Transesophageal echocardiograph y is the most sensitive method of detection, but it is invasive. Precordial Doppler ultrasound is almost as sensitive and poses no risk to the patient . End-tidal carbon dioxide monitoring is used on all patients and is a mode rately sensitive method of detection, which is useful during surgeries that have a low incidence of air embolism. For high-risk procedures, precordial Doppler ultrasound and a multi-orifice right heart catheter should be used to detect and treat pulmonary air embolism. Prevention measures include vo lume expansion, careful positioning, positive end-expiratory pressure, mili tary anti-shock trousers, and jugular venous compression. Treatment of pulm onary air embolism includes flooding the surgical site with saline, control ling sites of air entry, repositioning the patient with the surgical site b elow the right atrium, aspiration of air from a central venous catheter, ce ssation of inhaled nitrous oxide, and resuscitation with oxygen, intravenou s fluids, and inotropic agents. Some hypotheses on the effects of air in th e pulmonary vasculature and investigational treatment options are discussed .