Mechanism of fatal air embolism after gastrointestinal endoscopy

Although venous air embolism is a known complication in medical practice in general, only a single case of upper gastrointestinal endoscopy complicated by venous air embolism with consecutive acute cardiovascular failure has so far been described in literature. Here we show that gastroscopy may be accompanied by massive, i.e. fatal venous air embolism. If a vessel in the gastrointestinal tract is exposed but does not collapse (in the case of a gastric ulcer, for example) air insufflated under pressure by the gastroscope may lead to a fatal air embolism. Our tests using a commercial gastroscope revealed that an overpressure of up to 43 kPa (kiloPascals) is reached without the rinsing function while an overpressure of up to 45 kPa is measured if the rinsing function is operated simultaneously. The maximum flow rates without resistance were 100 ml/min for rinsing liquid (purified water) and 2000 ml/min for air. Our results suggest that air insufflation by the gastroscope may result in a critical air embolism within very few seconds on condition that a connection with the vascular system exists. However, this complication is extremely rarely encountered. We propose that CO2 should be administered in place of air or alternatively the maximum pressure should be considerably reduced to avoid a fatal outcome in routinely performed gastroscopical examinations.