The occurrence of venous air embolism in critically ill patients can cause profound cardiopulmonary compromise. Recognized causes include aspiration through an indwelling catheter and pneumothorax. We report three patients in whom we found continuous air embolism in the inferior vena cava that persisted for days. The bubbles appeared to arise from splanchnic veins, and they were associated with barotrauma and positive airway pressure. In the two survivors, the bubbling ceased when the ARDS resolved and airway pressures were decreased. We suspect that venous air embolism is not an uncommon occurrence in critically ill patients receiving high positive airway pressure.