We report a 53-year-old woman with ARDS who required positive pressure ventilation with positive end-expiratory pressure. She sustained an acute right ventricular myocardial infarction associated with cardiovascular instability. The next day she sustained a fatal cerebral arterial gas embolism. Intravascular gas was documented within the cerebral, coronary, and pulmonary arterial circulations. Clinicians need to be aware of venous and arterial gas embolism as a complication of mechanical ventilation.