Evaluation of the IMV bird and the Modified Mark 2 bird in a Hyperbaric Environment

Patients with vascular air embolism, gas gangrene, or carbon monoxide poisoning may require mechanical ventilatory support in conjunction with hyperbaric oxygen therapy. Performance characteristics of two pneumatically powered ventilators were evaluated during the therapy of a patient who sustained cerebral air embolism while scuba diving. At a simulated 60 feet of seawater (2.8 atmospheres absolute) the IMV bird underwent sufficient alteration in performance to render its function unacceptable. The modified bird Mark 2 ventilator had a slight alteration in performance but provided satisfactory mechanical ventilation (IMV) and PEEP at the treatment depth.