Prolonged interval jet ventilation. An alternative ventilation technique for patients with problematic cardiopulmonary pathophysiology.

Abstract

The initial clinical experience of using a technique of prolonged interval jet ventilation is reported. Periodic pulses, of from three to nine breaths, were delivered in rapid sequence from a jet ventilator during one-lung ventilation. The expiration phase was free to atmosphere, without added artificial expiratory assist or resistance, and of from 30 to 50 s duration before delivery of the next pulse of jet ventilation. The aim of the technique was to evaluate during anaesthesia the practicalities of securing a prolonged period during which intrathoracic pressure is low and hence optimal for venous return and deflation of pathological pulmonary regions with long time constants. The system used is flexible enough to allow for conventional positive pressure techniques to be applied if necessary. As the gas delivery was of oxygen of high concentration, episodes of hypoxaemia were minimal in this group of high risk patients and due to technical rather than physiological causes. The delivery of a minute volume adequate to prevent hypercapnia was not always possible and the technique may be contraindicated in those conditions in which a raised carbon dioxide concentration is disadvantageous.