Complications of tracheal gas insufflation

Numerous reports of patient, lung model, and animal use of tracheal gas insufflation (TGI) have appeared in the literature over the past 10 years. However, no commercial TGI system is available. As a result, extreme care must be exercised if attempts are made to provide TGI. Numerous problems with noncommercial systems have been identified. Continuous-flow TGI results in an increase in peak pressure and delivered tidal volume. The use of a flow-limiting or pressure relief valve or a ventilator with an exhalation valve active during exhalation minimizes these problems. Ideally, TGI should only be activated during the expiratory phase. However, this requires that the TGI system be integrated with the mechanical ventilator. In addition, appropriate system monitoring should be available, including measurement of total positive end-expiratory pressure, peak inspiratory pressure, and tidal volume, and there should be a method of identifying increased carinal pressure and deactivating the TGI system if an obstruction occurs proximal to the point of TGI injection. As a result of the potential complications of TGI, this technique cannot be recommended for routine use until commercial systems are available.