A bench study of ventilation via two self-assembled jet devices and the Oxygen Flow Modulator in simulated upper airway obstruction

Abstract

In managing an obstructed upper airway, an emergency transtracheal ventilation device needs to function as a bidirectional airway, allowing both insufflation of oxygen and egress of gas. The aim of the present study was to determine the capability of two self-assembled, three-way stopcock based jet devices and the Oxygen Flow Modulator to function as a bidirectional airway in conjunction with a small lumen catheter. For each device the effective pressures at the catheter's tip during the expiratory phase and the achievable minute volumes were determined in a laboratory set-up. Using the three-way stopcock based jet devices, changing the connection position of the transtracheal catheter from the in-line port to the side port of the three-way stopcock resulted in a decrease of expiratory pressure at the catheter's tip from a dangerous mean (SD) of 71.1 (0.08) cmH2O to )14.71 (0.05) cmH 2O. Yet this negative expiratory pressure did not facilitate the egress of gas. All devices tested impeded the expiratory outflow and hence decreased the achievable minute volume. This decrease in minute volume was smallest with the Oxygen Flow Modulator. © 2009 The Authors.