The efficacy of flow and pressure release in self-assembled emergency jet devices

Introduction: In current anesthesia literature [1,2] self-assembled devices consisting of a three-way stopcock connected to a high pressure oxygen source and a transtracheal catheter, have been proposed for transtracheal jet ventilation (TTJV) in airway emergencies. As a three-way stopcock acts as a “flow splitter”, it will never ensure complete flow and pressure release through its side port when connected to a continuous flow of oxygen. In an obstructed upper airway, this continuous oxygen flow to the patient will inevitably create positive end-expiratory pressure (PEEP), which can lead to barotrauma and hemodynamic instability. The aim of the present study was to measure the efficacy of flow and pressure release of three self-assembled devices for TTJV. Methods: Three self-assembled jet devices, consisting of a threeway stopcock with an inner diameter of 2.0 mm, 2.5 mm, or 3.0 mm (devices A, B, and C) connected inline to a flowmeter and a 75 mm long, 2 mm ID transtracheal catheter, were tested in a laboratory setup. The generated pressure at the catheter tip (PACT) of each self-assembled jet device with the side port in an open position was measured using the Calibration Analyzer series RT-200 (Timeter Instrument Corp., St. Louis, MO) at oxygen flows of 6, 9, 12, and 15 L/min, respectively. Five measurements were performed and the mean and standard deviation were calculated. Results: The generated PACT for each device at different oxygen flows is shown (Fig. 1). Conclusion: By merely connecting the self-assembled three-way stopcock devices A and B to a high-pressure oxygen source set at a continuous oxygen flow of more than 9 and 12 L/min, respectively, dangerously high airway pressures are inevitable in case of upper airway obstruction. Based on our findings, these self-assembled jet devices should not be used in airway emergencies, because upper airway obstruction can never be excluded.