Myths and pitfalls in emergency translaryngeal ventilation: correcting misimpressions.

Translaryngeal jet ventilation has been proven an effective emergency airway alternative. However, confusion exists as to the proper cannulae and oxygen sources for this technique. Our study was designed to determine the delivered volumes of gas using cannulae and oxygen sources recommended in previous reports on translaryngeal jet ventilation. From this, we hope to clarify the proper technique of translaryngeal jet ventilation. Using a variety of oxygen sources and cannulae, peak flow rates were measured using a digital flowmeter. Delivered volumes of gases generated with each combination were then calculated. All of the cannulae tested (standard 16-gauge IV cannulae and larger) provided peak flow rates high enough so that predicted tidal volumes would be adequate to maintain adequate ventilation in apneic adults when a 50-psi source was used. Only a 4-mm tracheal cannula provided comparable values when a bag-valve device was used. No cannulae provided sufficient flow rates to ensure adequate ventilation in apneic adults when a demand-valve mechanism of 60 cm H2O driving pressure served as the source. Our observations were consistent with previous clinical studies and suggest that standard translaryngeal jet ventilation cannulae (12 to 16 gauge) must be connected to an oxygen source of 50 psi in apneic adults. Demand-valve devices do not provide sufficient driving pressures for these cannulae. A cannula of 4 mm ID should be placed if only a bag-valve device is available for ventilation.