Techniques for emergency ventilation through a needle cricothyroidotomy.

We examined the pressures produced by a construction intended for emergency ventilation through a needle cricothyroidotomy. This construction consisted of a standard hospital wall oxygen supply, flowmeter, oxygen tubing and a three-way tap. We measured the flow achieved through a transtracheal catheter and compared the construction to a Manujet jet ventilator and to a Sanders injector. The construction performed similarly to the Manujet set at low pressures (0-100 kPa). To achieve similar pressures and flow to the Manujet set at pressures higher than 100 kPa required opening of the flowmeter beyond its calibrated range. The flow through the transtracheal catheter was almost three times higher when the flowmeters were fully opened than when they were opened to the 15 l x min(-1) mark (44.5 vs 15.8 l x min(-1), respectively; p < 0.0001). When the flowmeters were fully opened the pressure measured before the catheter was over four times higher than when they were only opened to the 15 l x min(-1) mark (285.3 vs 66.4 kPa, respectively; p < 0.0001). This system of ventilation is inferior to a Manujet in terms of robustness and calibration throughout its range of pressures and flows, but seems appropriate for emergency use in the absence of a purpose-made jet ventilator.