Low-flow endobronchial insufflation with air for 2 hours of apnea provides ventilation adequate for survival

We tested the efficacy of low-flow endobronchial insufflation (EI) with air, as it may be useful in emergency situations in which positive-pressure mechanical ventilation is not possible. The only equipment required is a source of compressed air with flow controller and a specially designed insufflation catheter. The insufflation catheter has forked ends that can be positioned blindly in the mainstem bronchi. In six anesthetized, apneic dogs averaging 9.6 kg, we determined that the average air flow needed to maintain PaO2 above 45 mm Hg and PaCO2 below 65 mm Hg after 30 min was 2.5 L/min. At these flow rates, all dogs survived 2 h of endobronchial insufflation with no neurologic dysfunction. The small internal diameters (0.8 mm) of the catheter ends increase gas exit velocity and allow for adequate oxygenation and CO2 removal at low flow rates. Endobronchial insufflation could also be employed with cricothyroidotomy and a compressor for emergency situations in the field involving mass casualties, where oxygen supplies and equipment are limited.