Low-Flow Endobronchial Insufflation With Air for 2 Hours of Apnea Provides Ventilation Adequate for Survival

Abstract

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.

Changes in blood-gas tensions during apnoeic oxygenation in paediatric patients

“…4 For this effect, catheters must be placed 2.0-3.5 cm beyond the carina 11 and catheters with internal diameters less than 2 mm are needed to create sufficient turbulence. Gas flows need to be large; up to 1 litre kg 91 min 91 has been used in animals and flows in excess of 0.3 litre kg 91 min 91 are generally required to maintain blood-gas stability, 12 although airway geometry may be more important than weight in determining necessary flows. In our study, all tubes were placed above the carina, had internal diameters in excess of 3.5 mm and gas flows did not exceed 0.26 litre kg 91 min 91 , making the possibility of significant continuous flow ventilation extremely unlikely.…”

A Resuscitation Option for Upper Airway Occlusion Based on Bolus Transtracheal Lung Inflation

“…In transtracheal insufflation, oxygen or room air is delivered via cannula at a steady flow of approximately 2 liters/minute directly into the trachea with a separate transtracheal port or an open airway providing the exhaust port . Its key utility has been as a continuous source of oxygen as an adjunct to surgical procedures involving the upper airway, an adjunct to mechanical ventilation, or as an alternate method to achieve oxygenation during cardiopulmonary resuscitation.…”

Apneic oxygen insufflation decreases the incidence of hypoxemia during one-lung ventilation in open and thoracoscopic pulmonary lobectomy: A randomized controlled trial

“…In closed-chest, two-lung apneic oxygenation, a gas flow greater than 0.3 L/kg/min is required for adequate CO 2 removal. 25 In an OLV situation, however, CO 2 is removed by the ventilated lung. Thus, large gas flows to remove CO 2 are not necessary.…”