A Simple “New” Method to Accelerate Clearance of Carbon Monoxide

Abstract

The currently recommended prehospital treatment for carbon monoxide (CO) poisoning is administration of 100% O₂. We have shown in dogs that normocapnic hyperpnea with O₂ further accelerates CO elimination. The purpose of this study was to examine the relation between minute ventilation (V˙ e) and the rate of elimination of CO in humans. Seven healthy male volunteers were exposed to CO (400 to 1,000 ppm) in air until their carboxyhemoglobin (COHb) levels reached 10 to 12%. They then breathed either 100% O₂ at resting V˙ e (4.3 to 9.0 L min) for 60 min or O₂ containing 4.5 to 4.8% CO₂ (to maintain normocapnia) at two to six times resting V˙ e for 90 min. The half-time of the decrease in COHb fell from 78 ± 24 min (mean ± SD) during resting V˙ e with 100% O₂ to 31 ± 6 min (p < 0.001) during normocapnic hyperpnea with O₂. The relation between V˙ e and the half-time of COHb reduction approximated a rectangular hyperbola. Because both the method and circuit are simple, this approach may enhance the first-aid treatment of CO poisoning.