Ventricular fibrillation during orotracheal intubation of hypothermic dogs

Physical manipulation of the hypothermic patient is well known to cause ventricular fibrillation. Careful review of the literature fails to demonstrate a true temporal relationship between orotracheal intubation and ventricular fibrillation (VF) when acceptable temperature-corrected arterial blood gases have been obtained. Eleven mongrel dogs were anesthetized and cooled, with orotracheal intubation and extubation performed every two degrees centrigrade, starting at 27 C. Ventilator setting were adjusted to maintain normal pH according to arterial blood gases drawn every two degrees and corrected for temperature. There was only one episode of VF during 42 intubations performed at temperatures less than 28 C (2.38%). There were eight separate episodes of spontaneous VF unrelated to intubation in five dogs. Four of these five with spontaneous VF were resuscitated with countershock only, further cooled, and reintubated an additional 11 times without a single episode of VF during intubation. Our data suggest that the incidence of VF during intubation in the hypothermic patient is much less than previously described, provided that normal pH is maintained and hypoxemia is corrected.