Modification of a new catheter for air retrieval and resuscitation from lethal venous air embolism: effect of nitrous oxide on air retrieval.

Abstract

A modification of a new Arrow prototype catheter was evaluated for its ability to retrieve venous air emboli and for its effect on the success rate of resuscitation from venous air emboli in dogs anesthetized with isoflurane and nitrous oxide (66%) in oxygen. In an additional group of dogs, nitrogen was substituted for nitrous oxide in the inspired gases to determine whether the presence of nitrous oxide (as traditionally used in this model of lethal venous air emboli) increased the apparent amount of gas retrieval or altered the success rate of resuscitation. Dogs were placed in the seated position with the head 90 degrees to the horizontal. The modified Arrow prototype catheter was placed with the proximal orifice just above the superior vena cava-right atrial junction and the distal orifice near the mid-right atrium. Dogs were then given a predetermined lethal dose of air (5 mL/kg) over 30 s through the jugular vein. Attempts to aspirate venous air emboli were begun with the first decrease in expired CO2. The amounts of gas retrieved, expressed as a percent of the injected air, and the incidence of successful resuscitation were compared between groups. In both treatment groups (nitrous oxide and nitrogen), the percent of injected venous air retrieved (73% +/- 13% and 65% +/- 21%, mean value +/- SD, respectively) and success rate of resuscitation (four of six dogs in each group) were significantly increased compared with the control group in which no attempt was made to retrieve injected venous air, and none of the six dogs survived.(ABSTRACT TRUNCATED AT 250 WORDS)