The Influence of Body Position on the Blood Gas and Acid‐base Status of Halothane‐anesithetized Sheep

Abstract

Eleven adult sheep were divided into three groups. Baseline arterial blood samples were taken with the sheep standing and breathing room air. They were then anesthetized and placed in right (group one), left (group two), or dorsal (group three) recumbency. Arterial blood samples were taken at 30, 60, 90, and 120 minute intervals during anesthesia, and 15 minutes after the discontinuation of halothane in oxygen. Anesthetic induction resulted in an increase in arterial oxygen (Pao 2 ) and carbon dioxide (Paco 2 ) tensions and a decrease in arterial pH (pHa) and base excess (BE). During anesthetic maintenance, no positional effects were noted, and pHa and BE increased in all groups. With the termination of anesthesia and the animals breathing room air, pHa increased, and Pao 2 and Paco, decreased; BE was elevated in group two when compared to group three. Only BE had returned to control values 15 minutes after halothane was discontinued.