Gastro-oesophageal reflux in halothane anaesthetized sheep. The effects of feeding and positioning.

The frequency of gastro-oesophageal reflux (GOR) in sheep anaesthetized with halothane was reduced by withholding food and water for 24 hours. The total reflux volume increased. The effect of body position on GOR was studied by inclining the operating table at angles to the horizontal and positioning the head up or down on sand bags. The operative positions investigated were: right and left lateral recumbency with head down, dorsal recumbency with head down and right lateral recumbency with head up. Least GOR occurred when the sheep was in right lateral recumbency with a head up tilt and the body inclined at 20 degrees from the horizontal. A cuffed oesophageal drainage tube increased the incidence of GOR but prevented the chances of the aspiration of rumen material.