EFFECTS OF ACEPROMAZINE, PETHIDINE AND ATROPINE PREMEDICATION ON LOWER ESOPHAGEAL SPHINCTER PRESSURE AND BARRIER PRESSURE IN ANESTHETIZED CATS

Combinations of acepromazine maleate, pethidine hydrochloride and atro pine sulphate (0-05 mg/kg) or acepromazine maleate and pethidine hydro chloride and acepromazine maleate alone or atropine sulphate (0-1 mg/k g) alone were used to premedicate cats before they were anaesthetised with thiopentone, to investigate their effects on gastric pressure, lo wer oesophageal sphincter pressure and barrier pressure under anaesthe sia. Manometric measurements were made by using a non-perfused manomet ric technique. The lower oesophageal sphincter pressure was lowest in the cats premedicated with atropine sulphate alone. The difference in barrier pressure between the atropine (0.1 mg/kg) and acepromazine tre ated cats was highly significant. The risk of gastro-oesophageal reflu x appeared to be highest with atropine (0.1 mg/kg) if barrier pressure is used as an indicator of the likelihood of reflux.