Doxapram infusion during halothane anaesthesia in ponies.
Doxapram, 0.05 mg/kg bodyweight/min, was infused during the second hour of 2 h halothane anaesthesia in six ponies. Two of the ponies were anaesthetised on a second occasion as controls and given 5 per cent dextrose in place of the doxapram. Respiratory depression typical of halothane anaesthesia in ponies developed in the first hour of anaesthesia and continued during the second hour in the control animals. During doxapram infusion arterial carbon dioxide tension decreased and pH increased. Arterial blood pressure increased but there was no change in pulse rate, the electrocardiogram or arterial oxygen tension. Anaesthesia lightened during doxapram infusion necessitating an increase in the vapouriser setting in order to prevent arousal. Recovery from anaesthesia appeared unaffected by the doxapram infusion.
Taylor
P M
PM
Animal Health Trust, Newmarket, Suffolk.
D000758:Anesthesia / Q000662:veterinary*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D004315:Doxapram / Q000494:pharmacology*; D006221:Halothane; D006736:Horses / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000097:blood; D011674:Pulse / Q000187:drug effects; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects
D002245:Carbon Dioxide; D004315:Doxapram; D010100:Oxygen; D006221:Halothane