GASTRIC MYOELECTRIC AND MOTOR-ACTIVITY IN DOGS AFTER ISOFLURANE ANESTHESIA

To characterize the effects of isoflurane on gastric motility, gastric electrical and contractile activities were assessed in six healthy ad ult dogs before and after recovery from anesthesia. Baseline recording s (fasting and fed state) were obtained in unanesthetized dogs 8 days after implantation of serosal electrodes and strain-gauge force transd ucers. After an overnight fast, dogs were anesthetized with 1.3 minimu m alveolar concentration (MAC) isoflurane for 4.5 hours (approximately 6 MAC hours). No other anesthetic or sedative drugs were administered . During anesthesia, ventilation was mechanically controlled to mainta in arterial carbon dioxide tension at 36 +/- 4 mm Hg. Gastric electric al and contractile activities (fasting and fed state) were recorded ag ain 18 hours after recovery from isoflurane anesthesia. Recordings wer e analyzed to determine gastric slow-wave frequency, presence of slow- wave dysrhythmias, slow-wave propagation velocity, coupling of contrac tions to slow waves, a motility index based on relative contractile am plitudes, and onset and duration of contractions after a standardized meal. The only variable that was significantly decreased 18 hours afte r 6 MAC hours of isoflurane anesthesia was the gastric motility index during fasting-state phase III. This decrease was not apparent in the fed-state test periods. Our results suggest that, with the exception o f gastric motility index during fasting-state phase III, variables for gastric electrical and contractile activities in dogs are unaffected by isoflurane 18 hours after anesthesia. (C) 1995 by The American Coll ege of Veterinary Surgeons