Seven Japanese domestic kittens, weighing 1.46±0.5 kg, were anesthetized for 24 hrs to evaluate a long term effects of controlled ventilation. Atropine (0.15 mg/kg i.m.) and ketamine (20 mg/kg i.m.) were administered, followed by pancuronium bromide (PB) and pentazosine injection (i.v.) . After the intubation, 100% oxygen for initial 1 hr then 40% oxygen was given during the controlled ventilation (conventional mechanical ventilation; CMV) . A respiratory rate was set at 25 times/min and the PEEP was maintained 4 cm H₂O. Maximum inspiratory pressure was adjusted to keep the PaC0₂ between 20-30 mmHg and The trachea was humidified. Anesthesia was maintained with a continuous infusion of PB (0.1 mg/kg/hr) and pentazosine (0.5 mg/kg/hr) . In addition, diazepam (0.5 mg/kg) was administered every 2 hrs. Heart rate, body temperature, blood pressure, and rate pressure product (RPP) were measured at 1 hr interval and blood gases were measured every 3 hrs during the experiment. As a result, the data measured were within normal or controlled levels, thus this anesthetic method can be used safely for the management of patients who require long term respiratory support.

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Antagonizing effects of yohimbine, α₂-adrenoceptor blocking agent, at various doses on sedation, bradycardia and hypothermia induced by xylazine in cats were studied. Cats were given a standard dose (2mg/kg) or an overdose (5mg/kg) of xylazine, followed by i.m. or i.v. injections of various doses of yohimbine. Both i.m. (0.1-0.3 mg/kg) and i.v. (0.05-0.5mg/kg) injections of yohimbine markedly reduced the recovery time from xylazine-induced sedative effects. In addition, yohimbine reduced or abolished xylazine-induced Bradycardia and hypothermia. Those antagonizing effects of yohimbine seemed to be dosedependent. However, yohimbine given i.v. at a dose of more than 0.3 mg/kg appeared to cause restlessness or excitation. These results suggest that yohimbine can be used as a safe and effective antagonist against xylazine at doses of 0.05 to 0.1 mg/kg i.v. or 0.1 to 0.3 mg/kg i.m..

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Comparative studies of halothane-O₂ (OF), enflurane-O₂ (OE), halothane-O₂-N₂O (GOF) and enflurane-O₂-N₂O (GOE) anesthesia on a number of clinically important features were made in the cat. Cats of each group were premedicated with atropine (0.05 mg/kg) subcutaneously and ketamine (5 mg/kg) intramuscularly. Anesthesia was induced (via face mask) and maintained for 60 minutes at surgical depth with halothane and enflurane in either O₂ or a combination of O₂ and N₂O (1: 2) via a semiclosed circle system under a spontaneous ventilation.
Mean alveolar concentrations of halothane and enflurane during maintenance anesthesia were 1.93% in OF group, 2.56% in OE group, 1.29% in GOF group and 1.81% in GOE group. Anesthetic induction was more rapid in GOF and GOE groups than in OF and OE groups. Recovery was significantly rapid in OE group compared with OF group. Respiration rates during anesthesia were significantly lower in OE and GOE groups than in OF and GOF groups, however, the changes in arterial pH and PCO₂ showed a nearly equal degree of respiratory acidosis in all groups. Abnormal electrocardiographic alterations were not observed in cats of all groups. Arterial blood pressure was significantly higher in GOF and GOE groups than in OF and OE groups, and was slightly higher in OF and GOF groups than in OE and GOE groups. Changes in serum GOT and BUN were within normal ranges in all cats examined. These results suggest that a use of N₂O is preferable in halothane and enflurane in the cat and that there are no significant differences between the two for the clinical application in cats.

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