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- Author or Editor: Cynthia M. Trim x
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SUMMARY
Lumbosacral csf pressure was measured in 6 horses via a catheter inserted through the lumbosacral space. Heart rate, facial artery pressure, central venous pressure, and csf pressure were measured before iv injection of a saline solution control, for 15 minutes after saline solution injection, and for 60 minutes after the iv injection of 1.1 mg of xylazine/kg of body weight. Arterial pH and blood gases were analyzed before saline solution injection, 15 minutes after saline solution injection, and at 15, 30, and 60 minutes after xylazine injection. Constant craniocervical posture was maintained during sedation. Lumbosacral csf pressure was significantly decreased for 15 minutes after xylazine injection. Diastolic arterial pressure was significantly increased 4 minutes after xylazine administration and diastolic and mean arterial pressure were increased at 6 and 8 minutes after xylazine administration. Small increases in systolic arterial blood pressure and central venous pressure, and a small decrease in heart rate were observed. There were no significant differences in the arterial blood gas values. It was concluded that iv injection of xylazine causes a decrease in intracranial pressure in healthy conscious horses. The effects may be different in horses with neurologic disease or cerebral trauma.
Abstract
Objective—To document complications associated with preanesthetic and anesthetic agents used in Vietnamese potbellied pigs and identify predictors of complications.
Design—Retrospective case series.
Animals—27 potbellied pigs (14 female and 13 male) ranging in age from 0.25 to 15 years old and ranging in body weight from 5.9 to 169 kg (13.0 to 371.8 lb) that were anesthetized on 32 occasions between 1999 and 2006.
Procedures—Data, including perianesthetic management, anesthetic agents and dosages, complications, and outcome, were retrieved from medical records. Patient information, anesthetic agents, and duration of anesthesia were evaluated as predictors for development of complications.
Results—Anesthesia was maintained with isoflurane or sevoflurane during 30 anesthetic episodes. Commonly used premedicants were butorphanol, atropine, and midazolam administered in combination with xylazine or medetomidine and a combination of tiletamine-zolazepam and butorphanol. Anesthesia was induced with an inhalation agent on 15 occasions, via injection of ketamine on 10 occasions, and via injection of propofol on 3 occasions. Complications included hypoventilation (16/24 [67%]), hypotension (16/25 [64%]), hypothermia (15/31 [48%]), bradycardia (9/32 [28%]), and prolonged recovery time (7/32 [22%]). None of the factors evaluated were associated with development of these complications. All pigs survived anesthesia.
Conclusions and Clinical Relevance—Results suggested that a variety of anesthetic agent combinations can be used to provide anesthesia in potbellied pigs with satisfactory outcomes. Although there were high incidences of hypoventilation, hypotension, and hypothermia, no specific anesthetic agent was associated with development of these complications.
Abstract
Objective—To evaluate the cardiorespiratory effects of controlled versus spontaneous ventilation in pigeons anesthetized for coelioscopy.
Design—Prospective study.
Animals—30 healthy adult pigeons (Columbia livia).
Procedure—During isoflurane anesthesia, 15 pigeons were allowed to breathe spontaneously (SP group) and 15 were mechanically ventilated (MV group) by use of a pressure-limited ventilator. In each group, cardiopulmonary variables (including end-tidal CO2 concentration [ETCO2]) were measured before (baseline), during, and after coelioscopy. An arterial blood sample was collected for blood gas analyses from each pigeon before coelioscopy and after the procedure, when the caudal thoracic air sac was still open.
Results—At baseline, hypoventilation was greater in the SP group than the MV group. Compared with the SP group values, ETCO2 overestimated PaCO2 to a greater degree in the MV group. Cardiovascular variables were not different between groups. After coelioscopy (when the air sac was open), PaCO2 had decreased significantly from baseline in the MV group. In the SP group, hypoventilation worsened despite an increase in respiratory rate. After coelioscopy, PaO2 in the SP group had decreased from baseline and was lower than PaO2 in the MV group; arterial blood pressure and heart rate in the MV group had decreased from baseline and were lower than values in the SP group.
Conclusions and Clinical Relevance—In adult pigeons, controlled ventilation delivered by a pressurelimited device was not associated with clinically important adverse cardiopulmonary changes but may be associated with respiratory alkalosis and cardiovascular depression when air sac integrity has been disrupted. (J Am Vet Med Assoc 2005;227:1424–1428)
Summary
On 74 occasions, 54 horses and 6 foals were anesthetized with xylazine and ketamine or xylazine, guaifenesin, and ketamine, with or without butorphanol. On 64 occasions, anesthesia was prolonged for up to 70 minutes (34 ± 15 min) by administration of 1 to 9 supplemental iv injections of xylazine and ketamine at approximately a third the initial dosage. All horses except 5 were positioned in lateral recumbency, and oxygen was insufflated.
In adult horses, the time from induction of anesthesia to the first supplemental xylazine and ketamine injection was 13 ± 4 minutes and the time between supplemental injections was 12.1 ± 3.7 minutes. These results were consistent with predicted plasma ketamine concentration calculated from previously published pharmacokinetic data for ketamine in horses. Respiratory and heart rates and coccygeal artery pressure remained consistent for the duration of anesthesia. The average interval between the last injection of ketamine and assumption of sternal position was approximately 30 minutes, and was the same regardless of the number of supplemental injections. The time to standing was significantly longer (P < 0.05) in horses given 2 supplemental injections, compared with those not given any or only given 1, but was not longer in horses given 3 supplemental injections. Recovery was considered unsatisfactory in 5 horses, but did not appear to be related to prolongation of anesthesia.