STUDIES ON XYLAZINE-KETAMINE, MIDAZOLAM- KETAMINE AND ISOFLURANE ANAESTHESIA IN BUTORPHANOL PREMEDICATED BIRDS
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Date
2016
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AAU, Anand
Abstract
A clinical study, on 28 birds of various surgical affections was undertaken to evaluate sedative and anaesthetic effects of various combinations. Birds were allotted to four groups of seven birds in each. Butorphanol tartrate was administered as a premedicant at the dose rate of 1 mg/kg b.wt. IM. Induction of anaesthesia was carried out 15 min. after premedication with midazolam-ketamine combination (@ 0.5-1.0 mg/kg and 10-25 mg/kg b. wt. respectively, IM in group-A), xylazine-ketamine combination (@ 2.5 mg/kg and 20 mg/kg b. wt. respectively, IM in group-B) and isoflurane (chamber induction in group-C1 and mask induction in group-C2). Maintenace of anaesthesia was done with midazolam-ketamine combination (group- A), xylazine-ketamine combination (group-B) and isoflurane (group-C1 and group-C2 following ET intubation). Mapleson-C and mapleson-F breathing systems were used and evaluated in group-C1 and group-C2, respectively following intubation to know the effective non-rebreathing system used in avian species. AH birds were evaluated for various physiological parameters viz. heart rate, respiratory rate, SpO2, cloacal temperature, EtCO2 and ICO2. Birds were monitored for various body reflexes. Clinical parameters i.e., quality of sedation, induction and recovery were also evaluated. Induction time and complete recovery time were also recorded for all groups. Post-operative pain management was achieved using meloxicam (0.5 mg/kg b. wt.) for 5-6 days after surgery. In present study, butorphanol provided excellent analgesia during surgical procedure. Butorphanol tartrate at the dose rate of 1 mg/kg, intra-muscularly proved as an excellent preanaesthetic drug in birds. It showed very smooth and quick induction with xylazine-ketaraine combination (group-B) and mask induction (group-C2) than with other agents. Anaesthetic induction was excellent with mask induction (group-C2) in terms of smoother and safer induction with moderate cardiopulmonary alterations, followed by xylazine-ketamine induction. Birds anaesthetized with chamber induction (group- C1) exhibited longest induction time (172.71 ± 42.16 sec). The time to induction in birds anaesthetized with xylazine-ketamine combination (group-B) (25.71 ± 1.39 sec.) was faster than anaesthetized with midazolam-ketamine combination (group-A) and isoflurane. Custom made face masks was found very useful in birds to accommodate widely diverse avian species. For induction with isoflurane, induction with face masks (group-C2) proved superior and was comparatively easy, safe and cost effective as compared to the anaesthetic chambers (group-C1). In all the five groups, there was highly significant decrease in respiratory rate just after induction. Butorphanol tartrate premedication may cause decrease in respiratory rate along with synergistic effects of induction agents. However, group-A (midazolam-ketamine) birds showed comparatively less respiratory depression as compared to other groups. In all the groups, there was non-significant decrease in heart rate just after induction. In group-A birds, heart rate is significantly higher at 40 and 50 minutes of anaesthesia, as compared to normal values. In group-C2 birds, heart rate was very uniform throughout anaesthesia as compared to other groups. All groups showed significant alterations in mean cloacal temperature from normal till 50 min. after induction, except group-A (midazolam-ketamine) birds. However, the cloacal temperature decreased gradually in all the groups anaesthetized with different compounds. Despite of the usage of orthopaedic clinical heating mats in the present study, the cloacal temperature decreased gradually in all the groups. Routine pulse oximeter was utilized for anaesthetic monitoring by applying Sp02 sensor around the wing. A reading of 94% or less during anaesthesia time 0 to time 50 minutes was considered abnormal and birds were considered hypoxemic based on pulse oximeter readings. In the present study, the readings varied from 55 to 94% and were often highly variable. The results were always underestimation of the actual saturation values in birds. In that way, routine pulse oximeters are not accurate in avian species and are not reliable in birds. Capnography was found very useful to assess ventilation status of anaesthetized patient. In group-C2 birds, EtCO2 values were very uniform throughout surgery. Capnograph appeared on the monitor was also accurate and ventilatory status of the patient was easily assessed. Sidestream capnography found very accurate and reliable to assess the ventilatory status of the patient and avoid waste and expense of fresh gas. Mapleson-F breathing system (Jackson-Rees paediatric circuit) was found superior compared to mapleson-C system, in terms of low flow rate requirement with minimum rebreathing, easy scavenging of waste gases to minimize theatre pollution and convenience to provide emergency resuscitation. Recovery time in birds anaesthetized with isoflurane alone (7.91 ± 2.23 min. and 6.16 ± 0.31 min. for group-C1 and group-C2 patients, respectively) was shortest than other groups. Recovery quality was also excellent in these group of birds as compared to other groups. Longest recovery time was observed in birds anaesthetized with xylazine-ketamine combination (group-B) (85.26 ± 5.20 min.). Overall quality of anaesthesia was excellent in group-C2 (mask induction) protocol, in terms of smooth induction, adequate sedation and analgesia, faster recovery and moderate physiological alterations, except respiratory depression. Group- C1 (Chamber induction) birds showed excellent anaesthesia, followed by group-B (xylazine-ketamine combination) birds.
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VETERINARY SURGERY AND RADIOLOGY, A STUDY