Dharmaceelan, S.Kathirvel, S.Subramanian, M.Selvaraj, P.Kumar, S. SenthilTANUVAS2018-02-072018-02-072013http://krishikosh.egranth.ac.in/handle/1/5810040572TNV_THE_Y2013_DPV(N)10014The study was conducted in 30 clinical cases of cattle presented to Department of Veterinary Surgery and Radiology for surgical interventions under general anaesthesia during March 2011 to March 2013. The animals were randomly divided into three equal groups viz., group I, II and III. In all the animals, acepromazine maleate was administered at the dose rate of 0.04mg per kg body weight intravenously. In group II and III, butorphanol tartrate and buprenorphine hydrochloride were administered intravenously at the dose rate of 0.02 and 0.06 mg per kg body weight, respectively. Guaifenesin as a 5 per cent solution in 5 per cent dextrose normal saline was administered at the dose rate of 50 mg per kg and anaesthesia was induced with administration of ketamine hydrochloride at the dose rate of 4 mg per kg body weight. Endotracheal intubation was accomplished in all the animals with cuffed Murphy type endotracheal tube to provide a secure leak-free airway. Maintenance of anaesthesia was carried out with isoflurane employing large animal anaesthetic machine with ventilator. The built-in manometer on the expiratory limb of the anaesthetic circle was used to record the changes in airway pressure during spontaneous ventilation. The positive end-expiratory pressure (PEEP) caused by the weight of the ascending bellows of the ventilator was recorded during maintenance of anaesthesia at 10 min interval. The oxygen flow was set at 10 litres per minute for the first 3 min to attain denitrogenation of the anaesthetic circle and also to increase the fraction of inspired-oxygen concentration. The fresh gas flow rate was then reduced to 3 to 5 litres based on the size of the animal. The changes made on the fresh gas flow rate and vapourizer setting at various times during maintenance of anaesthesia was recorded. The quantity of isoflurane utilized for maintenance of anaesthesia was calculated by Avogadro’s principle. The fraction of inspired oxygen, carbon dioxide and isoflurane concentration and end-tidal oxygen, carbon dioxide and isoflurane concentration were recorded using multigas monitor during low flow isoflurane anaesthesia. The tidal volume in group II was significantly lower (p<0.01) as compared to that of group I and III. The compensatory increase in respiratory rate maintained the minute volume during anaesthesia in group II animals. The minute volume in group III was significantly lower (p<0.01) as compared to that of group I and II indicating that the ventilation was depressed, as also observed from the elevated levels of end-tidal carbon dioxide concentration in group III. The fraction of inspired-oxygen concentration in group I was significantly higher (p<0.01) as compared to that of group II and III and this could be due to the increased fresh gas flow rate employed during maintenance of anaesthesia. The end-tidal concentration of isoflurane required to maintain anaesthesia was significantly lower in group II as compared to that of group I and III. The extubation time in group II and III was comparatively longer (p<0.05) than group I due to the inclusion of opioids which depressed the cough and swallowing reflex resulting in delayed extubation. Isoflurane utilization in group II and group III were significantly lower (p<0.05) as compared to that of group I indicating that opioids used in the study had isoflurane sparing effect. In the present study, untoward events or complications were not encountered in any of the animals indicating that the anaesthetic protocol employed was safe and effective. The serum cortisol estimation revealed that stress response was lower (p<0.05) in group II which could be due to the better analgesia provided by butorphanol tartrate during surgery.enVeterinary ScienceVeterinary Surgery and RadiologyThesis