Efficacy and cardiorespiratory effects of lumbosacral intrathecal 2% procaine and 2% xylazine with or without sedation in calves undergoing umbilical surgery.

Aims: To compare the effects of intrathecal anaesthesia using procaine and xylazine, with and without sedation with I/V xylazine and butorphanol, on sedation and cardiorespiratory measures in calves undergoing umbilical surgery. Methods: Male dairy calves, aged <3 months, were recruited that had enlargement of the umbilical stalk which was abnormal when palpated. They were assigned to receive either intrathecal injection between the sixth lumbar and first sacral vertebrae of 4 mg/kg of 2% procaine and 0.2 mg/kg 2% xylazine, with I/V injection of 0.02 mg/kg xylazine and 0.1 mg/kg of butorphanol (IT + SED group; n = 6), or the same intrathecal injection and I/V injection of 0.9% saline (IT group; n = 7). Surgery to correct abnormalities was carried out with calves positioned in dorsal recumbency. Rescue analgesia with injections of 2% procaine around the surgical wound was administered when movements triggered by surgery were observed. Post-operative analgesia was provided using I/V 0.5 mg/kg meloxicam. Duration of surgery was recorded, as well as degree of sedation, heart rate, systolic (SAP), diastolic (DAP) and mean (MAP) arterial blood pressure during surgery. Results: All anaesthetic and surgical procedures were successfully performed. Mean total duration of surgery was similar for the IT + SED and the IT groups (30.33 (SD 10.09) and 31.00 (SD 10.21) minutes, respectively) (p = 0.92). All calves were at least mildly sedated from 5 minutes after injections to the end of the surgery. One calf in the IT + SED group and three calves in the IT group required rescue analgesia when the umbilicus was manipulated. Between 0 and 10-15 minutes after injection, decreases in mean heart rate, SAP, MAP and DAP were observed in both groups. Mean SAP was lower in the IT + SED than the IT group. Hypotension (MAP<60 mm Hg) was present in four calves from the IT + SED group and in one from the IT group. Conclusions and clinical relevance: Intrathecal administration of 2% procaine and 2% xylazine allowed the successful completion of umbilical surgery, but 30% of calves needed rescue analgesia during surgery. Clinically, the addition of I/V sedation seemed to provide better analgesia than intrathecal block alone but resulted in greater hypotension.

A comparison of two morphine doses on the quality of recovery from general anaesthesia in horses.

Previous studies indicated that perioperative morphine improves recovery quality after general anaesthesia in horses. This clinical trial investigated whether this effect was dose-dependant. Twenty-six horses anaesthetised for surgery were block-randomised to receive one of two intraoperative morphine treatments: Treatment M1 consisted of a constant rate infusion (CRI) of morphine at 0.1mg/kg/h, begun after a loading dose (LD) of 0.15 mg/kg. Treatment M2 was a CRI of 0.2mg/kg/h preceded by an LD of 0.3mg/kg. During recovery, times at the first attempt and at achieving sternal recumbency and standing, and the total recovery duration were not different between groups. Total recovery quality score was not significantly different between groups. Scores for the "sternal phase" were higher (of poorer quality) for M2 but scores in both groups were low. Morphine doses of M2, which are greater than those described previously, do not appear to alter or improve the quality or duration of recovery in horses after surgical anaesthesia.

Arterial blood gas parameters in pet rabbits anaesthetized using a combination of fentanyl-fluanisone-midazolam-isoflurane.

OBJECTIVES: Blood gas analysis is a well-recognized method to monitor pulmonary function, blood oxygenation, ventilation and acid-base status during general anaesthesia. The aim of this study was to report blood gas analysis results in pet rabbits (Oryctolagus cuniculus) obtained during general anaesthesia using a portable clinical analyser. METHODS: Thirty-two rabbits were premedicated with 0·2 mL/kg fentanyl and fluanisone. Anaesthesia was induced with 0·2 mg/kg midazolam and maintained with 2% isoflurane in oxygen via endotracheal tube. Arterial blood samples were taken from the central ear artery 10 minutes after induction of anaesthesia. RESULTS: Respiratory acidaemia was observed during anaesthesia. Mean ±sd (range) arterial blood pH was 7·33 ±0·08 (7·15 to 7·48). PaCO2 and PaO2 were, respectively, 55·02 ±10·5 (37·7 to 92·1) mmHg and 370·0 ±120·5 (67 to 561) mmHg. Base excess was 2·8 ±3·6 (-3 to 11) mmol/L, HCO3 was 28·73 ±3·07 (23·7 to 35·4) mmol/L and TCO2 was 30·4 ±3·2 (25 to 37) mmol/L. None of the rabbits developed haematoma during arterial blood collection or ischaemia of the pinna during the hospitalization period. CLINICAL SIGNIFICANCE: Arterial blood gas analysis is a safe and easy to perform diagnostic technique that can contribute to improved safety of rabbit anaesthesia, by providing information on the respiratory and metabolic status of the patient.