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Objectives: The aim of this study was to compare the effects of butorphanol and buprenorphine, as part of a multimodal analgesic protocol, on recovery and analgesia in cats undergoing orchiectomy., Methods: In a prospective, randomized, blind clinical trial, 47 adult male cats were randomly assigned to receive either butorphanol (0.3 mg/kg, n = 24) or buprenorphine (0.02 mg/kg, n = 23) in combination with dexmedetomidine (25 μg/kg) and alfaxalone (2 mg/kg) as a single intramuscular injection for the induction of general anesthesia. Isoflurane carried in oxygen was supplemented as needed during orchiectomy. All cats received lidocaine (2 mg/kg intratesticular), meloxicam (0.3 mg/kg SC) and atipamezole (125 μg/kg IM) postoperatively. Pain and sedation scales were applied at baseline, and 2, 4 and 6 h postoperatively. Time to achieve sternal recumbency and to begin eating were also recorded., Results: Pain scale scores were low and showed no difference between the treatment groups at all time points ( P ⩾0.99, all time points). Four cats exceeded the analgesia intervention threshold for rescue analgesia (butorphanol, n = 3; buprenorphine, n = 1). There was no difference in sedation scores between groups at any time point ( P >0.99, all time points). Significantly more cats in the buprenorphine group (n = 12) required isoflurane than in the butorphanol group (n = 2) ( P  = 0.0013; relative risk 6.3, 95% confidence interval [CI] 1.8-23.5). There was no significant difference in time to achieve sternal recumbency ( P  = 0.96, 95% CI -20 to 20) between groups or in return to eating ( P  = 0.48, 95% CI -92.0 to 113.5), with most cats eating within 1 h of surgery (butorphanol, 79%; buprenorphine, 83%)., Conclusions and Relevance: There were no significant differences in analgesia or recovery between butorphanol and buprenorphine treatment groups as part of a multimodal injectable anesthetic protocol. Butorphanol is associated with superior depth of anesthesia, facilitating injectable anesthesia.

Objectives The use of physiological parameters such as respiratory rate and heart rate to assess pain has long been discussed. The aim of the study was to compare postoperative respiratory rate and heart rate in cats subjected to flank ovariohysterectomy treated with a preoperative non-steroidal anti-inflammatory drug (NSAID) or no NSAID, and determine whether these parameters are suitable for postoperative pain assessment in cats. We hypothesised that cats without an NSAID would experience more postoperative pain, which may increase heart rate and respiratory rate. Methods A total of 168 female privately owned cats were studied. All cats were premedicated with medetomidine (0.08 mg/kg) and butorphanol (0.4 mg/kg) subcutaneously and anaesthesia was induced with intramuscular ketamine (5 mg/kg). Cats were divided into subgroups; controls (no NSAID) or cats given an NSAID, carprofen (4 mg/kg) or meloxicam (0.3 mg/kg), at premedication or induction of anaesthesia. Cats were subjected to flank ovariohysterectomy by the same surgeon. Atipamezole was administered 2.5 h after induction of anaesthesia. Respiratory rate and heart rate were measured 3.5 h after the induction of anaesthesia. Data were analysed using one-way ANOVA with mixed procedure and Tukey's adjustment method for multiplicity. Results The postoperative respiratory rate and heart rate per minute for all cats were 34.0 ± 8.6 and 167.5 ± 27.4, respectively. Neither respiratory rate nor heart rate differed significantly between the control group and the NSAID groups or between different time points of administration of NSAIDs. Conclusion and relevance Assuming there was less postoperative pain in the group administered NSAIDs, the results of the study presented no support for use of respiratory rate and heart rate as parameters for postoperative pain assessment in individual cats. Study limitations included a lack of pain scoring and baseline data for respiratory rate and heart rate.

Objectives The aim of the study was to evaluate the cardiorespiratory effects, quality of sedation and recovery of intramuscular alfaxalone-dexmedetomidine-butorphanol (ADB) and ketamine-dexmedetomidine-butorphanol (KDB), in cats. Methods Nine adult, healthy cats (6.63 ± 1.42 kg) were enrolled in a blinded, randomized, crossover experimental design. Cats were sedated twice intramuscularly, once with ADB (alfaxalone 1 mg/kg, dexmedetomidine 0.005 mg/kg, butorphanol 0.2 mg/kg), and once with KDB (ketamine 5 mg/kg, dexmedetomidine 0.005 mg/kg, butorphanol 0.2 mg/kg), in random order. Data collected included heart rate (HR), arterial blood pressure and blood gas analysis, respiratory rate and sedation score. Analysis of variance with Bonferroni post-hoc correction was used for parametric data, and a Wilcoxon signed rank test was used for non-parametric data. Significance was set at P <0.05. Results Total sedation time was shorter for ADB (90.71 ± 15.12 mins vs 147.00 ± 47.75 mins). Peak sedation was observed within 15 mins in both groups. Quality of recovery was excellent in both groups. HR decreased over time in both groups. Diastolic and mean arterial pressure decreased over time for ADB, becoming significant after 30 mins. All cardiovascular variables were within the clinically acceptable range in both groups. Arterial partial pressure of oxygen was significantly decreased from baseline for KDB at all time points (73 ± 2.5 mmHg [9.7 ± 0.3 kPa] vs ADB 83 ± 2.6 mmHg [11 ± 0.3 kPa]). Hypoventilation was not observed. Conclusions and relevance Both protocols produced acceptable cardiovascular stability. Sedation and recovery quality were good, albeit sedation was shorter with ADB. Although oxygenation was better maintained in the ADB group, all sedated cats should receive oxygen supplementation.

Objectives The purpose of this pilot study was to evaluate the use of an intramuscular (IM) sedation protocol with butorphanol and alfaxalone in cats undergoing blood donation. We hypothesized that this drug combination would provide sufficient sedation to perform phlebotomy without causing hypotension or significant changes in heart rate. Methods Six purpose-bred, healthy adult cats were sedated using IM butorphanol (0.4 mg/kg) and alfaxalone (2-3 mg/kg). Pulse and Doppler blood pressure (BP) were recorded at baseline, after sedation and immediately following phlebotomy. Once laterally recumbent, 12 ml/kg blood was collected from the jugular vein. Sedation scores, duration of lateral recumbency and the ability to successfully perform phlebotomy were recorded. Results There was no significant change in heart rate post-sedation (median 190 beats per min [bpm], range 160-224 bpm) or post-phlebotomy (median 200 bpm, range 180-220 bpm) compared with baseline values (median 200 bpm, range 180-220 bpm) ( P = 0.395). A statistically significant change in BP was detected ( P = 0.029), attributed to a difference between post-sedation (median 113.3 mmHg, range 110.7-130.0) and baseline (median 133.3 mmHg, range 130.0-183.3) measurements. Hypotension was not observed in any cat. Collection of at least 80% of the target volume was achieved in 5/6 cats, although all were adequately sedated to allow jugular venous phlebotomy. Median recumbency time was 53 mins (range 43-83 mins). Phlebotomy duration lasted a median of 13 mins (range 5-21 mins). Conclusions and relevance The administration of IM alfaxalone and butorphanol provided sufficient restraint for blood donation without causing hypotension or significant changes in heart rate before or after phlebotomy.

Objectives The objective of this study was to compare the sedative effect of butorphanol-dexmedetomidine with buprenorphine-dexmedetomidine following intramuscular (IM) administration in cats. Methods Using a prospective, randomised, blinded design, 40 client-owned adult cats were assigned to receive IM dexmedetomidine (10 µg/kg) combined with either butorphanol (0.4 mg/kg) ('BUT' group) or buprenorphine (20 µg/kg) ('BUP' group). Sedation was scored using a previously published multidimensional composite scale before administration (T0) and 5, 10, 15 and 20 mins afterwards (T5, T10, T15 and T20, respectively). Alfaxalone (1.5 mg/kg) was administered IM at T20 if the cat was not deemed adequately sedated to place an intravenous catheter. Adverse events were recorded. Friedman two-way ANOVA analysed sedation scores within groups. Mann-Whitney Rank Sum test compared sedation scores between groups; Fisher's exact test analysed the frequency of alfaxalone administration and adverse events. P <0.05 was considered statistically significant. Results Sedation scores between groups were similar at baseline, but at T5, T10, T15 and T20 scores were higher in the BUT group ( P <0.01). Within both groups, sedation scores changed over time and the highest sedation scores were reached at T10. Requirement for additional sedation was similar between groups: two cats in the BUT group and five cats in the BUP group. One cat and 11 cats vomited ( P = 0.002) in the BUT and BUP groups, respectively. No other adverse events were recorded. Conclusions and relevance At these doses, IM buprenorphine-dexmedetomidine provides inferior sedation and a higher incidence of vomiting than butorphanol-dexmedetomidine in cats. Butorphanol-dexmedetomidine may be preferred for feline sedation, especially where vomiting is contraindicated.

Objectives Cardiorespiratory parameters and anaesthesia quality in cats anaesthetised with either intramuscular (IM) alfaxalone or ketamine both combined with dexmedetomidine and butorphanol for castration were evaluated. Methods Thirty-two client-owned cats were randomly assigned to receive either alfaxalone (A; 3 mg/kg IM) or ketamine (K; 5 mg/kg IM), combined with dexmedetomidine (10 μg/kg) and butorphanol (0.2 mg/kg). Heart rate (HR), respiratory rate (RR) and rectal temperature (T°) were recorded prior to drug administration. Pulse rate (PR) and RR were recorded 10 (T 10 ) and 15 (T 15 ) mins after injection (T 0 ). Cardiorespiratory values (PR, RR, SPO 2 , blood pressure, P E 'CO 2 ) were recorded every 5 mins for the duration of the procedure. Pain at injection, intubation and recovery were evaluated with simple descriptive scores. Feasibility of anaesthesia was evaluated by the number of top-ups of anaesthetic needed. Cat attitude, ability to walk and presence of ataxia were assessed several times after extubation (T exmin ) and the time between injection and extubation recorded. Pain was assessed at T ex120 and T ex240 with the 4Avet-pain score. Results The RR was significantly lower in group K at T 10 (RR K = 28 ±13.35 breaths per minute [brpm], RR A = 43.24 ±7.04 brpm) and T 15 (RR K = 28 ±11.53 brpm vs RR A = 43 ±12.18 brpm). Time to extubation was significantly longer in group A (T A = 62 ±14.6 mins, T K = 45.13 ± 7.38 mins). Cats in group K needed more top-ups, were more ataxic at T ex120 , had a worse recovery score at T ex60 and were less willing to walk at T ex30 . Conclusions and relevance Cats receiving alfaxalone had a longer but better quality recovery. Cardiorespiratory parameters were stable and within clinically acceptable values following IM injection of either alfaxalone or ketamine in healthy cats. Intramuscular alfaxalone is a suitable alternative to ketamine for short procedures requiring anaesthesia when used in combination with dexmedetomidine and butorphanol.

Objectives: The aim of this study was to optimise dexmedetomidine and alfaxalone dosing, for intramuscular administration with butorphanol, to perform minor surgeries in cats., Methods: Initially, cats were assigned to one of five groups, each composed of six animals and receiving, in addition to 0.3 mg/kg butorphanol intramuscularly, one of the following: (A) 0.005 mg/kg dexmedetomidine, 2 mg/kg alfaxalone; (B) 0.008 mg/kg dexmedetomidine, 1.5 mg/kg alfaxalone; (C) 0.012 mg/kg dexmedetomidine, 1 mg/kg alfaxalone; (D) 0.005 mg/kg dexmedetomidine, 1 mg/kg alfaxalone; and (E) 0.012 mg/kg dexmedetomidine, 2 mg/kg alfaxalone. Thereafter, a modified 'direct search' method, conducted in a stepwise manner, was used to optimise drug dosing. The quality of anaesthesia was evaluated on the basis of composite scores (one for anaesthesia and one for recovery), visual analogue scales and the propofol requirement to suppress spontaneous movements. The medians or means of these variables were used to rank the treatments; 'unsatisfactory' and 'promising' combinations were identified to calculate, through the equation first described by Berenbaum in 1990, new dexmedetomidine and alfaxalone doses to be tested in the next step. At each step, five combinations (one new plus the best previous four) were tested., Results: None of the tested combinations resulted in adverse effects. Four steps and 120 animals were necessary to identify the optimal drug combination (0.014 mg/kg dexmedetomidine, 2.5 mg/kg alfaxalone and 0.3 mg/kg butorphanol)., Conclusions and Relevance: The investigated drug mixture, at the doses found with the optimisation method, is suitable for cats undergoing minor clinical procedures., (© The Author(s) 2015.)

Objectives: The aim of the study was to evaluate the effects of intramuscular (IM) injections of alfaxalone combined with butorphanol on echocardiographic (ECG) measurements in cats., Methods: Client-owned adult domestic shorthair cats younger than 5 years of age were recruited. All cats that were considered healthy on the basis of physical examination, blood work, urinalysis, blood pressure measurement and baseline ECG underwent a second ECG under sedation. Cats were sedated with two separate IM injections of butorphanol at 0.2 mg/kg and alfaxalone at 2 mg/kg. ECG variables were analysed using a linear mixed model, and sedation scores were analysed using an ordinal mixed logistic model. The significance level was set at α = 0.05 and adjusted at α = 0.0017 for multiple comparisons of the ECG measurements., Results: Ten healthy cats were included. Sedation was uneventful, and recovery was smooth and quick for all cats. The mean duration of lateral recumbency was 36.3 ± 4.37 mins. Reduction in heart rate following sedation approached statistical significance (P = 0.002). The thickness of the interventricular septum, the thickness of the left ventricular free wall, and the left ventricular internal dimensions in diastole and systole were not affected by the sedation. The changes in left atrium/aortic ratio and shortening fraction were statistically significant. Although the peak velocity of early diastolic transmitral flow (E) and late diastolic transmitral flow (A), the peak early diastolic (Ea) mitral valve annulus velocity, and the peak late diastolic (Aa) mitral valve annulus velocity changed after sedation, the ratios E/A, E/Ea and Ea/Aa were not significantly different after sedation., Conclusions and Relevance: IM injections of alfaxalone and butorphanol induced rapid, deep and short-lasting sedation. The mean differences after sedation were not clinically significant for most echocardiographic measurements., (© ISFM and AAFP 2014.)

Acute stress induced by physical restraint can interfere with the validity of laboratory findings. Sedation could minimize such stress. However, it is not known whether sedation can affect hematologic and hemostatic parameters in cats. The purpose of this study was to evaluate hematologic and hemostatic parameters in domestic cats subjected to physical restraint in addition to one of two sedation protocols. In total, 50 cats were subjected to physical restraint and were then randomly divided into two groups of 25 animals, receiving dexmedetomidine (5 µg/kg) and butorphanol (0.3 mg/kg; DB group) or dexmedetomidine (5 µg/kg), butorphanol (0.3 mg/kg) and ketamine (3 mg/kg; DBK group). The cats were assessed for acute stress, sedation level, onset of sedation and duration of sedation. Blood samples were collected after handling and after sedation. The complete blood count (CBC), platelet count, buccal mucosal bleeding time (BMBT), whole-blood clotting time, prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) were determined for each sample, before and after chemical restraint. No statistically significant differences were found in the hematologic parameters. Certain hemostatic parameters (PT, aPTT and TT) were higher in the DB group (P <0.05). The onset of sedation was similar in the two groups, and the duration of sedation was longer in the DBK group. Both sedation protocols were effective for short-duration chemical restraint for blood collection from the studied cats, and no clinically relevant effects on hematologic or hemostatic parameters were detected., (© ISFM and AAFP 2014.)

Despite the fact that sheep are a widely used animal model in cardiovascular research, reference values for transthoracic echocardiography in normal growing animals are not available. Eight healthy female lambs underwent two-dimensional, M-mode and pulsed wave Doppler echocardiographic examination at 100 days of age and every three months thereafter over a 12-month period. The study was conducted under sedation with midazolam, butorphanol and constant rate infusion of intravenous propofol. Their growth phase was completed at about one year of age. All the echocardiographic parameters considered were significantly correlated with body weight and age class except for the left ventricular systolic and diastolic diameters. Functional indices were not correlated to body weight or age except for the E-point to septal separation distance (EPSS). Doppler-derived parameters were not influenced by independent variables. Transthoracic echocardiography can be considered an applicable method for cardiovascular research using a growing lamb animal model after appropriate adjustments for age and body size.

One hundred and fifty-three cats undergoing surgery in seven veterinary practices in Great Britain were studied. They were randomly allocated to receive either 10-20 microg/kg buprenorphine or 0.4 mg/kg butorphanol with acepromazine before anaesthesia with propofol, Saffan or thiopentone and isoflurane or halothane. Routine monitoring was undertaken. Pain and sedation were assessed blind using a four point (0-3) simple descriptive scale (SDS) at 1, 2, 4, 8 and 24h. Pain and sedation data were compared using non-parametric statistical tests and continuous data using t tests or analysis of variance (ANOVA). Anaesthesia and surgery were uneventful, and cardiorespiratory data were within normal limits. After surgery, overall, more cats had pain score 0 after buprenorphine and more had pain score 3 after butorphanol (P=0.0465). At individual time points, more cats had lower pain scores after buprenorphine at 2 (P=0.040) and 24 (P=0.036)h. At 24h 83% after buprenorphine and 63% after butorphanol had pain score 0 (P<0.04). Buprenorphine provided better and longer lasting postoperative analgesia than butorphanol., (Copyright 2009 ISFM and AAFP. Published by Elsevier Ltd. All rights reserved.)

The purpose of the study was to assess the haemodynamic (blood pressure and heart rate) changes and stress responses (serum cortisol and serum amyloid A [SAA] concentrations) to surgery in piglets during total intravenous anaesthesia (TIVA) with propofol and fentanyl. After preanaesthetic medication with intramuscular midazolam (0.5 mg/kg body mass), ketamine (10 mg/kg) and butorphanol (0.5 mg/kg) anaesthesia was induced in five piglets, with intravenous propofol (1 mg/kg) followed by tracheal intubation and mechanical lung ventilation. Soft tissue surgery was performed in the jugular and inguinal regions during TIVA with propofol (8 mg/kg/h) and fentanyl (35 microg/kg/h). Anaesthesia was maintained for 300 min after surgery as the piglets were the control group of a project involving extracorporeal membrane oxygenation. Mean plasma cortisol concentration decreased significantly (P<0.05) from 59+/-39.9 nmol/L (mean+/-1 SD) before surgery to 7.5+/-2.5 nmol/L 300 min after end of surgical procedure. The mean SAA concentrations increased over the same period from 1.6+/-2.3 microg/mL to 4.2+/-5.6 microg/mL without statistical significance. The baseline (presurgery) mean arterial pressure (MAP) was 72+/-9 mmHg compared with 72+/-11 mmHg 300 min after end of surgery. Neither heart rate nor lactate concentrations changed significantly over the same time points: heart rate was 104+/-11 and 103+/-15 beats/min whereas mean lactate concentrations were reduced from 1.14+/-0.45 mmol/L to 0.90+/-0.22 mmol/L. Haemodynamic stability, a decrease in serum cortisol and a non-statistically significant rise in mean SAA concentrations suggest that the anaesthetic described suppresses the stress response of piglets to surgery without adverse cardiovascular effects. Therefore, it may prove useful in cardiovascular research.

A mixture of ketamine, xylazine, and butorphanol was inadvertently injected into the right carotid artery of a 1-year-old alpaca. Injection was followed by a brief period of recumbency and seizure activity. The alpaca recovered, but was euthanatized 72 hr later because of development of progressive neurologic deficits. Pathologic findings were confined to the right cerebrum, meninges, thalamus, and hippocampus. Cerebrocortical edema with astrocytic reaction, perivascular hemorrhage and neutrophilic infiltration, and fibrinoid necrosis of vasculature within the meninges and thalamus were the most prominent lesions. Neuronal necrosis was mild. Astrocytic reaction within the right cerebral cortex was confirmed with immunohistochemistry for glial fibrillary acidic protein.

A combination of tiletamine/zolazepam, xylazine and butorphanol provides deep surgical, long-duration anaesthesia in guineapigs with a smooth induction and recovery period. The described dosages mainly affect the respiratory functions and blood gas parameters, with a minor-to-moderate effect on the cardiovascular system.