Postanesthetic hyperthermia in cats: a retrospective comparison between hydromorphone and buprenorphine

OBJECTIVE: To determine the prevalence of postanesthetic hyperthermia [rectal temperature >40 degrees C (104 degrees F)] in a clinical population of cats. STUDY DESIGN: Retrospective study. ANIMAL POPULATION: One hundred and twenty-five cats with an age range of 2 months to 16.1 years, and weighing 3.9 +/- 1.5 kg. MATERIALS AND METHODS: Data were obtained from the medical records of 125 cats that underwent general anesthesia. Information on perioperative rectal temperatures, breed, sex, weight, surgical procedure, anesthetic time, surgery time, anesthetic and analgesic drugs were retrieved. STATISTICAL ANALYSES: Five groups of cats were compared; group 1 (n = 15) received acepromazine and no opioids; group 2 (n = 17) received acepromazine and buprenorphine; group 3 (n = 19) received acepromazine, buprenorphine and ketoprofen; group 4 (n = 45) received acepromazine and hydromorphone and group 5 (n = 29) received acepromazine, hydromorphone and ketoprofen. Data conformed to a split-plot repeated measures analysis of variance and was analyzed using SAS PROC MIXED. Post hoc tests were by means of Bonferroni t-test; < or = 0.05 was considered significant. RESULTS: Rectal temperature was significantly decreased in all groups at the end of anesthesia. Rectal temperature was significantly elevated at 1, 1.5, 2, 3, 4 and 5 hours after the end of anesthesia in group 4, and at 2, 3 and 4 hours in group 5. Sixty-four percent of cats in group 4 and 69% in group 5 had rectal temperatures >40 degrees C (104 degrees F) at one or more times in the postanesthetic period. The highest temperature recorded was 42.5 degrees C (108.5 degrees F) in one cat in group 4. Mean rectal temperature did not exceed the preoperative temperature at any time during the postanesthetic period in group 1, 2 and 3 animals. CONCLUSIONS: This study indicates an association between hyperthermia and perioperative administration of hydromorphone in cats. CLINICAL RELEVANCE: When hydromorphone is used in cats their body temperature should be closely monitored.     

Post-operative analgesic effects of butorphanol or firocoxib administered to dogs undergoing elective ovariohysterectomy

ObjectiveTo compare the post-operative analgesic effects of butorphanol or firocoxib in dogs undergoing ovariohysterectomy.Study designProspective, randomized, blinded, clinical trial.AnimalsTwenty-five dogs >1 year of age.MethodsDogs received acepromazine intramuscularly (IM), 0.05 mg kg^?1 and either butorphanol IM, 0.2 mg kg^?1 (BG, n = 12) or firocoxib orally (PO), 5 mg kg^?1 (FG, n = 13), approximately 30 minutes before induction of anesthesia with propofol. Anesthesia was maintained with isoflurane. Ovariohysterectomy was performed by the same surgeon. Pain scores using the dynamic and interactive visual analog scale (DIVAS) were performed before and at 1, 2, 3, 4, 6, 8 and 20 hours after the end of surgery by one observer, blinded to the treatment. Rescue analgesia was provided with morphine (0.5 mg kg^?1) IM and firocoxib, 5 mg kg^?1 (BG only) PO if DIVAS > 50. Groups were compared using paired t-tests and Fisher’s exact test (p < 0.05). Data are presented as mean ± SD.ResultsThe BG required significantly less propofol (BG: 2.6 ± 0.59 mg kg^?1; FG: 5.39 ± 0.7 mg kg^?1) (p < 0.05) but the anesthesia time was longer (BG: 14 ± 6, FG: 10 ± 4 minutes). There were no differences for body weight (BG: 7.9 ± 5.0, FG: 11.5 ± 4.6 kg), sedation scores, and surgery and extubation times (BG: 10 ± 2, 8 ± 5 minutes; FG: 9 ± 3, 8 ± 4 minutes, respectively) (p > 0.05). The FG had significantly lower pain scores than the BG at 1, 2 and 3 hours following surgery (p < 0.05). Rescue analgesia was administered to 11/12 (92%) and 2/13 (15%) dogs in the BG and FG, respectively (p < 0.05).Conclusion and clinical relevanceFirocoxib produced better post-operative analgesia than butorphanol. Firocoxib may be used as part of a multimodal analgesia protocol but may not be effective as a sole analgesic.     

Comparison of preoperative carprofen and postoperative butorphanol as postsurgical analgesics in cats undergoing ovariohysterectomy

OBJECTIVE: To compare carprofen to butorphanol, with regard to postsurgical analgesic effects, duration of analgesia, and adverse side effects. STUDY DESIGN: Blinded, randomized clinical study. ANIMALS: Seventy-one cats, 0.5-5 years of age, weighing 3.24 +/- 0.61 kg, undergoing ovariohysterectomy (OHE). METHODS: Cats were premedicated with subcutaneous atropine (0.04 mg kg(-1)), acepromazine (0.02 mg kg(-1)), and ketamine (5 mg kg(-1)). Anesthesia was induced with ketamine (5 mg kg(-1)) and diazepam (0.25 mg kg(-1)) given intravenously, and maintained with isoflurane. There were three treatment groups: group C (4 mg kg(-1) carprofen SC at induction), group B (0.4 mg kg(-1) butorphanol SC at end of surgery), and group S (0.08 mL kg(-1) of sterile saline SC at induction and end of surgery). Behavioral data were collected using a composite pain scale (CPS), prior to surgery (baseline) and 1, 2, 3, 4, 8, 12, 16, 20, and 24 hours post-surgery. Interaction scores were analyzed separately. Cats with CPS scores >12 received rescue analgesia (meperidine, 4 mg kg(-1), intramuscular). RESULTS: Sixty cats completed the study. The CPS scores did not differ significantly between groups C and B at any time period. CPS scores for groups B and C were significantly increased for 12 hours post-surgery, and in group S for 20 hours. Both group C and B CPS scores were significantly lower than group S in this 20-hour postoperative period, except at 4 hours (B and C) and at 3 and 8 hours (B alone). Interaction scores for group C returned to preoperative baseline 4 hours after surgery, while both groups B and S remained increased for at least 24 hours post-surgery. Nine cats required meperidine. CONCLUSION: In this study, carprofen provided better postsurgical analgesia than butorphanol. Clinical relevance Neither drug completely abolished pain, however preoperative carprofen provided better pain control compared with postoperative butorphanol in the 24-hour period following OHE surgery in cats.     

Comparison of fentanyl and hydromorphone constant rate infusions for pain management in dogs in an intensive care unit

Objective

To compare the efficacy and quality of analgesia provided by constant rate infusions (CRIs) of hydromorphone and fentanyl in dogs in the intensive care unit (ICU).

A comparison of epidural buprenorphine plus detomidine with morphine plus detomidine in horses undergoing bilateral stifle arthroscopy

ObjectiveTo compare the analgesic efficacy of buprenorphine plus detomidine with that of morphine plus detomidine when administered epidurally in horses undergoing bilateral stifle arthroscopy.Study designProspective, randomized, blinded clinical trial.AnimalsTwelve healthy adult horses participating in an orthopedic research study. Group M (n = 6) received morphine (0.2 mg kg^?1) and detomidine (0.15 mg kg^?1) epidurally; group B (n = 6) received buprenorphine (0.005 mg kg^?1) and detomidine (0.15 mg kg^?1) epidurally.MethodsHorses received one of two epidural treatments following induction of general anesthesia for bilateral stifle arthroscopy. Heart rate (HR), mean arterial blood pressure (MAP), end-tidal CO₂ (Pe’CO₂), and end-tidal isoflurane concentrations (E’Iso%) were recorded every 15 minutes following epidural administration. Post-operative assessment was performed at 1, 2, 3, 6, 9, 12, and 24 hours after standing; variables recorded included HR, respiratory rate (f_R), abdominal borborygmi, defecation, and the presence of undesirable side effects. At the same times post-operatively, each horse was videotaped at a walk and subsequently assigned a lameness score (0-4) by three ACVS diplomates blinded to treatment and who followed previously published guidelines. Nonparametric data were analyzed using Wilcoxon’s rank-sum test. Inter- and intra-rater agreement were determined using weighted kappa coefficients. Statistical significance was set at p = 0.05.ResultsNo statistically significant differences were found between groups with respect to intra-operative HR, MAP, E’Iso%, or post-operative HR, gastrointestinal function and cumulative median lameness scores. Post-operative f_R in group B [24 (12-30), median (range)] breaths per minute was significantly higher than in group M [18 (15-20)] breaths per minute, p = 0.04.Conclusions and clinical relevanceIn horses undergoing bilateral stifle arthroscopy, these doses of buprenorphine plus detomidine injected epidurally produced analgesia similar in intensity and duration to that of morphine plus detomidine injected epidurally.     

Analgesic effects of morphine and butorphanol in broiler chickens

Objective

To evaluate analgesic efficacies of morphine and butorphanol in lame broiler chickens.

Pharmacokinetics of ammonium sulfate gradient loaded liposome‐encapsulated oxymorphone and hydromorphone in healthy dogs

ObjectiveTo evaluate the pharmacokinetics, in dogs, of liposome–encapsulated oxymorphone and hydromorphone made by the ammonium sulfate gradient loading technique (ASG).AnimalsFour healthy purpose–bred Beagles aged 9.5 ± 3.2 months and weighing 13.4 ± 2.3 kg.Study designRandomized cross–over design.MethodsEach dog was given either 4.0 mg kg^?1 of ASG–oxymorphone or 8.0 mg kg^?1 of ASG–hydromorphone SC on separate occasions with a 3–month washout period. Blood was collected at baseline and at serial time points up to 1032 hours (43 days) after injection for determination of serum opioid concentrations. Serum opioid concentrations were measured with HPLC–MS and pharmacokinetic parameters were calculated using commercial software and non–compartmental methods.ResultsSerum concentrations of oxymorphone remained above the limit of quantification for 21 days, while those for hydromorphone remained above the limit of quantification for 29 days. C_max for ASG–oxymorphone was 7.5 ng mL^?1; C_max for ASG–hydromorphone was 5.7 ng mL^?1.Conclusions and clinical relevanceOxymorphone and hydromorphone, when encapsulated into liposomes using the ammonium sulfate gradient loading technique, result in measureable serum concentrations for between 3 to 4 weeks. This formulation may have promise in the convenient use of opioids for clinical treatment of chronically painful conditions in dogs.     

Development of a xylazine constant rate infusion with or without butorphanol for standing sedation of horses

ObjectiveTo elaborate constant rate infusion (CRI) protocols for xylazine (X) and xylazine/butorphanol (XB) which will result in constant sedation and steady xylazine plasma concentrations.Study designBlinded randomized experimental study.AnimalsTen adult research horses.MethodsPart I: After normal height of head above ground (HHAG = 100%) was determined, a loading dose of xylazine (1 mg kg^?1) with butorphanol (XB: 18 μg kg^?1) or saline (X: equal volume) was given slowly intravenously (IV). Immediately afterwards, a CRI of butorphanol (XB: 25 μg kg^?1 hour^?1) or saline (X) was administered for 2 hours. The HHAG was used as a marker of depth of sedation. Sedation was maintained for 2 hours by additional boluses of xylazine (0.3 mg kg^?1) whenever HHAG >50%. The dose of xylazine (mg kg^?1 hour^?1) required to maintain sedation was calculated for both groups. Part II: After the initial loading dose, the calculated xylazine infusion rates were administered in parallel to butorphanol (XB) or saline (X) and sedation evaluated. Xylazine plasma concentrations were measured by HPLC-MS-MS at time points 0, 5, 30, 45, 60, 90, and 120 minutes. Data were analyzed using paired t-test, Wilcoxon signed rank test and a 2-way anova for repeated measures (p < 0.05).ResultsThere was no significant difference in xylazine requirements (X: 0.69, XB: 0.65 mg kg^?1 hour^?1) between groups. With treatment X, a CRI leading to prolonged sedation was developed. With XB, five horses (part I: two, part II: three) fell down and during part II four horses appeared insufficiently sedated. Xylazine plasma concentrations were constant after 45 minutes in both groups.ConclusionXylazine bolus, followed by CRI, provided constant sedation. Additional butorphanol was ineffective in reducing xylazine requirements and increased ataxia and apparent early recovery from sedation in unstimulated horses.Clinical relevanceData were obtained on unstimulated healthy horses and extrapolation to clinical conditions requires caution.     

Effects of vatinoxan in dogs premedicated with medetomidine and butorphanol followed by sevoflurane anaesthesia: a randomized clinical study

ObjectiveTo investigate effects of vatinoxan in dogs, when administered as intravenous (IV) premedication with medetomidine and butorphanol before anaesthesia for surgical castration.Study designA randomized, controlled, blinded, clinical trial.AnimalsA total of 28 client-owned dogs.MethodsDogs were premedicated with medetomidine (0.125 mg m^?2) and butorphanol (0.2 mg kg^?1) (group MB; n = 14), or medetomidine (0.25 mg m^?2), butorphanol (0.2 mg kg^?1) and vatinoxan (5 mg m^?2) (group MB-VATI; n = 14). Anaesthesia was induced 15 minutes later with propofol and maintained with sevoflurane in oxygen (targeting 1.3%). Before surgical incision, lidocaine (2 mg kg^?1) was injected intratesticularly. At the end of the procedure, meloxicam (0.2 mg kg^?1) was administered IV. The level of sedation, the qualities of induction, intubation and recovery, and Glasgow Composite Pain Scale short form (GCPS-SF) were assessed. Heart rate (HR), respiratory rate (f_R), mean arterial pressure (MAP), end-tidal concentration of sevoflurane (Fe′Sevo) and carbon dioxide (Pe′CO₂) were recorded. Blood samples were collected at 10 and 30 minutes after premedication for plasma medetomidine and butorphanol concentrations.ResultsAt the beginning of surgery, HR was 61 ± 16 and 93 ± 23 beats minute^?1 (p = 0.001), and MAP was 78 ± 7 and 56 ± 7 mmHg (p = 0.001) in MB and MB-VATI groups, respectively. No differences were detected in f_R, Pe′CO₂, Fe′Sevo, the level of sedation, the qualities of induction, intubation and recovery, or in GCPS-SF. Plasma medetomidine concentrations were higher in group MB-VATI than in MB at 10 minutes (p = 0.002) and 30 minutes (p = 0.0001). Plasma butorphanol concentrations were not different between groups.Conclusions and clinical relevanceIn group MB, HR was significantly lower than in group MB-VATI. Hypotension detected in group MB-VATI during sevoflurane anaesthesia was clinically the most significant difference between groups.     

Development of a romifidine constant rate infusion with or without butorphanol for standing sedation of horses

ObjectiveTo determine constant rate infusion (CRI) protocols for romifidine (R) and romifidine combined with butorphanol (RB) resulting in constant sedation and romifidine plasma concentrations.Study designBlinded randomized crossover study.AnimalsTen adult research horses.MethodsPart I: After determining normal height of head above ground (HHAG = 100%), loading doses of romifidine (80 μg kg^?1) with butorphanol (RB: 18 μg kg^?1) or saline (R) were given intravenously (IV). Immediately afterwards, a butorphanol (RB: 25 μg kg^?1 hour^?1) or saline (R) CRI was administered for 2 hours. The HHAG was used as marker of sedation depth. Sedation was maintained for 2 hours by additional romifidine (20 μg kg^?1) whenever HHAG > 50%. The dose rate of romifidine (μg kg^?1 hour^?1) required to maintain sedation was calculated for both treatments. Part II: After loading doses, the romifidine CRIs derived from part I were administered in parallel to butorphanol (RB) or saline (R). Sedation and ataxia were evaluated periodically. Romifidine plasma concentrations were measured by HPLC-MS-MS at 0, 5, 10, 15, 30, 45, 60, 90, 105, and 120 minutes. Data were analyzed using paired t-test, Fisher's exact test, Wilcoxon signed rank test, and two-way anova for repeated measures (p < 0.05).ResultsThere was no significant difference in romifidine requirements (R: 30; RB: 29 μg kg^?1 hour^?1). CRI protocols leading to constant sedation were developed. Time to first additional romifidine bolus was significantly longer in RB (mean ± SD, R: 38.5 ± 13.6; RB: 50.5 ± 11.7 minutes). Constant plasma concentrations of romifidine were achieved during the second hour of CRI. Ataxia was greater when butorphanol was added.ConclusionRomifidine bolus, followed by CRI, provided constant sedation assessed by HHAG. Butorphanol was ineffective in reducing romifidine requirements in unstimulated horses, but prolonged the sedation caused by the initial romifidine bolus.Clinical relevanceBoth protocols need to be tested under clinical conditions.     

Efficacy of tramadol for postoperative pain management in dogs: systematic review and meta-analysis

ObjectiveTo evaluate the evidence of analgesic efficacy of tramadol for the management of postoperative pain and the presence of associated adverse events in dogs.Databases usedA comprehensive search using PubMed/MEDLINE, LILACS, Google Scholar and CAB databases with no restrictions on language and following a prespecified protocol was performed from June 2019 to July 2020. Included were randomized controlled trials (RCTs) performed in dogs that had undergone general anesthesia for any type of surgery. Two authors independently classified the studies, extracted data and assessed their risk of bias using Cochrane’s tool. RevMan and GRADE methods were used to rate the certainty of evidence (CoE).ConclusionsOverall 26 RCTs involving 848 dogs were included. Tramadol administration probably results in a lower need for rescue analgesia versus no treatment or placebo [moderate CoE; relative risk (RR): 0.47; 95% confidence interval (CI): 0.26–0.85; I² = 0%], and may result in a lower need for rescue analgesia versus buprenorphine (low CoE; RR: 0.50; 95% CI: 0.20–1.24), codeine (low CoE; RR: 0.75; 95% CI: 0.16–3.41) and nalbuphine (low CoE; RR: 0.05; 95% CI: 0.00–0.72). However, tramadol administration may result in an increased requirement for rescue analgesia versus methadone (low CoE; RR: 3.45; 95% CI: 0.66–18.08; I² = 43%) and COX inhibitors (low CoE; RR: 2.27; 95% CI: 0.68–7.60; I² = 45%). Compared with multimodal therapy, tramadol administration may make minimal to no difference in the requirement for rescue analgesia (low CoE; RR: 1.12; 95% CI: 0.48–2.60; I² = 0%). Adverse events were inconsistently reported and the CoE was very low. The overall CoE of the analgesic efficacy of tramadol for postoperative pain management in dogs was low or very low, and the main reasons for downgrading the evidence were risk of bias and imprecision.     

The thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats

ObjectiveTo evaluate the thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats.Study designRandomized, blinded, placebo-controlled crossover study design.AnimalsA total of six purpose-bred, adult female ovariohysterectomized Domestic Short Hair cats.MethodsCats were allocated into three treatments each consisting of two injections, subcutaneous then intravenous (IV) administration, 2 hours apart: treatment SS, two injections of 0.9% saline; treatment BS, buprenorphine (0.24 mg kg^–1, 1.8 mg mL^–1) and saline; and treatment BH, buprenorphine (0.24 mg kg^–1) and hydromorphone (0.1 mg kg^–1). Skin temperature (ST) and thermal threshold (TT) were recorded before (baseline) and for 24 hours following first injection. TT data were analyzed using mixed linear models and a Benjamini–Hochberg sequential adjustment procedure (p < 0.05).ResultsThere were no significant differences among treatments for baseline ST and TT values, treatment SS over time and between treatments BS and BH. Compared with baseline, TT was significantly increased at all time points in treatments BH and BS except at 2 hours in treatment BS. TT was significantly higher than SS at 3–18 hours and 4–12 hours for treatments BS and BH, respectively. Maximal increases in TT were 47.5 °C at 2 hours, 53.9 °C at 3 hours and 52.4 °C at 6 hours in treatments SS, BS and BH, respectively.Conclusions and clinical relevanceAdministration of IV hydromorphone following high-concentration buprenorphine provided no additional antinociception and decreased the duration of effect when compared with high-concentration buprenorphine alone. Alternative analgesics should be considered if additional analgesia is required after administration of high-concentration buprenorphine.     

Epidural administration of combinations of ropivacaine,morphine and xylazine in bitches undergoing total unilateral mastectomy: a randomized clinical trial

ObjectiveTo investigate the epidural administration of combinations of ropivacaine, morphine and xylazine in bitches undergoing unilateral mastectomy.Study designProspective, randomized, blinded, clinical study.AnimalsA total of 22 bitches scheduled to undergo unilateral mastectomy for mammary tumor excision.MethodsDogs were anesthetized with acepromazine (0.02 mg kg^–1) and morphine (0.3 mg kg^–1) intramuscularly, propofol intravenously (IV) and isoflurane. Prior to the beginning of surgery, dogs were randomly administered one of three epidural treatments: ropivacaine (0.75 mg kg^–1) with morphine (0.1 mg kg^–1) (group RM, n = 7); ropivacaine with xylazine (0.1 mg kg^–1) (group RX, n = 8); or ropivacaine with morphine and xylazine (group RMX, n = 7). Cardiopulmonary variables and the expired concentration of isoflurane (Fe′Iso) were recorded intraoperatively. Meloxicam (0.1 mg kg^–1) was administered IV during skin closure. Postoperative pain scores were evaluated with the Glasgow composite measure pain scale short form for 24 hours, and rescue analgesia with morphine (0.5 mg kg^–1) was administered intramuscularly when pain scores were ≥ 6/24.ResultsFe′Iso was significantly higher in group RM than in groups RX and RMX. Heart rate decreased significantly in groups RX and RMX, but blood pressure remained within acceptable values. The number of dogs administered rescue analgesia within 24 hours was significantly higher in group RX (seven dogs, 87.5%) than in groups RM (one dog, 14.3%; p = 0.01) and RMX (two dogs, 28.6%; p = 0.04). Time to standing was significantly longer in group RX than in group RM.Conclusions and clinical relevanceAll epidural treatments provided adequate antinociception with minimal cardiovascular adverse effects during mastectomy. The inclusion of morphine (groups RM and RMX) provided the best postoperative analgesia. Owing to the undesirable effect of xylazine on ambulation, the combination ropivacaine–morphine appeared to provide greater benefits in bitches undergoing unilateral mastectomy.     

Effects of opioids and anesthetic drugs on body temperature in cats

ObjectiveTo determine which class of opioid alone or in conjunction with other anesthetic drugs causes post-anesthetic hyperthermia in cats.Study designProspective, randomized, crossover study.AnimalsEight adult, healthy, cats (four spayed females and four castrated males weighing 3.8 ± 0.6 kg).MethodsEach cat was instrumented with a wireless thermistor in the abdominal cavity. Temperature in all phases was recorded every 5 minutes for 5 hours. Population body temperature (PBT) was recorded for ～8 days. Baseline body temperature is the final 24 hours of the PBT. All injectable drugs were given intramuscularly. The cats were administered drugs in four phases: 1) hydromorphone (H) 0.05, 0.1, or 0.2 mg kg^?1; 2) morphine (M) (0.5 mg kg^?1), buprenorphine (BUP) (0.02 mg kg^?1), or butorphanol (BUT) (0.2 mg kg^?1); 3) ketamine (K) (5 mg kg^?1) or ketamine (5 mg kg^?1) plus hydromorphone (0.1 mg kg^?1) (KH); 4) isoflurane in oxygen for 1 hour. Fifteen minutes prior to inhalant anesthetic, cats received either no premed (I), hydromorphone (0.1 mg kg^?1) (IH), or hydromorphone (0.1 mg kg^?1) plus ketamine (5 mg kg^?1) (IHK).ResultsMean PBT for all unmedicated cats was 38.9 ± 0.6 °C (102.0 ± 1 °F). The temperature of cats administered all doses of hydromorphone increased from baseline (p < 0.03) All four opioids (H, M, BUP and BUT) studied increased body temperature compared with baseline (p < 0.005). A significant difference was observed between baseline temperature values and those in treatment KH (p < 0.03). Following recovery from anesthesia, temperature in treatments IH and IHK was different from baseline (p < 0.002).Conclusions and clinical relevanceAll of the opioids tested, alone or in combination with ketamine or isoflurane, caused an increase in body temperature. The increase seen was mild to moderate (<40.1 °C (104.2 °F) and self limiting.     

Evaluation of the sedative,analgesic, clinicophysiological and haematological effects of intravenous detomidine,detomidine‐butorphanol,romifidine and romifidine‐butorphanol in standing donkeys

The aim of this investigation was to determine and evaluate the sedative, analgesic, clinicophysiological and haematological effects of intravenous (i.v.) injection of detomidine, detomidine‐butorphanol, romifidine and romifidine‐butorphanol. Six standing donkeys were used. Each donkey received 4 i.v. treatments and the order of treatment was randomised with a one‐week interval between each treatment. We found that i.v. injection of a combination of detomidine‐butorphanol or romifidine‐butorphanol produced potent neuroleptanalgesic effects thus providing better, safe and effective sedation with complete analgesia in standing donkeys compared with injection of detomidine or romifidine alone. The changes and reduction in pulse rate were within acceptable limits. The changes in clinicophysiological, haematological and biochemical values were mild and transient in these clinically healthy donkeys.     

Comparison of the effects of methadone and butorphanol combined with acepromazine for canine gastroduodenoscopy

ObjectiveTo evaluate the feasibility of gastroduodenoscopy in dogs premedicated with acepromazine in combination with butorphanol or methadone.Study designProspective, randomized, double-blinded clinical trial.AnimalsA group of 40 client-owned dogs.MethodsDogs were randomly allocated to one of two groups and give intramuscular acepromazine 0.02 mg kg^–1 combined with either butorphanol 0.3 mg kg^–1 (group ACEBUT) or methadone 0.2 mg kg^–1 (group ACEMET). General anaesthesia was induced with propofol and ketamine and maintained with sevoflurane (2.3%) in oxygen. Cardiopulmonary variables were recorded at 5 minute intervals during anaesthesia. Feasibility of the entire gastroduodenoscopy was evaluated with a visual analogue scale (VAS) from 0 (best) to 100 (worst) (primary outcome of the study). Lower oesophageal sphincter dilatation and duodenal intubation were scored. Pylorus diameter was measured with standard endoscopic inflatable balloons. Overall cardiovascular stability was assessed during anaesthesia, using a VAS (0-100), as was the presence of fluid in the oesophagus, regurgitation, need for mechanical ventilation, and intraoperative and postoperative rescue analgesia (secondary outcomes of the study). Differences between treatments were analysed with Mann–Whitney U, Student t test, Fisher exact test or mixed model analysis of variance as appropriate. Subsequently, feasibility VAS of the gastroduodenoscopy was assessed for noninferiority between groups. The noninferiority margin was set as –10.ResultsAll gastroduodenoscopies were successfully completed in both groups using an endoscope tip diameter of 12.8 mm in all but one dog. Feasibility of gastroduodenoscopy was evaluated as 2.9 ± 5.6 in group ACEBUT and 5.1 ± 5.8 in group ACEMET. No significant differences between groups were detected in any measured or assessed variables, and noninferiority was confirmed.Conclusion and clinical relevanceIn our study population, the effects of methadone and butorphanol when combined with acepromazine were comparable.