Evaluation of the sedative and cardiorespiratory effects of dexmedetomidine,dexmedetomidine-butorphanol,and dexmedetomidine-ketamine in cats

OBJECTIVE: To determine sedative and cardiorespiratory effects of dexmedetomidine alone and in combination with butorphanol or ketamine in cats. DESIGN: Randomized crossover study. ANIMALS: 6 healthy adult cats. PROCEDURES: Cats were given dexmedetomidine alone (10 microg/kg [4.5 mg/lb], IM), a combination of dexmedetomidine (10 microg/kg, IM) and butorphanol (0.2 mg/kg [0.09 mg/lb], IM), or a combination of dexmedetomidine (10 microg/kg, IM) and ketamine (5 mg/kg [2.3 mg/lb], IM). Treatments were administered in random order, with > or = 1 week between treatments. Physiologic variables were assessed before and after drug administration. Time to lateral recumbency, duration of lateral recumbency, time to sternal recumbency, time to recovery from sedation, and subjective evaluation of sedation, muscle relaxation, and auditory response were assessed. RESULTS: Each treatment resulted in adequate sedation; time to lateral recumbency, duration of lateral recumbency, and time to recovery from sedation were similar among treatments. Time to sternal recumbency was significantly greater after administration of dexmedetomidine-ketamine. Heart rate decreased significantly after each treatment; however, the decrease was more pronounced after administration of dexmedetomidine-butorphanol, compared with that following the other treatments. Systolic and diastolic blood pressure measurements decreased significantly from baseline with all treatments; 50 minutes after drug administration, mean blood pressure differed significantly from baseline only when cats received dexmedetomidine and butorphanol. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in cats, administration of dexmedetomidine combined with butorphanol or ketamine resulted in more adequate sedation, without clinically important cardiovascular effects, than was achieved with dexmedetomidine alone.     

Effects of dissociative anesthesia opioid-free protocols combined with local anesthesia,with or without flumazenil or atipamezole postoperatively,for orchiectomy in cats

ObjectiveTo evaluate the anesthetic effects of two drug combinations with local anesthesia, with or without postoperative antagonists, for orchiectomy in cats.Study designProspective, randomized blinded clinical study.AnimalsA total of 64 healthy cats.MethodsCats were assigned to four equal groups: ketamine (5 mg kg^–1) and dexmedetomidine (10 μg kg^–1) were administered intramuscularly (IM), followed postoperatively with intravenous (IV) saline (5 mL; group KDS) or atipamezole (50 μg kg^–1; group KDA); and ketamine (14 mg kg^–1) with midazolam (0.5 mg kg^–1) and acepromazine (0.1 mg kg^–1) IM, with postoperative IV saline (5 mL; group KMAS) or flumazenil (0.1 mg kg^–1; group KMAF). Lidocaine (2 mg kg^–1) was divided between subcutaneous and intratesticular injection. Physiologic variables were recorded at time points during anesthesia. Ketamine rescue dose was recorded. The degree of sedation and the quality of recovery were evaluated postoperatively.ResultsTime to loss of pedal reflex was longer in groups KMAS and KMAF than in groups KDS and KDA (p = 0.010). Total rescue dose of ketamine was higher in KMAS and KMAF than in KDS and KDA (p = 0.003). Heart rate (HR) during anesthesia was higher in KMAS and KMAF than in KDS and KDA (p = 0.001). Times to head up (p = 0.0005) and to sternal recumbency (p = 0.0003) were shorter in KDA than in KDS, KMAS and KMAF. Lower sedation scores were assigned sooner to KDA than KDS, KMAS and KMAF (p < 0.001). Recovery quality scores were good in all groups.Conclusions and clinical relevanceBoth anesthetic protocols allowed the performance of orchiectomy. Groups KMAS and KMAF required higher rescue doses of ketamine before injecting lidocaine. HR and oscillometric systolic pressure were minimally changed in groups KD and tachycardia was recorded in groups KMA. Only atipamezole shortened the anesthetic recovery.     

Effects of intramuscular and intranasal administration of midazolam–dexmedetomidine on sedation and some cardiopulmonary variables in New Zealand White rabbits

ObjectiveTo compare the sedative and cardiopulmonary effects of intranasal (IN) and intramuscular (IM) administration of dexmedetomidine and midazolam combination in New Zealand White rabbits.Study designA randomized, crossover experimental study.AnimalsA total of eight healthy New Zealand White rabbits, aged 6–12 months, weighing 3.1 ± 0.3 kg (mean ± standard deviation).MethodsThe animals were randomly assigned to administration of dexmedetomidine (0.1 mg kg^–1) with midazolam (2 mg kg^–1) by either IN or IM route separated by 2 weeks. The electrocardiogram, pulse rate (PR), peripheral haemoglobin oxygen saturation (SpO₂), mean noninvasive arterial pressure (MAP), respiratory frequency (f_R) and rectal temperature were measured before drug administration (baseline), T₀ (onset of sedation) and at 5 minute intervals until recovery. The onset of sedation, duration of sedation and sedation score (SS) were also recorded.ResultsThe PR was significantly lower in treatment IM than in treatment IN over time (p = 0.027). MAP < 60 mmHg developed in two and four rabbits in treatments IN and IM, respectively. SpO₂ progressively decreased over time in both treatments. f_R was lower than baseline at several time points in both treatments. Onset of sedation was shorter in treatment IN (90 ± 21 seconds) than in treatment IM (300 ± 68 seconds) (p = 0.036). Duration of sedation was longer in treatment IM (55.2 ± 8.7 minutes) than in treatment IN (39.6 ± 2.1 minutes) (p = 0.047). No significant difference in SS was observed between treatments (p > 0.05).Conclusions and clinical relevanceCombination of dexmedetomidine (0.1 mg kg^–1) and midazolam (2 mg kg^–1) decreased f_R, PR and SpO₂ regardless of the administration route in New Zealand White rabbits. A more rapid action and shorter duration of sedation were observed after treatment IN than after treatment IM administration.     

A comparison of two combinations of xylazine-ketamine administered intramuscularly to alpacas and of reversal with tolazoline

ObjectiveTo evaluate the anesthetic and cardiorespiratory effects of two doses of intramuscular (IM) xylazine/ketamine in alpacas, and to determine if tolazoline would reduce the anesthetic recovery time.Study designProspective randomized crossover study.AnimalsSix castrated male alpacas.MethodsEach alpaca received a low dose (LD) (0.8 mg kg⁻¹ xylazine and 8 mg kg⁻¹ ketamine IM) and high dose (HD) (1.2 mg kg⁻¹ xylazine and 12 mg kg⁻¹ ketamine IM) with a minimum of one week between trials. Time to sedation, duration of lateral recumbency and analgesia, pulse rate, respiratory rate, hemoglobin oxygen saturation, arterial blood pressure, blood-gases, and the electrocardiogram were monitored and recorded during anesthesia. With each treatment three alpacas were randomly selected to receive tolazoline (2 mg kg⁻¹ IM) after 30 minutes of lateral recumbency.ResultsOnset of sedation, lateral recumbency and analgesia was rapid with both treatments. The HD was able to provide ≥30 minutes of anesthesia in five of six alpacas. The LD provided ≥30 minutes of anesthesia in three of six alpacas. Respiratory depression and hypoxemia occurred with the HD treatment during the first 10 minutes of lateral recumbency: two animals were severely hypoxemic and received nasal oxygen for 5 minutes. Heart rate decreased, but there were no significant changes in arterial blood pressure. Tolazoline significantly shortened the duration of recumbency with the HD.ConclusionsThe HD provided more consistent clinical effects in alpacas than the LD. Intramuscular tolazoline shortened the duration of lateral recumbency in alpacas anesthetized with the HD combination.Clinical relevanceBoth doses of the combination were effective in providing restraint in alpacas and the duration of restraint was dose dependent. Supplemental oxygen should be available if using the HD and IM administration of tolazoline will shorten the recovery time.     

Comparison of anesthetic effects of tiletamine–zolazepam–medetomidine or ketamine–medetomidine in captive Amur leopard cats (Prionailurus bengalensis euptailurus)

ObjectiveTo evaluate the effects and utility of tiletamine–zolazepam–medetomidine (TZM) and ketamine–medetomidine (KM) for anesthesia of Amur leopard cats (Prionailurus bengalensis euptailurus).Study designProspective, randomized experimental trial.AnimalsA total of six female (3.70 ± 0.49 kg) and six male (5.03 ± 0.44 kg; mean ± standard deviation) Amur leopard cats aged 2–6 years.MethodsEach animal was administered four protocols separated by ≥3 weeks. Each protocol included medetomidine (0.05 mg kg^–1) combined with tiletamine–zolazepam (1 mg kg^–1; protocol MTZ_LO); tiletamine–zolazepam (2 mg kg^–1; protocol MTZ_HI); ketamine (2 mg kg^–1; protocol MK_LO); or ketamine (4 mg kg^–1; MK_HI) administered intramuscularly. At time 0 (onset of lateral recumbency) and 30 minutes, heart rate (HR), respiratory rate (f_R), rectal temperature, noninvasive mean arterial pressure (MAP) and hemoglobin oxygen saturation (SpO₂) were recorded. Times to onset of lateral recumbency, duration of anesthesia and time to standing were recorded.ResultsOverall, animals were anesthetized with all protocols within 10 minutes, anesthesia was maintained ≥57 minutes, and recovery (time from the first head lift to standing) was completed within 5 minutes. During anesthesia with all protocols, HR, f_R, rectal temperature, SpO₂ and MAP were 99–125 beats minute^–1, 33–44 breaths minute^–1, 37.6–39.4 °C, 90–95% and 152–177 mmHg, respectively. No adverse event was observed.Conclusions and clinical relevanceTZM and KM at various dosages resulted in rapid onset of anesthesia, duration of >57 minutes and rapid recovery without administration of an antagonist. Accordingly, all these combinations are useful for anesthetizing Amur leopard cats and for performing simple procedures. However, the low doses of the anesthetic agents are recommended because there was no difference in duration of anesthesia between the dose rates studied.     

Evaluation of intramuscular anesthetic protocols in healthy domestic horses

ObjectiveTo assess anesthetic induction, recovery quality and cardiopulmonary variables after intramuscular (IM) injection of three drug combinations for immobilization of horses.Study designRandomized, blinded, three-way crossover prospective design.AnimalsA total of eight healthy adult horses weighing 470–575 kg.MethodsHorses were administered three treatments IM separated by ≥1 week. Combinations were tiletamine–zolazepam (1.2 mg kg⁻¹), ketamine (1 mg kg⁻¹) and detomidine (0.04 mg kg⁻¹) (treatment TKD); ketamine (3 mg kg⁻¹) and detomidine (0.04 mg kg⁻¹) (treatment KD); and tiletamine–zolazepam (2.4 mg kg⁻¹) and detomidine (0.04 mg kg⁻¹) (treatment TD). Parametric data were analyzed using mixed model linear regression. Nonparametric data were compared using Skillings–Mack test. A p value <0.05 was considered statistically significant.ResultsAll horses in treatment TD became recumbent. In treatments KD and TKD, one horse remained standing. PaO₂ 15 minutes after recumbency was significantly lower in treatments TD (p < 0.0005) and TKD (p = 0.001) than in treatment KD. Times to first movement (25 ± 15 minutes) and sternal recumbency (55 ± 11 minutes) in treatment KD were faster than in treatments TD (57 ± 17 and 76 ± 19 minutes; p < 0.0005, p = 0.001) and TKD (45 ± 18 and 73 ± 31 minutes; p = 0.005, p = 0.021). There were no differences in induction quality, muscle relaxation score, number of attempts to stand or recovery quality.Conclusions and clinical relevanceIn domestic horses, IM injections of tiletamine–zolazepam–detomidine resulted in more reliable recumbency with a longer duration when compared with ketamine–detomidine and tiletamine–zolazepam–ketamine–detomidine. Recoveries were comparable among protocols.     

Comparison of sedative and some cardiopulmonary effects of intramuscular medetomidine or medetomidine–tramadol in dogs

ObjectiveTo evaluate the clinical and physiologic effects of intramuscular (IM) administration of medetomidine with and without tramadol in dogs.Study designProspective experimental study.AnimalsA group of eight mixed breed dogs of both sexes, aged 1–2 years, weighing 16.0 ± 0.6 kg.MethodsEach dog was studied twice at ≥1 week interval. Medetomidine (5 μg kg^–1; treatment M) was administered IM alone or with tramadol (4 mg kg^–1; treatment MT). Sedation was scored by a system that included vocalization, posture, appearance, interactive behaviors, resistance to restraint and response to noise. Times from drug administration to ataxia, impaired walking, head drop, sternal and lateral position and standing were recorded. Sedation score, heart rate, respiratory rate, rectal temperature, end-tidal carbon dioxide (Pe′CO₂), hemoglobin oxygen saturation and mean noninvasive blood pressure were recorded and compared 15 minutes before and 15, 30 and 45 minutes after drug administration.ResultsDogs administered MT had higher sedation scores than dogs administered M at 30 and 45 minutes after drug administration (p < 0.05). Times to ataxia, impaired walking, head drop and sternal recumbency were not different between the treatments. Time to lateral recumbency was longer in M than in MT (21.1 ± 1.0 versus 17.6 ± 0.7 minutes, respectively; p < 0.05). Time to standing was longer in MT than in M (67.9 ± 1.4 versus 54.5 ± 1.9 minutes, respectively; p < 0.001). Measured physiological variables did not differ between the treatments, with the exception of Pe′CO₂, which was higher in MT than in M at all post-treatment evaluation times (p < 0.001).Conclusions and clinical relevanceTramadol combined with medetomidine resulted in greater sedation scores (deeper sedation) than medetomidine alone in dogs, and minimal adverse changes in the physiologic variables were measured.     

Sedative effects of two doses of alfaxalone in combination with methadone and a low dose of dexmedetomidine in healthy Beagles

ObjectiveTo evaluate the sedative effects of two doses of alfaxalone when added to a combination of dexmedetomidine and methadone injected intramuscularly (IM) in healthy Beagles.Study designRandomized, blinded, crossover, experimental study.AnimalsA group of six adult Beagles.MethodsDogs were sedated on three different occasions with IM dexmedetomidine (3 μg kg^–1) and methadone (0.3 mg kg^–1) combined with two doses of alfaxalone (0.5 and 1 mg kg^–1; A0.5 and A1, respectively) or saline (A0). Quality of sedation, response to tail clamping and rectal temperature were recorded at baseline, 5, 15, 25, 35 and 45 minutes. Pulse and respiratory rates, oxygen saturation of haemoglobin (SpO₂) and noninvasive blood pressure (NIBP) were recorded every 5 minutes. Onset of sedation and duration of recumbency, response to venous catheterization and recovery quality were assessed. Physiological variables (analysis of variance) were analysed between treatments and within treatments compared with baseline (Student t test). Nonparametric data were analysed using Friedman and Cochran’s Q tests. Significance was p < 0.05.ResultsSedation scores were significantly higher when alfaxalone was co-administered (area under the curve; p = 0.024, A0.5; p = 0.019, A1), with no differences between doses. Onset of sedation was similar, but duration of recumbency was longer in A0.5 than in A0 [median (minimum–maximum), 43 (35–54) versus 30 (20–47) minutes, p = 0.018], but not in A1. Response to venous catheterization and tail clamping, and quality of recovery (acceptable) presented no differences between treatments. A decrease in all physiological variables (compared with baseline) was observed, except for NIBP, with no differences between treatments. All dogs required oxygen supplementation due to reduced SpO₂.Conclusions and clinical relevanceAdding alfaxalone to methadone and dexmedetomidine enhanced sedation and duration of recumbency. Although cardiopulmonary depression was limited, oxygen supplementation is advisable.     

A preliminary trial of the sedation induced by intranasal administration of midazolam alone or in combination with dexmedetomidine and reversal by atipamezole for a short‐term immobilization in pigeons

ObjectiveTo assess the sedative and immobilization effect of intranasal administration (INS) of midazolam (MID) without or with INS dexmedetomidine (DXM), and some physiological changes induced by the drugs. The ability of INS atipamezole to reverse the DXM component was also assessed.Study designProspective ‘blinded’ experimental study.AnimalsIn total, 15 pigeons.MethodsPigeons were sedated by INS MID alone at a dose of 5 mg kg⁻¹ (group MID, n = 6) or in combination with INS DXM at a dose 80 μg kg⁻¹ (group MID-DXM, n = 6). Measurements were made of heart rate (HR), respiratory rate (f_R) and cloacal temperature (CT). The degree of sedation was assessed at 15 minutes prior to, immediately after, and at intervals until 100 minutes after drug administrations. Following MID-DXM, INS atipamezole (250 μg kg⁻¹) was administered and the same indices measured 5 and 10 minutes later.ResultsMID had no effect on HR and f_R, and although CT decreased, it remained within physiological range. MID-DXM caused significant falls in HR, f_R and CT that persisted until the end of sedation. Atipamezole antagonized sedation and cardiorespiratory side effects of MID-DXM within 10 minutes of application. In addition, for MID compared to MID-DXM, the lowest sedation scores [10 (7–14) and 10.5 (5–14) versus 2 (1–4) and 2 (1–5)] were achieved in the 10th and 20th minute versus the 20th and 30th minute of the sedation, respectively.Conclusions and clinical relevanceMID alone, given INS had minimal side effects on vital functions but caused inadequate immobilization of pigeons for restraint in dorsal recumbency. MID-DXM caused an effective degree of immobilization from 20 to 30 minutes after administration, at which time birds tolerated postural changes without resistance. Atipamezole antagonized both side effects and sedation, but complete recovery had not occurred within 10 minutes after its application.     

A comparison of the efficacy and cardiorespiratory effects of four medetomidine-based anaesthetic protocols in the red fox (Vulpes vulpes)

ObjectiveTo evaluate the anaesthetic and cardiorespiratory effects of four anaesthetic protocols in red foxes (Vulpes vulpes).Study designProspective, blinded and randomized complete block design.AnimalsTen adult captive red foxes.MethodsFoxes were anaesthetized by intramuscular (IM) injection using four protocols in random order: medetomidine 40 μg kg^?1, midazolam 0.3 mg kg^?1 and butorphanol 0.1 mg kg^?1 (MMiB), medetomidine 40 μg kg^?1 and ketamine 4 mg kg^?1 (MK40/4), medetomidine 60 μg kg^?1 and ketamine 4 mg kg^?1 (MK60/4), medetomidine 40 μg kg^?1 and tiletamine/zolazepam 2 mg kg^?1 (MTZ). Time to lateral recumbency, induction time and time to recovery following IM administration of atipamezole 0.2 mg kg^?1 were recorded. Heart rate (HR), respiratory rate (_fR) and rhythm, blood pressure, rectal temperature, end-tidal CO₂ tension (Pe′Co₂), functional oxygen saturation and presence/absence of interdigital, palpebral and ear reflexes were recorded every 10 minutes, and following administration of atipamezole. Data were analysed using two-way repeated-measures anova with Bonferroni post tests; p < 0.05 was considered significant.ResultsAll protocols produced profound sedation with good muscle relaxation. Only the MMiB protocol diverged significantly from the others. Induction of anaesthesia and recovery time following atipamezole were significantly longer, and f_R and initial HR significantly lower with MMiB than with the other protocols. With all protocols, mean arterial blood pressure (MAP) was initially relatively high (140–156 mmHg), and decreased significantly over time. With all protocols, the administration of atipamezole resulted in a rapid, significant decrease in MAP and an increase in HR.Conclusions and clinical relevanceAll four protocols provided anaesthetic conditions suitable for minor procedures and allowed endotracheal intubation. The cyclohexanone protocols provided quicker and more reliable inductions and recoveries than the MMiB protocol.     

Effects of intramuscular alfaxalone alone or in combination with diazepam in swine

ObjectiveTo describe the use of intramuscular (IM) premedication with alfaxalone alone or in combination with diazepam in pigs.Study designRandomised‐controlled trial.AnimalsTwelve healthy 2 month‐old Landrace x Large White pigs weighing 21.3 ± 2.4 kg.MethodsAnimals were distributed randomly into two groups: group A (n = 6) 5 mg kg^?1 of IM alfaxalone; and group AD (n = 6) 5 mg kg^?1 of IM alfaxalone + 0.5 mg kg^?1 of IM diazepam mixed in the same syringe. The total volume of injectate was standardized at 14 mL by dilution in 0.9% sodium chloride. Pain on injection, the degree of sedation and the quality of and time to induction of recumbency were evaluated. Once pigs were recumbent, reflexes were evaluated. Pulse and respiratory rates and arterial oxygen saturation were recorded at 5 and 10 minutes after drug administration. Pigs were then moved to another room for subsequent anaesthesia.ResultsTwo animals of group A and one of group AD showed slight pain on drug injection. Time to lateral recumbency (in seconds) was shorter in group AD (mean 203 ± SD 45 range 140–260) than group A (302 ± 75, range 220–420; p < 0.05). In group AD sedation was deeper, and on recumbency there was better muscle relaxation. When moved for anaesthesia, two pigs in Group A showed slight resistance but did not vocalize. There were no differences in physiologic measurements between groups, although in both groups, respiratory rate was significantly lower at ten compared with five minutes post drug injection. There was no apneoa.Conclusions and clinical relevanceIM administration of alfaxalone combined with diazepam resulted in a rapid onset of recumbency and deep sedation, with minimal side effects. The combination might be useful for premedication, but volume of injectate will limit its use to small pigs.     

Comparison of two injectable anesthetic regimes in feral cats at a large-volume spay clinic

Same‐day mass sterilization of feral cats requires rapid onset, short‐duration anesthesia. The purpose of this study was to compare our current anesthetic protocol, Telazol–ketamine–xylazine (TKX) with medetomidine–ketamine–buprenorphine (MKB). Feral female cats received either IM TKX (n = 68; 0.25 mL cat^?1; tiletamine 12.5 mg, zolazepam 12.5 mg, K 20 mg, and X 5 mg per 0.25 mL) or MKB (n = 17; M 40 µg kg^?1, K 15 mg kg^?1, and B 10 µg kg^?1). Intervals measured included time from injection to recumbency, time to surgery, duration of surgery, and time from reversal of anesthesia (TKX: yohimbine 0.50 mg cat^?1 IV; MKB: atipamezole 0.50 mg cat^?1 IM) to sternal recumbency. Following instrumentation (Vet/Ox 4403 and Vet/BP Plus 6500), physiological measurements were recorded at 5‐minute intervals, and included rectal temperature, heart rate (HR), respiratory rate (RR), SpO₂ (lingual or rectal probes), and indirect mean arterial blood pressure (MAP) (oscillometric method). Nonparametric means were compared using Mann–Whitney U‐tests. Parametric means were compared using a two‐factorial anova with Bonferroni's t‐tests. The alpha‐priori significance level was p < 0.05. Values were mean ± SD. Body weight (TKX: 2.9 ± 0.5 kg, MKB: 2.7 ± 0.7 kg), time to recumbency (TKX: 4 ± 1 minutes, MKB: 3 ± 1 minutes), time to surgery (TKX: 28 ± 7 minutes, MKB: 28 ± 5 minutes), and duration of surgery (TKX: 11 ± 7 minutes, MKB: 8 ± 5 minutes) did not differ between groups. In contrast, MKB cats required less time from reversal to sternal recumbency (TKX: 68 ± 41 minutes, MKB: 7 ± 2 minutes) and were recumbent for shorter duration (TKX: 114 ± 39 minutes, MKB: 53 ± 6 minutes). Temperature decreased during the study in both groups, but overall temperature was higher in MKB cats (38.0 ± 0.95 °C) than in TKX cats (37.5 ± 0.95 °C). RR, HR, and SpO₂ did not change during the study in either group. However, overall HR and RR were higher in TKX cats (RR: 18 ± 8 breaths minute^?1, HR: 153 ± 30 beats minute^?1) compared to MKB cats (RR: 15 ± 7 breaths minute^?1, HR: 128 ± 19 beats minute^?1). In contrast, overall SpO₂ was lower in the TKX group (90 ± 6%) compared to the MKB group (94 ± 4%). MAP was also lower in the TKX group (112 ± 29 mm Hg) compared to that in the MKB group (122 ± 20 mm Hg). However, MAP increased in the TKX group during surgery compared to pre‐surgical values, but did not change in the MKB group. The results of this study suggested that MKB might be more suitable as an anesthetic for the purpose of mass sterilization of feral female cats.     

Intramuscular alfaxalone and methadone with or without ketamine in healthy cats: effects on sedation and echocardiographic measurements

ObjectiveTo evaluate the effect of alfaxalone and methadone administered intramuscularly (IM), with or without ketamine, on sedation and echocardiographic measurements in healthy cats.Study designA randomized, blinded, clinical study.AnimalsA group of 24 client-owned cats.MethodsBaseline echocardiographic evaluation (bEchoCG) was performed. Cats were given IM alfaxalone (2 mg kg^–1) and methadone (0.3 mg kg^–1) with (AMK group) or without (AM group) ketamine (1 mg kg^–1). A sedation score (0–5, indicating none to good sedation) was assigned at 5 (T5), 10 (T10) and 15 (T15) minutes after IM injection. At T15, a second echocardiographic evaluation (sEchoCG) was performed. Data are shown as median (range). Significance was p < 0.05.ResultsFinally, 21 cats were included. Sedation score was significantly higher in the AMK (11 cats) than in the AM group (10 cats): 4 (1–5) versus 0.5 (0–4) at T5 (p = 0.003); 4 (1–5) versus 1.5 (0–5) at T10 (p = 0.043); and 4 (1–5) versus 2 (0–5) at T15 (p = 0.024). All echocardiographic measurements obtained were within reference ranges. Between the groups, aortic root area (p = 0.009) and end-diastolic aortic dimension (p = 0.011) were significantly higher in the AM group at bEchoCG and sEchoCG, respectively. Within each group, values at bEchoCG and sEchoCG showed no significant differences, except for pulmonary peak velocity (0.85 m second^–1; p = 0.028) in the AMK group and ejection time (154 m second; p = 0.03) in the AM group; both variables decreased after sedation.Conclusions and clinical relevanceIn this population of healthy cats, neither protocol produced clinically meaningful effects on the echocardiographic variables evaluated. Alfaxalone with methadone produced mild sedation, whereas the addition of 1 mg kg^–1 ketamine induced adequate sedation for diagnostic procedures.     

Evaluation of xylazine–alfaxalone anesthesia for field castration in donkey foals

ObjectiveTo evaluate the anesthetic and cardiopulmonary effects of xylazine–alfaxalone anesthesia in donkey foals undergoing field castration.Study designProspective clinical study.AnimalsA group of seven standard donkeys aged [median (range)] 12 (10–26) weeks, weighing 47.3 (37.3–68.2) kg.MethodsDonkeys were anesthetized with xylazine (1 mg kg⁻¹) intravenously (IV) followed 3 minutes later by alfaxalone (1 mg kg⁻¹) IV. Additional doses of xylazine (0.5 mg kg⁻¹) and alfaxalone (0.5 mg kg⁻¹) IV were administered as needed to maintain surgical anesthesia. Intranasal oxygen was supplemented at 3 L minute⁻¹. Heart rate (HR), respiratory rate (f_R) and mean arterial pressure (MAP) by oscillometry were recorded before drug administration and every 5 minutes after induction of anesthesia. Peripheral oxygen saturation (SpO₂) was recorded every 5 minutes after induction. Time to recumbency after alfaxalone administration, time to anesthetic re-dose, time to first movement, sternal and standing after last anesthetic dose and surgery time were recorded. Induction and recovery quality were scored (1, very poor; 5, excellent).ResultsMedian (range) induction score was 5 (1–5), and recovery score 4 (1–5). Overall, two donkeys were assigned a score of 1 (excitement) during induction or recovery. HR and MAP during the procedure did not differ from baseline. f_R was decreased at 5 and 10 minutes but was not considered clinically significant. SpO₂ was <90% at one time point in two animals.Conclusions and clinical relevanceXylazine–alfaxalone anesthesia resulted in adequate conditions for castration in 12 week old donkeys. While the majority of inductions and recoveries were good to excellent, significant excitement occurred in two animals and may limit the utility of this protocol for larger donkeys. Hypoxemia occurred despite intranasal oxygen supplementation.     

Intramuscular injection of alfaxalone in combination with butorphanol for sedation in cats

Objective

To assess quality of sedation following intramuscular (IM) injection of two doses of alfaxalone in combination with butorphanol in cats.

The effect of butorphanol on the incidence of dexmedetomidine‐induced emesis in cats

ObjectiveTo evaluate the antiemetic effect of butorphanol (BUT) when co-administered with dexmedetomidine (DEX) in cats.Study designDouble-blind, randomized controlled cross-over experimental study.AnimalsFourteen purpose-bred healthy Domestic Short Hair cats, seven females and seven males, aged median (range) 14–84 (78) months and weighing 1.7–5.5 (4.0) kg.MethodsEach cat received five different treatment protocols intramuscularly (IM): (A) 25 μg kg⁻¹ DEX; (B) 20 μg kg⁻¹ DEX and 0.2 mg kg⁻¹ BUT; (C) 20 μg kg⁻¹ DEX and 0.1 mg kg⁻¹ BUT; (D) 25 μg kg⁻¹ DEX and 0.2 mg kg⁻¹ BUT; and (E) 20 μg kg⁻¹ DEX. Episodes of emesis, incidence and severity of nausea, and time to lateral recumbency were recorded for a period of 8 minutes after treatment administration, and the sedation was scored at the end of this period. The Friedman test and the Cochran’s Q-test were used to analyse the data. Significance was evaluated at the 5% level.ResultsThe proportion of cats that vomited was significantly lower with the treatment protocols that included BUT (B, C and D) compared with the protocols that included only DEX (A and E). The proportion of cats that had nausea was significantly higher with the protocols that included only DEX (A and E) compared with protocols B and D. Time to lateral recumbency (p = 0.09) and sedation score (p = 0.07) was not statistically different between the treatment protocols.Conclusions and clinical relevanceButorphanol can be used to prevent emesis and reduce the incidence and the severity of nausea caused by DEX in cats. It seems that the combination of BUT and DEX is very useful not only when emesis could result in serious complications, but also to provide comfort and well-being in cats sedated for minor procedures.