Alfaxalone or ketamine-medetomidine in cats undergoing ovariohysterectomy: a comparison of intra-operative parameters and post-operative pain

Comparison of two injectable anaesthetic protocols in Egyptian fruit bats (Rousettus aegyptiacus) undergoing gonadectomy

Egyptian fruit bats have gained increasing interest being a natural reservoir for emerging zoonotic viruses. Anaesthesia is often required to allow safe handling of bats. We aimed to compare the sedative and cardiopulmonary effects of two balanced anaesthetic protocols in bats undergoing gonadectomy. Group DK (n = 10) received intramuscular dexmedetomidine (40 µg/kg) and ketamine (7 mg/kg), whereas group DBM (n = 10) received intramuscular dexmedetomidine (40 µg/kg), butorphanol (0.3 mg/kg) and midazolam (0.3 mg/kg). Induction time and cardiopulmonary parameters were recorded. If anaesthetic plan was inadequate, isoflurane was titrated-to-effect. At the end of surgery venous blood gas analysis was performed and atipamezole or atipamezole-flumazenil was administered for timed and scored recovery. In DBM group heart rate and peripheral oxygen saturation were significantly higher (p = 0.001; p = 0.003 respectively), while respiratory rate was significantly lower (p = 0.001). All bats required isoflurane supplementation with no significant differences between groups. Induction and recovery times showed no significant differences. In group DK a better recovery was scored (p = 0.034). Sodium and chloride were significantly higher in DBM group (p = 0.001; p = 0.002 respectively). Both anaesthetic protocols were comparable and can be recommended for minor procedures in bats.

Induction of General Anesthesia With Alfaxalone in the Domestic Chicken

Alfaxalone is a safe and effective anesthetic drug for the induction of general anesthesia in many nonavian companion animal species; however, its efficacy has not been fully evaluated in birds. In premedicated trials, the chickens were sedated with butorphanol 2 mg/kg intramuscularly and midazolam 0.5 mg/kg intramuscularly, 15 minutes before intravenous administration of alfaxalone. The chickens were classified as anesthetized if endotracheal intubation was achieved without eliciting a cough reflex, provoking no patient resistance, and with minimal glottis movement within 15 seconds after the administration of alfaxalone. Qualitative and quantitative data were recorded, including duration of anesthesia, quality of induction, quality of recovery, reflexes, time to sternal recumbency, time to standing, and time to normal behaviors. Survival analysis was used to analyze the association between alfaxalone dosage and premedication with time-related variables. Out of the evaluated doses, the lowest intravenous alfaxalone dose required to achieve anesthetic induction and endotracheal intubation in unpremedicated and premedicated chickens was 7.5 and 4 mg/kg, respectively. The duration of anesthesia for all dose rates within the study ranged from 51 seconds to 4 minutes 45 seconds. Premedication generally improved the quality of induction and recovery, but significantly (P < .001) increased the time required for the chickens to stand after being anesthetized and to return to normal behaviors. Most chickens exhibited varying degrees of hyperactivity on anesthetic induction and recovery. No postinduction apnea or deaths of the subject birds occurred during this investigation.

Current Topics in Marmoset Anesthesia and Analgesia

Anesthetic and analgesics are essential components of both clinical and research procedures completed in marmosets. A review of current anesthetic and analgesic regimens for marmosets has been complied to provide a concise reference for veterinarians and investigator teams. Published dose regimens for injectable and inhalant anesthetic drugs and analgesic drugs are included. Appropriate physiological monitoring is key to the success of the procedure and perianesthetic options are provided. Although recent publications have refined anesthesia and analgesia practices, our review demonstrates the continued need for evidence-based resources specific to marmosets.

Regional anesthesiological support for the implementation of surgical interventions in the abdomen of dogs

Widespread use of surgical interventions in the abdomen of dogs determines the relevance of the study. The research tested the influence of therapeutic epidural blockade with 0.2% bupivacaine after surgical interventions on the background of potentiated local anaesthesia on the body of clinically healthy dogs undergoing ovariohysterectomy. In the control group postoperative analgesia was performed with the nonsteroidal anti-inflammatory drug rimadyl on the background of potentiated thiopental anaesthesia. Wound healing rates were determined in 10 animals of both control and experimental groups; blood counts and the level of inflammatory response were indicated in 5 animals of each group. The dynamics of reparative processes and complete wound healing in dogs of the experimental group occurred earlier than in animals of the control group, which confirmed the fact that the use of bupivacaine had a beneficial effect on tissue regeneration. The results of morphological and biochemical parameters of blood in animals of the experimental group manifested only an increase of leukocytes by 1.58 times, fibrinogen by 2.02 times, while in dogs of the control group the level of erythrocytes, haemoglobin and hematocrit decreased, leukocytes increased by 1.74 times, platelets decreased by 2.87 times and fibrinogen increased by 1.72 times. Among the stress response markers in the control group there was a 1.94 times increase in glucose level after surgery. In the experimental group there was a decrease in the intensity of the inflammatory reaction in dogs, accompanied by an increase of anti-inflammatory interleukin 4 (IL-4) only on the seventh day – 1.86 times, while in the control group the level of anti-inflammatory interleukin 1 receptor antagonist (IL-1RA) after three days increased by 2.30 times, after seven days – by 2.48 times, and the level of proinflammatory interleukin 6 (IL-6) after surgery increased by 2.57 times. It will be promising to conduct further research on the influence of therapeutic blockades with bupivacaine in animals in cases of various surgical interventions and pathological conditions, which will lead to faster recovery of animals and alleviate pathological processes.

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

OBJECTIVE

To evaluate the effect of alfaxalone and methadone administered intramuscularly (IM), with or without ketamine, on sedation and echocardiographic measurements in healthy cats.

STUDY DESIGN

A randomized, blinded, clinical study.

ANIMALS

A group of 24 client-owned cats.

METHODS

Baseline 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.

RESULTS

Finally, 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 RELEVANCE

In 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.

Effects of buprenorphine, butorphanol or tramadol premedication on anaesthetic induction with alfaxalone in common marmosets (Callithrix jacchus)

OBJECTIVE

To investigate the clinical and physiological effects of intravenous (IV) alfaxalone alone or in combination with buprenorphine, butorphanol or tramadol premedication in marmosets.

STUDY DESIGN

Prospective, randomized, blinded, crossover design.

ANIMALS

Nine healthy marmosets (391 ± 48 g, 3.7 ± 2.2 years old).

METHODS

Meloxicam 0.20 mg kg^-1 subcutaneously, atropine 0.05 mg kg^-1 intramuscularly (IM) and either buprenorphine 20 μg kg^-1 IM (BUP-A), butorphanol 0.2 mg kg^-1 IM (BUT-A), tramadol 1.5 mg kg^-1 IM (TRA-A) or no additional drug (control) were administered to all marmosets as premedication. After 1 hour, anaesthesia was induced with 16 mg kg^-1 alfaxalone IV. All animals received all protocols. The order of protocol allocation was randomized with a minimum 28 day wash-out period. During anaesthesia, respiratory and pulse rates, rectal temperature, haemoglobin oxygen saturation, arterial blood pressure, palpebral and pedal withdrawal reflexes and degree of muscle relaxation were assessed and recorded every 5 minutes. Quality of induction and recovery were assessed. Duration of induction, immobilization and recovery were recorded. Blood samples were analysed for aspartate aminotransferase, creatine kinase and lactate dehydrogenase concentrations. The protocols were compared using paired t tests, Wilcoxon's signed-rank test with Bonferroni's corrections and linear mixed effect models where appropriate.

RESULTS

Out of nine animals, apnoea was noted in eight animals administered protocol BUP-A and two animals administered protocol BUT-A. With TRA-A and control protocols, apnoea was not observed. No other significant differences in any of the parameters were found; however, low arterial blood pressures and hypoxia occurred in TRA-A.

CONCLUSIONS AND CLINICAL RELEVANCE

Our study employing different premedications suggests that the previously published dose of 16 mg kg^-1 alfaxalone is too high when used with premedication because we found a high incidence of complications including apnoea (BUP-A), hypotension and hypoxaemia (TRA-A). Appropriate monitoring and countermeasures are recommended.

Assessing analgesia equivalence and appetite following alfaxalone- or ketamine-based injectable anesthesia for feline castration as an example of enhanced recovery after surgery

Objectives The primary study objective was to assess two injectable anesthetic protocols, given to facilitate castration surgery in cats, for equivalence in terms of postoperative analgesia. A secondary objective was to evaluate postoperative eating behavior. Methods Male cats presented to a local clinic were randomly assigned to receive either intramuscular ketamine (5 mg/kg, n = 26; KetHD) or alfaxalone (2 mg/kg, n = 24; AlfHD) in combination with dexmedetomidine (25 μg/kg) and hydromorphone (0.05 mg/kg). All cats received meloxicam (0.3 mg/kg SC) and intratesticular lidocaine (2 mg/kg). Species-specific pain and sedation scales were applied at baseline, 1, 2 and 4 h postoperatively. Time taken to achieve sternal recumbency and begin eating were also recorded postoperatively. Results Pain scale scores were low and showed equivalence between the treatment groups at all time points (1 h, P = 0.38, 95% confidence interval [CI] of the difference between group scores 0-0; 2 h, P = 0.71, 95% CI 0-0; 4 h, P = 0.97, 95% CI 0-0). Four cats crossed the threshold for rescue analgesia (KetHD, n = 1; AlfHD, n = 3). At 1 h, more cats in the KetHD (65%) group than in the AlfHD (42%) group were sedated, but statistical significance was not detected ( P = 0.15, 95% CI -1 to 0). Most AlfHD cats (88%) began eating by 1 h vs 65% of KetHD cats ( P = 0.039). Time to recover sternal recumbency did not differ between groups ( P = 0.86, 95% CI -14.1 to 11.8). Conclusions and relevance These results show that AlfHD and KetHD provide equivalent analgesia as part of a multimodal injectable anesthetic protocol. Alfaxalone is associated with an earlier return to eating.

Comparison of intramuscular alfaxalone and ketamine combined with dexmedetomidine and butorphanol for castration in cats

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 (T10) and 15 (T15) mins after injection (T0). Cardiorespiratory values (PR, RR, SPO2, blood pressure, PE'CO2) 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 (Texmin) and the time between injection and extubation recorded. Pain was assessed at Tex120 and Tex240 with the 4Avet-pain score. Results The RR was significantly lower in group K at T10 (RRK = 28 ±13.35 breaths per minute [brpm], RRA= 43.24 ±7.04 brpm) and T15 (RRK = 28 ±11.53 brpm vs RRA = 43 ±12.18 brpm). Time to extubation was significantly longer in group A (TA = 62 ±14.6 mins, TK = 45.13 ± 7.38 mins). Cats in group K needed more top-ups, were more ataxic at Tex120, had a worse recovery score at Tex60 and were less willing to walk at Tex30. 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.

Dexmedetomidine-methadone-ketamine versus dexmedetomidine-methadone-alfaxalone for cats undergoing ovariectomy

OBJECTIVE

To compare the duration, quality of anaesthesia and analgesia, and quality of recovery of dexmedetomidine and methadone combined with either ketamine or alfaxalone.

STUDY DESIGN

Randomized, prospective clinical trial.

ANIMALS

A group of 44 healthy client-owned cats presenting for ovariectomy.

METHODS

Cats were randomly assigned to one of the two treatment groups: DAM (n=22), which was administered intramuscularly (IM) dexmedetomidine (15 μg kg^-1), methadone (0.3 mg kg^-1) and alfaxalone (3 mg kg^-1), and DKM (n=22), which was administered IM dexmedetomidine (15 μg kg^-1), methadone (0.3 mg kg^-1) and ketamine (3 mg kg^-1). During anaesthesia, heart rate, respiratory rate and systolic arterial pressure were measured every 5 minutes. Cats that moved or had poor muscle relaxation were administered an additional 1 mg kg^-1 of either alfaxalone (DAM) or ketamine (DKM) intravenously (IV). In cases of increased autonomic responses to surgical stimulation, fentanyl (2 μg kg^-1) was administered IV. At the end of the surgery, atipamezole (75 μg kg^-1) was administered IM, and the times to both sternal recumbency and active interaction were recorded. Quality of recovery was evaluated with a simple descriptive scale. The UNESP-Botucatu multidimensional composite pain scale and a visual analogue scale were used to evaluate postoperative analgesia at the return of active interaction and 1, 2 and 3 hours later.

RESULTS

The additional anaesthesia and rescue fentanyl requirements were similar between groups. The quality of recovery was better in the DAM group than in the DKM group [simple descriptive scale scores: 0 (0-1) and 1 (0-3), respectively; p=0.002]. Postoperative pain scores decreased progressively over time in both groups, with no significant differences (p=0.08) between them.

CONCLUSIONS AND CLINICAL RELEVANCE

Both protocols provided comparable quality of anaesthesia and analgesia and were suitable for cats undergoing ovariectomy. In combination with methadone and dexmedetomidine, alfaxalone and ketamine showed comfortable and reliable recoveries.