Evaluation of the perioperative analgesic efficacy of buprenorphine, compared with butorphanol, in cats

Effects of Medetomidine-Butorphanol and Medetomidine-Buprenorphine on Oxidative Stress and Vital Parameters in Dogs Undergoing Ovariohysterectomy

Oxidative stress (OS) is caused by an imbalance between the production of oxygen-containing free radicals and their elimination. General anesthesia increases the production of reactive oxygen species (ROS) and therefore causes oxidative stress. Our objective was to determine the effects of medetomidine-butorphanol (MEDBUT) and medetomidine-buprenorphine (MEDBUP) on oxidative stress and cardiorespiratory parameters in dogs undergoing ovariohysterectomy (OHE). Ten healthy female dogs were randomly assigned to two groups: the MEDBUT group (n = 5) received medetomidine and butorphanol, while the MEDBUP group (n = 5) received medetomidine and buprenorphine. OS was evaluated by measuring total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) during five different time points (from the administration of anesthetic drugs to 2 h after surgery). The observed vital cardiorespiratory parameters included heart rate (HR), respiratory rate (fR), noninvasive systolic (SAP) and diastolic (DAP) arterial blood pressures, oxygen saturation (SpO2), end-tidal CO2 (EtCO2), and body temperature (BT). Cardiorespiratory parameters were altered at a significantly greater degree in animals sedated with MEDBUT (p < 0.05). The administration of medetomidine-butorphanol was more likely to increase OS parameters, while medetomidine-buprenorphine showed decreased levels of oxidative stress throughout the study.

Anesthetic and analgesic techniques used for cats undergoing ovariohysterectomies in general practice in the United States

OBJECTIVE

To better document anesthetic and analgesic protocols used by veterinarians in general practice within the United States (US) when performing elective ovariohysterectomy in cats.

STUDY DESIGN

Cross-sectional survey.

POPULATION

Veterinary practitioners in the US who are members of the Veterinary Information Network Inc. (VIN).

METHODS

An online anonymous survey was distributed to VIN members. The survey included questions pertaining to preanesthetic evaluation, premedication, induction, monitoring and maintenance protocols, and postoperative analgesia and sedation protocols when performing ovariohysterectomy in cats.

RESULTS

A total of 1324 veterinarians completed the survey. Respondents (number; %) reported performing preanesthetic laboratory tests [packed cell volume (256; 19.3%), complete blood cell count (893; 67.4%) and biochemistry panels (1101; 83.2%)] and preanesthetic examinations (1186; 89.6%) on the morning of surgery. The most frequently administered drugs for premedication were dexmedetomidine (353; 26.7%) and buprenorphine (424; 32.0%). The most frequently administered induction agent was propofol (451; 61.3%), and isoflurane (668; 50.4%) was the most common agent for maintenance of anesthesia. The majority of respondents reported placing intravenous catheters (885; 66.8%), administering crystalloid fluids (689; 52.0%) and providing heat support (1142; 86.3%). Participants reported using perioperative and postoperative analgesia including opioids (791; 59.7%), non-steroidal anti-inflammatory drugs (NSAIDs; 697; 52.6%) and NSAIDs dispensed for home use (665; 50.2%). Cats were commonly released home on the day of surgery (1150; 86.9%), and most participants reported contacting owners for follow-up within 1-2 days (989; 74.7%).

CONCLUSIONS AND CLINICAL RELEVANCE

Anesthetic protocols and management techniques for routine feline ovariohysterectomy differ widely among US veterinarians who are VIN members, and results from this study may be of use to evaluate anesthetic practices from this population of veterinarians.

Randomised clinical trial comparing the perioperative analgesic efficacy of oral tramadol and intramuscular tramadol in cats

OBJECTIVES

The aim of this study was to evaluate the analgesic efficacy of oral tramadol in cats undergoing ovariohysterectomy.

METHODS

Twenty-four female domestic cats, American Society of Anesthesiologists class I, aged 4-24 months, were included in this positive controlled, randomised, blinded clinical trial. Cats admitted for ovariohysterectomy were allocated to group oral tramadol (GOT, n = 12) or group intramuscular tramadol (GIMT, n = 12). In GOT, tramadol (6 mg/kg) was given orally 60 mins, and saline was given intramuscularly 30 mins, before induction of anaesthesia. In GIMT, granulated sugar in capsules was given orally 60 mins and tramadol (4 mg/kg) intramuscularly 30 mins before induction of anaesthesia. In both groups, dexmedetomidine (0.007 mg/kg) was given intramuscularly 30 mins before induction of anaesthesia with intravenous propofol. Anaesthesia was maintained with isoflurane in oxygen, and atipamezole (0.037 mg/kg) was given intramuscularly 10 mins after extubation. The UNESP-Botucatu multidimensional composite scale was used to conduct pain assessments before premedication and at 20, 60, 120, 240 and 360 mins post-extubation or until rescue analgesia was given. To compare groups, the 60 min postoperative pain scores and the highest postoperative pain scores were analysed via a two-tailed Mann-Whitney test, and the incidences of rescue analgesia were analysed via a Fisher's exact test; P <0.05.

RESULTS

There was no significant difference between groups for the 60 min (P = 0.68) pain scores. The highest postoperative pain score was higher for GIMT compared with GOT (P = 0.04). Only two cats required rescue analgesia, both from GIMT. The incidence of rescue analgesia was not significantly different between groups (P = 0.46).

CONCLUSIONS AND RELEVANCE

In the present study, preoperative administration of oral tramadol at 6 mg/kg to cats provided adequate analgesia for 6 h following ovariohysterectomy surgery.

Feline procedural sedation and analgesia: When, why and how

PRACTICAL RELEVANCE

Procedural sedation and analgesia (PSA) describes the process of depressing a patient's conscious state to perform unpleasant, minimally invasive procedures, and is part of the daily routine in feline medicine. Maintaining cardiopulmonary stability is critical while peforming PSA.

CLINICAL CHALLENGES

Decision-making with respect to drug choice and dosage regimen, taking into consideration the cat's health status, behavior, any concomitant diseases and the need for analgesia, represents an everyday challenge in feline practice. While PSA is commonly perceived to be an uneventful procedure, complications may arise, especially when cats that were meant to be sedated are actually anesthetized.

AIMS

This clinical article reviews key aspects of PSA in cats while exploring the literature and discussing complications and risk factors. Recommendations are given for patient assessment and preparation, clinical monitoring and fasting protocols, and there is discussion of how PSA protocols may change blood results and diagnostic tests. An overview of, and rationale for, building a PSA protocol, and the advantages and disadvantages of different classes of sedatives and anesthetics, is presented in a clinical context. Finally, injectable drug protocols are reported, supported by an evidence-based approach and clinical experience.

Controlled, non-inferiority trial of bupivacaine liposome injectable suspension

OBJECTIVES

Recently, a bupivacaine liposome injectable suspension (BLIS) became commercially available in the veterinary market that may provide local analgesia for 72 h. The purpose of this study was to compare a BLIS incisional block with a control protocol in cats after ovariohysterectomy (OHE). The hypothesis was that a BLIS block would provide equivalent pain relief.

METHODS

This study was designed as a randomized, double-blind, non-inferiority trial. Students performed an OHE followed by a two-layer incisional and body wall block with either standard bupivacaine (control) or BLIS. Postoperatively, cats in the control group received robenacoxib, whereas the BLIS cats received saline. All cats were evaluated using the feline Glasgow Composite Measure Pain Scale (GCMPS) at multiple time points postoperatively.

RESULTS

There were 24 control cats and 23 BLIS cats. One cat from each group required rescue medication. The mean GCMPS scores were low and the groups were equivalent at all time points (P <0.05). This study showed that BLIS was equivalent to the control group up to 42 h and pain scores remained low up to 68 h after surgery.

CONCLUSIONS AND RELEVANCE

BLIS incisional block is equivalent to a control pain protocol and reduces the need for continued postoperative drug administration.

A randomized clinical trial comparing butorphanol and buprenorphine within a multimodal analgesic protocol in cats undergoing orchiectomy

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.

Comparison of two high doses of subcutaneous buprenorphine in cats undergoing ovariohysterectomy

Objectives:

The aim of the study was to evaluate the analgesia and recovery effects of two doses (0.12 mg/kg and 0.24 mg/kg) of subcutaneous buprenorphine in cats undergoing ovariohysterectomy.

Methods:

This was an assessor-blinded, randomised, clinical study. A total of 83 cats were recruited and randomly allocated to receive 0.12 mg/kg buprenorphine or 0.24 mg/kg buprenorphine subcutaneously, followed 30 minutes later by 40 μg/kg medetomidine intramuscularly. Anaesthesia was induced with intravenous alfaxalone to effect and maintained with isoflurane in oxygen. All cats received meloxicam before surgery. Temperament score, quality of sedation, induction of anaesthesia, dose of alfaxalone and recovery were scored using simple descriptive scales. Atipamazole was administered following surgery. Physiological variables during anaesthesia were recorded. Cats were assessed postoperatively by the same blinded observer at 2, 4 and 24 hours using a modified Colorado Feline Acute Pain scale. The presence or absence of mydriasis was noted.

Results:

No significant differences were identified between groups. Three cats in the 0.12 mg/kg group and four in the 0.24 mg/kg group required rescue analgesia. Mydriasis persisting for at least 24 hours was evident in 75 cats.

Conclusions and relevance:

No differences in analgesia were detected between groups with these protocols; mydriasis was common in both groups.

Pharmacokinetics of low-dose and high-dose buprenorphine in cats after rectal administration of different formulations

OBJECTIVES

A prospective experimental study was performed in nine young healthy cats to investigate a pharmacokinetic profile and the clinical relevance of rectally administered buprenorphine. Rectal pH value was measured in all nine cats.

METHODS

Blood was collected 15, 30, 60, 90, 120, 240 and 480 mins and 24 h after the rectal administration of a suppository and a gel at doses between 0.02 mg/kg and 0.1 mg/kg buprenorphine to determine the plasma concentration of buprenorphine. Rectal pH was measured with pH paper.

RESULTS

Upon pharmacokinetic non-compartment analysis of high-dose buprenorphine (0.1 mg/kg), average maximal plasma concentration was found to be 1.13 ng/ml, time to maximal plasma concentration was 45 mins and area under the plasma concentration-time curve was 94.19 ng*min/ml, representing low but potential bioavailability. Mean residual time was 152.2 mins and the half-life was 92.6 mins. A wide range of plasma concentrations within the cohort was measured and two of the cats had to be excluded from statistical analysis owing to incomplete uptake. Vital parameters of all cats were considered to be normal but three of the cats showed mydriasis up to 8 h after application. After the administration of a low-dose suppository or a rectal gel (0.02 mg/kg) within pilot studies, no buprenorphine was detected in cat plasma. Rectal pH in all cats was between 7.7 and 8.

CONCLUSIONS AND RELEVANCE

The rectal application of buprenorphine at a dose of 0.1 mg/kg revealed a potential but weak uptake in cats. Regarding effective concentrations in previous pharmacokinetic investigations, rectal administration is currently not recommended for good provision of opioid analgesia in cats. Pharmacological investigations of formulation and galenics in order to improve the rectal bioavailability of buprenorphine remain to be clarified before further dose-finding and pharmacokinetic/pharmacodynamic studies are performed.

Comparison of intramuscular butorphanol and buprenorphine combined with dexmedetomidine for sedation in cats

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.

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.

A survey of dog and cat anaesthesia in a sample of veterinary practices in New Zealand

AIMS

To survey current anaesthesia practices for dogs and cats in small and mixed animal practices in New Zealand in order to improve anaesthesia education.

METHODS

A questionnaire was sent to 440 small and mixed animal practices, including questions regarding the type of practice, preanaesthetic examination, anaesthetic drugs and management, anaesthetic machines, monitoring and topics of interest for continuing professional development.

RESULTS

Responses were obtained from 113/440 (26%) practices, with 78 (69%) respondents from small and 35 (31%) from mixed animal practices. A preanaesthetic physical examination was carried out by >95% of respondents and premedication was usually given to dogs (112/113; 99%) and cats (95/113; 85%). Acepromazine was the preferred sedative for dogs and cats, with morphine or buprenorphine. Propofol and alfaxalone were the preferred induction agents, and isoflurane was preferred for maintenance in both dogs and cats. A venous catheter was usually placed for anaesthesia in dogs (59/113; 52%), but less so in cats (39/113; 35%). Perioperative fluid was administered at 10 mL/kg/hour by 62/110 (56%) respondents. Intubation was usually used for anaesthesia in dogs (111/112; 99%), and cats (87/112; 78%). Almost 40% of respondents usually administered supplementary oxygen if patients were not intubated. Local analgesia was used by 69/111 (88%) respondents sometimes or always if applicable. Morphine or buprenorphine, and meloxicam were common choices for post-operative analgesia after neuter surgery in dogs and cats. A semiclosed (non-rebreathing) system was used in animals weighing <10 kg, and a Mapleson E or F non-rebreathing circuit was used by 66/109 (61%) practices. Only 15/111 (14%) practices had a ventilator in their practice. A dedicated anaesthetist was usually used by 104/113 (92%) practices, and apnoea alarms, pulse oximeters, thermometers and oesophageal stethoscopes were the main monitoring devices available in practices. Loco-regional block, pain management, and anaesthetic drugs were the main topics of interest for continuing education.

CONCLUSIONS AND CLINICAL RELEVANCE

Responses by the veterinarians taking part in this survey indicated that they had a reasonably good standard of anaesthetic practice. A physical examination was carried out preanaesthesia, and premedication including analgesia was routinely administered to most patients. A dedicated anaesthetist usually monitored patients and most respondents reported they had access to basic anaesthetic monitoring equipment. Areas where changes could lead to improved anaesthetic practice were increased use of I/V catheterisation, endotracheal intubation, and supplementary oxygen, and reduced I/V fluid rates.

Influence of two administration rates of propofol at induction of anaesthesia on its relative potency in cats: a pilot study

Objectives This was a randomised, blinded trial to investigate the influence of administration rate on the dose of propofol required for the orotracheal intubation of cats. Methods Twenty-four female domestic cats undergoing ovariohysterectomy were premedicated with oral tramadol (6 mg/kg) or intramuscular tramadol (4 mg/kg), and intramuscular dexmedetomidine (0.007 mg/kg). Oral or intramuscular (IM) tramadol was administered 60 or 30 mins prior to induction of anaesthesia, respectively. Dexmedetomidine was administered 30 mins prior to anaesthetic induction. Sedation scores were established prior to anaesthesia induction with propofol intravenously at 4 mg/kg/min (fast) or 1 mg/kg/min (slow) to effect until orotracheal intubation was achieved without coughing. If coughing occurred, the intubation process was paused for 15 s. Four groups were determined: IM tramadol/propofol fast (GIMF, n = 6); IM tramadol/propofol slow (GIMS, n = 6); oral tramadol/propofol fast (GOF, n = 6); oral tramadol/propofol slow (GOS, n = 6). The Shapiro-Wilk test was used to evaluate for normality of residuals. Sedation scores and propofol anaesthetic induction doses were compared between GIMF and GIMS groups, and between GOF and GOS groups using the Mann-Whitney test and the t-test, respectively ( P = 0.05). The presence of hypotension (mean arterial blood pressure <60 mmHg) or apnoea (no breathing for 30 s or more) within the first 15 mins postintubation was recorded. Results The median sedation scores for GIMF and GOF were not significantly different compared with those for GIMS ( P = 0.94) and GOS ( P = 0.70). However, the mean ± SD propofol anaesthetic induction doses were higher in GIMF (9.1 ± 1.8 mg/kg) and GOF (7.9 ± 1.7 mg/kg) than in GIMS (5.1 ± 1.5 mg/kg; P <0.01) and GOS (5.4 ± 0.3 mg/kg; P <0.01). No hypotension or apnoea were detected. Conclusions and relevance Using the slower anaesthetic induction rate resulted in an increase in propofol relative potency.

Influence of two administration rates of alfaxalone at induction on its relative potency in cats: a pilot study

Objectives The aim of the study was to evaluate, in a controlled, randomised, masked clinical trial, the influence of administration rate of alfaxalone at induction on its relative potency in cats and to report the incidence of cardiorespiratory adverse effects. Methods Twelve healthy female domestic cats admitted for ovariohysterectomy were premedicated with buprenorphine 20 µg/kg intramuscularly and alfaxalone 3.0 mg/kg subcutaneously. Sedation scores were established (using a published scale ranging from 1 [no sedation] to 5 [profound sedation]) prior to anaesthesia induction with alfaxalone intravenously at 2 mg/kg/min (group A2; n = 6) or 0.5 mg/kg/min (group A0.5; n = 6) to effect until orotracheal intubation was achieved. Sedation scores and alfaxalone induction doses were compared between the groups, using a Mann-Whitney exact test. Results are reported as median and range. Presence of apnoea (no breathing for more than 30 s) or hypotension (mean arterial blood pressure <60 mmHg) within 5 mins postintubation was also reported. Results Although sedation scores (1.5 [range 1.0-3.0] and 2.5 [range 1.0-3.0] for A2 and A0.5, respectively) were not significantly different ( P = 0.32), cats in group A2 required significantly more alfaxalone (4.3 mg/kg [range 3.4-7.0 mg/kg]) than group A0.5 (2.1 mg/kg [range 1.5-2.5 mg/kg]) ( P = 0.002). Two cats in each group presented postinduction apnoea, and two cats in group A2 and three cats in group A0.5 presented postinduction hypotension. Conclusions and relevance The use of a slower induction infusion rate resulted in an increase in the alfaxalone relative potency without obvious cardiorespiratory benefit.

Analgesic efficacy of intraperitoneal administration of bupivacaine in cats

Objectives The aim of this study was to evaluate the analgesic efficacy of intraperitoneal (IP) bupivacaine in cats undergoing ovariohysterectomy (OVH). Methods Forty-five cats were included in a randomized, prospective, blinded study after owners' written consent was obtained. The anesthetic protocol included acepromazine-buprenorphine-propofol-isoflurane. A ventral midline incision was made and cats (n = 15/group) were administered either IP saline 0.9% (negative and positive control groups; NG and PG, respectively) or IP bupivacaine (2 mg/kg; bupivacaine group; BG). Cats in the PG received meloxicam (0.2 mg/kg SC). An OVH was performed and postoperative pain was evaluated using a dynamic interactive visual analog scale (DIVAS), the UNESP-Botucatu multidimensional composite pain scale (MCPS) and mechanical nociceptive thresholds (MNT) for up to 8 h after the end of surgery. Postoperative sedation was evaluated using DIVAS. Rescue analgesia was provided with buprenorphine and/or meloxicam. Repeated measures linear models and a Cochran-Mantel-Haenszel test were used for statistical analysis ( P <0.05). Results There was a significant effect of treatment on the number of times rescue analgesia was administered ( P = 0.002) (PG, n = 2, 13%; NG, n = 12, 80%; BG, n = 4, 27%) with the number of rescues being higher in the NG group than in the PG ( P = 0.0004) and BG ( P = 0.02) groups. The DIVAS, MCPS and MNT were significantly different when compared with baseline values at different time points; however, data were not significantly different among groups. Conclusions and relevance Treatments PG and BG produced similar analgesia in terms of pain scores, number of times rescue analgesia was administered and MNT. Based on rescue analgesia, IP administration of bupivacaine provides analgesia in cats after OVH.

Effects of ketamine and alfaxalone on application of a feline pain assessment scale

OBJECTIVES

The objective of this study was to compare the effects of ketamine and alfaxalone on the application of a validated feline-specific multidimensional composite pain scale (UNESP-Botucatu MCPS).

METHODS

In a prospective, randomized, blinded, crossover trial, 11 adult cats (weight 4.4 ± 0.6 kg) were given dexmedetomidine (15 μg/kg) and hydromorphone (0.05 mg/kg) with either alfaxalone (2 mg/kg) or ketamine (5 mg/kg) as a single intramuscular injection for the induction of general anesthesia. After orotracheal intubation, general anesthesia (without surgery) was maintained for 32 mins with isoflurane, followed by atipamezole. The following parameters were recorded at baseline, 1-8 h and 24 h post-extubation: pain (pain expression and psychomotor subscales) and sedation scale scores. Alfaxalone treatment injection sites were examined for inflammation at baseline, postinjection, and 8 h and 24 h post-extubation.

RESULTS

Psychomotor scores were higher with ketamine at hours 1 (3.5 [0-5.0], P <0.0001), 2 (2.5 [0-4.0], P <0.0001) and 3 (0.5 [0-4.0], P = 0.009) post-extubation compared with alfaxalone (hour 1, 0 [0-2]; hour 2, 0 [0-0]; hour 3, 0 [0-0]). Six cats in the ketamine group crossed the analgesic intervention threshold. In contrast, pain expression scores did not differ significantly between treatments at any time (P >0.05); one cat from each group crossed the analgesic intervention threshold. Sedation was greater with ketamine (1 [0-3], P = 0.02) than alfaxalone (0 [0-1]) 1 h post-extubation. No cats had visible inflammation at the injection sites at any time.

CONCLUSIONS AND RELEVANCE

Ketamine has a confounding effect on the psychomotor subscale of the pain scale studied, which may lead to erroneous administration of rescue analgesia. In contrast, alfaxalone was not associated with significant increases in either pain subscale. These effects of ketamine should be considered when evaluating acute postoperative pain in cats.

Evaluation of the influence of atipamezole on the postoperative analgesic effect of buprenorphine in cats undergoing a surgical ovariohysterectomy

OBJECTIVE

To evaluate the influence of atipamezole on postoperative pain scores in cats.

STUDY DESIGN

Controlled, randomized, masked clinical trial.

ANIMALS

Twelve healthy female domestic cats.

METHODS

Cats admitted for ovariohysterectomy (OVH) surgery were randomly allocated to group atipamezole (n = 6) or group saline (n = 6) and were premedicated with buprenorphine 20 μg kg(-1) intramuscularly (IM) and alfaxalone 3.0 mg kg(-1) subcutaneously (SC). Anaesthesia was induced with alfaxalone intravenously (IV) to effect and maintained with isoflurane in oxygen. Ten minutes after extubation, cats from group atipamezole received IM atipamezole (0.0375 mg kg(-1) ) whereas group saline received an equivalent volume [0.0075 mL kg(-1) (0.003 mL kg(-1) IM)] of 0.9% saline. A validated multidimensional composite scale was used to assess pain prior to premedication and postoperatively (20 minutes after extubation). If postoperative pain scores dictated, rescue analgesia consisting of buprenorphine and meloxicam were administered. Pain score comparisons were made between the two groups using a Mann-Whitney exact test. Results are reported as the median and range.

RESULTS

Preoperatively, all cats scored 0. At the postoperative pain evaluation, the pain scores from group atipamezole [16 (range, 12-20)] were not significantly different from group saline [18 (range, 15-23)] (p = 0.28). All cats required rescue analgesia post-operatively.

CONCLUSIONS AND CLINICAL RELEVANCE

Atipamezole (0.0375 mg kg(-1) IM) administration did not significantly affect the postoperative pain scores in cats after OVH. Preoperative administration of buprenorphine (20 μg kg(-1) IM) did not provide adequate postoperative analgesia for feline OVH.

2015 AAHA/AAFP pain management guidelines for dogs and cats

RATIONALE

The robust advances in pain management for companion animals underlie the decision of the American Animal Hospital Association (AAHA) and American Association of Feline Practitioners (AAFP) to expand on the information provided in the 2007 AAHA/AAFP Pain Management Guidelines. The 2015 Guidelines summarize and offer a discriminating review of much of this new knowledge.

RELEVANCE

Pain management is central to veterinary practice, alleviating pain, improving patient outcomes, and enhancing both quality of life and the veterinarian-client-patient relationship. These Guidelines support veterinarians in incorporating pain management into practice, improving patient care.

APPROACHES

The management of pain requires a continuum of care that includes anticipation, early intervention, and evaluation of response on an individual patient basis. A team-oriented approach, including the owner, is essential for maximizing the recognition, prevention and treatment of pain in animals.

EVIDENCE BASE

The Guidelines include both pharmacologic and non-pharmacologic modalities to manage pain; they are evidence-based insofar as possible and otherwise represent a consensus of expert opinion. Behavioral changes are currently the principal indicator of pain and its course of improvement or progression, and the basis for recently validated pain scores. Post-surgical pain is eminently predictable but a strong body of evidence exists supporting strategies to mitigate adaptive as well as maladaptive forms. Chronic pain is dominated by degenerative joint disease (DJD), which is one of the most significant and under-diagnosed diseases of cats and dogs. DJD is ubiquitous, found in pets of all ages, and inevitably progresses over time; evidence-based strategies for management are established in dogs, and emerging in cats.