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.

The influence of demeanor on scores from two validated feline pain assessment scales during the perioperative period.

OBJECTIVE: To evaluate the effects of demeanor on validated pain assessment scales. STUDY DESIGN: Prospective, blind, clinical trial. ANIMAL POPULATION: Thirty three adult domestic cats scheduled for orchiectomy. METHODS: Cats were assessed for pain pre (baseline) and 1, 2, 4 hours postoperatively using two validated pain scales [Composite Measures Pain Scale-Feline (rCMPS-F) and UNESP-Botucatu multidimensional composite pain scale (psychomotor and pain expression subscales; U-B MCPS-psych and -painex)], and a demeanor scale. Return of sternal recumbency and postoperative feeding were recorded. Anesthesia consisted of a single intramuscular injection of dexmedetomidine-ketamine-hydromorphone with intratesticular lidocaine and atipamezole and meloxicam postoperatively. Following data collection, cats were assigned to two groups based on baseline demeanor scores (LO ≤ 5/21, 18 cats; HI ≥ 6/21, 15 cats) and data from each group compared. RESULTS: Baseline demeanor predicted pain scores with the U-B MCPS-psych scale: baseline [LO 0 (0-0), HI 2 (0-6), p = 0.0005], 1 hour [LO 1 (0-5), HI 3 (1-5), p = 0.02], and 4 hours [LO 0 (0-2), HI 1 (0-6), p = 0.01]. A similar pattern was observed with the rCMPS-F. This resulted in more crossings of the analgesic intervention threshold in the HI group: U-B UNESP-psych (9 versus 1, p = 0.005) and rCMPS-F (23 versus 3, p < 0.0001). In contrast, U-B MCPS-painex scores did not differ between LO/HI groups: baseline (p > 0.99), 1 hour (p = 0.34), 2 hours (p > 0.99) and 4 hours (p = 0.31). LO cats ate sooner (61% versus 33% by 1 hour, p < 0.0001) despite similar times to sternal recumbency (p = 0.48). CONCLUSIONS AND CLINICAL RELEVANCE: Demeanor affected pain assessment with U-B UNESP-psych and rCMPS-F scales, but not U-B UNESP-painex scale. Demeanor had a significant effect on postoperative feeding. These data highlight the potential for demeanor to confound pain assessment.

Evaluation of a portable oxygen concentrator to provide fresh gas flow to dogs undergoing anesthesia.

This study evaluated the ability of a portable oxygen concentrator (POC) to provide fresh gas to an anesthetic machine via an Ayre's T-piece or a Bain circuit. Fraction of inspired oxygen (FiO2) was compared at flows of 0.5 to 3.0 L/min. Measured FiO2 was 96% at flow rates ≥ 1 L/min. Mean battery life at 1.0, 2.0, and 3.0 L/min was 4.21 ± 0.45, 2.62 ± 0.37 and 1.5 ± 0.07 hours, respectively. The POC proved to be useful and effective during 2 power outages. The POC was sufficient to prevent rebreathing in 70% of dogs using a T-piece circuit and 20% of dogs with a Bain circuit. A significant negative correlation between inspired CO2 and O2 flow rates was noted. A significant positive correlation between inspired CO2 and ETCO2 was documented. The occurrence of hypercarbia was associated with low O2 flow. Battery back-up was essential during power outages. The POC can be effectively used for delivery of anesthesia.

Évaluation d'un concentrateur d'oxygène portable pour fournir une circulation de gaz frais aux chiens subissant une anesthésie. Cette étude a évalué la capacité d'un concentrateur d'oxygène portable (COP) à fournir du gaz frais à l'aide d'une pièce en T d'Ayre ou d'un circuit de Bain. La fraction d'oxygène inspiré (FiO2) a été comparée à des débits de 0,5 à 3,0 L/min. La FiO2 mesurée était de 96 % à des taux de débit de ≥ 1 L/min. La durée de vie moyenne de la batterie à 1,0, à 2,0 et à 3,0 L/min était de 4,21 ± 0,45, de 2,62 ± 0,37 et 1,5 ± 0,07 heures, respectivement. Le COP s'est avéré utile et efficace durant deux pannes d'électricité. Le COP a été suffisant pour prévenir la réinspiration chez 70 % des chiens en utilisant un circuit de pièce en T et un circuit de Bain chez 20 % des chiens. Une corrélation négative importante entre le CO2 inspiré et les taux de débit d'O2 a été observée. Une corrélation positive importante entre le CO2 inspiré et l' ETCO2 a été documentée. L'occurrence de l'hypercarbie était associée à un faible débit d'O2. Une batterie de secours était essentielle durant les pannes d'électricité. Le COP peut être efficacement utilisé pour fournir de l'anesthésie.(Traduit par Isabelle Vallières).

Application of fast-track surgery principles to evaluate effects of atipamezole on recovery and analgesia following ovariohysterectomy in cats anesthetized with dexmedetomidine-ketamine-hydromorphone.

OBJECTIVE: To evaluate the effects of atipamezole hydrochloride on recovery and analgesia following ovariohysterectomy in cats anesthetized with a dexmedetomidine hydrochloride, ketamine hydrochloride, and hydromorphone hydrochloride combination, in accordance with fast-track surgery principles. DESIGN: Prospective, randomized, clinical trial. ANIMALS: 44 cats. PROCEDURES: Cats were anesthetized with a combination of dexmedetomidine (15 µg/kg [6.8 µg/lb]), ketamine (5 mg/kg [2.3 mg/lb]), and hydromorphone (0.05 mg/kg [0.023 mg/lb]), IM, supplemented with isoflurane in oxygen. Immediately after ovariohysterectomy, cats received meloxicam (0.2 mg/kg [0.09 mg/lb]) SC and either atipamezole (75 µg/kg [34.1 µg/lb]) or an equivalent volume of saline (0.9% NaCl) solution IM. Pain and sedation were scored at baseline (prior to surgery) and at predetermined intervals after surgery. Time to sternal recumbency was recorded. RESULTS: The atipamezole group recovered to sternal recumbency faster (median, 15 minutes; range, 5 to 60 minutes) than the saline solution group (median, 60 minutes; range, 15 to 90 minutes]). Pain scores did not differ between groups or at any time, compared with baseline, and were below the intervention threshold for most cats. Sedation scores were significantly greater in the saline solution group (median, 0; range, 0 to 2) at 2 hours after surgery, compared with the atipamezole group (median, 0; range, 0 to 0). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that administration of atipamezole, compared with saline solution, allowed for a faster recovery from anesthesia with dexmedetomidine-ketamine-hydromorphone in cats following ovariohysterectomy without compromising analgesia. These findings have implications for the provision of appropriate postoperative analgesia following ovariohysterectomy in cats.