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Objective: To evaluate the efficacy of a perineural injection of dexmedetomidine combined with ropivacaine for reducing postoperative methadone requirements in dogs after tibial plateau levelling osteotomy (TPLO)., Study Design: A prospective, clinical, randomized and blinded trial., Animals: A total of 58 client-owned dogs., Methods: Ultrasound-guided midfemoral sciatic and inguinal femoral nerve blocks with ropivacaine (1 mg kg -1 per nerve block) combined with either dexmedetomidine (0.5 μg kg -1 per nerve block; group DEX) or the same volume of saline (group CON) were performed in dogs undergoing TPLO. Pain was assessed 30 minutes, 2 hours and then every 4 hours for 24 hours after surgery with a validated pain scale (4AVet). Meloxicam (0.15 mg kg -1 ) was administered intravenously (IV) at recovery. Rescue methadone (0.2 mg kg -1 IV) was administered if a score ≥ 6 (maximal score 18) was recorded and the number of postoperative doses was analysed by Fisher exact tests. The study was performed in parallel at a Veterinary Teaching Hospital (VTH) and a private Veterinary Referral Centre (VRC)., Results: Dogs received a total of 22 and 31 postoperative doses of methadone in groups DEX (14 doses at VRC, eight doses at VTH) and CON (28 doses at VRC, three doses at VTH), respectively. Overall, there was no difference in the postoperative rescue analgesia requirements between groups (p = 0.244). At the VRC, dogs received less methadone (p = 0.026) in group DEX compared with group CON, whereas at the VTH, there was no difference between groups (p = 0.216)., Conclusions and Clinical Relevance: Perineural dexmedetomidine combined with ropivacaine did not reduce postoperative methadone requirements in dogs after TPLO, but results may differ from one centre to another. This discrepancy might be linked to variations in clinical practices and questions the validity of results obtained from single-centre randomized controlled trials but applied to different clinical settings., (Copyright © 2022 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To determine the intraoperative and early postoperative opioid requirement after ultrasound-guided sciatic and/or femoral nerve block or epidural anaesthesia in dogs undergoing tibial plateau levelling osteotomy (TPLO)., Study Design: Prospective, masked, pilot, randomized, clinical trial., Animals: A total of 40 client-owned dogs undergoing TPLO., Methods: Each dog was randomly assigned to group SF (combined sciatic and femoral nerve block), group S (sciatic nerve block), group F (femoral nerve block) or group E (epidural anaesthesia). A total of 0.3 mL kg -1 of ropivacaine 0.5% was administered to each nerve or in the epidural space. Intraoperatively, fentanyl (2 μg kg -1 ) was administered intravenously when heart rate, mean arterial pressure or respiratory rate increased by >30% compared with baseline values. Postoperatively, a visual analogue scale (VAS) and a modified German version of the French pain scale (4AVet) were used to assess pain every 30 minutes for 150 minutes and again once the morning after surgery. Methadone (0.1 mg kg -1 ) was administered intravenously if the VAS was ≥ 4 cm [maximal value 10 cm; median (interquartile range)] or the composite pain score was ≥5 [maximal value 15; median (interquartile range)]. Significance was defined as p ≤ 0.05., Results: Groups SF and E required less total intraoperative and early postoperative opioid doses compared with groups S and F (p = 0.031). No dogs in group SF had a block failure or required postoperative methadone. A reduced methadone requirement was found in group SF compared with all the other groups up to 150 minutes after recovery (p = 0.041)., Conclusions and Clinical Relevance: Combined sciatic and femoral nerve block and epidural anaesthesia lead to less cumulative consumption of perioperative opioids than single nerve blockade. Sciatic or femoral nerve block alone might be insufficient to control nociception and early postoperative pain in dogs undergoing TPLO., (Copyright © 2021 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To compare the isoflurane-sparing effects of sufentanil-lidocaine-ketamine (SLK) and fentanyl-lidocaine-ketamine (FLK) infusions in dogs undergoing total ear canal ablation and lateral bulla osteotomy (TECA-LBO)., Study Design: Randomized blinded clinical study., Animals: A group of 20 client-owned dogs undergoing TECA-LBO., Methods: Intravenous (IV) administration of lidocaine (3 mg kg -1 ) and ketamine (0.6 mg kg -1 ) with fentanyl (5.4 μg kg -1 ; n = 10; FLK group) or sufentanil (0.72 μg kg -1 ; n = 10; SLK group) was immediately followed by the corresponding constant rate infusion (CRI) (lidocaine 3 mg kg -1 hour -1 ; ketamine 0.6 mg kg -1 hour -1 ; either fentanyl 5.4 μg kg -1 hour -1 or sufentanil 0.72 μg kg -1 hour -1 ). Anaesthesia was induced with propofol 3-5 mg kg -1 IV and was maintained with isoflurane. End-tidal isoflurane concentration (Fe'Iso) was decreased in 0.2% steps every 15 minutes until spontaneous movements were observed (treated with propofol 1 mg kg -1 IV) or an increase of > 30% in heart rate or mean arterial pressure from baseline occurred (treated with rescue fentanyl or sufentanil). Quality of recovery and pain were assessed at extubation using the short-form Glasgow Composite Pain Scale (SF-GCPS), Colorado State University Canine Acute Pain scale (CSU-CAP), and visual analogue scale (VAS). Data were analysed with analysis of variance, t tests, Fisher test and Spearman coefficient (p < 0.05)., Results: Fe'Iso decreased significantly in SLK group (45%; p = 0.0006) but not in FLK (15%; p = 0.1135) (p = 0.0136). SLK group had lower scores for recovery quality (p = 0.0204), SF-GCPS (p = 0.0071) and CSU-CAP (p = 0.0273) than FLK at extubation. Intraoperative rescue analgesia and VAS were not significantly different between groups., Conclusions and Clinical Relevance: Compared with FLK infusion, CRI of SLK at these doses decreased isoflurane requirements, decreased pain scores and improved recovery quality at extubation in dogs undergoing TECA-LBO., (Published by Elsevier Ltd.)

Objective: To develop a modified ultrasound-guided parasacral approach to the sciatic nerve and compare the effects of a volume of 0.2 mL kg -1 of 0.5% levobupivacaine with an equivalent volume of 0.9% saline injected near the sciatic nerve., Study Design: Cadaveric and experimental, blinded, randomized study., Animals: Seven canine cadavers and seven experimental Beagle dogs., Methods: Both sciatic nerves of seven cadavers were identified using a modified in-plane ultrasound-guided approach. Methylene blue solution (0.2 mL) was injected perineurally, and success was evaluated through dissection. The same approach was repeated in seven Beagle dogs sedated with dexmedetomidine (50 μg kg -1 ) injected intramuscularly (IM). After randomization, 0.2 mL kg -1 of 0.5% levobupivacaine (limb L) and 0.2 mL kg -1 of 0.9% saline (limb C) were injected perineurally on either right or left limb. Block success was determined by sensory deficits every hour for 8 hours after an atipamezole injection (0.2 mg kg -1 ) IM. Reaction to pinprick (binary score) over the course of the sciatic nerve (four locations) and locomotion were assessed., Results: The overall sciatic nerve block success was 93% in cadavers and 86% in sedated dogs. It was impossible to localize the sciatic nerves in one obese sedated dog. Significant differences between limb L and limb C were observed for pinprick at great trochanter, caudal thigh and lateral tarsal joint (p < 0.0001). Reaction to pinprick was absent in all dogs at great trochanter and caudal thigh up to at least 3 hours on limb L. Locomotion was impaired in all but one dog for 60 (30-210) minutes (median; interquartile range). No complications were observed., Conclusions and Clinical Relevance: A volume of ≥0.2 mL kg -1 and a concentration of 0.5% levobupivacaine can be recommended when using a modified ultrasound-guided parasacral approach to the sciatic nerve in dogs., (Copyright © 2018 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To investigate whether an intravenous (IV) lidocaine bolus in calves premedicated with xylazine-butorphanol reduces the amount of ketamine required to allow endotracheal intubation., Study Design: Randomized, prospective clinical study., Animals: In total, 41 calves scheduled for elective umbilical surgery., Methods: Calves were randomly assigned to one of two groups (L: lidocaine or S: saline). The calves were administered xylazine (0.07 mg kg -1 ) and butorphanol (0.1 mg kg -1 ) intramuscularly and 10 minutes later lidocaine (2 mg kg -1 ; group L) or saline (group S) IV over 1 minute. After 2 minutes, ketamine (2.5 mg kg -1 ) was injected IV. If the depth of anaesthesia was insufficient for intubation, additional ketamine (1 mg kg -1 ) was administered every minute until intubation was successful. The amount of ketamine required for intubation, respiratory rate, pulse rate, arterial pressures, the depth of sedation and conditions of endotracheal intubation after induction of anaesthesia were compared between the two groups., Results: The calves in group L were sedated more deeply than those in group S; however, neither the median (range) amount of ketamine required for intubation, 3.5 (2.5-4.5) mg kg -1 and 3.5 (2.5-3.5) mg kg -1 , respectively, nor the induction quality differed significantly between the groups., Conclusion and Clinical Relevance: A bolus of lidocaine (2 mg kg -1 ) administered 10 minutes after xylazine-butorphanol in calves deepened the degree of sedation but did not decrease the requirement of ketamine for endotracheal intubation. No adverse effects were recorded in the physiological variables measured., (Copyright © 2017. Published by Elsevier Ltd.)