Retrospective comparison between low-volume high-concentration and high-volume low-concentration levobupivacaine for bilateral erector spinae plane block in dogs undergoing hemilaminectomy.

OBJECTIVE: To compare the analgesic effect of a bilateral ultrasound-guided erector spinae plane block (ESPB) in dogs undergoing hemilaminectomy using either a low-volume high-concentration (LV-HC) or a high-volume low-concentration (HV-LC) local anaesthetic solution. STUDY DESIGN: Retrospective observational equivalence trial. ANIMALS: A total of 391 client-owned dogs undergoing hemilaminectomy. METHODS: Dogs were assigned to group LV-HC or HV-LC depending on whether 0.2-0.25% levobupivacaine (0.4-0.5 mL kg-1) or 0.125-0.15% levobupivacaine (0.8-1 mL kg-1) was used to perform the ESPB, respectively. The number of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of fentanyl administered, the overall methadone consumption during the first 24 hours postoperatively and anaesthetic complications were recorded. Univariate and multivariate statistical analyses were performed considering p < 0.05 significant. RESULTS: A total of 248 and 143 dogs were assigned to groups LV-HC and HV-LC, respectively. In group HV-LC, the number of dogs requiring fentanyl intraoperatively (64.3%) was higher (p = 0.0001) than that in group LV-HC (43.5%). The overall intraoperative fentanyl consumption was higher in group HV-LC between the first skin incision and the end of the lamina drilling (p = 0.028). According to the regression analysis, the group allocation was the best variable to predict the intraoperative fentanyl consumption (p < 0.001). Antimuscarinic drugs were administered more frequently in group LV-HC (p < 0.02). However, the prevalence of hypotension and other pharmacological cardiovascular interventions did not differ between groups. No differences in methadone consumption during the first 24 hours postoperatively were found between the groups. CONCLUSIONSAND CLINICAL RELEVANCE: When performing a bilateral ESPB in dogs undergoing hemilaminectomy, compared with HV-LC, the use of LV-HC local anaesthetic solution reduces the intraoperative fentanyl consumption without affecting the postoperative methadone requirement.

Analgesic efficacy of a bilateral erector spinae plane block versus a fentanyl constant rate infusion in dogs undergoing hemilaminectomy: a retrospective cohort study.

BACKGROUND: Erector spinae plane block (ESPB) is an ultrasound-guided interfascial plane block used to provide analgesia in dogs undergoing hemilaminectomy. The aim of this study is to compare the analgesic efficacy of a bilateral ESPB with a fentanyl constant rate infusion (CRI) in dogs undergoing hemilaminectomy. METHODS: This is a retrospective cohort study. Anaesthetic records of client-owned dogs undergoing hemilaminectomy (June 2019-August 2020), and in which a bilateral ESPB was performed (group ESPB), were retrieved and compared to a cohort of 39 dogs that underwent hemilaminectomy (September 2014 - June 2017) and in which a fentanyl CRI (2 µg/kg bolus followed by 5 µg/kg/hour) was used as a primary intraoperative analgesia (group CRI). The prevalence of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of rescue fentanyl boluses administered, the postoperative methadone requirement and anaesthetic complications during the first 24 postoperative hours were evaluated. Univariate statistical analysis was used. RESULTS: Group ESPB comprised of 93 dogs. The bilateral ESPB was performed using a median (range) levobupivacaine volume of 1 (0.5-1.7) mL/kg per side, at a concentration of 0.125% (0.12-0.25). At least one rescue fentanyl bolus was administered in 54.8% and in 56.4% of dogs in group ESPB and CRI, respectively (p > 0.99). The number of rescue fentanyl boluses was higher in group CRI (p = 0.006), especially during lumbar hemilaminectomy. Rescue fentanyl boluses were more frequently administered from skin incision to end of vertebral lamina drilling in group CRI (p = 0.001), and from end of vertebral lamina drilling to end of surgery in group ESPB (p = 0.0002). During the first 6 (p = 0.0035) and 6-12 (p = 0.0005) postoperative hours, the number of dogs that required at least one dose of methadone was higher in group CRI. In group ESPB, dogs were more likely to become hypothermic (p = 0.04). One dog, not included in the study, developed sinus arrest after performing a caudal thoracic ESPB. CONCLUSIONS: Under the conditions of this study, a bilateral ESPB was associated with a lower number of rescue fentanyl boluses administered in dogs undergoing hemilaminectomy, especially between skin incision to end of vertebral lamina drilling. Despite ESPB being associated with a reduced opioid consumption during the first 12 hours postoperatively, differences in the postoperative management precluded any firm conclusion regarding its postoperative effect.

Success Rate and Perioperative Complications of Lumbosacral Extradural Anaesthesia in Dogs Undergoing Total Hip Replacement: A Double-Centre Retrospective Study.

OBJECTIVE: The aim of this study was to retrospectively evaluate the success rate and perioperative complications of lumbosacral extradural anaesthesia in dogs undergoing total hip replacement. STUDY DESIGN: Records of dogs undergoing total hip replacement in which lumbosacral extradural anaesthesia with 0.5% levo- or bupivacaine combined with either morphine or buprenorphine were retrieved. Success rate was defined as intraoperative fentanyl consumption <1 µg/kg/h with no intravenous infusion of other analgesic drugs and no additional morphine/methadone within the first 3 hours from premedication. Prevalence of intraoperative anaesthetic and postoperative surgical complications was calculated. RESULTS: Overall, 206 dogs were included in the study. Success rate was 88.7%. Hypercapnia (75.2%), hypotension (46.1%), hypothermia (27.7%) and regurgitation (6.3%) were recorded during anaesthesia. Within 24 hours post-surgery, urinary retention (17.8%), vomiting/regurgitation/diarrhea (8.2%) and sciatic neurapraxia of the operated limb (5.8%) were recorded. Luxation of the operated hip occurred at 48 and 72 hours after surgery in two dogs and one dog respectively. One dog had cardiopulmonary arrest at 52 hours after surgery. CONCLUSION: While hypercapnia, hypotension and hypothermia might develop intraoperatively, the high success rate and the relatively low prevalence of postoperative surgical complications directly associated with lumbosacral extradural anaesthesia justify its use in dogs undergoing total hip replacement.