The thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats.

OBJECTIVE: To evaluate the thermal antinociceptive effects of a high-concentration formulation of buprenorphine alone or followed by hydromorphone in conscious cats. STUDY DESIGN: Randomized, blinded, placebo-controlled crossover study design. ANIMALS: A total of six purpose-bred, adult female ovariohysterectomized Domestic Short Hair cats. METHODS: Cats were allocated into three treatments each consisting of two injections, subcutaneous then intravenous (IV) administration, 2 hours apart: treatment SS, two injections of 0.9% saline; treatment BS, buprenorphine (0.24 mg kg-1, 1.8 mg mL-1) and saline; and treatment BH, buprenorphine (0.24 mg kg-1) and hydromorphone (0.1 mg kg-1). Skin temperature (ST) and thermal threshold (TT) were recorded before (baseline) and for 24 hours following first injection. TT data were analyzed using mixed linear models and a Benjamini-Hochberg sequential adjustment procedure (p < 0.05). RESULTS: There were no significant differences among treatments for baseline ST and TT values, treatment SS over time and between treatments BS and BH. Compared with baseline, TT was significantly increased at all time points in treatments BH and BS except at 2 hours in treatment BS. TT was significantly higher than SS at 3-18 hours and 4-12 hours for treatments BS and BH, respectively. Maximal increases in TT were 47.5 °C at 2 hours, 53.9 °C at 3 hours and 52.4 °C at 6 hours in treatments SS, BS and BH, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of IV hydromorphone following high-concentration buprenorphine provided no additional antinociception and decreased the duration of effect when compared with high-concentration buprenorphine alone. Alternative analgesics should be considered if additional analgesia is required after administration of high-concentration buprenorphine.

Anesthetic management and anesthesia-related complications in dogs with a dilated cardiomyopathy phenotype: a retrospective study of 30 dogs (2010-2024).

OBJECTIVE: To describe perioperative anesthetic management in canines with a dilated cardiomyopathy (DCM) phenotype and to compare the frequency of general anesthesia-related complications with a control group of dogs without heart disease. ANIMALS: 30 dogs with DCM phenotype (cases) and 30 dogs without heart disease (controls). METHODS: Dogs presented to a teaching hospital between 2010 and 2024 that were diagnosed with a DCM phenotype via echocardiography were included in this study. Controls were dogs that presented during the same time period and were matched with cases based on their age, breed, and type of procedure; however, no standardization of treatment between the groups was performed. Medical records were reviewed to evaluate the occurrence of anesthetic complications. RESULTS: Of dogs with a DCM phenotype, 2 had overt DCM, 22 had occult DCM, and 6 had equivocal DCM. Dogs with DCM exhibited a lower likelihood of being premedicated with dexmedetomidine or induced with propofol. Conversely, DCM dogs were more likely to be induced with etomidate or midazolam compared to their counterparts without DCM. Dogs with DCM demonstrated an increased likelihood of experiencing cardiac arrhythmias during anesthesia, received comparatively lower volumes of IV fluids, and were more likely to be administered dobutamine during anesthesia. No significant differences were identified in terms of postanesthesia complications or survival rates to discharge. CLINICAL RELEVANCE: Dogs with a DCM phenotype, primarily characterized by asymptomatic presentation, demonstrated comparable perioperative outcomes under general anesthesia when compared to matched controls, though the lack of standardization in anesthetic management limits definitive conclusions.