Retrospective evaluation of acute hyperkalemia of unknown origin during general anesthesia in dogs.

OBJECTIVE: To report and characterize cases of acute hyperkalemia of unknown origin in dogs under anesthesia. STUDY DESIGN: Multicentric retrospective clinical study. ANIMALS: Medical records of 19 client-owned dogs that developed acute hyperkalemia during anesthesia. METHODS: Anesthetic records of dogs developing acute hyperkalemia from January 2015 to December 2022 were evaluated. Data collected included demographics, duration of anesthesia until the episode, electrolytes and blood gas measurements, electrocardiogram (ECG) abnormalities, drugs used as part of the anesthetic protocol, hyperkalemia treatment and outcome. RESULTS: A total of 13 cases met the inclusion criteria with documented acute hyperkalemia with no apparent underlying cause during anesthesia. Dogs were [mean ± standard deviation (range)] 6.5 ± 5.0 (3-10) years old and weighed 18.0 ± 14.3 (5.1-40.0) kg. All dogs were administered dexmedetomidine and an opioid as part of the premedication. All dogs had inhalation anesthesia of >60 minutes' duration. The first clinical sign was bradycardia that was minimally responsive to anticholinergic administration and was often accompanied by moderate/severe hypotension. These signs were rapidly followed by ECG changes compatible with hyperkalemia and/or cardiac arrest. Rapid identification and treatment for hyperkalemia, with or without dexmedetomidine reversal, resulted in survival of 12 dogs and one fatality. CONCLUSIONS AND CLINICAL RELEVANCE: Unknown origin hyperkalemia is a life-threatening complication that can occur during general anesthesia. In healthy dogs, preanesthetic administration of dexmedetomidine in association with an opioid and followed by inhalation anesthesia of more than 1 hour duration may predispose to this complication. A sudden decrease in heart rate >90 minutes after dexmedetomidine administration, or ECG changes, may warrant measurement of blood potassium concentrations.

Effects of intratesticular and incisional local anesthetic administration for castration of alpacas anesthetized with intramuscular ketamine-xylazine-butorphanol.

OBJECTIVE: To determine the effects of intratesticular and incisional injection of local anesthetics on response to castration, surgical ease, and recovery in alpacas. STUDY DESIGN: Prospective, blinded, randomized, and clinical trial. ANIMALS: Intact male alpacas (n = 38). METHODS: Alpacas were anesthetized with intramuscular butorphanol, ketamine, and xylazine (BKX). Once recumbent, alpacas were instrumented with electrocardiogram, pulse oximeter, oscillometric blood pressure, and capnography. Heart rate (HR), respiratory rate (RR), and blood pressure (BP) were recorded every minute. Treatment drug (lidocaine, bupivacaine, or saline) was infiltrated along the incision and into both testicles followed by a prescrotal closed castration. Timing of major events, presence of movement during the procedure, need for additional anesthesia, and ease of surgery were recorded. Alpacas were administered postoperative oral meloxicam and assessment was made 24 hours after recovery. RESULTS: Median RR and mean BP (MBP) were lower in the lidocaine compared with the saline treated group. Median RR, HR, and MBP were significantly lower in the bupivacaine group compared with the saline group. Fewer alpacas displayed physical response to surgical stimulus with bupivacaine. No significant differences were found between groups for timing of events, need for additional anesthesia, ease of surgery, or postoperative assessment. CONCLUSION: Intratesticular local anesthetic blunts autonomic response and facilitates castration in alpacas anesthetized with BKX with minimal negative effects. Bupivacaine may have some benefit for local anesthesia during castration compared with lidocaine.

Upregulation of proinflammatory cytokine production in response to bacterial pathogen-associated molecular patterns in dogs with diabetes mellitus undergoing insulin therapy.

BACKGROUND: Metabolic alterations associated with diabetes mellitus alter innate immunity. Dogs often develop infectious or inflammatory complications related to diabetes mellitus, yet little is known about the effects of diabetes mellitus on the immune system in this species. METHODS: Prospective evaluation in dogs with poorly regulated spontaneous type 1 diabetes mellitus (T1DM). In vitro leukocyte cytokine response to lipopolysaccharide (LPS), lipoteichoic acid (LTA), and peptidoglycan (PG) was compared between dogs with T1DM and healthy dogs. Additionally, the effect of acute in vitro glucose exposure on leukocyte tumor necrosis factor (TNF) production from healthy dogs was measured. RESULTS: Leukocytes from dogs with T1DM had significantly greater TNF production after LTA and PG stimulation compared with leukocytes from healthy dogs. Leukocyte interleukin (IL)-6 production was greater after stimulation with LPS, LTA, PG, and phosphate-buffered saline in the T1DM group. No such difference was noted when evaluating IL-10 production between groups regardless of stimulant. Dogs with T1DM had significantly greater IL-6 to IL-10 production ratios than healthy dogs. Acute exposure to dextrose did not augment cytokine production from healthy canine leukocytes. CONCLUSIONS: Dogs with T1DM have altered innate immunity characterized by upregulation of proinflammatory cytokine production without a concurrent change in anti-inflammatory cytokine production. This may be one explanation for the common infectious and inflammatory complications associated with T1DM in dogs.