o:3576 Unanticipated hyperkalaemia and associated perioperative complications in three captive grey wolves (Canis lupus) undergoing general anaesthesia en Intraoperative hyperkalaemia has been described in dogs, cats, non-domestic felids and in a calf. This case series reports the occurrence and associated complications in three captive-held grey wolves anaesthetised for root canal treatment. Severe bradyarrhythmia associated with hypotension was detected in two cases before hyperkalaemia was confirmed. These also presented with signs compatible with malignant hyperthermia and rhabdomyolysis. In the third wolf, regular arterial blood gas analysis revealed a progressive increase in plasma potassium exceeding reference values 240 min after premedication. Hyperkalaemia was treated symptomatically with standard protocols, and the recovery was uneventful in all three wolves. The cause of hyperkalaemia in the described cases remains unknown and is most likely multifactorial. Prolonged recumbency, long anaesthetic duration and the administration of alpha(2)-adrenoceptor agonists are potential influencing factors. Additionally, malignant hyperthermia, rhabdomyolysis, acidaemia and drug effects are discussed for their potential of causing the described intraoperative hyperkalaemia. Atropine-Resistant Bradycardia; Malignant Hyperthermia; Potassium Concentration; Induced Rhabdomyolysis; Plasma Potassium; Fluid Therapy; Acid-Base; Medetomidine; Dogs; Ketamine 1552099 10.1002/vrc2.597 2024-10-11T08:30:43.220Z 44 yes 46 Giorgio Mattaliano University of Veterinary Medicine Vienna 0000-0001-6488-6283 Marianne Heberlein University of Veterinary Medicine Vienna person Inga-Catalina Cruz Benedetti University of Veterinary Medicine Vienna / Université de Montréal person 0000-0002-0749-4141 application/pdf 681718 https://phaidra.vetmeduni.ac.at/o:3576 no yes 18 70 1552253 Veterinary Record - Case Reports 10 11 2 Wiley 2023