Successful cardiopulmonary resuscitation in an adult horse following cardiovascular collapse on recovery from general anaesthesia in the Trendelenburg position

Abstract

Equine anaesthesia is associated with a high risk of perioperative morbidity and mortality, particularly in the recovery period. Cardiovascular collapse and cardiopulmonary arrest (CPA) have been reported to account for one-third of anaesthesia-related perioperative deaths in the horse. This case report describes the successful cardiopulmonary resuscitation of a healthy adult Thoroughbred mare that developed cardiovascular collapse and subsequent CPA following positioning in the recovery box after general anaesthesia in the Trendelenburg position. Cardiopulmonary resuscitation (CPR) was instigated and included thoracic compressions, intermittent positive pressure ventilation and adrenaline administered via the intravenous and intra-tracheal routes. Return of spontaneous circulation (ROSC) was detected 5 min and 50 s after the start of CPR. A stable stance was achieved approximately 100 min after ROSC. The mare was discharged from the hospital 3 days later with no known complications. To the authors' knowledge, this is the first case report documenting CPA following general anaesthesia in the Trendelenburg position in a horse, with subsequent successful CPR. The precise cause of the CPA is unknown but a number of plausible hypothesis are discussed including hypoventilation and a Bezold-Jarisch reflex.

REassessment Campaign On VEterinary Resuscitation: Has the time come for horses?

“…We often disguise our deferment behind the belief that any effort for successful CPR in horses is vain (Muir and Hubbell 2009). The report published by Duggan et al (2022) in this issue proves us wrong.…”

“…Given that perioperative CPA in horses is an uncommon but not extraordinarily rare event, practitioners should be prepared to face this emergency. What stands out from the current literature is the substantial variabilities in equine cardiopulmonary resuscitation (CPR) techniques, that often blend practices echoing the Veterinary Emergency and Critical Care Society REassessment Campaign On VEterinary Resuscitation (RECOVER) guidelines (Fletcher et al 2012) with empirical interventions (Conde Ruiz and Junot 2018;Duggan et al 2022).…”

“…It is futile to try to ascertain the exact cause of the CPA in the report published by Duggan et al (2022) in this issue. The negligible monitoring during the last 15 min of anaesthesia makes it difficult to determine the precise moment at which the CPA happened.…”

“…When CPA happens in the post-operative period, as in Duggan et al (2022), all the equipment is available, and the horse is likely intubated. However, how many equine practices keep essential emergency drugs readily available?…”

“…Faster rates may be warranted (Palmer 2007;Fletcher et al 2012;Kleinman et al 2015). As both Duggan et al (2022) and Conde Ruiz and Junot (2018) highlighted, a single operator rapidly thrusting the knee onto the horse chest just behind its elbow is unlikely to reach the frequency of 80 compressions per minute or above, and frequencies closer to 30/min are more commonly obtained. From a feasibility perspective, chest compressions in adult horses may be a twopeople job.…”