Maxillomandibulocardiac reflex in a dog

Abstract

BackgroundThe trigeminocardiac reflex (TCR) is a brainstem reflex that may be observed in anaesthesia during surgical procedures stimulating the intracranial or peripheral portion of the trigeminal nerve. The peripheral TCR is divided into the oculocardiac reflex and the maxillomandibulocardiac reflex based on the affected sensory branches of the trigeminal nerve. In veterinary medicine the oculocardiac reflex has been described, however the maxillomandibulocardiac reflex has never been reported.Case presentationA 5-year-old male Epagneul Breton was presented for surgical management of an upper lip mass. During surgery, a sudden severe bradycardia and a decrease in systemic arterial blood pressure developed. The occurrence of a maxillomandibulocardiac reflex was suspected on the basis of the temporary link between surgical stimulation and haemodynamic changes. Three doses of atropine were given before starting a dopamine infusion due to lack of response. The dopamine infusion normalized heart rhythm and blood pressure. The dog recovered uneventfully and he was discharged 24 h later with a sinus rhythm and no sign of recurrence of arrhythmias.ConclusionThe TCR is a rare but potentially life-threatening complication of procedures involving the sensory areas innervated by the three branches of the trigeminal nerve and it may cause bradycardia with hypotension. The use of a β1-adrenergic receptor agonist such as dopamine may be indicated in cases of a refractory response to the conventional treatment with atropine.

Suspected vagal reflex and hyperkalaemia inducing asystole in an anaesthetised horse

“…A trigeminocardiac reflex (TCR) is a vagal reflex frequently documented in human medicine, and subtypes such as the oculocardiac reflex (OCR) are well documented in veterinary medicine throughout numerous species 1‐3 . A further TCR subtype, the maxillomandibulocardiac reflex (MCR) has been documented in human literature associated with facial fractures and has recently been described in a sole case report in a dog 4 . Thus far, it has not been documented in a horse.…”

“…1-3 A further TCR subtype, the maxillomandibulocardiac reflex (MCR) has been documented in human literature associated with facial fractures and has recently been described in a sole case report in a dog. 4 Thus far, it has not been documented in a horse. The current case report aims to describe the perianaesthetic management of a horse that developed asystole due to a suspected TCR of either OCR or MCR in origin, in combination with hyperkalaemia of unknown cause which may or may not have contributed to the suspected vagal event, a relationship that has been previously documented.…”