Trigemino Cardiac Reflex and Its Importance in Maxillofacial Surgery- A Review

Abstract

Trigemino cardiac reflex (TCR) is a sudden physiological response due to the pressure effect or stretching of the largest cranial nerve, the trigeminal nerve.TCR is a triad of bradycardia ,bradypnea and gastric motility changes due to the efferent activation of the vagal nerve in response to the pressure distribution in V5.TCR was originally called as oculo cardiac reflex ( OCR ) and the terminology was changed because the response is not only limited to the ophthalmic branch ,but for the entire nerve V5.Activation of TCR is seen in post traumatic patients and during surgical manipulation in cranio facial surgeries.TCR is more common in children with orbital fractures and in extra ocular surgeries. It is well documented in cases of ophthalmic injuries and ocular surgeries. It is imperative to know about this sudden physiological response in maxillofacial surgery which is bound to happen with any oral surgical procedures ranging from extractions, elevation of palatal flaps to maxillary disimpactions. Knowledge of the TCR is essential as it may mimic a closed cranial injury or a cardiac dysarrythmia in a post traumatic patient to avoid unwarranted surgical intervention. A detailed ophthalmic examination in maxillofacial injuries is essential. Whenever surgery is planned in maxillofacial region and if TCR is anticipated a discussion with the anaesthesiologist is mandatory. This paper reviews about the clinical papers and abstracts on TCR relevant to maxillofacial surgery.