Bezold-Jarisch Reflex-Induced Cardiac Arrest During Colonoscopy Under Sedation: A Case Report

BACKGROUND Bezold-Jarisch reflex (BJR) is a physiologic cardioinhibitory reflex, but its occurrence can lead to severe bradycardia and hypotension, or even cardiac arrest. Due to the rarity of its occurrence and the lack of awareness among most anesthesiologists, this clinical presentation may be mistaken for other adverse cardiovascular events, and effective preventive and curative measures may not be taken. CASE REPORT We report a case of cardiac arrest during a routine sedated colonoscopy. Following the arrest, the patient underwent cardiopulmonary resuscitation and received atropine and epinephrine. After 2 minutes of cardiopulmonary resuscitation, the patient's heart rate and blood pressure normalized, and he regained consciousness with no discomfort reported except for fatigue. We excluded organic pathology after a thorough systematic examination, and after discussion with our multidisciplinary team in the context of intraoperative hemodynamic alterations, it was concluded that intraoperative cardiac arrest was caused by BJR in this patient. The patient's clinical course - characterized by initial recurrent bradycardia with hypotension progressing to syncope or cardiac arrest - was more consistent with BJR than with typical vasovagal syncope. Prolonged fasting prior to sedated colonoscopy likely induced hypovolemia, and subsequent sedation further exacerbated peripheral vasodilation, collectively triggering BJR. The patient was discharged on day 5 after cardiac arrest, with no recurrence of syncope noted during a 4-month telephone follow-up. CONCLUSIONS This is the first reported case of BJR-induced cardiac arrest during sedated colonoscopy. It underscores the need for anesthesiologists to consider BJR in the differential diagnosis of recurrent bradycardia and hypotension, and to implement targeted interventions to mitigate the risk of associated severe complications.