Analgesia & Resuscitation : Current ResearchISSN: 2324-903X

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Case Report, Analg Resusc Curr Res Vol: 2 Issue: 2

Reflex Bradycardia and Cardiac Arrest Following Sigmoidoscopy under General Anesthesia

Alia S Dabbous*, Jean J Esso, Mabelle C Baissari and Ahmad M Abu Leila
American University of Beirut Medical Center, Lebanon
Corresponding author : Alia S Dabbous
American University of Beirut Medical Center, PO Box: 11-0236, Riad El Solh, Beirut, Lebanon
E-mail: [email protected]
Received: March 27, 2013 Accepted: July 27, 2013 Published: July 31, 2013
Citation:Dabbous AS, Esso JJ, Baissari MC, Abu Leila AM (2013) Reflex Bradycardia and Cardiac Arrest Following Sigmoidoscopy under General Anesthesia. Analg Resusc: Curr Res 2:2.doi:10.4172/2324-903X.1000107

Abstract

Reflex Bradycardia and Cardiac Arrest Following Sigmoidoscopy under General Anesthesia

Reflex bradycardia is a rare but well recognized complication that may occur during anesthesia. Anesthestic drugs, surgical stimuli and hypoxia can be its triggering agents. There are many factors that augment this entity and may result in severe bradycardia or arrest. To the best of our knowledge, this is the first report on the development of asystole during sigmoidoscopy under general anesthesia.

Keywords:

Introduction

Reflex bradycardia is a rare but well recognized complication that may occur during anesthesia. Anesthestic drugs, surgical stimuli and hypoxia can be its triggering agents [1]. There are many factors that augment this entity and may result in severe bradycardia or arrest [2-4]. To the best of our knowledge, this is the first report on the development of asystole during sigmoidoscopy under general anesthesia.

Case

A 47-year-old man was scheduled for sigmoidoscopy and hemorrhoidectomy; his past medical history was significant for chronic hypertension, gastroesophageal reflux disease and dyslipidemia. He was on Telmisartan, Atorvastatin, Aspirin, and Rabeprazole. He had no previous history of vasovagal reaction. His preoperative vital signs were essentially normal and physical examination was unremarkable. The routine laboratory examination taken preoperatively including electrolytes were normal. A twelve-lead Electrocardiogram (EKG) showed normal sinus rhythm.
A proposed plan of general anesthesia was discussed with the patient. He received no premedication. On arrival to the operating room, intravenous access was secured and one liter Lactated Ringer was started. Monitors (EKG, pulse oximetry and noninvasive blood pressure) were placed. Anesthesia was induced with fentanyl 150 mcg, lidocaine 100 mg, propofol 200 mg, and cisatracurium 10 mg. The airway was secured with an 8.0mm endotracheal tube. Anesthesia was maintained by oxygen: N2O (35: 65%) and isoflurane (0.4-0.8%). During the next 20 minutes, the patient’s pulse and blood pressure remained stable with a heart rate around 70/min and a blood pressure of about 120/80mmHg, ETCO2 of 30-35 mmHg and ET isoflurane 0.6%. A total of 500 ml of Lactated Ringer was given. The patient was then placed in a lithotomy position in view of sigmoidoscopy. At the time of anal dilation, 25 minutes later, an episode of bradycardia immediately occurred with a drop in heart rate from 72 to 33/ min accompanied by a remarkable decrease in the systolic blood pressure from 120 to 68 mmHg and a drop in ETCO2 to 14mmHg, 0.5 mg atropine was given to no avail and asystole followed. The sigmoidoscope was immediately removed; cardiopulmonary resuscitation was initiated with chest compressions, intravenous administration of epinephrine 1mg and rapid intravenous infusion of Lactated Ringer. The patient responded to this management in one minute with a momentary escalation of the heart rate to 90/ min, blood pressure to 170/70 mmHg and ETCO2 to 35mmHg. The hemodynamics gradually settled to baseline in a couple of minutes (Table 1). The sigmoidoscope was again introduced slowly and the proposed surgery was continued with no further untoward incident. Surgery lasted around 45 minutes; the patient was hemodynamically stable and, was extubated uneventfully. In the post anesthesia care unit, a cardiac consultation was obtained; EKG was done and was completely normal.
Table 1: Hemodynamics changes.
The patient was transferred to the regular floor; postoperative course was uneventful. He was discharged home the following day without any further incident.

Discussion

We put forth the following reasons to substantiate our case in favor of increased vagal tone culminating in asystole. During induction of general anesthesia, we gave 150 mcg of fentanyl simultaneously with 200 mg of propofol. There was no hemodynamic response to anesthesia induction or tracheal intubation. No further analgesia was given. Maintenance of anesthesia was by 35-65 % Oxygen-N2O and 0.4-0.8% isoflurane. Heart rate remained stable for 25 minutes after induction. Symptomatic bradycardia with hypotension only occurred at the time of anal dilation that was resistant to 0.5 mg atropine and led to asystole.
The mechanism of vagal reflex during sigmoidoscopy is primarily due to the stimulation of the pelvic splanchnic nerves that supply the anal canal. These nerves carry parasympathetic fibers and, consequently the intense vagal stimulation that occurs following anal dilation results in cardiac changes and bradycardia [5]. This bradycardia leading to asystole has been described during colonoscopy with sedation in a patient with history of neurocardiogenic syncope [6]. This effect can be more prominent in young age, for there is an inverse relationship between vagal modulation and age [7]. Also, the light level of anesthesia can potentiate the occurrence of bradycardia [8].
In our patient, the sudden onset of asystole during anal dilation, is the result of reflex bradycardia that could have occurred in view of the relatively young age of our patient and, the light level of anesthesia.

Conclusion

This is the first case of asystole reported during sigmoidoscopy. Reflex bradycardia, coupled to the young age of the patient and the light level of general anesthesia seem to be the direct cause. Prompt resuscitation saved our patient. Symptomatic bradycardia leading to asystole can happen during sigmoidoscopy under general anesthesia. Adequate prevention, recognition and management can be effective.

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