Intraoperative cardiac arrest during elective, non-cardiac surgery is a rare but potentially catastrophic event. The incidence of intraoperative cardiac arrest varies in different hospitals and countries, and studies have shown an incidence rate ranging from 1.1 to 34.6 per 10,000 anesthesia and a survival rate of 35% to 46.6% (1,2).

The risk factors associated with cardiac arrest in patients undergoing non-cardiac surgery include unstable coronary artery disease, cardiac arrhythmias, heart failure, valvular heart disease. pulmonary embolism, electrolyte abnormalities, hemorrhage, and the anesthetic used at the time of arrest (1,2).

Although congenital coronary artery anomalies are relatively uncommon, they are the second most common cause of sudden cardiac arrest among the young (3). Approximately 1% of the general population have been reported to have an anomalous coronary artery, ranging from 0.3% to 5.6% in studies on patients undergoing coronary angiography (3). These are often not diagnosed until late adolescence or adulthood because of the lack of symptoms, and some teens or adults with unknown anomalies may have an initial episode of chest pain, heart failure, or even sudden cardiac death before the condition is recognized (3).

We herein report a rare case of a patient who experienced recurrent intraoperative cardiac arrest that was associated with a previously undiagnosed anomaly in the coronary arteries.

Case report

The patient is a 25-year-old man weighing 89kg who presented to our facility with an 8-week history of paraplegia following a road traffic accident. There was no loss of consciousness or other major systemic injuries. Neurological examination revealed flaccid paralysis of both lower limbs, with a power of 0/5 and hyporeflexia; sensations were intact. Magnetic resonance imaging was requested, which revealed a traumatic burst fracture of T12 with retropulsion and compression of the conus medullaris. He was scheduled for a laminectomy and pedicle screw fixation under general anesthesia.

Pre-anesthesia review revealed a young man with no known comorbid conditions, history of prior exposure to anesthesia, or drug allergy. General examination revealed no abnormalities; chest and cardiovascular examinations were normal, with a good volume pulse of 74 bpm and blood pressure of 110/80mmHg; heart sounds were S1 and S2 only. He had good mouth opening with a Mallampati score of 2. Investigations available were urea electrolyte and creatine, full blood count and differential, fasting blood sugar, and clotting profile, and all were within normal limit ranges. Fasting guidelines were given, and a request was made for two pints of blood.

In the operating suite, a cockpit drill was done to check for oxygen supply, anesthesia equipment, and resuscitative gadgets; baseline vital signs taken with a multiparameter monitor were pulse rate, non-invasive blood pressure, and oxygen saturation (SpO2), which were all within normal limits. An intravenous access was secured with a 16-gauge cannula with 0.9% saline infusion running. He was given a pre-medication of 0.6mg atropine and 30mg pentazocine, and he was pre-oxygenated with 100% oxygen for 3 minutes. Induction was performed with a sleeping dose of sodium thiopentone (500mg), and intubation was aided with 100mg suxamethonium. Isoflurane for maintenance of anesthesia was switched on at 2%, and 6mg pancuronium given. The patient had a witnessed cardiac arrest 5 minutes after induction of anesthesia. The inhalational agent was switched off, and cardiopulmonary resuscitation (CPR) immediately commenced with an intravenous dose of adrenaline (1mg); return of spontaneous cardiac activity (ROSC) was achieved after defibrillation with 200 J. The patient regained consciousness without any neurological sequalae and was observed in the intensive care unit for 24 hours.

The patient was reviewed by a cardiologist who ordered an electrocardiography (Figure 1) and an echocardiography (Figure 2), both of which revealed no anomalies; chest X-ray also revealed a normal lung field. A repeat of urea, electrolyte, creatinine, full blood count, and differential blood count also showed normal results.

Click to view Figure 1. This is an image of the Electrocardiography of the patient with no abnormality detected

A second attempt at anesthesia was made 2 weeks after the first, with resuscitation gadgets and drugs available and ready for use. Pre-medication was performed with 0.6mg atropine and 30mg pentazocine. Induction was performed with 200mg propofol, and 100mg suxamethonium was used to aid intubation. Isoflurane (1.4%) was switched on for maintenance of anesthesia, but the patient again had a witnessed cardiac arrest with sinus bradycardia, and then asystole was seen on ECG monitoring. CPR was commenced, and 1mg adrenaline was administered; ROSC was again achieved after a 200 J defibrillation, and the patient had full recovery on the operating table.

Click to view Figure 2. This is an image of the echocardiography of the patient with no abnormality detected

A further review of the patient was then carried out with a request for coronary angiography (Figures 3 and 4), which revealed features of a tortuous right coronary artery, and all coro