Severe autonomic dysreflexia induced cardiac arrest under isoflurane anesthesia in a patient with lower thoracic spine injury
A 25-year-old man sustained fracture dislocation at T7-T8 vertebrae following a road traffic accident. He was scheduled for pedicle screw fixation of T7-T8 vertebrae two weeks after injury. On pre-anesthetic evaluation, patient presented with complaints of inability to move his lower limbs and numbness in lower half of body. Clinical examination revealed a conscious, well oriented, afebrile patient with pulse rate of 76 beats per minute and blood pressure of 110/70 mmHg. Central nervous examination revealed complete bilateral flaccid paralysis (paraplegia) and loss of all sensations below T9 dermatome with areflexia. There was no voluntary contraction of the anal sphincter with absence of sensation around the anus. Magnetic resonance imaging showed complete transaction of spinal cord at T10 level. All routine investigations were within normal limits.\nWhile applying standard monitoring in the operating room, it was found that patient’s urinary bladder was distended up to the umbilicus though a bladder was in situ. It was decided to induce anesthesia and thereafter change of blocked urinary catheter and place central venous pressure and intra-arterial pressure monitoring lines. After adequate preloading, general anesthesia was induced with fentanyl 100 mcg and thiopentone 250 mg intravenous (IV). Tracheal intubation was done after adequate relaxation with 6 mg vecuronium. Anesthesia was maintained with isoflurane in mixture of oxygen and nitrous oxide. Post-induction vitals were stable with 100% saturation and end-tidal carbon dioxide of 36 mmHg. Blocked urinary catheter was removed and re-catheterization done. 1500 ml of urine was drained. Subsequent to bladder catheterization and decompression, patient developed polymorphic premature ventricular contractions with hypertension. Isoflurane concentration was increased, but it was followed by severe bradycardia (38 beats per minute) with malignant hypertension (220 mmHg/100 mmHg). Sodium nitroprusside was started at a rate of 1 mcg/kg/min. As bradycardia was refractory, atropine 1 mg IV was administered. Despite this, patient developed asystole. Cardiopulmonary resuscitation (CPR) was started with 100% oxygen. Sodium nitroprusside was stopped immediately and repeat dose of atropine 1 mg IV was given. Advanced cardiac life support was continued for 30 min with no return of spontaneous circulation. Autopsy revealed mildly dilated heart with a weight of 350 g. All three major coronary arteries were normal and histological examination showed no infarction.