Coma Reversal With Cerebral Dysfunction Recovery After Repetitive Hyperbaric Oxygen Therapy for Severe Carbon Monoxide Poisoning

The accepted beneficial effects of hyperbaric oxygen (HBO) include a greatly diminished carboxyhemoglobin (COHgb) half-life, enhanced tis sue clearance of residual carbon monoxide (CO), reduced cerebral edema, and reversal of cytochrome oxidase inhibition, and prevention of central nervous system lipid peroxidation. Debate regarding the criteria for selection of HE0 versus 100% normobaric oxygen therapy continues, and frequently is based solely on the level of COHgb saturation. Patients who manifest signs of serious CO intoxication (unconsciousness, neuro psychiatric symptoms, cardiac or hemodynamic instability) warrant im mediate HBO therapy. An unresponsive 33-year-old woman was found in a closed garage, inside her automobile with the ignition on. Her husband admitted to seeing her 6 hours before discovery. 100% normobaric oxy gen was administered in the prehospital and emergency department set tings. The patient had an initial COHgb saturation of 46.7%, a Glasgow coma score of 3, and was transferred for HBO therapy. Before HBO ther apy, the patient remained unresponsive and demonstrated decerebrate posturing and a positive doll’s eyes (negative oculocephalic reflex). The electroencephalogram pattern suggested bilateral cerebral dysfunction consistent with a toxic metabolic or hypoxic encephalopathy. The patient underwent HBD therapy at 2.4 ATA for 90 minutes twice a day for 3 consecutive days. On day 7, the patient began to awaken, was weaned from ventilatory support, and was soon verbalizing appropriately. A Fol stein mental status examination showed a score of 26 of 30. Neurological examination demonstrated mild residual left upper extremity weakness and a normal gait. There was no evidence of significant neurological sequelae at 1 month follow-up. Aggressive repetitive HBO therapy re sulted in significant resolution of coma and cerebral dysfunction after severe acute CD poisoning. HBO should be considered even in patients suffering from severe neurological damage that was CO-induced. (Am J Emerg Med 1993;11:616-616. Copyright 0 1993 by W.B. Saunders Com pany)