Acute carbon monoxide poisoning. Risk of late sequelae and treatment by hyperbaric oxygen

The indications for hyperbaric oxygen therapy (HBO) in the treatment of acute carbon monoxide (CO) poisoning are discussed far too little in the literature. Depending on the author reasons for referral to a hyperbaric center include the carboxyhemoglobin level, change in state of consciousness or neurological abnormalities. In our opinion, HBO should be used on much wider indications than is usual, not only because of the rapid relief from symptoms it provides but mainly because it may prevent severe delayed sequelae. During a period of 9 months 230 patients with CO poisoning were admitted to our intensive care unit; 203 were treated with HBO and 27 with normobaric oxygen. Our indications for HBO treatment were: coma, pathological neurological findings or loss of consciousness during CO exposure irrespective of normal clinical findings on admission. Four patients died and the others were discharged 12 hours to 25 days after the incident. Seven patients had minor neurological problems within two weeks of discharge and which disappeared within one month. Two patients were re-hospitalized for neuropsychiatric sequelae and recovered in 3 and 6 months respectively. Neither the clinical status upon admission nor COHb predicted the outcome of the poisoning. Referral to a HBO center should be considered when: --the patient is comatose --there are abnormal clinical findings --patients have been unconsciousness during exposure, irrespective of whether they are conscious on admission and have normal clinical status.