Pattern shift visual evoked potential screening for HBO2 in mild-to-moderate carbon monoxide poisoning

Pattern shift visual evoked potential (PSVEP) N75 and P100 latencies were evaluated as an objective, widely available and rapid test of brain dysfunction in a group of 11 patients in the acute phase (first 6 h) of mild-to-moderate carbon monoxide (CO) poisoning. N75 and P100 latency results were compared to nearly simultaneously obtained standard CO Neuropsychological Screening Battery (CONSB). Patients were sought in whom treatment decisions concerning hyperbaric oxygen (HBO2) vs. normobaric oxygen (NBO2) might be difficult, and were excluded from the study if confounding variables existed for CONSB or PSVEP. N75 and P100 latencies were also obtained after completion of NBO2 or HBO2 therapies. Only one patient, judged clinically to have the mildest poisoning in the series, had significantly abnormal initial PSVEP latencies. This patient's simultaneous CONSB was normal and the abnormal PSVEP latencies failed to normalize post treatment with NBO2. PSVEP latencies were not found to be a sensitive screening tool for treatment decision making in a group of acutely CO poisoned patients where treatment decisions might be difficult.