Carbon monoxide poisoning: correlation of neurological findings between accident and emergency departments and a hyperbaric unit

Objectives-To investigate and quantify the differences in neurological exam ination findings in patients acutely poisoned with carbon monoxide, between initial assessment at accident and emergency (A&E) departments and subsequ ently at a hyperbaric unit. Methods-Retrospective case note review of all patients referred to the Hull Hyperbaric Unit for treatment of acute carbon monoxide poisoning between A ugust 1998 and August 1999. Patients who were ventilated or less than 16 ye ars old were excluded because of difficulty in assessing their neurological status. Results-Thirty patients were included for analysis. The mean duration from exposure to assessment in A&E was four hours while patients were reviewed o n average three hours later at the hyperbaric unit. Referrals came from 14 different hospitals. A history of loss of consciousness accounted for 70% o f referrals. A mean of 3.2 neurological signs per patient was documented in A&E compared with 9.2 at the hyperbaric unit. Seventy nine per cent of abn ormal neurological signs were not detected at A&E departments compared with 3% at the hyperbaric unit. The major source of discrepancy was in sharpene d Rhomberg's test and heel-toe gait, in 13% of patients examined in A&E dep artments these signs were recorded as abnormal compared with 90% at the hyp erbaric unit. Conclusion-There is a large discrepancy in neurological findings between as sessment in A&E departments and the Hull Hyperbaric Unit. A number of facto rs may account for this including interobserver variation, patient deterior ation during transfer, poor documentation, lack of understanding of the seq uelae of carbon monoxide poisoning and inadequate examinations. Further res earch is required to quantify the impact of the various factors that may co ntribute to the differences in neurological findings.