Psychological sequelae of carbon monoxide poisoning: Delayed hyperbaric treatment

Abstract

Carbon Monoxide (CO) poisoning causes over 3,000 deaths per year in the United States. Thousands more may have neurological and cognitive injuries as a result of being exposed to toxic levels of CO. This study was designed to explore the cognitive and posttraumatic stress sequelae related to delayed hyperbaric oxygen (HBO) treatment.;The hypothesis tested was that the longer the delay to HBO the worse the cognitive and PTSD sequelae would be. The severity of cognitive sequelae was also predicted to be positively related to PTSD symptomatology 1--2 months after treatment in the chamber.;Twenty-six moderately-to-severely poisoned patients received one standardized 46 minute treatment at 2.8 atmospheres of pressure in the hyperbaric chamber. Delay was measured by the ambulance crew and Emergency Department personnel and was used as the predictor variable. Measures of cognitive functioning included the Mini Mental State Exam (MMSE), Clock Drawing & Trail Making Test which were administered immediately prior to HBO treatment (Time 1) and again 1--2 months later (Time 2) along with the Dementia Rating Scale (DRS). In addition, the Posttraumatic stress indices; including the Stroop Color naming task, the Posttraumatic Stress Checklist-Civilian version (PCL-C) and the Posttraumatic Diagnostic Scale (PDS) were administered at time 2. The results of the study revealed that there was a lack of support for the hypothesized relationship between the delay time to HBO and worsened cognitive or PTSD sequelae. However, individuals, (N = 10) who had higher PTSD symptom severity scores (PCL-C) performed significantly worse on the DRS Conceptualization Scale (t = 2.76, p < .05). Additionally, the scores on the Trail Making and Stroop measures were worse the greater the PTSD symptom severity level (Pearson r = --.75, p < .05 and Pearson r = .66, p < .05, respectively).