Abstract
Background: This study was conducted to elucidate the relationships between various factors and abnormal findings of basal ganglia in head CT/MRI in acute CO poisoning. These factors included the exposure time to CO gas, transport time to the hospital, and blood gas analysis on admission.
Method: The subjects were 41 patients with acute CO poisoning who had known exposure times to CO and underwent hyperbaric oxygen therapy (HBOT) between January 2006 and December 2009. Head CT or MRI was performed within 3 days of admission. If patients had abnormal CT or MRI findings, they were placed in an“abnormal”group. Abnormal CT findings were low density areas in the basal ganglia, including the globus pallidus, and abnormal MRI findings were high intensity areas in T2-weighted MRI at the same site. If patients had no abnormal imaging findings, they were placed in a“normal”group. The following were retrospectively examined in both groups: characteristics of patients, exposure time to CO, transport time, GCS when the emergency rescue team first came into contact with the patients, GCS on admission to our hospital, and blood gas analysis at our hospital.
Result: There were 30 patients in the normal group and 11 patients in the abnormal group. The exposure time to CO was statistically significantly longer in the abnormal group compared to the normal group. There were no significant differences between these groups for other factors. The receiver operating characteristic (ROC) curve was obtained for the prediction of occurrence of abnormal CT/MRI findings. Its area underneath the curve was 0.759 and the optimal cutoff point was 570 minutes.
Conclusion: The exposure time to CO was long in patients with acute CO poisoning who had abnormal CT/MRI findings in onset early stage. The occurrence of such abnormal findings can be predicted using the cutoff point of 570 minutes. In the future, it might be possible to determine the indications for HBOT from exposure time.
