The relation between persistent coma and brain ischemia after severe brain injury

Aim: To investigate the relation between brain ischemia and persistent vegetative state after severe traumatic brain injury. Methods: The 66 patients with severe brain injury were divided into two groups: The persistent coma group (coma duration >= 10 d) included 51 patients who had an admission Glasgow Coma Scale (GCS) of 5-8 and were unconscious for more than 10 d. There were 15 patients in the control group, their admission GCS was 5-8, and were unconscious for less than 10 d. The brain areas, including frontal, parietal, temporal, occipital lobes and thalamus, were measured by Single Photon Emission Computed Tomogrophy (SPECT). Results: In the first SPECT scan, multiple areas of cerebral ischemia were documented in all patients in both groups, whereas bilateral thalamic ischemia were presented in all patients in the persistent coma group and were absented in the control group. In the second SPECT scan taken during the period of analepsia, with an indication that unilateral thalamic ischemia were persisted in 28 of 41 patients in persistent coma group(28/41,68.29%). Conclusion: Persistent coma after severe brain injury is associated with bilateral thalamic ischemia.