Effect of mild hypothermia on the cerebral hypoperfusion-hyper perfusion phases in patients with severe traumatic brain injury

Objective To investigate the effect of mild hypothermia on cerebral hyperfusion-hyper perfusion phases in severe traumatic brain injury(sTBI) patients and its clinical significance.Methods Thirty-six patients with sTBI(GCS≤8) were randomly divided into the conventional therapy group(control group) and the mild hypothermia therapeutic group(therapeutic group),with 18 patients in each.The cerebrovascular hemodynamic indices(CVDI) was measured in 0,1,3,7,10,14,21 days after sTBI with the cerebrovascular hemodynamics analyzer.The changing phase of CVDI,the size of brain edema in the traumatic focus and prognosis were compared and analyzed through the combination of CT dynamic observation.Twenty-four normal persons were selected to definite the normal value of CVDI(normal group).Results Compared with normal group,posttraumatic CVDI in the control group could be divided into 4 phases: hypoperfusion(day 0),hyperperfusion(days 1～3),cerebral vasospasm(days 4～14),intermediary(days 15).There were 3 phases in the mild therapeutic group:hypoperfusion(day 0),intermediary(days 1～3),recovery(days4),without emerges hyperperfusion and cerebral vasospasm.The volume of brain edema area was the largest postinjury in 14th day for the control group(140.9±22.95) cm3 and therapeutic group was(81.72±15.95) cm3(P0.05).The rates of consciousness in a week were 22.2%(4/18) in control group and 55.6%(10/18) in therapeutic group(P0.05).After 3 years follow-up,the rates of unfavorable prognosis were 55.6%(10/18) in control group and 22.2%(4/18) in therapeutic group(P0.05).Conclusions Mild hypothermia treatment can improve the prognosis through stabilizing the cerebral circulation especially by inhibiting acute hyperperfusion and improving tardive hypoperfusion after the injury,so then the volume of cerebral edema in focus is lessened remarkably and the prognosis is improved.