Linear Decrease in Brain Tissue Oxygenation (PbtO2) with Decreasing Body Temperature during Induce Hypothermia

Background: Induced mild hypothermia (MIH) is generally an effective intervention for reducing intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI). Unfortunately, MIH also influences brain tissue oxygenation (PbtO2). The significance of the PbtO2 change is unknown. We report a patient with severe traumatic brain injury (TBI) with refractory intracranial hypertension requiring MIH which resulted in a decrease in his PbtO2 values. Case report: The patient presented in a coma following an altercation. He was found to have a large left subdural hemorrhage with significant mass effect requiring craniectomy. He subsequently developed refractory intracranial hypertension requiring medically induced coma and MIH. As temperature decreased, his PbtO2 values decreased from 23-35 mmHg to 6-10 mmHg. There was a significant reduction in PbtO2 values as temperature decreased (p<0.001). ICP did not change with a decrease in temperature and remained elevated (p=0.78). Conclusion: PbtO2 significantly decreased linearly with the decrease in body temperature. Future studies should evaluate the clinical significance of the reduction in PbtO2 in patients with severe TBI and refractory intracranial hypertension requiring MIH. Recognizing expected changes in PbtO2 monitoring with MIH is important for managing neurocritically ill patients.