Measurements of cortical cellular pH by intracranial tonometer in severe head injury

Objective: To evaluate the cortical cellular damage in acute severe head injury, we measured the cortical cellular pH by using an intracranial tonometer made in our institution, Design: Prospective, 3.5-yr data collection. Setting: University hospital trauma intensive care unit. Patients: Severely head-injured patients (0 = 29) with Glasgow Coma Scale score <8, Intervention: Routine emergency neurologic procedure. Measurements and Main Results: We made 98 measurements of cortical cellular pH by intracranial tonometer in 29 severely head-injured patients in the acute phase, Each patient's intracranial pressure was recorded, and in 16 patients, the saturation of jugular venous oxygen was monitored. The outcome at 6 months after injury was significantly better in patients having a cortical cellular pH of >7.2 than those with <7,2. The cerebral perfusion pressure and cortical cellular pH correlated significantly (p < .0001), Conclusions. Our study suggests the usefulness of measurement of cortical cellular pH by intracranial tonometer for evaluating the severity of focal anaerobic cerebral metabolism and predicting patient prognosis.