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 (n = 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.