Estimation of intracranial pressure using computed tomography scan findings in patients with severe head injury.

The relationship between initial intracranial pressure and the findings of the first computed tomography scan on admission was assessed in 100 consecutive moderate-to-severe head injury patients using a method of multiple regression analysis. Intracranial pressure was measured through a slender subarachnoid catheter with a transducer. Thirty-nine checkpoints of computed tomography findings, including a shift of midline structure, the status of ventricles or cisterns, and the amount of subarachnoid hemorrhage, were investigated. The results were as follows: (1) The computed tomography findings that contributed to estimating intracranial pressure were the appearance of cisterns, the size of a subdural hematoma (number of slices), ventricular size, status of subarachnoid hemorrhage, status of cerebral contusion, magnitude of midline shift, and ventricular index, in that order. (2) Approximately 80% of predicted cases of intracranial pressure were included within the range of measured intracranial pressure +/- 10 mmHg. When the predicted intracranial pressure was less than 30 mmHg, the discrepancy between both intracranial pressures was small. It is concluded that an equation using several computed tomography findings gives a reasonably accurate intracranial pressure for the initial stage of severe head injury.