Comparison of Two Intracranial Pressure Calculation Methods and Their Effects on the Mean Intracranial Pressure and Intracranial Pressure Dose.

This study compared two methods of calculating the intracranial pressure (ICP) in a patient: end-hour ICP and hour-averaged ICP. A total of 1060 patients with traumatic brain injury and a known clinical outcome were studied. For each patient, the end-hour ICP and hour-averaged ICP were calculated. The mean ICP and the ICP dose above 20 mmHg were evaluated using both calculation methods. The results for patients who survived and those who died were compared using a Student's t test. The average correlation between the end-hour and hour-averaged mean ICP was 0.747, indicating that the end-hour ICP method agrees moderately with the hour-averaged method. However, the comparison between surviving and dead patients did not present significant differences between ICP values averaged with these two different methods. The Student's t test gave similar results for both the mean ICP and ICP dose. The results suggest that the end-hour and hour-averaged methods have similar predictive power for patients' clinical outcome.