Pressure volume index withdrawal could be express by linear curve and it also has a significant prognostic value.

Introduction: High intracranial pressure (ICP) correlated well with poor clinical outcomes in neurosurgical patient. Timely and proper treatment to normalize the increased ICP, is critical for the patient clinical outcomes. On authors experience, initial ICP and ICP values we after several cc of craniospinal fluid (CSF) withdrawal (PVIw) was correlate well with patient outcome. In this study, authors expressed PVI as a linear curve instead of exponential curve. And evaluate the significance of the PVIw3 as a prognostic factor.

Methods: A total of 217 out of 242 patients with validated linear PVIw3 curves (R20.95) were included in the analysis. PVIw3, calculated as the difference between initial ICP and ICP at 3 cc of cerebrospinal fluid (CSF) withdrawal divided by 3, was used as a measure of brain compliance, this slop is negative value because the curve is decreasement. Clinical outcomes were evaluated using the Glasgow Outcome Scale (GOS) at 6 months after initial treatment, with a favorable outcome defined as GOS 4-5.

Results: PVIW could be expressed by liner curve. The correlation between these two types of curves exponential curve and linear curve (P=0.000). On χ2 analysis showed that PVIw3 values less than -3 were associated with a significant high favorable outcome (p=0.017).

Conclusion : This study demonstrates that ventricular pressure changes resulting from CSF withdrawal can be accurately represented by both linear and exponential curves. Calculating brain compliance using a linear curve (CSF 3 cc withdrawal=PVIw3) is a more convenient method compared to an exponential curve. Furthermore, combining initial ICP with PVIw3 provides a more significant prognostic value than considering initial ICP alone. And the PVIw3 values above 3 were associated with a significant high favorable outcome.