Pulse and mean intracranial pressure analysis in pediatric traumatic brain injury.

OBJECTIVE We investigated the relationship between the intracranial pulse pressure (ICPpp) and the mean intracranial pressure (ICP(M)) in pediatric patients with traumatic brain injury (TBI). METHODS We screened ICP records of 42 patients admitted to the Pediatric Intensive Care Unit at Doernbecher Children's Hospital (OHSU) for segments in which the ICPM varied at least 5 mmHg. We found 54 ICP segments in 9 pediatric TBI patients (ages 0.2-17.8 years, mean = 9.9). ICP was continuously monitored (fs = 125 Hz). We used an automatic algorithm to detect ICP beat components. We then calculated the ICPpp and ICPM for each beat and created density plots of ICPpp vs. ICPM. RESULTS The coefficient of linear correlation was r > 0.70 in 43/54 segments (p < 0.01). We found that an underlying linear relationship exits between ICPpp and ICPM in most 1-hour records of pediatric patients with TBI. This finding is consistent with the data in adult studies, suggesting that children with TBI demonstrate similar changes in brain compliance. However, density plots revealed that there are also nonlinear ICPpp-ICPM patterns present that are not captured by linear metrics. CONCLUSION Although there is an underlying linear relationship between ICPpp and ICPM, nonlinear patterns are also present. Further research is required to determine if specific nonlinear ICPpp-ICPM patterns correlate with clinically significant information.