# Innovative Method for Real-time Assessment of Intracranial Compliance

> **NIH NIH R21** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 2020 · $430,375

## Abstract

"Standard of care" neurological monitoring for patients with severe traumatic brain injury (TBI) - a leading
cause of death and long-term neurological impairment in children and adults-has not changed in decades,
relying mainly on intracranial pressure {ICP) monitoring. Remarkably, the use of ICP alone as a therapeutic
target for severe TBI is currently controversial due to a lack of robust supporting evidence, especially for its use
in children.
To address this clinical need, we developed the ICP-PC02 Compliance Index (ICP-PCI), an algorithm
to compute dynamic intracranial compliance in real-time by integrating continuous ICP and end tidal CO,
(ETC02) data streams. Bedside assessment of intracranial compliance-the relationship between changes in
ICP and concomitant changes in intracranial volume, has been limited because of the lack of point-of-care
devices to measure cerebral blood flow (CBF)/cerebral blood volume (CBV). The ICP-PCI is based on the well-known
and robust relationship between the partial pressure of CO2 in blood (PC02) and CBV, where a change
in PC02 of 1 mmHg induces an -3% change in CBF in patients with severe TBI. Since CBF is proportional to
blood vessel radius to the fourth power, changes in CBF reflect immediate changes in CBV. As continuous ICP
and ETC02 monitoring are standard of care for patients with severe TBI, ICP-PCI can be determined using
existing ICU monitoring. To date we have obtained preliminary data in children with severe TBI in an IRB
approved study that validates the physiologic premise and demonstrates feasibility for measurement of ICPPCI
using existing, continuous ICU monitoring deemed guidelines-based standard of care. In this proposal,
dense time series data, including continuous ETC02, ICP, and other physiologic waveforms will be
interrogated. ICP-PCI will be calculated as the running moment-to-moment correlation between ETC02 and
ICP across optimized temporal epochs, and subject to additional signal processing. We will confirm our
findings across a larger cohort and define the temporal pattern of ICP-PCI and associations with relevant
clinical variables: ICP, CPP, duration of ICP monitoring, medical and surgical interventions, and ICU and
hospital length of stay. In addition, high-density, time series data will be integrated and time-synchronized with
electronic health record (EHR) data and simulation models will be generated and refined to define the capacity
for ICP-PCI to predict the need and response to relevant medical and surgical interventions. Clinical
application of ICP-PCI will be compared head-to-head with ICP alone. Successful validation of ICP-PCI
would lay the groundwork for the development of a valuable clinical tool for all Centers managing
children and possibly adults with severe TBI, that could be readily integrated and implemented using
existing ICU monitoring.

## Key facts

- **NIH application ID:** 9901747
- **Project number:** 1R21NS115174-01
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **Principal Investigator:** Robert S B Clark
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $430,375
- **Award type:** 1
- **Project period:** 2020-04-15 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9901747

## Citation

> US National Institutes of Health, RePORTER application 9901747, Innovative Method for Real-time Assessment of Intracranial Compliance (1R21NS115174-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9901747. Licensed CC0.

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