A Spectral Approach to Model-Based Noninvasive Intracranial Pressure Estimation.

Rohan Jaishankar,Thomas Heldt,Aristotelis Filippidis,Thai Vu,Andrea Fanelli,James Holsapple

doi:10.1109/jbhi.2019.2961403

Abstract

Intracranial pressure (ICP) normally ranges from 5 to 15mmHg. Elevation in ICP is an important clinical indicator of neurological injury, and ICP is therefore monitored routinely in several neurological conditions to guide diagnosis and treatment decisions. Current measurement modalities for ICP monitoring are highly invasive, largely limiting the measurement to critically ill patients. An accurate noninvasive method to estimate ICP would dramatically expand the pool of patients that could benefit from this cranial vital sign. This article presents a spectral approach to model-based ICP estimation from arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV) measurements. The model captures the relationship between the ABP, CBFV, and ICP waveforms and utilizes a second-order model of the cerebral vasculature to estimate ICP. The estimation approach was validated on two separate clinical datasets, one recorded from thirteen pediatric patients with a total duration of around seven hours, and the other recorded from five adult patients, one hour and 48 minutes in total duration. The algorithm was shown to have an accuracy (mean error) of 0.4mmHg and -1.5mmHg, and a precision (standard deviation of the error) of 5.1 mmHg and 4.3mmHg, in estimating mean ICP (range of 1.3mmHg to 24.8mmHg) on the pediatric and adult data, respectively. These results are comparable to previous results and within the clinically relevant range. Additionally, the accuracy and precision in estimating the pulse pressure of ICP on a beat-by-beat basis were found to be 1.3mmHg and 2.9mmHg respectively. These contributions take a step towards realizing the goal of implementing a real-time noninvasive ICP estimation modality in a clinical setting, to enable accurate clinical-decision making while overcoming the drawbacks of the invasive ICP modalities.

Highlights

I NJURIES to and disorders of the brain – such as traumatic brain injury (TBI), hemorrhagic stroke, hydrocephalus, or brain tumor – are responsible for a significant fraction of the total hospital visits in the United States each year [1]–[6]
The diagnosis, monitoring and treatment of patients with the aforementioned conditions often rely on the measurement and tracking of intracranial pressure (ICP), as elevations in Intracranial pressure (ICP) are correlated with poor outcome in brain injury patients
The blood flow through the cerebrovascular system is driven by the difference of arterial blood pressure (ABP) and ICP, denoted as the cerebral perfusion pressure (CPP), which we will denote as x(t)

Summary

Introduction

I NJURIES to and disorders of the brain – such as traumatic brain injury (TBI), hemorrhagic stroke, hydrocephalus, or brain tumor – are responsible for a significant fraction of the total hospital visits in the United States each year [1]–[6]. These conditions have in common that one of the intracranial compartments (brain tissue, cerebrospinal fluid (CSF), or blood) expands at the expense of the volumes occupied by the other two, owing to the volume constraint imposed by the rigid skull and relatively inelastic dura mater [7]. Both approaches are used for decision making in current clinical practice [14]

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Discussion

Conclusion