Noninvasive characterization of intracranial pulsatile dynamics in neurosurgical conditions using near infrared spectroscopy and peripheral photoplethysmography.
Study ID: STU-2022-0143
intracranial pulsatility will be studied by comparing cerebral niRS waveforms with peripheral (finger or ear lobe) photoplethysmography waveforms, with a focus on the cardiac and respiratory frequency bands. These sensors are noninvasive, low power, portable, and use red and near infrared wavelengths to measure oxyhemoglobin and deoxyhemoglobin absorbance at a high sampling frequency to provide high time resolution. These sensors are already used in clinical practice for all ages, from pre-term infants to adults. For example, continuous cerebral and renal niRS monitoring is routinely used at Dallas Children's Hospital in the intensive care units and by anesthesiologists. Subjects will be recruited and studied prospectively, with a target of ten subjects in each of the categories below to provide pilot data for analysis to guide further research. normal physiologic perturbation of CSF and venous systems will be accomplished by altering posture (laying, squatting, standin[See protocol for complete text]
We hypothesize that niRS and peripheral photoplethysmography can be used to detect perturbations of the intracranial mechanical resonant state caused by neurosurgical conditions and treatments. Though niRS and peripheral photoplethysmography waveforms in frequency bands i and ii are highly coherent, we hypothesize that neurosurgical pathology will also have detectable signatures in these bands, and that waveform morphology will carries additional useful information. This research could lead to a better mechanistic understanding that will improve diagnosis and treatment.