PhysiologicalData.zip

Comparison of static and dynamic cerebral autoregulation under anesthesia influence in a controlled animal modelAbstractThe brain’s ability to maintain cerebral blood flow approximately constant despite cerebral perfusion pressure changes is known as cerebral autoregulation (CA) and is governed by vasoconstriction and vasodilation. Cerebral perfusion pressure is defined as the pressure gradient between arterial blood pressure and intracranial pressure. Measuring CA is a challenging task and has created a variety of evaluation methods, which are often categorized as static and dynamic CA assessments. Because CA is quantified as the performance of a regulatory system and no physical ground truth can be measured, conflicting results are reported. The conflict further arises from a lack of healthy volunteer data with respect to cerebral perfusion pressure measurements and the variety of diseases in which CA ability is impaired, including stroke, traumatic brain injury and hydrocephalus. To overcome these differences, we present a healthy non-human primate model in which we can control the ability to autoregulate blood flow through the type of anesthesia (isoflurane vs fentanyl). We show how three different assessment methods can be used to measure CA impairment, and how static and dynamic autoregulation compare under challenges in intracranial pressure and blood pressure. We reconstructed Lassen’s curve for two groups of anesthesia, where only the fentanyl anesthetized group yielded the canonical shape. Cerebral perfusion pressure allowed for the best distinction between the fentanyl and isoflurane anesthetized groups. The autoregulatory response time to induced oscillations in intracranial pressure and blood pressure, measured as the phase lag between intracranial pressure and blood pressure, was able to determine autoregulatory impairment in agreement with static autoregulation. Static and dynamic CA both show impairment in high dose isoflurane anesthesia, while low isoflurane in combination with fentanyl anesthesia maintains CA, offering a repeatable animal model for CA studies. <br>MethodsPlease see original article for information on experimental design and data acquisition. Usage NotesFor every measurement at least one blood flow data stream is available. Due to a change in data acquisition hardware, two diffuse correlation spectroscopy (DCS) systems were used, which manly vary in sampling frequency. They are titled "slow DCS" and "high speed DCS (HSDCS)" in the data set. All measurements have arterial blood pressure and intracranial pressure measurements available. Blood flow and pressure data was aligned at the beginning of each individual measurement and trimmed. Therefore, all data sets are set to start at the same time. The end time of every data stream can vary. The same alignment was done for vital signs recorded by the patient monitor, which includes ETCO2, SPO2, heart rate and respiration rate, temperature, etc. Data is saved as a *.mat file, for use in Matlab. Libraries to load the data into python (see SciPy) and other languages can be found elsewhere. Anesthesia information is provided as an average of %ISO per measurement and was extracted from handwritten anesthesia protocols. The data is provided as an excel spreadsheet (*.xlsx).