Near-Infrared Spectroscopy to Assess Cerebral Autoregulation and Optimal Mean Arterial Pressure in Patients With Hypoxic-Ischemic Brain Injury: A Prospective Multicenter Feasibility Study.

Abstract

A prospective multicenter cohort study was conducted in ICUs in three teaching hospitals across Canada. Patients (≥ 16 yr old) were included if their cardiac arrest occurred within the previous 36 hours, they had greater than or equal to 20 consecutive minutes of spontaneous circulation following resuscitation, and they had a post-resuscitation Glasgow Coma Scale of less than or equal to 8. Recruitment rates were calculated across sites, and patients underwent continuous regional cerebral oxygenation monitoring using near-infrared spectroscopy, as well as invasive blood pressure monitoring. Exploratory multivariable logistic regression was performed. Although it was feasible to recruit patients across multiple centers, there was variability in the recruitment rates. Physiologic data were captured in 86.2% of the total monitoring time and the median monitoring time was 47.5 hours (interquartile interval, 29.4-65.0 hr) across 59 patients. Specifically, 88% of mean arterial pressure and 96% of bilateral frontal regional cerebral oxygenation data were acquired, and 90% of cerebral oximetry index and 70% of optimal mean arterial pressure values were quantified. However, there was substantial variation in the amount of data captured among individuals. Time to return of spontaneous circulation was associated with an increased odds of an unfavorable neurologic outcome. We demonstrated feasibility to recruit and collect high frequency physiologic data in patients after cardiac arrest. Future investigations will need to systematically document the reasons for data attrition, as well as how these methodological complications were resolved. Due to underpowered analyses and the inability to control for potential confounds, further studies are needed to explore the association between cerebral autoregulatory capacity and individualized mean arterial pressure thresholds with neurologic outcomes.