Feasibility of Calculating and Maintaining Near-Infrared Spectroscopy-Guided Personalized Mean Arterial Pressure Targets in Adults With Critical Illness: A Pilot Clinical Study.

OBJECTIVES

Critically ill patients have a high risk for delirium, which may result from inadequate cerebral perfusion. One resuscitation goal for adult critically ill patients is maintaining mean arterial pressure (MAP) greater than 65 mm Hg, regardless of diagnosis or patient characteristics. Recent data suggest a high degree of individual variability in optimal MAP (MAPopt) due, in part, to whether autoregulation is intact or absent. The overall objective of this study was to evaluate the feasibility of maintaining critically ill patients within an individualized MAPopt range identified noninvasively with near-infrared spectroscopy, a technology that measures regional cerebral oxygen saturation (rSo2).

DESIGN

Pilot interventional feasibility study.

SETTING

Mixed ICU at a tertiary hospital.

PATIENTS: Sixteen adult critically ill patients were enrolled within 24 hours of ICU admission. Exclusion criteria included expected survival less than 24 hours, neurologic or neurosurgical diagnoses, absence of an arterial catheter, or pregnancy.

INTERVENTIONS: MAP and rSo2 data were recorded for 24 hours and processed through a custom algorithm. A running correlation coefficient between MAP and rSo2 was generated. Periods where there was zero or negative correlation between MAP and rSo2 reflected intact autoregulation. The MAP range where this correlation was near zero was determined to be the MAPopt. Vasoactive medications were used to maintain patients within that target range for the next 48 hours.

MEASUREMENTS AND MAIN

RESULTS

The enrollment rate was 0.5 patients/mo (goal 1/mo). MAPopt was successfully identified in 12 patients (75%) and maintained for 61% ± 17% of the follow-up period. The proportion of time spent within MAPopt strongly correlated with the width of the MAPopt range (r = 0.729; p = 0.017). There were no adverse events associated with the intervention.

CONCLUSIONS

Although enrollment was lower than expected, MAPopt was calculated in the majority of patients. Maintaining patients within individualized MAPopt ranges was challenging, particularly when this range was narrow.