Evaluate cerebrovascular autoregulation (CAR) using near-infrared spectroscopy (NIRS) after pediatric cardiac arrest and determine if deviations from CAR-derived optimal mean arterial pressure (MAP) are associated with outcomes.
CAR was quantified by a moving, linear correlation between time-synchronized mean arterial pressure (MAP) and regional cerebral oxygenation, called cerebral oximetry index (COx). MAP was calculated using a multi-window weighted algorithm. We calculated burden (magnitude and duration) of MAP less than 5mmHg below MAP (MAP-5), as the area between MAP and MAP-5 curves using numerical integration and normalized as percentage of monitoring duration. Unfavorable outcome was defined as death or pediatric cerebral performance category (PCPC) at hospital discharge ≥3 with ≥1 change from baseline. Univariate logistic regression tested association between burden of MAP less than MAP-5 and outcome.
Thirty-four children (median age 2.9 [IQR 1.5,13.4] years) were evaluated. Median COx in the first 24 hours post-cardiac arrest was 0.06 [0,0.20]; patients spent 27% [19,43] of monitored time with COx ≥0.3. Patients with an unfavorable outcome (n=24) had a greater difference between MAP and MAP-5 (13 [11,19] vs. 9 [8,10] mmHg, p=0.01) and spent more time with MAP below MAP-5 (38% [26,61] vs. 24% [14,28], p=0.03). Patients with unfavorable outcome had a higher burden of MAP less than MAP-5 than patients with favorable outcome in the first 24 hours post-arrest (187 [107,316] vs. 62 [43,102] mmHg×Min/Hr; OR 4.93 [95% CI 1.16 to 51.78]).
Greater burden of MAP below NIRS-derived MAP-5 during the first 24 hours after cardiac arrest was associated with unfavorable outcomes.

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