Real-time cerebral oximetry and outcomes during out-of-hospital resuscitation.

BACKGROUND

Anoxic brain injury is a common mode of death following out-of-hospital cardiac arrest (OHCA). We assessed the course of regional cerebral oxygen saturation (rSO) during resuscitation to understand its association with return of spontaneous circulation (ROSC) and functional survival.

METHODS

We conducted a prospective observational investigation of OHCA patients treated by Emergency Medical Services (EMS) in a suburban community. Real-time rSO was characterized overall and according to ROSC and favorable survival defined by Cerebral Performance Category (CPC) 1-2. We also calculated ΔrSO, defined as the change in rSO from pre- to post-ROSC among those who achieved ROSC, and compared to a time-matched rSO difference among those receiving CPR who did not achieve ROSC.

RESULTS

Of 140 eligible cases, 93 were enrolled. Of these, 55 % (n = 51) achieved ROSC and 10 % (n = 9) survived with CPC 1-2. Upon cerebral oximeter application, the median rSO was 33 % (interquartile range = 22.45 %). Initial rSO did not predict subsequent ROSC (38 % ROSC vs 27 % no ROSC, AUC = 0.61, p = 0.13) or subsequent favorable survival (45 % CPC 1-2 vs 32 % no survival with CPC 1-2, AUC = 0.77, p = 0.17). However, real-time rSO and ΔrSO were greater upon ROSC versus time-matched ongoing pulselessness (rSO = 60 % vs. 33 %, AUC = 0.84, p < 0.001; ΔrSO = 11 % vs. 1 %, AUC = 0.85, p < 0.001). Among those who achieved ROSC, rSO and ΔrSO during the peri-ROSC period was greater among those with subsequent favorable survival (rSO = 63 % vs. 46 %, AUC = 0.74, p = 0.06; ΔrSO = 29 % vs. 10 %, AUC = 0.77, p = 0.04) CONCLUSION: Greater values of rSO and ΔrSO identified instantaneous ROSC and predicted favorable neurological survival among those who achieved ROSC.