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 (rSO2) 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 rSO2 was characterized overall and according to ROSC and favorable survival defined by Cerebral Performance Category (CPC) 1-2. We also calculated ΔrSO2, defined as the change in rSO2 from pre- to post-ROSC among those who achieved ROSC, and compared to a time-matched rSO2 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 rSO2 was 33 % (interquartile range = 22.45 %). Initial rSO2 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 rSO2 and ΔrSO2 were greater upon ROSC versus time-matched ongoing pulselessness (rSO2 = 60 % vs. 33 %, AUC = 0.84, p < 0.001; ΔrSO2 = 11 % vs. 1 %, AUC = 0.85, p < 0.001). Among those who achieved ROSC, rSO2 and ΔrSO2 during the peri-ROSC period was greater among those with subsequent favorable survival (rSO2 = 63 % vs. 46 %, AUC = 0.74, p = 0.06; ΔrSO2 = 29 % vs. 10 %, AUC = 0.77, p = 0.04)

CONCLUSION

Greater values of rSO2 and ΔrSO2 identified instantaneous ROSC and predicted favorable neurological survival among those who achieved ROSC.