Regional cerebral oxygen saturation on hospital arrival is a potential novel predictor of neurological outcomes at hospital discharge in patients with out-of-hospital cardiac arrest

Aim To investigate the association between regional brain oxygen saturation (rSO₂) on hospital arrival and neurological outcomes at hospital discharge in patients with out-of-hospital cardiac arrest (OHCA).Methods A prospective cohort study was conducted, registering 179 patients with OHCA who were referred to Senri Critical Care Medical Centre between April 2009 and June 2010. Of these patients, 92 met the inclusion criteria. The primary end point was “neurological outcomes” at hospital discharge according to the “Utstein style” guidelines.Results The overall rate of good neurological outcome at hospital discharge was 14% (n = 13). Sixty-one patients with rSO₂ ≤25% showed poor neurological outcome in the receiver operating curve analysis (optimal cut-off point, 25%; sensitivity, 0.772; specificity, 1.000; positive predictive value, 1.000; area under the curve (AUC), 0.919; p < 0.0001). The AUC for rSO₂ was greater than that for base excess (p = 0.0461) or lactate (p = 0.0128) measured on hospital arrival. Since rSO₂ >40% was previously collated with good neurological outcome after cardiovascular surgery, we categorised our patients into three groups in a post hoc analysis: patients with rSO₂ ≤25% (n = 61); patients with rSO₂ 26-40% (n = 9) and patients with rSO₂ >40% (n = 22). Patients with good neurological outcome were as follows: 0 (0%)/61 with rSO₂ ≤25%; two (22.2%)/9 with rSO₂ 26-40% and 11 (50.0%)/22 with rSO₂ >40% (p < 0.0001).Conclusion rSO₂ on hospital arrival may help predict neurological outcomes at hospital discharge in patients with OHCA.