Background: Sudden cardiac arrest causes numerous deaths worldwide. High-quality chest compressions are important for good neurological recovery. Arterial pressure is considered useful to monitor the quality of chest compressions by the American Heart Association. However, arterial pressure catheter might be inconvenient during resuscitation. Conversely, cerebral regional oxygen saturation (rSO2) during resuscitation may be associated with a good neurological prognosis. Therefore, we aimed to evaluate the correlation between mean arterial pressure and rSO2 during resuscitation to use rSO2 as the indicator of the quality of chest compressions.
Methods: This study was a single-centre, prospective, observational study. Patients with out-of-hospital cardiac arrest who were transported to a tertiary care emergency centre between October 2014 and March 2015 in Japan were included. The primary outcome was the regression coefficient between MAP and rSO2. MAP and rSO2 were measured during resuscitation (at hospital arrival [0 min], 3 min, 6 min, 9 min, 12 min, 15 min), and MAP was measured by an arterial catheter inserted into the femoral artery. For analysis, we used the higher value of rSO2 obtained from the left and right forehead of the patient and measured using a near-infrared spectrometer. Regression coefficients were calculated using the generalized estimating equation (GEE) with MAP and SAP as response variables and rSO2 as an explanatory variable, because MAP and rSO2 were repeatedly measured in the same patient. Since the confounding factors between MAP or SAP and rSO2 were not clear clinically or from previous studies, the GEE was analysed using univariate analysis.
Results: Thirty-seven patients were analysed. rSO2 and MAP during resuscitation from hospital arrival to 15 min later were expressed as follows (median [interquartile range]): rSO2, 29.5 (24.3–38.8) %, and MAP, 36.5 (26–46) mmHg. The regression coefficient (95% confidence interval) of log-rSO2 and log-MAP was 0.42 (0.03–0.81) (p=0.035).
Conclusion: rSO2 and MAP showed a mild but statistically significant association. rSO2 could be used to assess the quality of chest compressions during resuscitation as a non-invasive and simple method.
Trial registration: This study was registered in the University hospital Medical Information Network Clinical Trials Registry (UMIN000015479).