Blood pressure immediately after return of spontaneous circulation is associated with increased survival on admission following out-of-hospital cardiac arrest

Background: In patients with out-of-hospital cardiac arrest (OHCA), low blood pressure after return of spontaneous circulation (ROSC) can be a sign of hemodynamic instability. We aimed to investigate whether systolic blood pressure (SBP) measured immediately after ROSC is associated with survival on admission. Methods: Patients with ROSC after OHCA between 2015 and 2018 were included. The primary outcome was survival on admission. Included patients were divided into three groups based on the SBP measured at the time of ROSC: group 1 (SBP <= 90 mmHg), group 2 (SBP 90-120 mmHg), and group 3 (SBP >120 mmHg). Multivariable logistic regression was used to investigate the relationship between the groups by SBP and outcomes. Results: In the final analysis, 519 patients were included. In the restrictive cubic spline curve, the probability of achieving survival on admission increased gradually from low SBP to approximately 120-130 mmHg, then plateaued at a higher SBP. In the multivariable logistic regression analysis, group 1 was independently associated with decreased survival on admission compared to group 2. There was no significant difference between groups 2 and 3. Conclusions: Low blood pressure (SBP <= 90 mmHg) at the time of ROSC was independently associated with a lower likelihood of survival on admission in patients with non-traumatic OHCA. However, high blood pressure (SBP >120 mmHg) was not associated with a higher likelihood of survival. These suggest that low blood pressure measured in the prehospital phase can serve as an indicator predicting the poor short-term prognosis of patients.