Association Between Central Venous Pressure and 30‐Day Postoperative Outcomes After Cardiopulmonary Bypass: A Retrospective Observational Study

Objective To evaluate the association between the minimum invasive central venous pressure (CVP) recorded within the first 24 h after intensive care unit (ICU) admission following cardiopulmonary bypass (CPB) and 30‐day postoperative outcomes. Methods A total of 3348 patients undergoing cardiac surgery who required CPB were selected from the Medical Information Mart for Intensive Care III (MIMIC‐III) database. Based on the minimum valid invasive CVP value recorded within the first 24 h after ICU admission following CPB, patients were divided into three groups: ≤ 5 mmHg, 6–9 mmHg, and ≥ 10 mmHg ( n = 2018, 1018, and 312, respectively). The perioperative characteristics among the three groups were compared. The log‐rank test was used to explore the differences in survival rates among various CVP groups, and the Cox regression analysis was employed to explore the effect of different CVP levels on a 30‐day mortality. Results In unadjusted analysis, CVP ≥ 10 mmHg was strongly associated with an increased 30‐day mortality compared with CVP ≤ 5 mmHg ([hazard ratio, HR] = 8.07, 95% CI: 4.92–13.25). After sequential adjustment for disease severity scores, laboratory indices, and intraoperative variables, this association was attenuated but remained statistically significant in the fully adjusted model (HR = 3.34, 95% [confidence interval, CI]: 1.77–6.32, p < 0.001). In contrast, CVP 6–9 mmHg was not significantly associated with a 30‐day mortality compared with CVP ≤ 5 mmHg (fully adjusted HR = 1.12, 95% CI: 0.61–2.04). The 30‐day mortality rates were 1.44%, 2.06%, and 10.90% in the CVP ≤ 5 mmHg, CVP 6–9 mmHg, and CVP ≥ 10 mmHg groups, respectively. Conclusion CVP ≥ 10 mmHg was strongly associated with an increased 30‐day mortality in unadjusted analysis, and this association persisted after full adjustment, although the effect size was attenuated. CVP 6–9 mmHg was not significantly associated with mortality compared with CVP ≤ 5 mmHg. Early postoperative minimum CVP may serve as a risk‐stratification marker, but causal relationships cannot be inferred from this observational study.