Effect of intraoperative fluid overload on prognosis of patients after cardiopulmonary bypass cardiac operation：a prospective observational study / 中华危重病急救医学

ABSTRACT

Objective To explore the clinic values of intraoperative fluid overload in evaluating the perioperative prognosis of patients after cardiopulmonary bypass cardiac operation. Methods A prospective observational study was conducted. The adult patients admitted to the Third People's Hospital of Chengdu from April 2014 to March 2016 for selective cardiopulmonary bypass cardiac operation monitored by pulmonary artery catheter or pulse-indicated continuous cardiac output (PiCCO) were selected. All patients received therapy with restrictive fluid management strategy after admission to the intensive care unit (ICU) and were divided into two groups based on the value of intraoperative fluid accumulation ratio at the time of admission to the ICU group A with intraoperative fluid accumulation ratio of less than 10% and group B with equal to or more than 10%. Then the changes and different prognosis of the patients in groups were observed. Risk factors affecting the prognosis were analyzed using logistic regression, and the predictive values of various parameters on prognosis were analyzed using receiver operating characteristic curve (ROC). Results 224 cases were included, with 172 in group A and 52 in group B. No significant differences were found between both groups in gender, age, pre-operative scores by European system for cardiac operative risk evaluation (EuroScore), acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA), operation ways, operation time, cardiopulmonary bypass time and blood loss (all P > 0.05). Both APACHE Ⅱ score and SOFA score in group B were significantly higher than those in group A at admission and 24, 48 and 72 hours after ICU admission (APACHE Ⅱ 24.5±4.1 vs. 21.8±3.5, 14.8±6.5 vs. 9.9±3.9, 12.3±5.4 vs. 9.4±3.7, 10.9±5.0 vs. 8.9±3.3, SOFA 12.3±2.9 vs. 10.6±2.1, 8.8±2.8 vs. 5.7±1.7, 7.2±3.0 vs. 5.0±2.0, 6.4±3.6 vs. 5.2±1.7, all P < 0.05). Compared with group A, incidence of combination with acute kidney injury (AKI) was significantly increased in group B (92.3% vs. 68.6%, P < 0.01), the level of post operation cardiac index (CI) was significantly lower in group B (mL·s-1·m-2 40.67±4.00 vs. 49.84±7.50, P < 0.01). Both the duration of mechanical ventilation and the length of stay in the ICU in group B were significant longer than those in group A (days 3.2±2.1 vs. 1.8±1.3, 5.0±1.7 vs. 3.6±1.2, both P < 0.01). The post-operation complications, 7-day and 28-day mortality in group B were all significantly higher than those in group A (65.4% vs 30.2%, 19.2% vs. 1.7%, 26.9% vs. 3.5%, all P < 0.01). Logistic regressive analysis showed that after controlling the influence of postoperative AKI and CI on mortality, the intraoperative fluid accumulation ratio at ICU admission was still an independent risk factor [odds ratio (OR) of 7-day mortality = 1.380, 95% confidence interval (95%CI) = 1.019-1.869, P = 0.037; OR of 28-day mortality = 1.302, 95%CI = 1.026-1.654, P = 0.030]. The area under the curve of ROC (AUC) in predicting the 28-day mortality of patients after operation using intraoperative fluid accumulation ratio was 0.874 (P = 0.000), with a sensitivity of 95.0 % and a specificity of 78.4% at the optimal threshold value of 7.5%. Conclusions Intraoperative fluid overload in patients admitted to the ICU would aggravate their condition, prolong the duration of mechanical ventilation and the length of ICU stay, and increase post-operative complications morbidity and mortality. After controlling the influence of AKI and cardiac insufficiency on mortality, the fluid overload was still an independent risk factor for the death of patients after cardiopulmonary bypass cardiac operation.