Impact of estimated plasma volume status on postoperative outcomes in patients undergoing open abdominal aortic aneurysm repair.

Background: Major surgeries often lead to significant insensible fluid losses, posing challenges in achieving optimal fluid balance. Estimated plasma volume status (ePVS), calculated using the Kaplan-Hakim formula from hemoglobin and hematocrit values, serves as a marker for volume status and has been associated with adverse outcomes in various medical conditions. This study aims to explore the correlation of preoperative ePVS with postoperative outcomes in patients undergoing open abdominal aortic aneurysm (AAA) repair.

Methods: This retrospective cohort study included 329 patients who underwent open AAA repair between 2018 and 2023, requiring intensive care unit admission for more than 24 hours. Data were included demographic information, comorbid conditions, preoperative laboratory values, intraoperative data, and postoperative outcomes. ePVS was calculated preoperatively and its association with postoperative outcomes was analyzed using statistical tests including student's t-test, chi-square test.

Results: Patients with preoperative ePVS at or above the median (-11.5) had significantly higher rates of postoperative vasopressor support (P = .003), thrombotic events (P = .008), reintubation (P = .004), and sepsis (P = .044). ePVS at or above the median was also associated with longer surgery duration (P = .011). Multivariable logistic regression identified ePVS as an independent predictor of major postoperative complications (odds ratio [OR], 1.047; 95% confidence interval [CI], 1.019-1.078; P = .001) and 30-day operative mortality (OR, 1.042; 95% CI, 1.000-1.083; P = .038).

Conclusions: Preoperative ePVS can be a predictor of postoperative outcomes in patients undergoing open AAA repair. Higher preoperative ePVS is associated with increased risk of complications and 30-day mortality.