Association of perioperative weight-based fluid balance with 30-day mortality and acute kidney injury among patients in the surgical intensive care unit.

PURPOSE: Perioperative positive fluid balance has negative effects on short-term outcomes, such as surgical complications, although the associations with postoperative mortality remain unclear. This study evaluated the associations of perioperative fluid balance (FB) with 30-day mortality and acute kidney injury (AKI) after postoperative intensive care unit (ICU) admission.
METHODS: This retrospective study evaluated data from adult patients who were admitted to the ICU after surgery during 2012-2016. Weight-based cumulative FB (%) was calculated for 3 time periods [postoperative day (POD) 0 (24 h), 0-1 (48 h), and 0-2 (72 h)] and was categorized as positive (≥ 5%), mild to moderate positive (5-10%), severe positive (> 10%), normal (0-5%), or negative (< 0%).
RESULTS: Data from 7896 patients were included in the analysis. The multivariable Cox regression model revealed that increased 30-day mortality was associated with positive FB groups (≥ 5%) compared to normal FB groups (0-5%) during 3 time periods [hazard ratio (HR) on POD 0 (24 h): 1.87, HR on POD 1 (48 h): 1.91, and HR on POD 2 (72 h): 4.62, all P < 0.05]. These trends were more evident in the severe positive FB group across the three time periods. Additionally, similar association was found for incidence of AKI during POD 0-2.
CONCLUSION: Perioperative cumulative weight-based FB was positively associated with increased postoperative 30-day mortality or postoperative AKI in ICU patients; this association was consistent with the positive FB on POD 0 (24 h), 0-1 (48 h), and 0-2 (72 h).