Impact of intraoperative hypotension and blood loss on acute kidney injury after pancreas surgery

PURPOSE: This study aimed to investigate factors associated with postoperative Acute Kidney Injury (AKI) focusing on intraoperative hypotension and blood loss volume. METHODS: This was a retrospective cohort study of patients undergoing pancreas surgery between January 2013 and December 2018. The primary outcome was AKI within 7 days after surgery and the secondary outcome was the length of hospital stay. Multivariate analysis was used to determine explanatory factors associated with AKI; the interaction between the integrated value of hypotension and blood loss volume was evaluated. The differences in length of hospital stay were compared using the Mann-WhitneyU-test. RESULTS: Of 274 patients, 22 patients had experienced AKI. The cube root of the area under intraoperative mean arterial pressure of < 65 mmHg (Odds Ratio = 1.21; 95% Confidence Interval 1.01–1.45; p = 0.038) and blood loss volume of > 500 mL (Odds Ratio = 3.81; 95% Confidence Interval 1.51–9.58; p = 0.005) were independently associated with acute kidney injury. The interaction between mean arterial hypotension and the blood loss volume in relation to acute kidney injury indicated that the model was significant (p < 0.0001) with an interaction effect (p = 0.0003). AKI was not significantly related with the length of hospital stay (19 vs. 28 days, p = 0.09). CONCLUSION: The area under intraoperative hypotension and blood loss volume of > 500 mL was associated with postoperative AKI. However, if the mean arterial pressure is maintained even in patients with large blood loss volume, the risk of developing postoperative AKI is comparable with that in patients with small blood loss volume.