The association between modifiable perioperative parameters and renal function after nephrectomy.

Abstract

To evaluate the association between intraoperative anesthetic parameters, primarily intraoperative hypotension, and postoperative renal function in patients undergoing nephrectomy. We reviewed data from 3,240 consecutive patients who underwent nephrectomy between 2010-2018. Anesthetic parameters evaluated included duration of hypotension, tachycardia, hypothermia, volatile anesthetic use and mean arterial pressure at the post-anesthesia care unit. Outcomes included acute kidney injury (AKI) and estimated glomerular filtration rate (eGFR) within the first year after nephrectomy. Associations between anesthetic parameters and outcomes were evaluated with multivariable logistic regression and generalized estimating equation, respectively, adjusted for predictors of renal function after nephrectomy. Before nephrectomy, 677 (21%) patients had moderate-severe chronic kidney disease. A quarter of patients (n=809) had postoperative AKI and 35% (n=746) had stage ≥3 chronic kidney disease 12-months after surgery. Only 12% of patients (n=386) had >5 minutes of intraoperative hypotension. While not statistically significant, longer duration of intraoperative hypotension was associated with slightly higher rates of AKI (OR per 10-minutes 1.14; 95% CI 0.98, 1.32). Prolonged hypothermia was associated with increased rate of AKI (OR per 10-minutes 1.02; 95% CI 1.00, 1.04), and decreased eGFR (change in eGFR per 10-minutes -0.19; 95% CI -0.27, -0.12), however, these results have limited clinical significance. Under current practice, intraoperative anesthetic parameters are tightly maintained, restricting the significance of their effect on postoperative renal function. Future studies should evaluate whether hemodynamic parameters during the early post-operative period, when they are monitored less frequently, are associated with renal functional outcome.