Relationship between Intraoperative Blood Pressure Variability and postoperative Acute Kidney Injury following Non-cardiac Surgery

BACKGROUND We aimed to determine the effect of intraoperative blood pressure variability on postoperative acute kidney injury (PO-AKI) following non-cardiac surgery. METHODS We studied 2,224 patients who underwent non-cardiac surgery under general anesthesia from the Kailuan study cohort. Blood pressure variability was assessed using the coefficient of variation (CV) of the mean arterial pressure (MAP), pulse pressure (PP), systolic pressure (SBP), and diastolic pressure (DBP). The outcome was PO-AKI, defined using the Kidney Disease Improving Global Outcomes criteria. Multivariate logistic regression was used to analyze the effect of short-term intraoperative blood pressure variability on PO-AKI, and the effect of such variability on the change in serum creatinine concentration during surgery was analyzed using a generalized linear model. RESULTS PO-AKI occurred in 88 of 1,503 participants. After adjustment for potential confounding factors, the risk of high postoperative serum creatinine and PO-AKI increased with increasing blood pressure variability; generalized linear models showed that increases of single units in MAP_CV, PP_CV, and SBP_CV were associated with increases in serum creatinine of 0.23 µmol/L, 0.17 µmol/L, and 0.30 µmol/L, respectively. Multivariate logistic regression showed that with MAP_CV and SBP_CV quartiles as independent variables, the odds ratios (95% confidence intervals) for PO-AKI in the highest quartiles were 2.00 (1.03–3.92) and 2.24 (1.08–4.60), respectively, versus the lowest quartiles. CONCLUSIONS During non-cardiac surgery, high blood pressure variability is positively associated with increases in the risks of high serum creatinine and PO-AKI, with SBP variability having the strongest relationship.