Impact of intraoperative hypotension on early postoperative acute kidney injury in cystectomy patients - A retrospective cohort analysis.

STUDY OBJECTIVE

To assess the risk for postoperative acute kidney injury (AKI) after major urologic surgery for different intraoperative hypotension thresholds in form of time below a fixed threshold. We hypothesize that the duration of hypotension below a certain hypotension threshold is a risk factor for AKI also in major urologic procedures.

DESIGN

Retrospective observational cohort series.

SETTING

Single tertiary high caseload center.

PATIENTS

416 consecutive patients undergoing open radical cystectomy, pelvic lymph node dissection and urinary diversion between 2013 and 2019.

INTERVENTIONS

None.

MEASUREMENTS

We analyzed intraoperative data and their correlation to postoperative AKI judged according to the Acute Kidney Injury Network criteria. Patients were divided into groups falling below MAP <65 mmHg, MAP <60 mmHg and MAP <55 mmHg. The probability of developing postoperative AKI using all risk variables as well as the hypotension threshold variables (minutes under a certain threshold) was calculated using logistic regression methods.

MAIN RESULTS

Postoperative AKI was diagnosed in 128/416 patients (30.8%). Multiple logistic regression analysis showed that minutes below a threshold of 65 mmHg (OR 1.010 [1.005-1.015], P < 0.001) and 60 mmHg (OR 1.012 [1.001-1.023], P = 0.02) are associated with an increased risk of AKI. On average, 26.5% (MAP <65 mmHg), 50.0% (MAP <60 mmHg) and 76.5% (MAP <55 mmHg) of minutes below a certain threshold occurred between induction of anesthesia and start of surgery and are thus fully attributable to anesthesiological management.

CONCLUSIONS

Our results suggest that avoiding intraoperative MAP lower than 65 mmHg and especially lower than 60 mmHg will protect postoperative renal function in cystectomy patients. The time between induction of anesthesia and surgical incision warrants special attention as a relevant share of hypotension occur in this period.