Reduction in acute kidney injury post cardiac surgery using balanced forced diuresis: a randomized, controlled trial

Abstract

OBJECTIVES Our goal was to investigate the efficacy of balanced forced diuresis in reducing the rate of acute kidney injury (AKI) in cardiac surgical patients requiring cardiopulmonary bypass (CPB), using the RenalGuard® (RG) system. METHODS Patients at risk of developing AKI (history of diabetes and/or anaemia; estimated glomerular filtration rate 20–60 ml/min/1.73 m2; anticipated CPB time >120 min; log EuroSCORE > 5) were randomized to the RG system group (n = 110) or managed according to current practice (control = 110). The primary end point was the development of AKI within the first 3 postoperative days as defined by the RIFLE (Risk, Injury, Failure, Loss of kidney function, End-stage renal disease) criteria. RESULTS There were no significant differences in preoperative and intraoperative characteristics between the 2 groups. Postoperative AKI rates were significantly lower in the RG system group compared to the control group [10% (11/110) vs 20.9% (23/110); P = 0.025]. This effect persisted even after controlling for a number of potential confounders (odds ratio 2.82, 95% confidence interval 1.20–6.60; P = 0.017) when assessed by binary logistic regression analysis. The mean volumes of urine produced during surgery and within the first 24 h postoperatively were significantly higher in the RG system group (P < 0.001). There were no significant differences in the incidence of blood transfusions, atrial fibrillation and infections and in the median duration of intensive care unit stays between the groups. The number needed to treat with the RG system to prevent AKI was 9 patients (95% confidence interval 6.0–19.2). CONCLUSIONS In patients at risk for AKI who had cardiac surgery with CPB, the RS RG system significantly reduced the incidence of AKI and can be used safely and reproducibly. Larger studies are required to confirm cost benefits. Clinical trial registration number: NCT02974946

Balanced forced-diuresis compared to control as a reno-protective approach in cardiac surgery: Secondary outcome of a randomized controlled trial, assessment of neutrophil gelatinase-associated lipocalin levels

“…Post-operative AKI rates (as per RIFLE de nition) were signi cantly lower in RG group as compared to control (10% (11/110) v/s 20.9% (23/110), p= 0.025) and has, previously, been reported in details [10].…”

“…Likewise the MAP and the central venous pressure (CVP) were not signi cantly different during CPB being 57.5 (8.9) vs 57.5 (9.4) mmHg and 3 (4.9) vs 3 (4.6) cmH 2 O respectively. Although the median lactate levels during surgery were statistically different between the two groups, these levels were not clinically signi cantly different, being around 2 mmol/L (Table 1) Post-operative AKI rates (as per RIFLE de nition) were signi cantly lower in RG group as compared to control (10% (11/110) v/s 20.9% (23/110), p= 0.025) and has, previously, been reported in details [10].…”

“…The various aspects of the device have been described in details previously [9]. Its use in adult cardiac surgery has also been reported and the clinical bene t con rmed [10]. In brief, the RG system is a closed-loop system of urine collection via a Foley's catheter and an intravenous uid administration-set interfaced through a monitoring console to adjust for even, positive or negative uid balance.…”

“…The primary end-point of the study was recently reported and published [10]. It was the RIFLE-de ned AKI rate (criteria de nition -50% increase in pre-op "baseline" serum creatinine within rst 3 days of surgery) comparing patients managed with the RG system to controls.…”

“…Consented patients were randomized using sealed opaque envelopes system generated by a research independent person in the research & development department. Management of patients randomised to the RenalGuard ® system has been previously described [10] and included instantaneously-matched balanced forced-diuresis with furosemide and intravenous rehydration with Hartmann's solution. Patients in the control group were managed as per current medical practice without forced-diuresis with intravenous furosemide in the OR.…”