Balanced forced-diuresis as a renal protective approach in cardiac surgery: Secondary outcomes of electrolyte changes

Abstract

Objectives: Forced-diuresis during cardiopulmonary bypass (CPB) can be associated with significant electrolyte shifts. This study reports on the serum electrolyte changes during balanced forced-diuresis with the RenalGuard® system (RG) during CPB.

Methods: Patients at risk of acute kidney injury (AKI)-(history of diabetes &/or anaemia, e-GFR 20-60 ml/min/1.73 m2 , anticipated CPB time >120 min, Log EuroScore >5)-were randomized to either RG (study group) or managed as per current practice (control group).

Results: The use of RG reduced AKI rate (10% for RG and 20.9% in control, p = .03). Mean urine output was significantly higher in the RG group during surgery (2366 ± 877 ml vs. 765 ± 549 ml, p < .001). The serum potassium levels were maintained between 3.96 and 4.97 mmol/L for the RG group and 4.02 and 5.23 mmol/L for the controls. Median potassium supplemental dose was 60 (0-220) mmol (RG group) as compared to 30 (0-190) mmol for control group over first 24 h (p < .001). On Day 1 post-op, there were no significant differences in the serum sodium, potassium, calcium, magnesium, phosphate, and chloride levels between the two groups. Otherwise, postoperative clinical recovery was also similar.

Conclusions: Balanced forced-diuresis with the RG reduced AKI rates after on-pump cardiac surgery compared to controls. Although the RG group required higher doses of IV potassium replacement in the postoperative period, normal serum levels of potassium were maintained by appropriate intravenous potassium supplementation and the clinical outcomes between groups were similar.

Keywords: acute kidney injury; balanced forced diuresis; cardiac surgery.

Conflict of interest statement

The authors declare that there are no conflict of interests.

© 2021 The Authors. Journal of Cardiac Surgery published by Wiley Periodicals LLC.

Figures

Figure 1

Haemoglobin levels in the perioperative period. Pre‐op: in anaesthetic room, Pre‐CBP: before initiation of cardiopulmonary bypass. On‐CPB1: on cardiopulmonary bypass for 15 min, On‐CPB2: before stopping cardiopulmonary bypass, Post‐CPB: poststopping cardiopulmonary bypass for 15 min. ICU1: on arrival to ICU, ICU2: on ICU for 6 h, ICU3: On ICU for 12 h, ICU4: On ICU for 24 h. ICU, intensive care unit

Figure 2

The strong ion difference levels (not significantly different except at ICU2* and ICU3* periods) at various time periods—Pre‐op: In anaesthetic room, Pre‐CBP: before initiation of cardiopulmonary bypass. On‐CPB1: on cardiopulmonary bypass for 15 min. On‐CPB2: before stopping cardiopulmonary bypass, post‐CPB: poststopping cardiopulmonary bypass for 15 min. ICU‐0 h: on arrival to ICU, ICU‐6 h: on ICU for 6 h, ICU‐12 h: on ICU for 12 h, ICU‐24 h: on ICU for 24 h. ICU, intensive care unit

Figure 3

Electrolytes (A) sodium, (B) potassium, (C) lactate, and (D) pH levels in the perioperative period—pre‐op: in anaesthetic room, pre‐CBP: before initiation of cardiopulmonary bypass. On‐CPB1: on cardiopulmonary bypass for 15 min. On‐CPB2: before stopping cardiopulmonary bypass, post‐CPB: poststopping cardiopulmonary bypass for 15 min. ICU1: on arrival to ICU, ICU2: on ICU for 6 h, ICU3: on ICU for 12 h. ICU, intensive care unit