Renal Function and Proteinuria After Cardiopulmonary Bypass

Abstract

We studied three groups of patients without previous renal impairment, undergoing elective coronary artery bypass surgery. Group H (n = 7) underwent open heart surgery using moderate hypothermia (28 degrees C); Groups N and M (n = 8, each) were managed at normothermia. The extracorporeal circuit was primed with Hartmann's solution 2.5 L with the addition of mannitol 0.5 g/kg in Group M. Serum concentrations of sodium and creatinine, and the urinary concentrations of microalbumin and N-acetyl-beta-D-glucosaminidase (NAG) were measured in each patient at six different time intervals: T0, 6 h prior to surgery; T1, between sternotomy and 45 min into cardiopulmonary bypass (CPB); T2, in the interval from 45 min into, to prior to weaning off CPB; T3, from coming off CPB to skin closure; T4, in the first 6 h in the intensive care unit; and T5, at 6 days postoperatively. Creatinine clearance (CCR) and fractional sodium excretion (FENA) were calculated at each time point. Urine output during CPB at Interval T2 was significantly higher in Group H compared to Group N (P = 0.03) but not Group M. We found no significant differences in CCR, FENA, microalbuminuria, and urinary NAG among the three groups at any time. However, there were overall significant changes in measured variables over time compared to baseline. We conclude that CPB is associated with a significant alteration in renal function as shown by increased FENA, microalbuminuria, and urinary NAG. The use of hypothermic or normothermic CPB and the use of prophylactic mannitol did not produce any significant modification of these changes.

2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery

“…990 Diltiazem and mannitol have been used to prevent AKI after cardiac surgery. 988 Diltiazem may inhibit the inflammatory response that occurs with CPB, 992 whereas mannitol produces an osmotic diuresis. 1000 The role of mannitol in preventing AKI is unclear.…”

The effect of mannitol on renal function after cardiopulmonary bypass in patients with established renal dysfunction*

“…However, the incidence of postoperative ARF remains virtually unchanged. CPB is known to cause renal damage [9,14]; total CPB time >140 min and mean perfusion pressure below 60 mmHg both increase the risk of developing ARF [15]. It is probable that a degree of renal damage occurs in all patients, but not sufficiently to influence routine measurements of renal function in the majority [16].…”

AKI Associated with Cardiac Surgery

“…Despite this, the renal outcomes associated with the use of mannitol in cardiac surgery are mixed (210)(211)(212)(213). There are some data suggesting that atrial natriuretic peptide (214) and B-type natriuretic peptide (215) may be of benefit in patients undergoing cardiac surgery.…”