Influence of two different volume replacement regimens on renal function in elderly patients undergoing cardiac surgery: comparison of a new starch preparation with gelatin.

OBJECTIVE

There is continuing concern on the influence of hydroxethyl starch (HES) on renal function.

DESIGN

Prospective, randomized study.

SETTING

University-affiliated medical center.

PATIENTS

Forty consecutive patients aged >70 years undergoing cardiac surgery using cardiopulmonary bypass.

INTERVENTIONS

Either low-molecular HES (mean molecular weight: 130 kD) with low degree of substitution (0.4) (6% HES 130/0.4) (n=20) or gelatin ( n=20) was given after induction of anesthesia until the 2nd postoperative day (POD) to keep central venous pressure between 12-14 mmHg.

MEASUREMENTS AND RESULTS

Creatinine clearance (CC) and fractional sodium clearance (FSC) were measured. N-acetyl-beta-D-glucosamidase, alpha-1-microglobulin, glutathione transferase-pi, and glutathione transferase-alpha were measured from urine specimens. Measurements were made after induction of anesthesia, at the end of surgery, and at the first and the second POD. More gelatin (total: 4150+/-490 ml) than HES 130/0.4 (total: 3450+/-450 ml) was infused within the study. CC and FSC were without differences between the two groups. All measured kidney-specific proteins were almost within normal range at baseline. They increased significantly after surgery, however, without significant group differences. At the 2nd POD, kidney-specific proteins had returned almost to normal values. None of the patients developed acute renal failure.

CONCLUSIONS

Sensitive markers of kidney dysfunction increased in our elderly patients indicating moderate alterations in kidney integrity during cardiac surgery. The two volume replacement regimens did not differ with regard to kidney integrity in elderly patients undergoing cardiac surgery.