Introduction: Severe hemodilution result in renal injury and so, acute Renal failure can occured. This problem increases hospital stay in ICU and patients face to the serious problems- even death- can be occurred.

In this study, we evaluated renal function after CABG in patients whom their hematocrit levels during cardiopulmonary bypass have been preserved in recommended range by text books.

Methods and Materials:

In 200 patients who scheduled for CABG in first 6  half of year 1387 in educational hospitals of the shiraz university, aged between 40-65- years old, renal function tests including BUN, serum cr and urinalysis (for detection of proteinuria) were registered in pre operation and post operation period. Hematocrit level of these patients was checked before operation, during bypass ((in 3 times)) and immediately after stoppage of cardio pulmonary by pass pump. Then we evaluated changes which have been occurred in post operation renal function tests in comparison with these data which checked at pre operation time and proceeded to existing probable relations between these changes and hematocrit levels during pump time.

Results: It was observed that if hematocrit levels are maintained at range of 21-26% in limitation of hematocrit during pump time, renal function will be  preserved in majority of these patients In four patienents, post operation serum creatinine increased twice in comparison with pre operation which seems that, mean level hematocrit in these four patients during pump time, situated in upper limit of preserved Hematocrit limitation during pump.

Conclusion:

It seems that kidney function will protect better if hematocrit level preserved about 21-22%. We recommend another study with larger sample size for better evaluation of this finding.