RENAL-INSUFFICIENCY IN NEONATES AFTER CARDIAC-SURGERY

Renal failure after cardiac surgery using cardiopulmonary bypass (CPB) is well understood for infants, children and adults. The perioperativ e risk factors after CPB for immature kidneys in newborns are not well known. This restrospective study investigates perioperative risk fact ors for renal insufficiency in neonates. I) Preoperative: Age; weight, performed angiography, amount of dye used in angiography, renal disea se and creatinine. LT) Intraoperative: Duration of operation, duration of MAP <40 mmHg, use of deep hypothermia, in-out fluid balance, durat ion of CPB, duration of circulatory arrest and cross-clamp time. III) Postoperative: Creatinine, use of catecholamines, use of nitroglycerin e (NG) or phosphodiesterase inhibitors (PDI) and additional antibiotic s. From Jan. 1990 to Dec. 1994 50 neonates underwent cardiac surgery u sing CPB (n = 23 transposition of the great arteries; n = 4 pulmonary atresia; n = 6 critical pulmonary stenosis; n = 5 hypoplastic left hea rt syndrome; n = 3 Ebstein's anomaly; n = 2 interrupted arch with hypo plastic left ventricle; n = 2 single ventricle; n = 1 each: double out let right ventricle, tricuspid atresia, critical aortic stenosis, rhab do-myosarkoma, corrected transposition of the great arteries.) Thirty- one patients entered the study. Depending on the postoperative creatin ine level two groups (group I: creatinine <1 mg/dl and group II: >1 mg /dl) were created. The diureses between the two groups did not differ. Comparing the patients of group I vs. group II, patients of group I w ere younger (mean age: 7.7 d. vs. 11.4 d), lighter (mean weight: 3260 g vs. 3430 g), less had angiography (44% vs. 77%), received more dye ( mean amount: 14 ml vs. 7 ml), the duration of MAP <40 mmHg while on CP B was longer (mean duration 3 min vs. 21 min), more patients were oper ated on using deep hypothermia (55% vs. 27%), the postoperative in-out -fluid balance was more positive (mean balance +413 ml vs. +221 ml), r eceived postop. more frequently high doses of catocholamines and less common NG or PDI, but more often additional antibiotics. The duration of circulatory arrest (mean time: 60 min vs. 55 min) and cross clamp t ime (mean time: 68 min vs. 65 min) seems not to be a risk factor and v asodilators given simultaneously with catecholamines may have preventi ve effects on postoperative renal insufficiency. Immature kidneys may play an outstanding role in the susceptibility of damaging factors. Fu rther investigation with a larger number of patients allowing to obtai n statistical significant risk factors are required.