Renal function and cardiopulmonary bypass in pediatric cardiac surgical patients

Area of Science:

• Pediatric Nephrology
• Cardiovascular Surgery
• Renal Physiology

Background:

• Cardiac surgery in children often involves cardiopulmonary bypass (CPB), raising concerns about potential renal complications.
• Assessing perioperative renal function is crucial for managing pediatric patients undergoing these procedures.

Purpose of the Study:

• To prospectively evaluate perioperative changes in renal function in children undergoing cardiac surgery with CPB.
• To assess markers of renal tubular damage and overall renal performance during and after surgery.

Main Methods:

• Prospective study of nine children undergoing cardiac surgery with CPB.
• Measurement of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) using inulin and (131)I-hippuran clearances at multiple time points.
• Analysis of urinary alpha glutathione S-transferase (alpha GS-T) as a marker of tubular damage, alongside creatinine, electrolytes, and calculated renal function indices.

Main Results:

• GFR remained normal throughout the perioperative period.
• Effective renal plasma flow (ERPF) increased significantly after CPB, despite being low preoperatively and postoperatively.
• Filtration fraction (FF) decreased during normothermic CPB and sternal closure. Urinary alpha GS-T and fractional excretion of sodium (FeNa) showed minor, non-significant increases postoperatively, indicating no significant tubular damage or dysfunction.

Conclusions:

• Cardiac surgery with CPB in children does not lead to clinically significant renal function deterioration.
• Postoperative increases in urinary alpha GS-T are not indicative of significant tubular cellular damage.
• Renal tubular function remains intact during the perioperative period in this pediatric cohort.