Effect of intravascular volume expansion on renal function during prolonged CO2 pneumoperitoneum

Objective To evaluate whether intravascular volume expansion would improve renal blood flow and function during prolonged CO2 pneumoperitoneum. Summary Background Data Although laparoscopic living donor nephrectomies have a considerably reduced risk of complications for the donors, significant concerns exist regarding procurement of a kidney in the altered physiologic environment of CO2 pneumoperitoneum. Recent studies have documented adverse effects of CO2 pneumoperitoneum on renal hemodynamics. Methods Renal and systemic hemodynamics and renal histology were studied in a porcine CO2 pneumoperitoneum model, After placement of a pulmonary artery catheter, carotid arterial line, Foley catheter, and renal artery ultrasonic flow probe, CO2 pneumoperitoneum (15 mmHg) was maintained for 4 hours. Pigs were randomized into three intravascular fluid protocol groups: euvolemic (3 mL/kg/hour isotonic crystalloid), hypervolemic (15 mL/kg/hour isotonic crystalloid), or hypertonic (3 mL/kg/hour isotonic crystalloid plus 1.2 mL/kg/hour 7.5% NaCl). Results In the euvolemic group, prolonged CO2 pneumoperitoneum caused decreased renal blood flow, oliguria, and impaired creatinine clearance. Both isotonic and hypertonic volume expansions reversed the changes in renal blood flow and urine output, but impaired creatinine clearance persisted. Conclusions Intravascular volume expansion alleviates the effects of CO2 pneumoperitoneum on renal hemodynamics in a porcine model, Hypertonic saline (7.5% NaCl) solution may maximize renal blood flow in prolonged pneumoperitoneum, but it does not completely prevent renal dysfunction in this setting, This study suggests that routine intraoperative volume expansion is important during laparoscopic live donor nephrectomy.