BENEFICIAL EFFECT OF VOLUME EXPANSION ON THE ALTERED RENAL HEMODYNAMICS OF PROLONGED PNEUMOPERITONEUM

Abstract

85 Purpose: Prolonged pneumoperitoneum, as required for laparoscopic nephrectomy, decreases renal blood flow (RBF). We hypothesized that intravascular isotonic, and possibly hypertonic volume expansion may improve renal hemodynamics in this setting. Methods: Renal and systemic hemodynamics were studied in a porcine pneumoperitoneum model. After placement of pulmonary artery catheter, arterial line, and ultrasonic renal artery probe, pneumoperitoneum (15mm Hg CO2) was maintained for 4 hours. Pigs (n=6/group) received euvolemic (3 ml/kg/hr isotonic crystalloid), hypervolemic (15 ml/kg/hr isotonic crystalloid) or hypertonic (4.2 ml/kg/hr of 7.5% NaCl) volume expansion during this time. Results: As shown (see table), in the euvolemic group 4 hrs of pneumoperitoneum decreased RBF, urine output, and creatinine clearance as compared to baseline (paired t-test). Both iso- and hypertonic volume expansion prevented the decrease in RBF and urine output, but the reduction of creatinine clearance persisted. When RBF was compared among groups (see figure), hypertonic volume expansion had the highest RBF (P=.02, .076, and .093 at 1, 2 and 3 Hr, respectively, ANOVA).TableFigureConclusions: Intravascular volume expansion alleviates the adverse effects of pneumoperitoneum on renal hemodynamics. Hypertonic saline may maximize RBF in chronic pneumoperitoneum, but further intervention will be necessary to prevent renal dysfunction in this setting.