Optimization of cardiac preload during laparoscopic donor nephrectomy: A preliminary study of central venous pressure versus esophageal doppler monitoring

Background: While the popularity of laparoscopic donor nephrectomy (LDN) has increased, concern persists about the potential deleterious effects of pneumoperitoneum on renal function. Thus, preload optimization with vigorous intravenous hydration has been recommended. The purpose of this study was to compare central venous pressure (CVP) monitoring with a noninvasive measure of cardiac preload (esophageal Doppler) during LDN. Methods: Thirteen patients were studied. Following induction of general anesthesia, a Doppler probe was inserted in the lower third of the esophagus to measure flow time corrected for heart rate (FTc), which is an index of preload. In 10 patients, a catheter was placed in the right internal jugular vein and CVP measured. CVP and FTc were measured at baseline in the supine and right lateral decubitus positions, then 15 and 60 min after the establishment of CO₂ pneumoperitoneum (12–15 mmHg). IV fluids were increased if the FTc fell below 300 msec. Results are expressed as means (±SD). Data were analyzed using repeated measures ANOVA. Results: Lateral positioning and pneumoperitoneum significantly increased CVP from baseline (p < 0.01), while the FTc did not change (p = 0.57). After 60 min of pneumoperitoneum, the FTc was <300 msec in only one patient. Conclusion: CVP is not an accurate guide for administration of IV fluids during LDN. Esophageal Doppler monitoring can be used to noninvasively follow changes in preload during LDN and is worthy of further study.