Plethysmography Variability Index as an Indicator of Adequacy of Preload

In the researchers' words

The investigators propose a prospective observational trial. The investigators plan to enroll 40 female subjects scheduled for elective robotic gynecological surgery under general anesthesia. Hemodynamic data will be recorded at the following intervals: after induction of anesthesia (Baseline), after initiation of pneumoperitoneum, after positioning the patient in Trendelenburg position, and every 15 minutes thereafter. At the end of surgery measurements will be recorded after reversal of Trendelenburg position and after deflation of the peritoneum. Forearm - fingertip temperature gradients will be measured by Mon-a-thermometer (Mallinckrodt Medical, Inc. St. Louis, MO) and disposable Mon-a-therm thermocouples. Vasoconstriction will be identified when forearm - fingertip temperature gradient is ≥ 00C and PI \<1. Intra-abdominal pressures will be recorded during each measurement of hemodynamic parameters. Trendelenburg position will be measured with an angle ruler. The aim of our study is to test the hypothesis that stroke volume will drop significantly after initiation of pneumoperitoneum and that it will increase after placement in Trendelenburg position in patients undergoing robotic gynecological procedures. Secondly, the investigators will test the hypothesis that PVI changes correlate with changes in stroke volume and pulse pressure variation (PPV) and can predict an…