Goal-Directed Fluid Management Based on Non- Invasive Monitoring of Pulse Oximeter-Derived Pleth Variability Index

The aim of this study is to test the hypothesis that monitoring and minimizing the respiratory variations in the pulse oximeter waveform amplitude by volume loading has potential to decrease postoperative morbidity and length of stay in the hospital in patients undergoing routine, moderate-risk elective surgery.

In this study the investigators will test the impact of hemodynamic optimization based on the respiratory variations in the plethysmographic waveform amplitude to decrease postoperative morbidity and length of stay in the hospital in patients undergoing routine, moderate-risk elective surgery. The primary outcome variable is the incidence of postoperative complications. Secondary outcome variables are the duration of hospital and ICU stays, postoperative mortality, and cost of surgery.