Goal-directed fluid therapy (GDFT) strategies based on cardiac output (CO) optimization have been shown to benefit moderate- to high-risk surgery patients and have recently been recommended by professional societies in the UK, in France, and in Europe. However, despite the growing evidence, these strategies are often not implemented in current practice. One of the reasons for this lack of implementation is that GDFT strategies, like any other complex clinical protocol, require significant provider attention and vigilance for consistent implementation and it is well known that even under study conditions protocol compliance rates are often not greater than 50%. To overpass this problem, our CO monitoring devices (EV1000, Edwards Lifesciences) have now an incorporated assisted fluid management software. This software determines fluid responsiveness by estimating the predicted change in stroke volume and suggests to the anesthesiologist when fluid is required .

The aim of this study was to assess an assisted fluid management strategy in a moderate-to-high risk surgical cohort and compare that cohort to matched patients who received manual GDFT. Our hypothesis was that the assisted fluid management system would result in higher mean percentage time spent during surgery with a SVV < 13%

Inclusion Criteria:

• All patients undergoing major abdominal surgery and requiring a CO monitoring for fluid management

Exclusion Criteria:

Emergency surgery Arrhythmia (e.g. atrial fibrillation) Aortic regurgitation

All patients undergoing major abdominal surgery and requiring a CO monitoring for fluid management