Evaluate the feasibility and quality of automated anesthesia, analgesia and fluid management based on a combination of several physiological variables (bispectral index [BIS], stroke volume [SV], and stroke volume variation [SVV]) using 2 independent physiologic closed-loop systems (PCLS) in patients undergoing high risk vascular surgery.~All patients will receive total intravenous anesthesia in target controlled infusion mode using the population pharmacokinetic sets of Schnider for propofol and Minto for remifentanil to target the effect-site concentration. Infusion Toolbox 95 version 4.11 software (Free University of Brussels, Brussels, Belgium) implemented in a personal computer serving as a platform for: calculating effect-site concentrations of propofol and remifentanil; displaying effect-site concentration estimates in real time; providing a user interface that permits entry of patients' demographic data (sex, age, weight, and height) and modifications to target concentrations; controlling the propofol and remifentanil infusion pumps (Alaris Medical, Hampshire, United Kingdom); and recording calculated effect-site drug concentrations.~All patients will receive a baseline crystalloid infusion (PlasmaLyte, Baxter, Belgium) delivered by a pump at a rate of 3 mL/ kg/h (Fresenius Kabi, Belgium). Additional fluid was given using a goal-directed fluid therapy protocol guided by the cardiac output monitor (EV-1000; Edwards Lifesciences) and consisted of 100 mL boluses (Voluven, Fresenius Kabi, Germany) delivered by our PCLS (Learning Intravenous Resuscitator [LIR]). For fluid output, a Q-Core Sapphire Multi-Therapy Infusion Pump (Q-Core, Israel) was controlled by the LIR using software provided by Q-Core via a serial connection (Commands Server R.01). If hypotension occurred (defined as mean arterial pressure <20% of baseline blood pressure) and no fluid is delivered by the LIR, it will be treated by the anesthesiologist using a vasopressor drug.~In this pilot study, each closed loop also will operate independently, guided only by its own respective inputs (BIS for the propofol; SV and SVV for the fluid boluses).~The investigators will also measure analgesia using the PhysioDoloris monitoring device (MDoloris Medical Systems, Lille, France).
Evaluate the feasibility and quality of automated anesthesia, analgesia and fluid management based on a combination of several physiological variables (bispectral index [BIS], stroke volume [SV], and stroke volume variation [SVV]) using 2 independent physiologic closed-loop systems (PCLS) in patients undergoing high risk vascular surgery