The purpose of this pilot study is to evaluate the performance of a novel closed-loop (automated) vasopressor administration system that delivers norepinephrine using feedback from standard operating room hemodynamic monitor (EV1000 Monitor-Flotrac Edwards Lifesciences, IRVINE, USA) in 10 to 12 critically ill patients in the intensive care unit.

The investigators have developed an automated closed-loop system for vasopressor administration . They will test it in critically ill patients. The investigators want to demonstrate that the closed-loop system can maintain mean arterial pressure ( MAP) within a very narrow range (within +/- 5 mmHg of the predefined MAP target) for more than 85 % of the treatment time.

The Investigators have shown this to be the case in simulation studies and in-vivo animal studies and in surgical patients but not yet in the Intensive care unit (ICU). Investigators will recruit 10 to 12 ICU patients equipped with a mini-invasive cardiac output monitoring and under continuous norepinephrine infusion.

These patients will typically include: septic patients, neuro ICU patients, ARDS patients, trauma patients or postoperative patients.

The target MAP will be determined by the ICU physician in charge of the patient.

Fluids will be given standard of care. The closed loop (automated) system will use an infusion pump (Q-Core and chemyx pump) and a controller (a computer run index and algorithm developed by Sironis) to make frequent, regular and accurate adjustments of vasopressor (norepinephrine)

The goal is to register a period of two hours of closed-loop control of MAP.

Inclusion Criteria:

- ICU patients under norepinephrine administration and equipped with a advanced hemodynamic monitoring device

Exclusion Criteria:

• Subjects under 18 years of age
• Subjects not requiring cardiac output monitoring or an arterial line
• Subject with Atrial Fibrillation
• Subjects who are pregnant