Tight Closed-loop Systolic Arterial Pressure Control

In this case series, the investigators will report the percentage of case time in hypotension (defined as systolic arterial pressure (SAP) < 117mmHg). The target mean arterial pressure (MAP) will be set at a SAP of 130mmHg in all patients. Definition of Hypotension is target SAP - 10% (130mmHg - 13 mmHg = 117 mmHg). We will use the same SAP target in all patients even if we used a modified definition of hypotension from the study of Futier and colleagues ( JAMA 2017). We won't use a individualized SAP for each patient but the same SAP target in all patients.

The investigators want to demonstrate that the closed-loop system can prevent hypotension at this specific set point.

The Investigators have shown the system works well based on a target MAP but not yet using a target of SAP.

The investigators will test the system in a pilot study of 13 patients undergoing High-risk abdominal surgery which require the placement of a arterial catheter, the optimization of fluid therapy and a tight SAP control.

Participants will receive standard patient care in that in no way will their anesthetic or surgical procedure will be altered as part of the study, with the exception of vasopressor administration ( automatically delivery instead of manually adjustments)

Fluids will be given as goal directed fluid therapy in order to maintain stroke volume variation below 13% (hospital guidelines).

Inclusion criteria

• Adult patients (age of >17)
• Elective high-risk abdominal surgery
• Patients with an arterial line and in whom a goal directed fluid therapy protocol is applied manually (administration of fluid bolus to maintain a stroke volume variation < 13%)

Exclusion criteria

• Atrial Fibrillation
• Pregnancy
• Subjects without the capacity to give informed consent