Automated Closed-Loop Versus Restrictive Fluid Therapy in Abdominal Surgery

Study Overview
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Brief Summary
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The aim of this study is to compare hemodynamic variables and outcome in patients undergoing laparoscopic and/or robotic elective abdominal surgery. Patients will receive either an automated closed-loop goal-directed fluid therapy (GDFT) guided by non-invasive flow monitoring or a restrictive fluid therapy of 4ml/kg/h.

Detailed Description
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Perioperative fluid management is a topic of much debate that has intensified over recent years. Studies have shown improved postoperative outcomes with restricted fluid administration in the perioperative period for moderate risk abdominal surgery. They concluded that in patients undergoing elective abdominal surgery, intraoperative restrictive fluid management was associated with a reduction in postoperative morbidity and shortened hospital stay. Current standard practice is a crystalloid based fluid therapy guided by static hemodynamic parameters such as heart rate, blood pressure, and diuresis. However, several studies have criticized this cookbook approach and recommend tailoring management to specific physiologic dynamic endpoints such as stroke volume variation and cardiac output using a flow monitoring device. Our team has demonstrated that the use of a closed-loop system is feasible and allows precise titration of fluid administration in abdominal and vascular surgery using either a minimally or a non-invasive monitoring system. Goal: This study compares hemodynamic variables and outcome in patients who will receive either automated closed-loop fluid therapy guided by non-invasive flow monitoring or restrictive fluid therapy of 4ml/kg/h. Both groups consist of the same population undergoing laparoscopic and/or robotic surgery. Hypothesis: A closed-loop assisted intraoperative GDFT when compared to restrictive fluid therapy will provide better hemodynamic variables.

Official Title
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Automated Closed-Loop Versus Restrictive Fluid Therapy in Abdominal Surgery: a Pilot Randomized Controlled Trial

Conditions
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Abdominal Laparoscopic and/or Robotic Surgery

Intervention / Treatment
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* Device: Closed-Loop GDFT
* Other: Restrictive Fluid Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Laparoscopic and/or robotic elective abdominal surgery( colorectal, gynecological, urological) Exclusion Criteria: Intraoperative invasive monitoring (arterial line) Open colorectal surgery (laparotomy) Emergency surgery Expected intraoperative blood loss greater than 1000ml Arrhythmia (e.g. atrial fibrillation)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Closed-loop GDFT<br>This group consists of patients undergoing laparoscopic and/or robotic abdominal surgery where fluid maintenance with Plasmalyte is carried out using a closed-loop system guided by the Clearsight non-invasive hemodynamic flow monitor. | Device: Closed-Loop GDFT<br>* Patients receive fluids in the form of 100ml boluses of crystalloid (Plasmalyte) over 6 minutes via an automated closed-loop goal-directed fluid therapy (GDFT) system guided by non-invasive flow monitoring (Clearsight system). Additional boluses of colloid or crystalloid can be administered under the attending anesthesiologist's discretion (e.g. to compensate blood loss) .<br>|
| Active Comparator: Restrictive fluid therapy<br>This group consists of patients undergoing laparoscopic and/or robotic abdominal surgery where fluid management is based on a restrictive (4ml/kg/h) Plasmalyte infusion. | Other: Restrictive Fluid Therapy<br>* Patients receive fluids (Plasmalyte) via a restrictive approach with a baseline of of 4ml/kg/h. Additional boluses of colloid or crystalloid can be administered under the attending anesthesiologist's discretion (e.g. to compensate blood loss) .<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Preload independent state | The percentage intraoperative time spent with stroke volume variation < 13% and/or cardiac index > 2.4 L/min/m2 | 6 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Additional fluids administered intraoperatively |  | 6 hours | 
| Number of closed-loop override by the attending anesthesiologist |  | 6 hours | 
| Hospital length of stay |  | up to 90 days post surgery | 
| Postoperative complications | Major complications include cardiac (acute coronary syndrome/ arrhythmia), pulmonary (embolism/edema), gastrointestinal (bowel and surgical anastomotic leak/internal or external fistulas/peritoneal effusions), renal (renal failure requiring dialysis), infectious (peritonitis/ sepsis), coagulation (bleeding), wound dehiscence, stroke, reoperation, readmission, and death. Minor complications include unplanned ICU admission, pneumonia/pleural effusion, deep venous thrombosis, paralytic ileus, renal insufficiency, infection (superficial wound infection/fever/urinary infection) and confusion/delirium. | up to 90 days after hospitalization | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fluid therapy, Hemodynamic flow monitoring, Closed-loop system, Goal-directed fluid therapy, Anesthesiology