Management of Intraoperative Fluids in Ambulatory Surgery

Study Overview
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Brief Summary
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This is a single-center prospective randomized control trial (RCT) to determine whether the continuous monitoring of the plethysmographic variability index (PVI) during low-risk surgeries, can be used to optimize the intraoperative fluid administration. Low-risk patients that attend our day surgery unit, and who will be operated under general anesthesia, will be randomized to either a liberal fluid group, a restrictive fluid group or a dynamic monitoring group (PVI-directed). The amount of fluid infused together with the time to discharge, will be assessed in each participant during the postoperative period along with additional secondary outcomes.

Official Title
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Intraoperative Fluid Therapy Management in Low-risk Patients Under General Anesthesia- a Randomized Controlled Trial Comparing Liberal, Restrictive and Pleth Variability Index (PVI)-Guided Fluid Administration in a Day Surgery Setting

Conditions
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Anesthesia, General, Fluid Therapy, Ambulatory Surgical Procedures

Intervention / Treatment
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* Other: Fluid therapy protocol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: participants attending the unit for a day surgery procedure participants whose surgeries will be performed under general anesthesia aged between 18-65 years no abnormal findings on chest x-ray or electrocardiogram on preoperative evaluation patients undergoing procedures which do not require opening of the abdominal or thoracic cavities Exclusion Criteria: ASA score III or higher patients undergoing surgeries which require additional pain management procedures (e.g. selective nerve blockade, epidural anesthesia, etc.) known pregnant women known kidney disease (or serum creatinine >1.8 mg/dl) known liver disease (or AST/ALT >60 U/l) known chronic heart failure (determined by a LVEF <55%) participants who develop hypotension intraoperatively and do not respond to 4 fluid challenges (1000 ml), requiring aggressive fluid resuscitation OR vasopressors estimated blood loss during surgery >250 ml development of an adverse reaction to any of the drugs administered during surgery (requiring additional medical management)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Liberal group protocol<br>Fluid loading with 500 ml at induction. Baseline fluid infusion - 8 ml/kg/h. Fluid challenge - if mean arterial pressure (MAP) falls to < 65 mmHg, a fluid challenge will be administered. | Other: Fluid therapy protocol<br>* Only ringer lactate (RL solution will be used). 1. Fluid loading at induction with 500 ml of ringer lactate solution will be given to some groups. 2. Base infusion rate varies according to group. 3. Fluid challenges - infusion of 250 ml over 5 min, a hemodynamic parameter specific to each group will be monitored for 10 min after the end of infusion to look for changes. Patients who do not respond to four (4) fluid challenges (volume infused 1000 ml) will be excluded.<br>|
| Active Comparator: Restrictive group protocol<br>No fluid loading at induction. Baseline fluid infusion - 4 ml/kg/h. Fluid challenges - if mean arterial pressure (MAP) falls to < 65 mmHg, a fluid challenge will be administered. | Other: Fluid therapy protocol<br>* Only ringer lactate (RL solution will be used). 1. Fluid loading at induction with 500 ml of ringer lactate solution will be given to some groups. 2. Base infusion rate varies according to group. 3. Fluid challenges - infusion of 250 ml over 5 min, a hemodynamic parameter specific to each group will be monitored for 10 min after the end of infusion to look for changes. Patients who do not respond to four (4) fluid challenges (volume infused 1000 ml) will be excluded.<br>|
| Experimental: PVI-guided group protocol<br>No fluid loading at induction. Baseline fluid infusion - 2 ml/kg/h. PVI will be monitored continuously since anesthesia induction. Fluid challenges - if PVI rises >=13 (or MAP falls < 65 mmHg), a fluid challenge will be administered. | Other: Fluid therapy protocol<br>* Only ringer lactate (RL solution will be used). 1. Fluid loading at induction with 500 ml of ringer lactate solution will be given to some groups. 2. Base infusion rate varies according to group. 3. Fluid challenges - infusion of 250 ml over 5 min, a hemodynamic parameter specific to each group will be monitored for 10 min after the end of infusion to look for changes. Patients who do not respond to four (4) fluid challenges (volume infused 1000 ml) will be excluded.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total volume of fluid infused intraoperatively | Total volume of ringer lactate solution infused intraoperatively to participants (ml). | 0 min after extubation | 
| Time to discharge | Time in hours (h) from anesthesia reversal to fulfillment of patient discharge criteria. Patients will be assessed by an attending nurse every 30 min to assess the fulfillment of these criteria. | 240 min after extubation (discharge) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Significant postoperative nausea and vomiting (PONV) | Presence of significant PONV as determined by a score ≥5 on the scale proposed by Myles SA et al. (BJA 2012) | 240 min after extubation (discharge) | 
| Postoperative dizziness | Presence of patient self-reported dizziness in the post-operative period. | 30 min after reversal | 
| Postoperative fatigue | Presence of patient self-reported fatigue after surgery. | 30 min after reversal | 
| Postoperative thirst | Presence of patient self-reported thirst after surgery | 30 min after reversal | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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PVI, plethysmographic variability index