Preoperative Volume Substitution in Elective Surgery Patients

Study Overview
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Brief Summary
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Preoperative fasting can evoke a hypovolemia which may cause a hemodynamic instability during introduction of anesthesia. The purpose of this study is to test the hypothesis that a defined preoperative volume substitution compared to standard procedure will result in a reduced incidence of hemodynamic instabilities during introduction of anesthesia in elective surgery patients.

Detailed Description
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The preoperative fasting period often lasts longer than 2 hours as recommended by various national and international anesthetic guidelines. Thus, hypovolemia is more often then anticipated. In awake patients this condition is often masked. Introduction of anesthesia often leads to an unmasking of hypovolemia with a consecutive hemodynamic instability. Aim of the study is to test the hypothesis that a preoperative volume substitution (8 ml/kg RingerAcetate Solution in 15 min. prior to introduction of anesthesia) reduces possible hemodynamic instabilities during initiation of anesthesia.

Official Title
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Preoperative Volume Substitution in Fasting Patients Undergoing Elective Surgery - Impact on Hemodynamic Stability During Anesthesia

Conditions
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Hemodynamic Instability, Hypovolemia, Anesthesia

Intervention / Treatment
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* Other: Volume
* Other: Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years thyreoid, parathyroid or gallbladder surgery general anesthesia Exclusion Criteria: coronary artery disease congestive heart disease (≥ New York Heart Association (NYHA) 2) insulin dependent diabetes mellitus renal insufficiency (creatinine > 2,0 mg/dl) cerebrovascular disease severe hypertension (≥ antihypertensive drugs)

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 |
| --- | --- |
| Sham Comparator: Control<br>preoperative none substitution of i.v. fluids. | Other: Control<br> <br> |
| Active Comparator: Volume<br>preoperative substitution of a defined amount of i.v. fluids (8 ml/kg RingerAcetate solution for 15 min prior to introduction of anesthesia). | Other: Volume<br> <br> * Other names: cristalloide;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| hemodynamic instability | Hemodynamic instability during induction of anesthesia (0-10 min), defined as at least one of the following: Systolic blood pressure < 80 mmHg or decrease of 20% in preexistent hypertension Mean blood pressure < 50 mmHg or decrease of 20% or > 20 mmHg in preexistent hypertension Bradycardia < 45/min or decrease of 20% in preexistent bradycardia < 60/min. Tachycardia > 120/min Cardiac index < 2.0 l/min/m² | at time of introduction of anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stroke volume index > 35 ml/m2 |  | at time of anesthesia | 
| Stroke volume variation < 12 % |  | at time of anesthesia | 
| Enddiastolic area (EDA) > 10 cm2 | transthoracic echocardiographic parasternal short axis enddiastolic area | at time of anesthesia | 
| inferior vana cava diameter (VCI) > 15 mm | transthoracic echocardiographic inferior vena cava diameter | at time of anesthesia | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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preoperative volume substitution, hypovolemia, preoperative fasting