Vasodilation Effect of Inhalational Anesthetics

Study Overview
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Brief Summary
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Previous studies on animals suggest that inhalational anesthetics can reduce vascular tension in vitro resulting in vasodilation and decrease in blood pressure. This role for inhalational anesthetics has essential clinical implications such as the condition of sepsis or septic shock or other shock-associated states during which the blood vessel constricts strongly and leads to circulation dysfunction. The vasodilation property of these anesthetics including halothane, isoflurane, sevoflurane, desflurane and enflurane enables them to be better options than other general anesthetics in many clinical conditions needing the vasculature to be dilated. The investigators hypothesized that these inhalational anesthetics can evoke vasodilation measured with ultrasonography during general anesthesia in vivo as the in vitro studies displayed.

Official Title
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Vasodilation Effect of Inhalational Anesthetics Including Halothane, Isoflurane, Sevoflurane, Desflurane and Enflurane

Conditions
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General Anesthesia

Intervention / Treatment
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* Drug: Halothane
* Drug: Isoflurane
* Drug: Sevoflurane
* Drug: Desflurane
* Drug: Enflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Must be undergoing general anesthesia Age between 19-45 years Exclusion Criteria: With hypertension Existing organic dysfunction Allergic to inhalant anesthetics Alcohol addictive or narcotic dependent patients A history of the use of centrally-acting drugs of any sort, chronic pain and psychiatric diseases records

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 45 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: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 1<br>Halothane anesthesia: induction and maintenance with different doses | Drug: Halothane<br>* Induction: 2-4% halothane pluses 3-5 L/min oxygen Maintenance: different doses from 0.5% to 3% with 1-2 L/min oxygen<br>* Other names: Fluothane;|
| Experimental: 2<br>Isoflurane anesthesia: induction and maintenance with different doses | Drug: Isoflurane<br>* Induction: 2-5% isoflurane pluses 3-5 L/min oxygen Maintenance: different doses from 1% to 4% with 1-2 L/min oxygen<br>* Other names: Forane;|
| Experimental: 3<br>Sevoflurane anesthesia: induction and maintenance with different doses | Drug: Sevoflurane<br>* Induction: 3-8% sevoflurane pluses 3-5 L/min oxygen Maintenance: different doses from 1% to 4% with 1-2 L/min oxygen<br>* Other names: Sevorane;|
| Experimental: 4<br>Desflurane anesthesia: induction and maintenance with different doses | Drug: Desflurane<br>* Induction: 2-8% desflurane pluses 3-5 L/min oxygen Maintenance: different doses from 1% to 4% with 1-2 L/min oxygen<br>* Other names: Suprane;|
| Experimental: 5<br>Enflurane anesthesia: induction and maintenance with different doses | Drug: Enflurane<br>* Induction: 2-5% enflurane pluses 3-5 L/min oxygen Maintenance: different doses from 1% to 4% with 1-2 L/min oxygen<br>* Other names: Ethrane;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ultrasonography of blood vessels including radial artery, brachial artery, femoral artery, popliteal artery |  | Ten min prior to anesthesia; 0 min of anesthesia; 0 min of the end of anesthesia induction; 5, 10, 20, 30, 60 min during maintenance of the anesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood flow volume during anesthesia of the vasculature |  | Ten min prior to anesthesia; 0 min of anesthesia; 0 min of the end of anesthesia induction; 5, 10, 20, 30, 60 min during maintenance of the anesthesia | 
| Blood pressure including systolic, diastolic and mean artery blood pressures |  | Ten min prior to anesthesia; 0 min of anesthesia; 0 min of the end of anesthesia induction; 5, 10, 20, 30, 60 min during maintenance of the anesthesia | 
| The time interval of between the initiation of the inhalational anesthetics delivered to the beginning of decreasing of blood pressure |  | From the beginning of anesthesia (0 min) till the first time of blood pressure decreased, this measure would be varied according to different individuals | 
| The total dose of phenylephrine required to maintain baseline arterial blood pressure |  | From the beginning of anesthesia (0 min) to 20 min after anesthesia begun | 
| Regression and correlation analyses between different doses of the anesthetics and the extent of vasodilation |  | Forty eight hours after operation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inhalant anesthetic, Vasodilation, General anesthesia, Ultrasonography