1-1-8 Wash-in for Sevoflurane Low Flow Anesthesia

Study Overview
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Brief Summary
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The investigators propose a new wash-in technique for sevoflurane low flow anesthesia with fresh gas flow of O2:N2O or O2:air 1:1 L/min with sevoflurane 8%. The objective of this study is to identify time to achieve alveolar concentration of sevoflurane at 1, 1.5, 2, 2.5, 3, and 3.5%

Detailed Description
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The benefits of low flow anesthesia are economic, less pollution, more heat and humidity preservation but it requires appropriate wash-in phase. The current wash-in protocols for sevoflurane are complicated and time consuming. The investigators propose a new 1-1-8 sevoflurane wash-in protocol which is more simple and predictable. The objective of this study is to identify time to achieve alveolar concentration of sevoflurane at 1, 1.5, 2, 2.5, 3, and 3.5% with 1-1-8 wash-in protocol. All patients will receive iv propofol 2 mg/kg as induction agent and succinyl choline 1.5 mg/kg for intubation. Then the ventilation will be controlled to achieve end-tidal CO2 30-35 mmHg with O2:N2O or O2:air 1:1 L/min with sevoflurane 8%. Time to achieve alveolar concentration of sevoflurane at 1, 1.5, 2, 2.5, 3, and 3.5% will be recorded and analyzed. After that, the concentration of sevoflurane and anesthetic technique will be adjusted to requirement of anesthesiologist.

Official Title
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1-1-8 Wash-in for Sevoflurane Low Flow Anesthesia

Conditions
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Anesthesia

Intervention / Treatment
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* Procedure: 1-1-8 wash-in
* Drug: Sevoflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA classification I-II age 18-65 years Exclusion Criteria: BMI > 35 contraindicated for N2O • with pulmonary or cardiac disease

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: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: All participants will receive sevoflurane 8% with O2:N2O or O2:air 1:1 L/min under controlled ventilation. Time to achieve alveolar concentration of sevoflurane of 1%, 1.5%, 2%, 2.5%, 3% and 3.5% will be recorded.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1-1-8 wash-in<br>Wash-in using O2:N2O or O2:air 1:1 L/min with sevoflurane 8% | Procedure: 1-1-8 wash-in<br>* wash-in phase during start of low flow anesthesia<br>Drug: Sevoflurane<br>* Drug used for wash-in protocol<br>* Other names: Inhalation anesthetic;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time | Time (in second) to achieve alveolar concentration of sevoflurane 1, 1.5, 2, 2.5, 3, and 3.5% | participants will be followed until alveolar concentration of sevoflurane reaches 3.5%, as expected of 10 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Heart rate (beat/min) at alveolar concentration of sevoflurane of 1, 1.5, 2, 2.5, 3 and 3.5% | participants will be followed until alveolar concentration of sevoflurane reaches 3.5%, as expected of 10 minutes] | 
| Blood pressure | Blood pressure (systolic and diastolic (mmHg)) at alveolar concentration of sevoflurane of 1, 1.5, 2, 2.5, 3 and 3.5% | participants will be followed until alveolar concentration of sevoflurane reaches 3.5%, as expected of 10 minutes] | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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low flow anesthesia, wash-in, sevoflurane