Effect-site Concentration of Remifentanil for Smooth Induction With Desflurane

Study Overview
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Brief Summary
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Desflurane is a halogenated ether with low solubility, giving rapid induction and emergence from anesthesia This character is suitable for Volatile Induction and Maintenance Anesthesia (VIMA). But desflurane can cause airway irritation when it used as a sole induction agent to adult or children, so there were many studies about reducing the airway reflex combined with desflurane. Remifentanil is a short acting opioid and is quickly hydrolyzed by nonspecific esterase in the plasma and multiorgan. Several studies suggest the optimal dose of remifentanil for reducing airway reflex or cardiovascular response for intubation combined with desflurane. But these studies were under 1 Minimal Alveolar Concentration (MAC) of desflurane and this point could be a limitation because desflurane concentration over 1 MAC increase airway irritation significantly. This study this study was designed to determine a median effective effect-site concentration (EC50) of remifentanil to prevent airway irritation during desflurane anesthesia over 1 MAC.

Official Title
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Effect-site Concentration of Remifentanil for Smooth Induction With Desflurane

Conditions
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Anesthesia

Intervention / Treatment
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* Drug: Remifentanil
* Drug: Desflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients for surgery requiring general anesthesia American Society of Anesthesiologists(ASA) classification I, II Exclusion Criteria: history of gastroesophageal reflux, High grade obesity, Predicted difficult airway, Asthma, Chronic obstructive pulmonary disease(COPD), Upper respiratory infection (URI) within 3 weeks

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 60 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: Other
Intervention Model: Single Group Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Remifentanil<br>When the particapants arrived into the operating room, the investigators applied standard monitoring and after preoxygenation, 2 mg remifentanil was diluted into 50 ml of normal saline (40 μg/ml solution) and was infused by Target concentration infusion (TCI) via syringe pump (Pilot Anesthesia 2. Fresenius vial, France) using the pharmacokinetic model. Investigator started to infuse remifentanil at 4 ng/ml and after the Ce of remifentanil reached the target concentration level, opened the dial of desflurane vaporizer at 4 vol%. After 30 seconds, increase the concentration of desflurane 8% and 12% at last. If there is no spontaneous respiration or loss of consciousness, the muscle relaxant esmerone 0.6mg/kg is injected and after 90 seconds the tracheal intubation is performed. | Drug: Remifentanil<br> <br> * Other names: Ultiva;Drug: Desflurane<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fail or success for induction with desflurane | Failure for induction with desflurane is defined if there is a cough, laryngospasm, hypoxia or any refusal movement of patient. | After loss of consciousness, 5 seconds | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Remifentanil, smooth induction, desflurane