Safe Time for Apnea After Preoxygenation

Study Overview
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Brief Summary
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The use of 100% oxygen during the induction of general anesthesia is always preferable to have enough time to secure the airway by endotracheal intubation, because preoxygenation with a low oxygen concentration may reduce the safe time for apnea. However, using a low oxygen concentration during preoxygenation might prevent the formation of atelectasis. There is still no clear conclusion about the best oxygen concentration for preoxygenation. Our study is designed to evaluate the safety of preoxygenation with 80%, 60%, 40%, 30% and 21% oxygen by the safe time for apnea during the induction of general anesthesia.

Detailed Description
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We decide to add 3 groups (80%, 60%, and 40% oxygen) in our study to fully evaluate the safety of preoxygenation with different oxygen concentration. Zijia Li 2018.3.2

Official Title
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Safe Time for Apnea After Preoxygenation With Different Oxygen Concentration During the Induction of General Anesthesia

Conditions
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Anesthesia, General

Intervention / Treatment
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* Drug: 100% Oxygen
* Drug: 30% Oxygen
* Drug: 21% Oxygen
* Drug: 40% Oxygen
* Drug: 60% Oxygen
* Drug: 80% Oxygen


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Nonsmoking patients aged 18 years to 60 years Undergoing general anesthesia for elective surgery Pulse oxygen saturation ≥95% when breathing air quietly in bed American Society of Anesthesiologists(ASA) physical status class I-II Informed consent can be obtained Exclusion Criteria: A suspected difficult airway Be allergic to midazolam, propofol , fentanyl or Cisatracurium Severe disease of respiratory system or cardiovascular system,or obstruction of the digestive tract Oxygen reserve is suspected low,or patient who does not tolerate hypoxemia well A history of mental disorder or patient who can not collaborate well Body mass index more than 30 kg/㎡

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: group A<br>100% Oxygen | Drug: 100% Oxygen<br>* Conventional preoxygenation with 100% oxygen<br>* Other names: 100% O2;|
| Experimental: group B<br>30% Oxygen. | Drug: 30% Oxygen<br>* preoxygenation with 30% oxygen<br>* Other names: 30% O2;|
| Experimental: group C<br>21% Oxygen | Drug: 21% Oxygen<br>* preoxygenation with 21% oxygen<br>* Other names: 21% O2;|
| Experimental: group D<br>40% Oxygen | Drug: 40% Oxygen<br>* preoxygenation with 40% oxygen<br>* Other names: 40% O2;|
| Experimental: group E<br>60% Oxygen | Drug: 60% Oxygen<br>* preoxygenation with 60% oxygen<br>* Other names: 60% O2;|
| Experimental: group F<br>80% Oxygen | Drug: 80% Oxygen<br>* preoxygenation with 80% oxygen<br>* Other names: 80% O2;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Safe time for apnea | Time when peripheral oxygen saturation (SpO2) is ≥ 90% after preoxygenation. | 10 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time needed for endotracheal intubation | Time from when the laryngoscope blade first passes the lips to when the cuff of tracheal tube is inflated. | 1 min | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Preoxygenation, Oxygen Concentration