The Optimum Time for Preoxygenation Based on Body Mass Index

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the relationship between the time needed to raise the oxygen concentration in patient's blood to 90% and his/or her body mass index. The prevalence of obesity in our society continues to rise. No studies have shown the time required for preoxygenation (oxygen given) in relation to body mass index (body weight in kg/height in meter2).

Detailed Description
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100% oxygen given to patient before induction of anesthesia (asleep) is the standard clinical care. However, studies using various methods have shown differences in terms of the optimal time, technique and number of breaths needed for efficient oxygenation. The only difference to the standard pre-anesthesia care is that we will record the time to raise patient oxygen to 90%. Age is recorded to ensure that the subjects fall within our inclusion criteria. The weight (W) in kilograms and height (H) in meters will be used to calculate the body mass index (BMI): BMI = W/H2. Alveolar oxygen uptake is dependent on respiratory rate, heart rate, blood pressure, temperature and hemoglobin level. These parameters are measured in order to identify factors that may affect the accuracy of the study. We will record the pulse oximetry value to note the initial oxygen saturation on room air and after the oxygenation. Facial hair and mask fit are recorded to assess possible failure of an optimal facemask seal. End-tidal carbon dioxide (FE'CO2) is also measured to ensure an adequate facemask seal. Anxiety can increase the respiratory rate, heart rate and affect patient compliance with a fitted facemask. All of the aforementioned values are recorded to assess reasons for possible failure of the preoxygenation technique and inaccurate results.

Official Title
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The Optimum Time for Preoxygenation Based on Body Mass Index

Conditions
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Body Weight, Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants between the ages of 18-50 years with no limitations as to gender or race Participants classified as ASA 1 or 2 Participants capable of understanding and signing an informed consent Exclusion Criteria: Conditions which would affect their oxygenation such as heart disease, lung disease, anemia (Hemoglobin less than 12 g/dL) History of smoking (smoking can affect pulmonary function and oxygen carrying capacity) Acute substance abuse (substance abuse can affect respiratory function). Maxillofacial abnormalities which would interfere with proper face mask seal.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| BMI-I<br>Patients with BMI values between 18.5-24.9 | |
| BMI-II<br>Patients with BMI values between 25-29.9 | |
| BMI-III<br>Patients with BMI values between 30-49.9 | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to reach 90% end tidal oxygen saturation using monitor and stop watch | Using monitors on the anesthesia machine, we recorded the end tidal oxygen saturation value and also recorded the time at which the end tidal oxygen was recorded. From the information collected the relationship between BMI and gender with the time to 90% end tidal oxygen saturation will be evaluated. | 1 to 10 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pre-oxygenation, body mass index, end-tidal O2, anesthesia induction