Effectiveness of Preoxygenation With Positive Airway Pressure: a Comparison of the Supine and 25° Head up Position

Study Overview
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Brief Summary
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Several techniques such as positive airway pressure and head-up tilt during preoxygenation have shown to prolong non-hypoxic apnea period compared to conventional technique. However, uniform recommendations have not yet been made. Therefore, in the present study the investigators attempted to find out the effect of combination of 5 cmH2O CPAP and 25° head up position during preoxygenation.

Detailed Description
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In this study 60 non-obese healthy adult patients were divided into three groups; Group C receiving preoxygenation in conventional technique, Group S receiving preoxygenation with 5 cmH2O CPAP and Group H receiving preoxygenation in 25° head-up position with 5 cmH2O CPAP. After 3 min of preoxygenation, anesthesia was induced and trachea intubated. After confirming the tracheal intubation by direct visualization, all patients were left apneic in supine position with the tracheal tube exposed to atmosphere till the SpO2 dropped to 92%. The primary outcome compared between the groups was the non-hypoxic apnoeic period (time to fall SpO2 to 92%).

Official Title
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Effectiveness of Preoxygenation With Positive Airway Pressure in Non-obese Healthy Patient: a Comparison of the Supine and 25° Head up Position

Conditions
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Intubation;Difficult

Intervention / Treatment
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* Other: 5 cmH2O CPAP
* Other: head-up position


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adult patients of ASA physical status I and II undergoing surgery under general anaesthesia Exclusion Criteria: anticipated difficult mask ventilation/ intubation individuals with significant cardiorespiratory or cerebrovascular disease pregnant ladies patient with history of epilepsy body mass index >25 kg/m2 hemoglobin <8 gm/dL patients who were non-ambulant for >24 h, having SpO2 < 97% while breathing in room air phobia to facemask.

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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Accepts Healthy Volunteers

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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Conventional<br>preoxygenation done with 100% oxygen in supine position | |
| Experimental: Positive-pressure<br>preoxygenation done with 5 cmH2O CPAP (continuous positive airway pressure) in supine position with 100% oxygen | Other: 5 cmH2O CPAP<br> <br> |
| Experimental: Head-up<br>preoxygenation done in 25 degree head-up position with 5 cmH2O CPAP with 100% oxygen | Other: 5 cmH2O CPAP<br> <br> Other: head-up position<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| non-hypoxic apnoeic period (time to fall SpO2 to 92%) | After 3 min of preoxygenation, anesthesia was induced and trachea intubated. After confirming the tracheal intubation by direct visualization, all patients were left apneic in supine position with the tracheal tube exposed to atmosphere till the SpO2 dropped to 92%. | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of pH at different time points | Arterial blood gas analysis was done and the pH at the start of preoxygenation, after preoxygenation and at desaturation (SpO2= 92%) were compared. | 2 hours | 
| Comparison of PaO2 at different time points | Arterial blood gas analysis was done and the PaO2 at the start of preoxygenation, after preoxygenation and at desaturation (SpO2= 92%) were compared. | 2 hours | 
| Comparison of PaCO2 at different time points | Arterial blood gas analysis was done and the PaCO2 at the start of preoxygenation, after preoxygenation and at desaturation (SpO2= 92%) were compared. | 2 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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apnea, CPAP, Preoxygenation