Intrinsic PEEP During Mechanical Ventilation of Patients With Obesity

Study Overview
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Brief Summary
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It is demonstrated that expiratory flow limitation and as a consequence, intrinsic positive end-expiratory pressure (PEEP) is present in grossly obese subjects especially in the supine position. The investigators tried to investigate the effect of low respiratory rate and high tidal volume on the intrinsic PEEP and gas exchange for obese subjects undergoing general anesthesia.

Detailed Description
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Impaired gas exchange is a common anesthetic problem in obese subjects. It is demonstrated that expiratory flow limitation and as a consequence, intrinsic positive end-expiratory pressure (PEEPi) is present in grossly obese subjects especially in the supine position. It is known that there is a significant negative correlation between PEEPi present and PaO2. Therefore, the investigators postulated that if the reduce the PEEPi by reducing the respiratory rate in obese subjects, the impaired gas exchange might improve. The investigators tried to research the effect of low respiratory rate and high tidal volume on the intrinsic PEEP and gas exchange for obese subjects undergoing general anesthesia.

Official Title
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Intrinsic PEEP During Mechanical Ventilation of Patients With Obesity. Influence of Low Respiratory Rate With Unchanged Minute Volume.

Conditions
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General Anesthesia, Laparoscopic Cholecystectomy

Intervention / Treatment
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* Device: RR 6 + 0
* Device: RR 10 + 0
* Device: RR 16 + 0
* Device: RR 6 + 5
* Device: RR 10 + 5
* Device: RR 16 + 5


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA class I or II obesity, Body-mass index > 27.5 undergoing laparoscopic cholecystectomy Exclusion Criteria: patients with severe cardiopulmonary disease peak inspiratory pressure > 40 in the study setting

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: RR 6 + 0<br>Respiratory rate 6 Tidal volume 16.7 ml/kg external PEEP = 0 | Device: RR 6 + 0<br>* Respiratory rate 6 Tidal volume 16.7 ml/kg external PEEP = 0<br>* Other names: Ventilator setting;|
| Experimental: RR 10 + 0<br>Respiratory rate 10 Tidal volume 10 ml/kg external PEEP = 0 | Device: RR 10 + 0<br>* Respiratory rate 10 Tidal volume 10 ml/kg external PEEP = 0<br>* Other names: Ventilator setting;|
| Experimental: RR 16 + 0<br>Respiratory rate 16 Tidal volume 6.25 ml/kg external PEEP = 0 | Device: RR 16 + 0<br>* Respiratory rate 16 Tidal volume 6.25 ml/kg external PEEP = 0<br>* Other names: Ventilator setting;|
| Experimental: RR 6 + 5<br>Respiratory rate 6 Tidal volume 16.7 ml/kg external PEEP = 5 | Device: RR 6 + 5<br>* Respiratory rate 6 Tidal volume 16.7 ml/kg external PEEP = 5<br>* Other names: Ventilator setting;|
| Experimental: RR 10 + 5<br>Respiratory rate 10 Tidal volume 10 ml/kg external PEEP = 5 | Device: RR 10 + 5<br>* Respiratory rate 10 Tidal volume 10 ml/kg external PEEP = 5<br>* Other names: Ventilator setting;|
| Experimental: RR 16 + 5<br>Respiratory rate 16 Tidal volume 6.25 ml/kg external PEEP = 5 | Device: RR 16 + 5<br>* Respiratory rate 16 Tidal volume 6.25 ml/kg external PEEP = 5<br>* Other names: Ventilator setting;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gas change parameters | PaO2 and PaCO2 the result of arterial blood gas analysis | 15 minute interval | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| intrinsic positive end-expiratory pressure | PEEPi measured by expiratory port occlusion method | every 15 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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intrinsic positive end-expiratory pressure, obesity, ventilator setting, respiratory rate