Non Invasive Pressure Support Ventilation (NIPPV) Versus Recruitment Maneuver (RM) and Preoxygenation

Study Overview
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Brief Summary
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The purpose of this study is to compare the effects of noninvasive pressure support ventilation and early alveolar recruitment maneuver during anesthesia induction of morbidly obese patients on both oxygenation and functional residual capacity modifications.

Detailed Description
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Atelectasis formation during general anesthesia, leading to reduced end-expiratory lung volume, is an important cause of intrapulmonary shunt leading to impaired gas-exchange and hypoxemia. During general anesthesia and the immediate postoperative period, morbidly obese patients, who develop a larger amount of atelectasis than non-obese patient, are more likely to present impairment of gas exchange and respiratory mechanics. Noninvasive positive-pressure support ventilation (NIPPV) and positive end-expiratory pressure (PEEP) are effective to provide oxygenation during intubation of hypoxemic patients. Recent data suggest that NIPPV enhances preoxygenation in morbidly obese patients. Moreover, the application of PEEP during induction of anesthesia prevents atelectasis formation and increases nonhypoxic apnea duration in obese patients despite the use of high-inspired oxygen fraction. However, the use of both NIPPV is widely used in the operating room, because of technical and materials constraints. Several trials have demonstrated that alveolar recruitment maneuvers (RM) are effective to remove atelectasis and improve lungs mechanics and gas-exchange. The purpose of this randomized and controlled study is to compare the effects of two ventilatory strategies during anesthesia induction of morbidly obese patients on both gas-exchange and functional residual capacity (FRC) modifications: 1- Control group: preoxygenation using 100% O2 via a face-mask and PEEP 10 cmH2O after intubation; 2- NIPPV group: preoxygenation using NIPPV and PEEP 10 cmH2O after intubation; 3- RM group: preoxygenation using 100% O2 via a face-mask and early RM plus PEEP 10 cmH2O after intubation.

Official Title
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Non Invasive Pressure Support Ventilation (NIPPV) Versus Conventionnal Approach and Early Recruitment Maneuver (RM) for Preoxygenation of Morbidly Obese Patient

Conditions
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Obesity

Intervention / Treatment
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* Procedure: NIPPV and IRM


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body mass index (BMI > 30 kg/m2) Age > 18 years ASA I-III Exclusion Criteria: Age < 18 years Patient refusal Pregnancy Emergency surgery COPD with FEV1 < 50% History of pneumothorax Severe asthma Cardiac failure (NYHA > 2) Ischemic heart disease

Ages Eligible for Study
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Minimum Age: 18 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: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: NIPPV and IRM|non invasive positive pressure support ventilation (NIPPV group) alveolar recruitment maneuver (IRM group)|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygenation (PaO2) measured 5min after the onset of mechanical ventilation |  | 5 min after the oneset of mechanical ventilation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| - FRC after tracheal intubation and after 5 min of mechanical ventilation |  | after 5 min of mechanichal ventilation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anesthesia induction, Obese patients, Noninvasive ventilation, Alveolar recruitment