Open Lung Strategy in Critically Ill Morbid Obese Patients

Study Overview
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Brief Summary
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The goal of this interventional crossover study in morbidly obese intubated and mechanically ventilated patients is to describe the respiratory mechanics and the heart-lung interaction at titrated positive end-expiratory pressure levels following a recruitment maneuver with transthoracic echocardiography and electric impedance tomography imaging.

Detailed Description
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Obese patients under mechanical ventilation are more likely to develop atelectasis as a consequence of the increased abdominal weight. Atelectasis is the primary responsible for respiratory insufficiency and impossibility to wean obese patients from respiratory support. In a previous study we demonstrated the efficacy of the application of titrated PEEP levels following a recruitment maneuver in obese patients, i.e. improvement in respiratory mechanics and gas exchanges without negative hemodynamic effects. The application of lung and heat imaging will allow us to quantitatively describe: Increase in aerated lung tissue (reduction of atelectasis) Reduction of over-inflation of the ventilated regions Recoupling of ventilation and perfusion Improvement in right heart function by reduction of right heart afterload

Official Title
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Open Lung Strategy in Critically Ill Morbid Obese Patients Lung Imaging and Heart-lung Interaction

Conditions
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Obesity, Respiratory Insufficiency, Right-Sided Heart Failure, Pulmonary Atelectasis, Respiratory Mechanics

Intervention / Treatment
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* Procedure: PEEP INCREMENTAL
* Procedure: PEEP DECREMENTAL


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ICU admitted requiring intubation and mechanical ventilation BMI ≥ 35 kg/m2 Waist circumference > 88 cm (for women) Waist circumference > 102 cm (for men) Exclusion Criteria: Known presence of esophageal varices Recent esophageal trauma or surgery Severe thrombocytopenia (Platelets count ≤ 5,000/mm3) Severe coagulopathy (INR ≥ 4) Presence or history of pneumothorax Pregnancy Patients with poor oxygenation index (PaO2/FiO2< 100 mmHg with at least 10 cmH2O of PEEP) Pacemaker and/or internal cardiac defibrillator Hemodynamic parameters: systolic blood pressure (SBP) <100 mmHg and >180 mmHg, or if SBP is between 100-180 mmHg on high dose of IV continuous infusion norepinephrine (>20 μg per minute), or dobutamine (>10 μg per minute), or dopamine (>10 μg per Kg per minute), or epinephrine (>10 μg per minute).

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

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Physiologic crossover study. There is no randomization. All participants will receive the same interventions in the same order.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PEEP_Titration_INCREMENTAL<br>The investigators will compare 3 levels of PEEP (BASELINE versus PEEP INCREMENTAL versus PEEP DECREMENTAL). Baseline PEEP is based in the standard of care PEEP used in the participant units. PEEP incremental value is based in transpulmonary pressure. Intervention : PEEP INCREMENTAL | Procedure: PEEP INCREMENTAL<br>* PEEP was progressively increased by steps of 2 cmH2O every 60 second until the end-expiratory transpulmonary pressure became positive between 0-2 cmH2O.<br>* Other names: PEEP_Titration;Procedure: PEEP DECREMENTAL<br>* Lung recruitment maneuver (LRM) is a transitory and controlled increase in airway pressure to open collapsed alveoli. LRM is the first step of the PEEP DECREMENTAL method. After LRM, PEEP is systematically decreased, in small decrements, until the best respiratory system mechanics is identified.<br>* Other names: PEEP_Titration;|
| Experimental: PEEP_Titration_DECREMENTAL<br>The investigators will compare 3 levels of PEEP (BASELINE versus PEEP INCREMENTAL versus PEEP DECREMENTAL). Baseline PEEP is based in the standard of care PEEP used in the participant units. PEEP decremental value is based in lung recruitment maneuver followed by a best compliance curve during PEEP decrements. Intervention :PEEP DECREMENTAL | Procedure: PEEP INCREMENTAL<br>* PEEP was progressively increased by steps of 2 cmH2O every 60 second until the end-expiratory transpulmonary pressure became positive between 0-2 cmH2O.<br>* Other names: PEEP_Titration;Procedure: PEEP DECREMENTAL<br>* Lung recruitment maneuver (LRM) is a transitory and controlled increase in airway pressure to open collapsed alveoli. LRM is the first step of the PEEP DECREMENTAL method. After LRM, PEEP is systematically decreased, in small decrements, until the best respiratory system mechanics is identified.<br>* Other names: PEEP_Titration;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory System Elastance | Difference in Respiratory System Elastance measured in cmH2O/L | During study time points :baseline, PEEP incremental, PEEP decremental | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lung mechanics - Compliance | Difference in respiratory system, lung and chest wall compliance measured in mL/cmH2O | Study time points: baseline, PEEP incremental, PEEP decremental | 
| Lung mechanics - Airway resistances | Difference in resistances of the airways measured as cmH2O/L/sec (Raw) | During study time points: baseline, PEEP incremental, PEEP decremental | 
| Survival | Incidence of death among the study population | 28 days after the performance of the study protocol |