Open Lung Strategy in Critically Ill Morbid Obese Patients

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

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.

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

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).