Regional Lung Ventilation During Prone Position in in Intubated Children

Mechanical ventilation can lead to pulmonary, diaphragmatic, and hemodynamic complications due to an increase in global and regional transpulmonary pressure. Optimizing protective mechanical ventilation by using low tidal volumes and positive end-expiratory pressure (PEEP), or by positioning the patient in prone position, is recommended to limit these effects. Prone positioning during mechanical ventilation results in: i) a decrease in airway resistance; ii) a decrease in thoracic compliance, which leads to a redistribution of ventilation-perfusion ratios and, consequently, more homogeneous ventilation. In adults with acute respiratory distress syndrome, prone position reduces mortality and the duration of ventilation. The physiological benefits of prone position, along with its ease of implementation in children, make its use common in pediatrics. However, the clinical benefit of this practice in children has never been demonstrated. The effect of prone position is, hard to predict and varies from one patient to another. The heterogeneity of children in terms of age and respiratory mechanics highlights the importance of individualizing mechanical ventilation in this population, in order to identify which children might benefit from this practice. Thoracic electrical impedance tomography (EIT) is the only technique that allows for real-time, noninvasive, and radiation-free assessment of pulmonary ventilation distribution at the patient's bedside. In children, it can be easily performed without any additional risk. In this population, a few studies have described the heterogeneity of lung volumes induced by recruitment maneuvers or different ventilation settings using thoracic electrical impedance. The impact of the response to prone positioning on the improvement of global and regional respiratory mechanics has not yet been evaluated. This study is a comparative cohort study (with each subject serving as their own control) conducted in the pediatric intensive care unit at Necker-Enfants Malades Hospital in Paris, France.

Inclusion Criteria: * Patients aged 0 to 18 years * on controlled invasive mechanical ventilation (no spontaneous breathing) for an expected duration of at least 16 hours * for whom an initial prone positioning session is indicated (regardless of the indication; left to the clinician's discretion) * notification of legal guardians and written consent from legal guardians Exclusion Criteria: * Corrected gestational age ≤ 37 weeks * Contraindication or impracticality of Thoracic electrical impedance tomography : presence of a pacemaker or a bandages covering chest wall, significant skin lesions * Pneumothorax or pneumomediastinum * Significant hemodynamic instability (rapid increase in vasoactive or inotropic agents to maintain adequate peripheral circulation and blood pressure), refractory hypoxemia, or moribund patient * Child on unconventional mode of invasive ventilation (high-frequency oscillatory ventilation) or noninvasive ventilatory support