Evaluation of Perfusion and Ventilation Distribution in Children: a Pilot Study.

Feasibility Study of the Evaluation of Perfusion and Ventilation Distribution in Children : a Pilot Study

Electrical impedance tomography (EIT) is a recent monitoring technique that provides information on regional ventilation distribution. Following the injection of a hypertonic saline bolus, EIT can also assess regional pulmonary perfusion distribution, allowing evaluation of the ventilation/perfusion (V/Q) ratio.

In adults, protocols for assessing perfusion distribution require the injection of 10 mL of a 7.5% or 10% NaCl solution or sodium bicarbonate over a few seconds. Studies have reported good hemodynamic tolerance, adequate image quality, and no significant changes in serum sodium levels. However, this volume and sodium load are not appropriate for small children.

To date, no pediatric protocol exists for assessing pulmonary perfusion distribution and the ventilation/perfusion ratio using EIT. It is therefore proposed to conduct a pilot study to evaluate the feasibility of assessing pulmonary perfusion by EIT using a weight-adjusted bolus of hypertonic saline (NaCl or sodium bicarbonate).

Inclusion Criteria:

• patients < 12 years hospitalized in pediatric intensive care
• intubated, under conventional invasive mechanical ventilation and sedated
• between 3 and 40 kg
• with central venous access in the superior vena cava
• consent signed by parents or legal guardians

Exclusion Criteria:

• Patients with significant leaks > 20% around the endotracheal tube
• Patients receiving spontaneous ventilation (inspiratory support, NIV, etc.)
• Natremia > 150 mmol/L at inclusion
• Hyperchloremia ≥ 115 mmol/L and/or hypokaliema ≤ 3 mmol/L
• Patients with intracranial hypertension
• Patients with active bleeding or persistent hemodynamic instability despite amines
• Patients with heart failure, uncorrected cyanotic heart disease, or a history of cardiac arrhythmia
• Patients with contraindications to the use of the electrical impedance pulmonary tomography belt (skin lesions, burns, or recent thoracic surgery)
• Conditions in which EIT data acquisition will be disrupted (chest dressings, pneumothorax, ECMO)
• Patients with severe hypoxemia defined as FiO2 > 90% to maintain SpO2 > 88%
• Individuals not affiliated with a social security system or beneficiaries of a similar system