Ventilation Perfusion Mismatch

In preterm infants \< 34 weeks' gestation at birth receiving respiratory support with invasive positive pressure ventilation, the positive end-expiratory pressure (PEEP) of best compliance will increase the cardiac output and improve oxygenation. This study may emphasize using point-of-care echocardiography along with electrical impedance tomography (EIT) to optimize ventilator settings in preterm infants. Infants will be randomized to a 4-hour crossover period of increasing and decreasing PEEP in random order from baseline to determine compliance, oxygenation, and cardiac hemodynamics at each step using echocardiography (ECHO) and EIT measurements. There will be a 15-minute washout period after changes prior to data collection.

This study aims to compare lung perfusion distribution between inspiratory breath-hold and expiratory breath-hold phases using the saline indicator method combined with electrical impedance tomography (EIT). A self-controlled crossover design will be used in which each participant undergoes both breath-hold conditions with standardized rapid intravenous saline injections. The primary objective is to evaluate changes in global and regional pulmonary perfusion under different lung volume states. The findings may improve understanding of perfusion redistribution with lung inflation and support optimized ventilatory strategies in clinical practice.

This study evaluates the effects of prone positioning on homogenization of ventilation.