Influence of Flow Rate Change on CO2 Levels During High Flow Nasal Ventilation (HFNV) in Preterm Infants.
Design: Prospective, crossover observational study. Participants: Preterm newborns (24-33.6 weeks' gestation) on HFNV. Procedure: Randomized flow rate adjustments, monitoring tcCO2 and other respiratory parameters over three hours. Outcomes Primary: Change in tcCO2. Secondary: Study terminations due to unsafe CO2 levels and changes in other respiratory metrics. Statistical Analysis Sample size: 45 infants. Analysis: Paired and unpaired t-tests for comparison within and between groups.
• Gestational age 240 to 336.
• At least 6 hours of stabilized HFNP settings, i.e. minor changes in settings (FiO2 ≤0.10, no change in flow).
• At least 6 hours of stabilized tcCO2, i.e. ≤5 mmHg variation.
• At least 6 hours from surfactant administration.
• Parental consent