Functional Residual Capacity During Different Levels of High-flow in Preterm Infants (FUNK-FLOW)

The FUNK-FLOW Study - Functional Residual Capacity During Different Levels of High-flow in Preterm Infants

Although there is a widespread use of HighFlow therapy around the world, there is still uncertainty about the most appropriate initial HighFlow level after nasal continuous positive airway pressure therapy. Higher levels might produce excessive and harmful intra-alveolar pressures exceeding those reached during nasal continuous positive airway pressure therapy. Low levels may not generate sufficient distending pressures, which may result in a loss of functional residual capacity and an increased risk of respiratory failure. Therefore, the aim of this study is to assess the effect of different HighFlow levels on the functional residual capacity and to compare these findings to the functional residual capacity during nasal continuous positive airway pressure therapy.

Non-invasive respiratory support, HighFlow, continuous positive airway pressure, functional residual capacity

Standard HighFlow therapy after weaning from continuous positive airway pressure therapy will be applied on different flow levels. Starting with a flow level of 8l/min, the flow-rates will be changed every 30 minutes subsequently from 8-6-4-2-4-6-8 l/min. Meanwhile, data lung volume changes will be measured using electrical impedance tomography.

Standard HighFlow therapy after weaning from continuous positive airway pressure therapy will be applied on different flow levels. Starting with a flow level of 8l/min, the flow-rates will be changed every 30 minutes subsequently from 8-6-4-2-4-6-8 l/min. Meanwhile, data on lung volume changes will be measured using electrical impedance tomography.

Change in global end-expiratory lung impedance (EELI) during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in mean respiratory rate (RR) during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in regional end-expiratory lung impedance (EELI) during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in mean minute volume during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in mean ventilation distribution during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in mean ventilation distribution over time using electrical impedance tomography (EIT), (%, left/right and ventral/dorsal)

Change in mean silent spaces during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in mean silent spaces over time using electrical impedance tomography (EIT), (%, dependent, non-dependent lung)

Change in mean tidal volume during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in number of apnoea that required stimulation during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in heart rate during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in oxygen saturation during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in fraction of inspired oxygen during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Change in reaching 'failure criteria' to stop HighFlow therapy during the weaning procedure from nasal continuous positive airway pressure (nCPAP) to HighFlow (HF)

Definition of failure criteria: Respiratory rate > 100/min for at least 30 minutes during the intervention Increase in FiO2 by ≥ 0.25 from baseline to maintain oxygen saturation level within physician-ordered parameters > 2 apnoea requiring stimulation per 30-minute-intervention

Inclusion Criteria: Written Informed Consent by one or both parents or legal guardians as documented by signature 30 - 35 weeks postmenstrual age Respiratory support with nCPAP PEEP 5mbar and FiO2 < 0.30 > 72 hours old Exclusion Criteria: Inability of the parents to understand the study concept or procedures due to cognitive or linguistic reasons Congenital malformations adversely affecting lung aeration or pulmonary perfusion (e.g. congenital heart or lung defects)

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