PT  - JOURNAL ARTICLE
AU  - Aris Bertzouanis
AU  - Sotirios Fouzas
AU  - Gabriel Dimitriou
AU  - Sotirios Fouzas
TI  - Influence of breathing dynamics on the effective concentration of oxygen delivered to infants via high-flow nasal cannula
AID  - 10.1183/13993003.congress-2021.OA3957
DP  - 2021 Sep 05
TA  - European Respiratory Journal
PG  - OA3957
VI  - 58
IP  - suppl 65
4099  - http://erj.ersjournals.com/content/58/suppl_65/OA3957.short
4100  - http://erj.ersjournals.com/content/58/suppl_65/OA3957.full
SO  - Eur Respir J2021 Sep 05; 58
AB  - Background: The fractional inspired concentration of oxygen (FiO2) provided to infants via high-flow nasal cannula (HFNC) is regulated by the air-oxygen blender and is considered stable. The effect of breathing dynamics on the effective FiO2, especially at lower HFNC flows, is unknown.Objective: To examine the influenced of breathing dynamics on the effective FiO2 delivered to small infants via HFNC.   Methods: We performed simulations at varying target (set) FiO2 values, nasal cannula (NC) flows, and minute ventilation (MV), using a mechanical infant lung model (ventilation compartment, FiO2 sampling, upper airway model, NC, air-oxygen blender).Results: The effective FiO2 approximated the target (set) value at HFNC flows >5 L/min, irrespective of the breathing pattern (Figure). At lower flows, however, the effective FiO2 diverges from the target value depending on MV; higher MV (higher tidal volume and/or respiratory rate) results in lower effective FiO2 (higher FiO2 bias) and vice versa. At NC flows <2 L/min the FiO2 bias becomes significant even for lower MVs.Conclusions: The effective concentration of oxygen delivered to small infants via HFNC diverges significantly from the target FiO2 at higher MVs and/or at nasal cannula flows <2 L/min. The weaning of oxygen dependent small infants from the HFNC requires attention.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, OA3957.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).