Abstract
nHFOV was reported as a promising tool to increase CO2 removal in neonates and infants (De Luca et al. 2016). In HFOV, the CO2 diffusion coefficient (DCO2=2 ×) describes the relationship between the efficacy of gas washout and oscillatory tidal volume () and frequency (f). During nHFOV, upper airways (UA) may influence the mechanisms of gas exchange.
We hypothesize that, during nHFOV, UA’s compliance may contribute to CO2 removal thanks to an increased washout of the anatomical deadspace.
An in vitro model comprising a UA compartment with constant deadspace but adjustable compliance was connected to one resembling lung volume and mechanical properties. CO2 production was simulated by injecting a constant CO2 flow into the lung model. nHFOV was applied from 5 to 20Hz, adjusting the amplitude to keep a constant DCO2=5000 ml2/s. A volumetric pump connected to the model simulated patient breathing. Tests were repeated with compliant and non-compliant UA.
Despite constant DCO2, CO2 elimination was frequency-dependent and maximal at 10Hz in both model configurations. The compliant UA promoted a frequency-dependent increase of CO2 removal from 5 to 15Hz compared to non-compliant UA (Figure).
During nHFOV, UA compliance contributes to CO2 removal. This contribution depends on both oscillatory frequency and UA compliance, making the tailoring of nHFOV frequency crucial for this ventilation approach’s overall effectiveness.
Footnotes
Cite this article as: European Respiratory Journal 2021; 58: Suppl. 65, OA3958.
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).
- Copyright ©the authors 2021
