Photo Credit: PatrikSlezak

The following is a summary of “Impact of different prong-nares ratio on ventilation in COPD patients using nasal high-flow (NHF) – a physiological study,” published in the November 2024 issue of Pulmonology by Bräunlich et al.  

Researchers conducted a retrospective study to verify the clinical applicability of experimental findings regarding airway pressure variations with different cannula sizes and prongs-nare ratios in nasal high flow (NHF) therapy. 

They characterized changes in ventilation parameters and hypercapnia related to prong size and flow rate in an interventional clinical setting. Outcome measures included mean airway pressure, tidal volume (TV), respiratory rate (RR), minute volume (MV), and reduction in pCO₂. The ventilatory parameters were assessed at flow rates of 20, 30, 40, and 50 L/min using 3 different prong sizes. The Changes in pCO₂ were documented at 20 and 40 L/min across the 3 prong sizes. 

The results showed an increased flow rate of NHF leading to significant changes in ventilation. A 10 L/min increase in flow rate resulted in a significant rise in mean airway pressure, RR and MV showed notable changes with larger increases in flow rate, particularly with larger prongs, while TV remained unaffected. A 20 L/min increase in flow rate (from 20 L/min to 40 L/min) caused a significant decrease in capillary pCO₂  and prong size did not significantly influence any of the measured values. 

Investigators concluded that different NHF cannula prong sizes do not significantly impact essential respiratory parameters or carbon dioxide elimination in patients with COPD . 

Source: bmcpulmmed.biomedcentral.com/articles/10.1186/s12890-024-03397-9