Consistency of Aerosol Delivery across High Flow Therapy Systems  

Gavin Bennett, Mary Joyce, Sorcha Murphy, Ian McDonnacha, Louise Sweeney & Ronan MacLoughlin

Aerogen, IDA Business Park, Dangan, Galway, Ireland.

Summary

High Flow nasal therapy (HFNT) is an increasingly adopted means of ventilatory support. This study evaluated the consistency of aerosol delivery facilitated by two market leading HFNT systems.

This comparison of two HFNT systems (Teleflex Hudson RCI Neptune™ and Fisher & Paykel Airvo 2) was completed by assessing the tracheal dose of albuterol sulphate (2mg/ml) under simulated adult breathing settings at 10 and 60LPM high flow gas flow rates. Adult high flow nasal cannula were positioned on a previously described adult head model (LUCY), which was connected to a breathing simulator (Ingmar ASL 5000), using a standard adult breathing pattern (15 BPM, Vt 500 mL, I:E 1:1). Tracheal dose was characterised by quantifying the mass of drug captured on a filter positioned distal to the model oropharyngeal region, as a predictor of aerosol that could potentially reach the lung.

At 10LPM, the range in tracheal dose recorded across both systems was 21.00 – 21.35%. At 60LPM, the range in tracheal dose recorded was 1.00 – 2.15%. Consistent with previous reports, higher gas flow rates were associated with reduced efficiency of aerosol delivery. At 10LPM, no significant difference was observed in the mean tracheal dose between the two systems. At 60LPM, paired t-test results indicate that the nominal difference in mean tracheal dose between the two humidification systems is quite low, it is nevertheless statistically significant (P = 0.027).

This study has demonstrated that for the systems under test, similar levels of aerosol delivery can be achieved during simulated HFNT.