In-Line Aerosol Therapy via Nasal Cannula during Adult and Paediatric Normal, Obstructive, and Restrictive Breathing

Abstract

High-flow nasal oxygen therapy is being increasingly adopted in intensive and home care settings. The concurrent delivery of aerosolised therapeutics allows for the targeted treatment of respiratory illnesses. This study examined in-line aerosol therapy via a nasal cannula to simulated adult and paediatric models with healthy, obstructive and restrictive lung types. The Aerogen Solo vibrating mesh nebuliser was used in combination with the InspiredTM O2FLO high-flow therapy system. Representative adult and paediatric head models were connected to a breathing simulator, which replicated several different states of lung health. The aerosol delivery was quantified at the tracheal level using UV-spectrophotometry. Testing was performed at a range of supplemental gas flow rates applicable to both models. Positive end-expiratory pressure was measured pre-, during and post-nebulisation. The increases in supplemental gas flow rates resulted in a decrease in aerosol delivery, irrespective of lung health. Large tidal volumes and extended inspiratory phases were associated with the greatest aerosol delivery. Gas flow to inspiratory flow ratios of 0.29–0.5 were found to be optimum for aerosol delivery. To enhance aerosol delivery to patients receiving high-flow nasal oxygen therapy, respiratory therapists should keep supplemental gas-flow rates below the inspiratory flow of the patient.

Towards More Precise Targeting of Inhaled Aerosols to Different Areas of the Respiratory System

“…However, aerosolized therapeutics are also delivered to the lungs through the nose using inhalation masks, which are useful when aerosol administration through the mouthpiece is not possible or ineffective (e.g., small children, and disabled or uncooperative patients). Transnasal administration can also be performed during oxygen supplementation using a high-flow nasal cannula (HFNC), when oxygen-enriched air is used to carry the aerosol which is preferably delivered from a nebulizer with a low internal flow, such as VMN [53,54]. They can be used both with or without holding chamber (or spacer)…”

Performance Characterisation of the Airvo2TM Nebuliser Adapter in Combination with the Aerogen SoloTM Vibrating Mesh Nebuliser for in Line Aerosol Therapy during High Flow Nasal Oxygen Therapy

“…Numerous bench studies [ 6 , 7 , 8 , 9 , 10 ] and clinical data sets [ 11 , 12 , 13 , 14 , 15 ] have contributed to our understanding of the factors that influence aerosol drug delivery during HFO therapy. In a recent review paper of HFO therapy, Li et al [ 16 ] summarised the current state of the art knowledge in terms of the main factors influencing aerosol drug delivery.…”