Comparative in-vitro Study of the Trachospray, a New Device for Topical Anaesthesia of the Upper Airway

Abstract

Geert-Jan van Geffen,1 Hielke Markerink,1 Marc van Barneveld,2 Frank Verhoeven,3 Gert Jan Scheffer,1 Jörgen Bruhn1 1Department of Anesthesiology, Pain and Palliative Care, Radboud University Medical Centre (RUMC), Nijmegen, The Netherlands; 2Medspray Anesthesia BV, Enschede, The Netherlands; 3Medspray T&M, Enschede, The NetherlandsCorrespondence: Geert-Jan van GeffenDepartment of Anesthesiology, Pain and Palliative Care, Radboud University Medical Center, Internal Mail 717, P.O. Box 9101, Nijmegen, HB 6500, The NetherlandsTel [phone]Email [email protected]: Obtaining complete topical anaesthesia of the airway remains a clinical challenge. Particle size is one of the most important variables for the dose deposited and the distribution of aerosols in the airways. The mass median aerodynamic diameter of the particles should be in the range of 5– 20 μm. We developed the “Trachospray” as a soft mist spray device for local anaesthetics. This in-vitro comparative test was designed to compare the performance of the new Trachospray device with two existing medical devices. The performance was determined by comparing the spray deposition patterns in the mouth, throat, trachea and lungs.Methods: The human airway was simulated with an artificial idealized mouth and throat model, connected to a Next Generation Impactor. Four measurements were taken for each device (Trachospray, jet nebulizer and a spray pump) with 5.85% NaCl. A fifth measurement was carried out with 0.5% fluorescein solution for a visual inspection of the deposition patterns. The mass median aerodynamic diameter and geometric standard deviation of the droplets were measured.Results: The Trachospray produced an even coverage in the mouth, hypopharynx and vocal cords, with only a small lung fraction. The jet nebulizer produced a much thinner layer coverage of the tongue and surface around the vocal chords with a high lung deposition. The spray pump produced big droplets which deposited mainly at the hypopharynx.Conclusion: The Trachospray device deposits local anaesthetics in the targeted areas for topical anaesthesia of the airway and has promising characteristics for providing effective airway anaesthesia.Keywords: airway model, geometric standard deviation, mass median aerodynamic diameter, medical device, topical airway anaesthesia

Keywords

• airway model
• geometric standard deviation
• mass median aerodynamic diameter
• medical device
• topical airway anaesthesia.