Aerosol Delivery During Continuous High Frequency Oscillation for Simulated Adults During Quiet and Distressed Spontaneous Breathing

Background:Continuous high-frequency oscillation (CHFO) of the airway is a therapeutic mode for secretions mobilization. The device also incorporates aerosol administration using an integrated jet nebulizer. However, the effectiveness of aerosol delivery and influential factors remain largely unreported. Methods:A collecting filter was placed between an adult manikin with representative upper airway and a breath simulator, set to represent quiet and distressed patterns of adult spontaneous breathing. The CHFO device (Metaneb, Hill Rom) was attached to the manikin via a mask. Two jet nebulizers (JN) were tested with placement in the manifold and between manifold and mask. A vibrating mesh nebulizer (VMN, Aerogen) was placed between the manifold and mask with and without extension tubing. Aerosol administration was compared during CHFO and nebulization mode alone. Albuterol (2.5mg in 3mL) was nebulized for each condition (n = 3). Drug was eluted from the filter and assayed with UV spectrophotometry (276 nm). Results:During CHFO, inhaled dose with JN were low (∼2%), regardless of nebulizer placement. Inhaled dose was improved with VMN placed between manifold and mask (12.48 ± 2.24 vs 2.58 ± 0.48 %, P = .004). Inhaled dose of JN in manifold with nebulization mode alone was lower than JN with aerosol mask (4.03 ± 1.82 vs 10.39 ± 2.79 %, P = .004). Inhaled dose was greater with distressed breathing than quiet breathing. VMN (P < .001) and distressed breathing (P = .001) were identified as predictors of increased inhaled dose. Conclusions:Inhaled dose with JN via Metaneb was lower than JN alone. Placement of VMN at airway and distressed breathing increased inhaled dose.Inhaled dose in quiet and distressed breathing with different nebulizer and its placementNebulizerPlacementInhaled dose (%)PQuiet breathingDistressed breathingCHFO with JN (Salter lab)Manifold1.53 ± .162.77 ± .36.05CHFO with JN (AirLife)Manifold1.84 ± .222.20 ± .12.077CHFO with JN (Salter lab)Between manifold and mask2.26 ± .062.89 ± .53.077CHFO with VMNBetween manifold and mask with extention tubing9.39 ± .8410.67 ± .12.05CHFO with VMNDirectly connected to mask10.45 ± .0914.51 ± .37.05Nebulization alone with JN (Salter lab)Manifold2.87 ± .285.19 ± .66.05JN (AirLife) with aerosol maskNA7.95 ± .5912.83 ± 1.16.05CHFO, continuous high-frequency oscillation; JN, jet nebulizer; VMN, vibrating mesh nebulizer