Effect of Interrupting Heated Humidification on Nebulized Drug Delivery Efficiency, Temperature, and Absolute Humidity During Mechanical Ventilation: A Multi-Lab In Vitro Study

Sophie Jacquier; Hui-Ling Lin; Jie Li; Caylie A Sheridan; Paul Karabelas; Jui-Fang Liu; Stephan Ehrmann; James B Fink

doi:10.1089/jamp.2023.0028

Effect of Interrupting Heated Humidification on Nebulized Drug Delivery Efficiency, Temperature, and Absolute Humidity During Mechanical Ventilation: A Multi-Lab In Vitro Study

J Aerosol Med Pulm Drug Deliv. 2024 Apr 2. doi: 10.1089/jamp.2023.0028. Online ahead of print.

Authors

Sophie Jacquier^{1

2}, Hui-Ling Lin^{3

4}, Jie Li^{5

6}, Caylie A Sheridan^{5

6}, Paul Karabelas^{5

6}, Jui-Fang Liu⁴, Stephan Ehrmann^{1

2}, James B Fink^{4

5

6}

Affiliations

¹ CHRU Tours, Médecine Intensive Réanimation, INSERM CIC 1415, CRICS-TriggerSep F-CRIN Research Network, Tours, France.
² INSERM, Centre D'étude des Pathologies Respiratoires, Université de Tours, Tours, France.
³ Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan.
⁴ Department of Respiratory Care, Chang Gung University of Science and Technology, Chiayi, Taiwan.
⁵ Division of Respiratory Care, Department of Cardiopulmonary Sciences, Rush University, Chicago, Illinois, USA.
⁶ Aerogen Pharma Corp., San Mateo, California, USA.

PMID: 38563793
DOI: 10.1089/jamp.2023.0028

Abstract

Introduction: During mechanical ventilation (MV), inspired gases require heat and humidification. However, such conditions may be associated with reduced aerosol delivery efficiency. The practice of turning off heated humidification before nebulization and the impact of nebulization on humidity in a dry ventilator circuit remain topics of debate. This study aimed to assess the effect of turning off heated humidification on inhaled dose and humidity with nebulizer use during adult MV. Methods: A bronchodilator (albuterol) and two antibiotics (Colistimethate sodium and Amikacin sulfate) were nebulized with a vibrating mesh nebulizer placed at the humidifier inlet and in the inspiratory limb at the Y-piece. Additionally, albuterol was nebulized using a jet nebulizer in both placements. Aerosol particle size distribution was determined through a cascade impactor. Absolute humidity (AH) and temperature of inspired gases were determined with anemometer/hygrometers before, during, and after nebulization, before, during, and up to 60 minutes after interrupting active humidification. Aerosol collected on a filter distal to the endotracheal tube and on impactor stages were eluted and assayed by spectrophotometry. Results: The inhaled dose was greater when both nebulizers were placed at the humidifier inlet than the inspiratory limb at the Y-piece. Irrespective of the nebulizer types and placements, the inhaled dose either decreased or showed no significant change after the humidifier was turned off. The aerosol particle size ranged from 1.1 to 2.7 μm. With interruption of active humidification, humidity of inspired gas quickly dropped below recommended levels, and nebulization in dry ventilator circuit produced an AH between 10 and 20 mgH₂O/L, lower than the recommended minimum of 30 mgH₂O/L. Conclusion: Interrupting active humidification during MV before nebulization did not improve aerosol delivery efficiency for bronchodilator or antibiotics, but did reduce humidity below recommended levels.

Keywords: aerosol; heated humidifier; humidification; jet nebulizer; mechanical ventilation; vibrating-mesh nebulizer.