Optimization of aerosol deposition by pressure support in children with cystic fibrosis: an experimental and clinical study

Am J Respir Crit Care Med. 2000 Dec;162(6):2265-71. doi: 10.1164/ajrccm.162.6.2003069.


Nebulized aerosols are commonly used to deliver drugs into the lungs of patients with cystic fibrosis (CF). The aim of this study was to assess the effectiveness of pressure-support (PS) ventilation in increasing aerosol deposition within the lungs of children with CF. An in vitro study demonstrated the feasibility of coupling a breath-actuated nebulizer to a PS device. An in vivo study was done with 18 children (ages 6 to 21 yr) with clinically stable CF, each of whom underwent both a standard and a PS-driven ventilation scan (control session and PS session, respectively). In addition, a perfusion scan was used to determine lung outlines and to construct a geometric model for quantifying aerosol deposition by radioactivity counting in MBq. Homogeneity of nebulization was evaluated from the four first-order moments of aerosol distribution in the peripheral and central lung regions. The time-activity nebulization curve was linear in all patients, with higher slopes during the PS than during the control session (0.43 +/- 0.07 [mean +/- SD] MBq/min and 0.32 +/- 0.23 MBq/min, respectively; p < 0.018). Quantitatively, aerosol deposition was about 30% greater after the PS session (4.4 +/- 2.7 MBq) than after the control session (3.4 +/- 2.1 MBq; p < 0.05). Similarly, deposition efficacy (as a percentage of nebulizer output) was significantly better during the PS session than during the control session (15.3 +/- 8.3% versus 11.5 +/- 5.7%, p < 0.05). No differences in the regional deposition pattern or in homogeneity of uptake were observed. In conclusion, our data show that driving the delivery of a nebulized aerosol by noninvasive PS ventilation enhances total lung aerosol deposition without increasing particle impaction in the proximal airways.

Publication types

  • Clinical Trial
  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Aerosols
  • Child
  • Combined Modality Therapy
  • Cystic Fibrosis / diagnostic imaging
  • Cystic Fibrosis / therapy*
  • Female
  • Humans
  • In Vitro Techniques
  • Linear Models
  • Lung / diagnostic imaging
  • Male
  • Nebulizers and Vaporizers* / statistics & numerical data
  • Organotechnetium Compounds
  • Phytic Acid
  • Positive-Pressure Respiration / instrumentation*
  • Positive-Pressure Respiration / statistics & numerical data
  • Radionuclide Imaging
  • Radiopharmaceuticals
  • Technetium Tc 99m Aggregated Albumin
  • Ventilators, Mechanical


  • Aerosols
  • Organotechnetium Compounds
  • Radiopharmaceuticals
  • Technetium Tc 99m Aggregated Albumin
  • technetium phytate
  • Phytic Acid