Am. J. Respir. Crit. Care Med.,
Volume 162, Number 6, December 2000, 2265-2271
Optimization of Aerosol Deposition by Pressure
Support in Children with Cystic Fibrosis
An Experimental and Clinical Study
BRIGITTE
FAUROUX,
EMMANUEL
ITTI,
JÉRÔME
PIGEOT,
DANIEL
ISABEY,
MICHEL
MEIGNAN,
GILLES
FERRY,
FRÉDÉRIC
LOFASO,
JEAN-MARIE
WILLEMOT,
ANNICK
CLÉMENT,
and
ALAIN
HARF
Departments of Pediatric Pulmonology and Nuclear Medicine, Armand Trousseau Hospital, Air Liquide Santé International, Paris; and Departments
of Nuclear Medicine and Physiology/Functional Testing and Research Unit INSERM U492, Henri Mondor Hospital, Créteil, France
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.
