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Titolo:
A mathematical model of aerosol holding chambers
Autore:
Zak, M; Madsen, J; Berg, E; Bulow, J; Bisgaard, H;
Indirizzi:
Rigshosp, Dept Pediat, DK-2100 Copenhagen, Denmark Rigshosp Copenhagen Denmark DK-2100 Pediat, DK-2100 Copenhagen, Denmark
Titolo Testata:
JOURNAL OF AEROSOL MEDICINE-DEPOSITION CLEARANCE AND EFFECTS IN THE LUNG
fascicolo: 3, volume: 12, anno: 1999,
pagine: 187 - 196
SICI:
0894-2684(199923)12:3<187:AMMOAH>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
YOUNG-CHILDREN; SPACER DEVICE; DRUG-DELIVERY; IN-VITRO; INFANTS; ASTHMA;
Keywords:
modelling; spacer;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
12
Recensione:
Indirizzi per estratti:
Indirizzo: Bisgaard, H Rigshosp, Dept Pediat, Blegdamsvej, DK-2100 Copenhagen, Denmark Rigshosp Blegdamsvej Copenhagen Denmark DK-2100 agen, Denmark
Citazione:
M. Zak et al., "A mathematical model of aerosol holding chambers", J AEROSOL M, 12(3), 1999, pp. 187-196

Abstract

A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (V-T), chamber volume (V-ch), apparatus dead space (V-D), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol in the chamber with time. Four different spacers were connected via filtersto a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London, Ontario, Canada), NebuChamber (Astra, Sodirtalje, Sweden) and Nebuhaler (Astra) adapted for babies. The dose of fluticasone proprionate delivered by the Babyhaler (Glaxco Wellcome, Oxbridge, Middlesex, UK) was 80% of that predicted, probably because of incomplete priming of this spacer. Ofthe above-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a V-T of 195 mt, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies ofthe expiratory valves were demonstrated by comparison of pressure flow curves during "inspiratory" flow with and without occluded expiratory openings. Insufficient inspiratory valves were demonstrated by comparison of "expiratory" pressure flow curves with and without occluded inspiratory openings. With children breathing through the spacers, mask pressure variations weregenerally on the same order as that seen with the mechanical respirator, supporting the clinical relevance of the in vitro findings.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/07/20 alle ore 06:22:45