eprintid: 16344
rev_number: 24
eprint_status: archive
userid: 602
dir: disk0/00/01/63/44
datestamp: 2009-08-21 10:25:24
lastmod: 2015-07-23 09:37:09
status_changed: 2009-08-21 10:25:24
type: thesis
metadata_visibility: show
creators_name: Sonnappa, S.
creators_id: SSONN49
title: Ventilation inhomogeneity as an indicator of airways disease in preschool children with wheeze
ispublished: unpub
subjects: 22800
divisions: IC3D
note: Authorisation for digitisation not received
abstract: Ventilation inhomogeneity is a well recognised feature in older children and adults with asthma, even during asymptomatic periods. However, little is known about
physiological changes in the airways, particularly small airways in preschool wheezers.
This thesis investigated whether indices of ventilation inhomogeneity derived from multiple breath washout (MBW) were abnormal in asymptomatic preschool wheezers;
whether MBW indices were more sensitive for detecting airways disease than specific airways resistance (sRaw); and whether there were differences in pulmonary function
according to wheeze phenotype and atopic status.
Preschool children (aged between 4-6 years) with recurrent wheeze, underwent pulmonary function assessments and were compared with age matched healthy controls.
Fraction of exhaled nitric oxide (FeNO); MBW indices [lung clearance index (LCI), functional residual capacity (FRC), conductive (Scond) and acinar (Sacin) airways ventilation inhomogeneity] and sRaw were measured. Subgroup analysis was performed according to temporal wheeze phenotype of episodic (viral) and multi-trigger wheeze, and atopic status.
FeNO and pulmonary function were compared in 72 healthy controls and 62 wheezers [episodic (n=28), multi-trigger (n=34; atopic (n=39), non-atopic (n=23)]. Group differences between healthy controls and wheezers were seen for FeNO, LCI, Scond and sRaw. FeNO was abnormal in 9/62 (15%), LCI in 16/62 (26%), Scond in 22/60 (37%) and sRaw in 12/62 (19%) wheezers. Multi-trigger wheezers had significantly higher LCI, Scond and sRaw than episodic wheezers. LCI was abnormal in 13/34 (38%), Scond in 21/34 (62%), and sRaw in 10/34 (29%) multi-trigger wheezers. In contrast, LCI was abnormal in 3/28 (11%) and Scond in 1/28 (3.5%), and sRaw in 2/28 (7%) episodic (viral) wheezers.
There were no differences between atopic and non-atopic phenotypes.
MBW indices in particular Scond detect airways disease in preschool wheezers more frequently than sRaw. Pulmonary function tests in particular Scond discriminate between
episodic (viral) and multi-trigger wheezers, irrespective of atopic status providing physiological validation to clinical patterns of wheeze.
date: 2009-06
vfaculties: VFPHS
thesis_class: doctoral_md_only
language: eng
thesis_view: UCL_Thesis
lyricists_name: Sonnappa, S
lyricists_id: SSONN49
full_text_status: none
pages: 289
institution: UCL (University College London)
department: UCL Institute of Child Health
thesis_type: Doctoral
citation:        Sonnappa, S.;      (2009)    Ventilation inhomogeneity as an indicator of airways disease in preschool children with wheeze.                   Doctoral thesis , UCL (University College London).