Publications by authors named "Samantha Irving"

14 Publications

  • Page 1 of 1

A Short extension to multiple breath washout provides additional signal of distal airway disease in people with CF: A pilot study.

J Cyst Fibros 2021 Jul 15. Epub 2021 Jul 15.

Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom; National Heart and Lung Institute, Imperial College London, Manresa Rd, London, United Kingdom; European Cystic Fibrosis Society Lung Clearance Index Core Facility, London, United Kingdom.

Background: Adding a slow vital capacity (SVC) to multiple breath washout (MBW) allows quantification of otherwise overlooked signal from under/un-ventilated lung units (UVLU) and may provide a more comprehensive assessment of airway disease than conventional lung clearance index (LCI).

Methods: We conducted a pilot study on people undergoing MBW tests: 10 healthy controls (HC) and 43 cystic fibrosis (CF) subjects performed an SVC after the standard end of test. We term the new outcome LCI with Short extension (LCI). We assessed (i) CF/ HC differences, (ii) variability (iii) effect of pulmonary exacerbation (PEx)/treatment and (iv) relationship with CF computed tomography (CFCT) scores.

Results: HC/ CF group differences were larger with LCI than LCI (P<0.001). Within the CF group UVLU was highly variable and when abnormal it did not correlate with corresponding LCI. Signal showed little variability during clinical stability (n = 11 CF; 2 visits; median inter-test variability 2.6% LCI 2.5% LCI). PEx signal was significantly greater for LCI both for onset and resolution. Both MBW parameters correlated significantly with total lung CT scores and hyperinflation but only LCI correlated with mucus plugging.

Conclusions: UVLU captured within the LCI varies between individuals; the lack of relationship with LCI demonstrates that new, additional information is being captured. LCI repeatability during clinical stability combined with its larger signal around episodes of PEx may lend it superior sensitivity as an outcome measure. Further studies will build on this pilot data to fully establish its utility in monitoring disease status.
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http://dx.doi.org/10.1016/j.jcf.2021.06.013DOI Listing
July 2021

Paediatric severe asthma biologics service: from hospital to home.

Arch Dis Child 2021 09 15;106(9):900-902. Epub 2021 Feb 15.

Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Foundation Trust, London, UK

Children with severe asthma may be treated with biologic agents normally requiring 2-4 weekly injections in hospital. In March 2020, due to COVID-19, we needed to minimise hospital visits. We assessed whether biologics could be given safely at home. The multidisciplinary team identified children to be considered for home administration. This was virtually observed using a video link, and home spirometry was also performed. Feedback was obtained from carers and young people. Of 23 patients receiving biologics, 16 (70%) families agreed to homecare administration, 14 administered by parents/patients and 2 by a local nursing team. Video calls for omalizumab were observed on 56 occasions, mepolizumab on 19 occasions over 4 months (April-July). Medication was administered inaccurately on 2/75 occasions without any adverse events. Virtually observed home biologic administration in severe asthmatic children, supported by video calls and home spirometry, is feasible, safe and is positively perceived by children and their families.
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http://dx.doi.org/10.1136/archdischild-2020-320626DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8380910PMC
September 2021

Nitrogen offset in N multiple washout method.

ERJ Open Res 2020 Jan 16;6(1). Epub 2020 Mar 16.

Imperial College London, London, UK.

http://bit.ly/2ug0fAi.
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http://dx.doi.org/10.1183/23120541.00043-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7073412PMC
January 2020

Lung clearance index and steroid response in pediatric severe asthma.

Pediatr Pulmonol 2020 04 6;55(4):890-898. Epub 2020 Feb 6.

Royal Brompton and Harefield NHS Foundation Trust, London, UK.

Introduction: Lung clearance index (LCI) is a measure of airway disease that has been shown to be abnormal in asthma. We hypothesized that LCI would be higher (worse) in children with severe therapy-resistant asthma (STRA) compared with difficult asthma (DA) and healthy controls and that LCI would fall in response to parenteral steroids in STRA.

Methods: Sixty-four children with asthma who were prescribed high-dose asthma therapy (GINA steps 4 or 5) performed LCI and spirometry. Forty-three had STRA and 21 DA. Thirty-nine of forty-three STRA patients attended for a clinically indicated bronchoscopy during which an intramuscular injection of triamcinolone was given. LCI, spirometry, and fractional exhaled nitric oxide (FeNO) were performed on the day of the bronchoscopy and repeated 4 weeks later.

Results: LCI was more abnormal in STRA (median: 7.40, range: 5.58-12.34) than in DA (6.55, 5.77-7.75), P = .0006, and healthy controls (6.53, 5.57-7.35), P = .005. In contrast to the first second forced expired volume (FEV ), LCI improved following systemic steroids; of 20 STRA patients with an abnormal LCI at baseline, 13 improved following triamcinolone. LCI and FeNO responses were concordant.

Conclusions: There is a subgroup of children with STRA in whom LCI is elevated who improve following parenteral steroids. LCI may be a valuable additional domain in assessing steroid response in pediatric asthma.
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http://dx.doi.org/10.1002/ppul.24675DOI Listing
April 2020

Simultaneous sulfur hexafluoride and nitrogen multiple-breath washout (MBW) to examine inherent differences in MBW outcomes.

ERJ Open Res 2019 Oct 4;5(4). Epub 2019 Nov 4.

Imperial College London, London, UK.

Multiple-breath washout (MBW) can be performed with different gases (sulfur hexafluoride (SF) and nitrogen (N)) and different devices, all of which give discrepant results. This study aimed to confirm previously reported differences and explore factors influencing discrepant results; equipment factors or the physical properties of gases used.

Methods: Healthy controls (HCs) and participants with cystic fibrosis (CF) completed MBW trials on two commercially available devices (Exhalyzer D (N) and Innocor (SF)). Simultaneous washout of both gases at the same time on the commercial equipment and simultaneous washouts using a respiratory mass spectrometer (RMS) were completed in subsets. Primary outcomes were lung clearance index (LCI), breath number and time required to washout.

Results: Breath number was higher with N washout than SF in both HCs and patients with CF, whether washouts were completed individually or simultaneously. The difference was greater in more advanced disease, largely caused by differences in the final part of the washout. Results from commercial devices were similar to those obtained with the RMS.

Conclusions: N MBW results were higher than SF MBW, with some of the largest differences reported to date being observed. The biggest impact was at the end of the washout and this was even the case when gases were washed out simultaneously. N and SF MBW results are inherently different and should be considered as independent measurements.
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http://dx.doi.org/10.1183/23120541.00234-2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826248PMC
October 2019

Developments in multiple breath washout testing in children with cystic fibrosis.

Curr Med Res Opin 2017 04 2;33(4):613-620. Epub 2017 Feb 2.

a NHLI, Imperial College London , UK.

Background: Lung clearance index (LCI) is becoming recognized as an important addition in the monitoring of pediatric cystic fibrosis (CF). The non-invasive technique is easy to perform in all ages, reproducible and increasingly being used in clinical trials. There is interest in utilizing it within the clinic setting but its current use is mostly as a research tool. The procedure is highly dependent on skilled operators and a relaxed testing environment is key to obtaining good quality measurements.

Conclusions: Standardization of LCI is part of an ongoing collaborative, multicenter process. This review describes the background to LCI, discusses technical issues and limitations and provides examples of its utility in clinical and research contexts.
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http://dx.doi.org/10.1080/03007995.2016.1268999DOI Listing
April 2017

Feasibility of lung clearance index in a clinical setting in pre-school children.

Eur Respir J 2016 10 7;48(4):1074-1080. Epub 2016 Jul 7.

NHLI, Imperial College London, and Royal Brompton and Harefield NHS Foundation Trust, London, UK

Lung function testing in pre-school children in the clinical setting is challenging. Most cannot perform spirometry and many infant lung function tests require sedation. Lung clearance index (LCI) derived from the multiple-breath washout (MBW) test has been shown to be sensitive to early disease changes but may be time consuming and so a shortened test (LCI) may be more feasible in young children. We sought to establish feasibility of MBW in unsedated pre-school children in a clinic setting and hypothesised use of LCI would increase success rates.116 pre-school children (28 healthy controls and 88 with respiratory disease), median age 4.0 years (range 2-6 years), underwent MBW tests unsedated in a clinic setting, using sulfur hexafluoride as a tracer gas and an adapted photoacoustic gas analyser.81 (70%) out of 116 children completed LCI and 72% completed LCI measurement. Test success increased significantly in patients over 3 years (0% at <2.5 years, 33% at 2.5-3 years and 70% at >3 years, p<0.0001). LCI was elevated in those with respiratory disease compared with healthy controls.MBW is feasible in a clinic setting in unsedated pre-schoolers, particularly in those >3 years old, and LCI is raised in those with respiratory disease. Use of LCI did not increase success rate in pre-schoolers.
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http://dx.doi.org/10.1183/13993003.00374-2016DOI Listing
October 2016

Multiple breath washouts in children can be shortened without compromising quality.

Eur Respir J 2015 Dec 9;46(6):1814-6. Epub 2015 Oct 9.

National Heart and Lung Institute, Imperial College London, London, UK Royal Brompton and Harefield NHS Foundation Trust, London, UK

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http://dx.doi.org/10.1183/13993003.00791-2015DOI Listing
December 2015

The reproducibility and responsiveness of the lung clearance index in bronchiectasis.

Eur Respir J 2015 Dec 4;46(6):1645-53. Epub 2015 Sep 4.

Imperial College, London, UK Host Defence Unit, Royal Brompton Hospital, London, UK

Lung clearance index (LCI) is a potential clinical outcome marker in bronchiectasis. Its responsiveness to therapeutic intervention has not been determined. This study evaluates its responsiveness to a session of physiotherapy and intravenous antibiotic treatment of an exacerbation.32 stable and 32 exacerbating bronchiectasis patients and 26 healthy controls were recruited. Patients had LCI and lung function performed before and after physiotherapy on two separate occasions in the stable patients and at the beginning and end of an intravenous antibiotic course in the exacerbating patients.LCI was reproducible between visits in 25 stable patients, with an intraclass correlation of 0.978 (0.948, 0.991; p<0.001). There was no significant difference in LCI (mean±sd) between stable 11.91±3.39 and exacerbating patients 12.76±3.47, but LCI was significantly higher in both bronchiectasis groups compared with healthy controls (7.36±0.99) (p<0.001). Forced expiratory volume in 1 s improved after physiotherapy, as did alveolar volume after intravenous antibiotics, but LCI did not change significantly.LCI is reproducible in stable bronchiectasis but unlike conventional lung function tests, is unresponsive to two short-term interventions and hence is unlikely to be a useful clinical tool for short-term acute assessment in these patients. Further evaluation is required to establish its role in milder disease and in the evaluation of long-term interventions.
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http://dx.doi.org/10.1183/13993003.00152-2015DOI Listing
December 2015

Nitrogen washout measurements of lung clearance index (LCI).

Thorax 2015 Sep 16;70(9):896-7. Epub 2015 Jun 16.

Department of Paediatrics, Royal Brompton and Harefield NHS Foundation Trust, London, UK.

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http://dx.doi.org/10.1136/thoraxjnl-2015-207309DOI Listing
September 2015

Wavering in the breeze: is multiple breath washout useful in primary ciliary dyskinesia?

Thorax 2015 Apr 13;70(4):305-6. Epub 2015 Feb 13.

Royal Brompton Harefield NHS Foundation Trust, London, UK.

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http://dx.doi.org/10.1136/thoraxjnl-2015-206822DOI Listing
April 2015

Lung clearance index in primary ciliary dyskinesia and bronchiectasis.

Am J Respir Crit Care Med 2014 May;189(9):1147-8

1 Royal Brompton and Harefield NHS Foundation Trust London, United Kingdom and.

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http://dx.doi.org/10.1164/rccm.201402-0206LEDOI Listing
May 2014

Lung clearance index and high-resolution computed tomography scores in primary ciliary dyskinesia.

Am J Respir Crit Care Med 2013 Sep;188(5):545-9

Department of Paediatrics, Royal Brompton and Harefield NHS Foundation Trust, London, United Kingdom.

Rationale: Lung clearance index (LCI) is a more sensitive measure of lung function than spirometry in cystic fibrosis (CF) and correlates well with abnormalities in high-resolution computed tomography (HRCT) scanning. We hypothesized LCI would be equally sensitive to lung disease in primary ciliary dyskinesia (PCD).

Objectives: To test the relationships between LCI, spirometry, and HRCT in PCD and to compare them to the established relationships in CF.

Methods: Cross-sectional study of 127 patients with CF and 33 patients with PCD, all of whom had spirometry and LCI, of which a subset of 21 of each had HRCT performed. HRCT was scored for individual features and these features compared with physiological parameters.

Measurements And Main Results: Unlike in CF, and contrary to our hypothesis, there was no correlation between spirometry and LCI in PCD and no correlation between HRCT features and LCI or spirometry in PCD.

Conclusions: We show for the first time that HRCT, spirometry, and LCI have different relationships in different airway diseases and that LCI does not appear to be a sensitive test of airway disease in advanced PCD. We hypothesize that this results from dissimilarities between the components of large and small airway disease in CF and PCD. These differences may in part lead to the different prognosis in these two neutrophilic airway diseases.
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http://dx.doi.org/10.1164/rccm.201304-0800OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827705PMC
September 2013

Increased airway smooth muscle in preschool wheezers who have asthma at school age.

J Allergy Clin Immunol 2013 Apr 12;131(4):1024-32, 1032.e1-16. Epub 2012 Oct 12.

Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, and Leukocyte Biology, National Heart and Lung Institute, Imperial College London, London, United Kingdom.

Background: Increased airway smooth muscle (ASM) is a feature of established asthma in schoolchildren, but nothing is known about ASM in preschool wheezers.

Objective: We sought to determine endobronchial biopsy specimen ASM area fraction in preschool wheezers and its association with asthma at school age.

Methods: ASM area, reticular basement membrane thickness, and mucosal eosinophil and ASM mast cell values were quantified in endobronchial biopsy specimens previously obtained from preschool children undergoing clinically indicated bronchoscopy: severe recurrent wheezers (n=47; median age, 26 months) and nonwheezing control subjects (n=21; median age, 15 months). Children were followed up, and asthma status was established at age 6 to 11 years. Preschool airway pathology was examined in relation to asthma at school age.

Results: Forty-two (62%) of 68 children had 1 or more evaluable biopsy specimens for ASM. At school age, 51 of 68 children were followed up, and 15 (40%) of 37 preschool wheezers had asthma. Children who had asthma and an evaluable biopsy specimen had increased preschool ASM area fraction (n=8; median age, 8.2 years [range, 6-10.4 years]; median ASM, 0.12 [range, 0.08-0.16]) compared with that seen in children without asthma (n=24; median age, 7.3 years [range, 5.9-11 years]; median ASM, 0.07 [range, 0.02-0.23]; P=.007). However, preschool reticular basement membrane thickness and mucosal eosinophil or ASM mast cell values were not different between those who did or did not have asthma at school age.

Conclusion: Increased preschool ASM is associated with those children who have asthma at school age. Thus a focus on early changes in ASM might be important in understanding the subsequent development of childhood asthma.
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http://dx.doi.org/10.1016/j.jaci.2012.08.044DOI Listing
April 2013
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