Pinelopi Anagnostopoulou1,2,3, Philipp Latzin1, Renee Jensen4, Mirjam Stahl5,6, Alana Harper7, Sophie Yammine1, Jakob Usemann1,8, Rachel E Foong7,9, Ben Spycher10, Graham L Hall7,9, Florian Singer1, Sanja Stanojevic4, Marcus A Mall5,6,11,12, Felix Ratjen13,14, Kathryn A Ramsey1,7,14. 1. Division of Respiratory Medicine, Dept of Pediatrics, Inselspital, University of Bern, Bern, Switzerland. 2. Insitute of Anatomy, University of Bern, Bern, Switzerland. 3. Medical School, University of Cyprus, Nicosia, Cyprus (current affiliation). 4. Division of Respiratory Medicine, The Hospital for Sick Children and Translational Medicine, SickKids Research Institute, University of Toronto, Toronto, ON, Canada. 5. Dept of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany. 6. Division of Pediatric Pulmonology and Allergy and Cystic Fibrosis Center, Dept of Pediatrics, University of Heidelberg, Heidelberg, Germany. 7. Telethon Kids Institute, Perth, Australia. 8. University of Basel Children's Hospital (UKBB), Basel, Switzerland. 9. School of Physiotherapy and Exercise Science, Curtin University, Perth, Australia. 10. Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland. 11. Dept of Pediatric Pulmonology, Immunology and Intensive Care Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany. 12. Berlin Institute of Health (BIH), Berlin, Germany. 13. Division of Respiratory Medicine, Dept of Pediatrics, Inselspital, University of Bern, Bern, Switzerland felix.ratjen@sickkids.ca. 14. F. Ratjen and K.A. Ramsey contributed equally as last authors.
Abstract
BACKGROUND: The multiple breath nitrogen washout (N2MBW) technique is increasingly used to assess the degree of ventilation inhomogeneity in school-aged children with lung disease. However, reference values for healthy children are currently not available. The aim of this study was to generate reference values for N2MBW outcomes in a cohort of healthy Caucasian school-aged children. METHODS: N2MBW data from healthy Caucasian school-age children between 6 and 18 years old were collected from four experienced centres. Measurements were performed using an ultrasonic flowmeter (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and were analysed with commercial software (Spiroware version 3.2.1, Eco Medics AG). Normative values and upper limits of normal (ULN) were generated for lung clearance index (LCI) at 2.5% (LCI2.5%) and at 5% (LCI5%) of the initial nitrogen concentration and for moment ratios (M1/M0 and M2/M0). A prediction equation was generated for functional residual capacity (FRC). RESULTS: Analysis used 485 trials from 180 healthy Caucasian children aged from 6 to 18 years old. While LCI increased with age, this increase was negligible (0.04 units·year-1 for LCI2.5%) and therefore fixed ULN were defined for this age group. These limits were 7.91 for LCI2.5%, 5.73 for LCI5%, 1.75 for M1/M0 and 6.15 for M2/M0, respectively. Height and weight were found to be independent predictors of FRC. CONCLUSION: We report reference values for N2MBW outcomes measured on a commercially available ultrasonic flowmeter device (Exhalyzer D, Eco Medics AG) in healthy school-aged children to allow accurate interpretation of ventilation distribution outcomes and FRC in children with lung disease.
BACKGROUND: The multiple breath nitrogen washout (N2MBW) technique is increasingly used to assess the degree of ventilation inhomogeneity in school-aged children with lung disease. However, reference values for healthy children are currently not available. The aim of this study was to generate reference values for N2MBW outcomes in a cohort of healthy Caucasian school-aged children. METHODS: N2MBW data from healthy Caucasian school-age children between 6 and 18 years old were collected from four experienced centres. Measurements were performed using an ultrasonic flowmeter (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) and were analysed with commercial software (Spiroware version 3.2.1, Eco Medics AG). Normative values and upper limits of normal (ULN) were generated for lung clearance index (LCI) at 2.5% (LCI2.5%) and at 5% (LCI5%) of the initial nitrogen concentration and for moment ratios (M1/M0 and M2/M0). A prediction equation was generated for functional residual capacity (FRC). RESULTS: Analysis used 485 trials from 180 healthy Caucasian children aged from 6 to 18 years old. While LCI increased with age, this increase was negligible (0.04 units·year-1 for LCI2.5%) and therefore fixed ULN were defined for this age group. These limits were 7.91 for LCI2.5%, 5.73 for LCI5%, 1.75 for M1/M0 and 6.15 for M2/M0, respectively. Height and weight were found to be independent predictors of FRC. CONCLUSION: We report reference values for N2MBW outcomes measured on a commercially available ultrasonic flowmeter device (Exhalyzer D, Eco Medics AG) in healthy school-aged children to allow accurate interpretation of ventilation distribution outcomes and FRC in children with lung disease.
Authors: Katherine O'Neill; Gokul R Lakshmipathy; Curtis Neely; Denise Cosgrove; Kathryn Ferguson; Rebecca McLeese; Adam T Hill; Michael R Loebinger; Mary Carroll; James D Chalmers; Timothy Gatheral; Chris Johnson; Anthony De Soyza; John R Hurst; Ian Bradbury; Joseph S Elborn; Judy M Bradley Journal: Ann Am Thorac Soc Date: 2022-09
Authors: Matthew M Willmering; David J Roach; Elizabeth L Kramer; Laura L Walkup; Zackary I Cleveland; Jason C Woods Journal: J Cyst Fibros Date: 2020-12-04 Impact factor: 5.482
Authors: Liv Andrés-Jensen; Mette Tiedemann Skipper; Kristian Mielke Christensen; Pia Hedegaard Johnsen; Katrine Aagaard Myhr; Martin Kaj Fridh; Kathrine Grell; A M L Pedersen; Sune Leisgaard Mørck Rubak; Martin Ballegaard; Arne Hørlyck; Rikke Beck Jensen; Trine-Lise Lambine; Kim Gjerum Nielsen; Ruta Tuckuviene; Peder Skov Wehner; Birgitte Klug Albertsen; Kjeld Schmiegelow; Thomas Leth Frandsen Journal: BMJ Open Date: 2021-02-09 Impact factor: 2.692