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Barreto M, Veneroni C, Caiulo M, Evangelisti M, Pompilio PP, Mazzuca MC, Raponi G, Pagani J, Parisi P. Within-breath oscillometry for identifying exercise-induced bronchoconstriction in pediatric patients reporting symptoms with exercise. Front Pediatr 2024; 11:1324413. [PMID: 38274467 PMCID: PMC10808442 DOI: 10.3389/fped.2023.1324413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/27/2023] [Indexed: 01/27/2024] Open
Abstract
Background Evaluating oscillometry parameters separately for the inspiratory and expiratory breath phases and their within-breath differences can help to identify exercise-induced bronchoconstriction (EIB) in pediatric outpatients disclosing exercise-induced symptoms (EIS). Aims To assess the response in impedance parameters following an exercise challenge in patients reporting EIS. Methods Sixty-eight patients reporting EIS (34 asthmatics and 34 suspected of asthma, age mean = 10.8 years, range = 6.0-16.0) underwent an incremental treadmill exercise test. Spirometry was performed at baseline and 1, 5-, 10-, 15-, and 20-min post exercise. Oscillometry was performed at baseline and at 3- and 18-min post exercise. Bronchodilator response to 200 µg albuterol was then assessed. EIB was defined as a forced expiratory volume in 1 s (FEV1) fall ≥10% from baseline. Expiratory and inspiratory resistance (Rrs) and reactance (Xrs), their z-score (Ducharme et al. 2022), and their mean within-breath differences (ΔRrs = Rrsexp-Rrsinsp, ΔXrs = Xrsexp-Xrsinsp) were calculated. Receiver operating characteristic (ROC) curves and their areas (AUCs) were used to evaluate impedance parameters' performances in classifying EIB. Results Asthmatic patients developed EIB more frequently than those suspected of asthma [18/34 (52.9%) vs. 2/34 (5.9%), p < 0.001]. In the 20 subjects with EIB, Rrsinsp, Rrsexp, Xrsinsp, and Xrsexp peaked early (3'), and remained steady except for Xrsinsp, which recovered faster afterward. ΔXrs widened 18 min following the exercise and reversed sharply after bronchodilation (BD) (-1.81 ± 1.60 vs. -0.52 ± 0.80 cmH2O × s/L, p < 0.001). Cutoffs for EIB leading to the highest AUCs were a rise of 0.41 in z-score Rrsinsp (Se: 90.0%, Sp: 66.7%), and a fall of -0.64 in z-score Xrsinsp (Se: 90.0%, Sp: 75.0%). Accepting as having "positive" postexercise oscillometry changes those subjects who had both z-scores beyond respective cutoffs, sensitivity for EIB was 90.0% (18/20) and specificity, 83.3% (40/48). Conclusion Oscillometry parameters and their within-breath differences changed markedly in pediatric patients presenting EIB and were restored after the bronchodilator. Strong agreement between z-scores of inspiratory oscillometry parameters and spirometry supports their clinical utility, though larger studies are required to validate these findings in a broader population.
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Affiliation(s)
- Mario Barreto
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Chiara Veneroni
- Department of Electronics, Information and Bioengineering, Politecnico di Milano University, Milano, Italy
| | - Mariaclaudia Caiulo
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Melania Evangelisti
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | | | - Maria Cristina Mazzuca
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Giorgia Raponi
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Jacopo Pagani
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
| | - Pasquale Parisi
- NESMOS Department, Pediatric Unit Sant’Andrea Hospital, Faculty of Medicine and Psychology, “Sapienza” University, Rome, Italy
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Fouzas S, Kogias C, Gioulvanidou M, Bertzouanis A, Chrysochoou EA, Anthracopoulos MΒ, Tsanakas J, Hatziagorou E. Low-frequency oscillometry indices to assess ventilation inhomogeneity in CF patients. Pediatr Pulmonol 2023; 58:3147-3155. [PMID: 37555768 DOI: 10.1002/ppul.26635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 07/21/2023] [Accepted: 07/29/2023] [Indexed: 08/10/2023]
Abstract
BACKGROUND The utility of the forced oscillations technique (FOT) in cystic fibrosis (CF) remains uncertain. The aim of this study was to explore the ability of lower-frequency FOT indices, alone and after adjustment for the lung volume, to assess the extent of ventilation inhomogeneity in CF patients with varying disease severity. METHODS Forty-five children, adolescents, and adults with CF (age 6.9-27 years) underwent spirometry, FOT, and nitrogen multiple-breath washout (N2-MBW) measurements. The respiratory resistance and reactance at 5 Hz (Rrs5 and Xrs5, respectively) were recorded, and a novel FOT index, the specific respiratory conductance (sGrs), was computed as the reciprocal of Rrs5 divided by the functional residual capacity. RESULTS The sGrs correlated well with the lung clearance index (LCI) (Spearman's r: -.797), whereas the correlation of Rrs5 and Xrs5 with the LCI, albeit significant, was weaker (r: .643 and -.631, respectively). The sGrs emerged as the most robust predictor of LCI regardless of the severity of lung disease, as reflected by patients' age and lung function measurements. Most importantly, the relationship between sGrs and LCI remained unaffected by lung hyperinflation, as opposed to that of the LCI with the spirometric and standard FOT indices. CONCLUSIONS In CF patients, the FOT indices at 5 Hz and the novel, volume-adjusted parameter sGrs, reflect the extent of lung involvement and the underlying ventilation inhomogeneity in a way comparable to N2-MBW. Future research should explore the role of lower-frequency FOT in assessing the severity and monitoring the progression of CF lung disease.
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Affiliation(s)
- Sotirios Fouzas
- Pediatric Respiratory Unit, Pediatric Department, University Hospital of Patras, Patras, Greece
| | - Christos Kogias
- Pediatric Respiratory and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria Gioulvanidou
- Pediatric Respiratory and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Aris Bertzouanis
- Pediatric Respiratory Unit, Pediatric Department, University Hospital of Patras, Patras, Greece
| | - Elisavet-Anna Chrysochoou
- Pediatric Respiratory and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - John Tsanakas
- Pediatric Respiratory and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Elpis Hatziagorou
- Pediatric Respiratory and Cystic Fibrosis Unit, 3rd Paediatric Department, Aristotle University of Thessaloniki, Thessaloniki, Greece
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3
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Savant AP, McColley SA. Cystic fibrosis year in review 2019: Section 2 pulmonary disease and infections. Pediatr Pulmonol 2023; 58:672-682. [PMID: 32970381 DOI: 10.1002/ppul.25091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/19/2020] [Accepted: 09/21/2020] [Indexed: 11/07/2022]
Abstract
During the year 2019, research and case reports or series in the field of cystic fibrosis (CF) were in abundance. To adequately address the large body of CF research published during 2019, the CF year in review will be divided into three sections. This report is the second section, focusing specifically on new research related to pulmonary disease and infections. Additional sections will concentrate on CF transmembrane conductance regulator modulators and the multisystem effects of CF. It is an exciting time to be providing care for patients and their families with CF with all the exciting new discoveries that will be shared in these reviews.
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Affiliation(s)
- Adrienne P Savant
- Department of Pediatrics, Children's Hospital of New Orleans, New Orleans, Louisiana, USA.,Department of Pediatrics, Tulane University, New Orleans, Louisiana, USA
| | - Susanna A McColley
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.,Department of Clinical and Translational Research, Stanley Manne Children's Research Institute, Chicago, Illinois, USA.,Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
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4
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Kaminsky DA, Simpson SJ, Berger KI, Calverley P, de Melo PL, Dandurand R, Dellacà RL, Farah CS, Farré R, Hall GL, Ioan I, Irvin CG, Kaczka DW, King GG, Kurosawa H, Lombardi E, Maksym GN, Marchal F, Oostveen E, Oppenheimer BW, Robinson PD, van den Berge M, Thamrin C. Clinical significance and applications of oscillometry. Eur Respir Rev 2022; 31:31/163/210208. [PMID: 35140105 PMCID: PMC9488764 DOI: 10.1183/16000617.0208-2021] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/29/2021] [Indexed: 12/28/2022] Open
Abstract
Recently, “Technical standards for respiratory oscillometry” was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunction and the effects of environmental exposures. However, despite great promise as a useful clinical tool, we identify a number of areas in which more evidence of clinical utility is needed before oscillometry becomes routinely used for diagnosing or monitoring respiratory disease. This paper provides a current review of the interpretation, clinical significance and application of oscillometry in respiratory medicine, with special emphasis on limitations of evidence and suggestions for future research.https://bit.ly/3GQPViA
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Affiliation(s)
- David A Kaminsky
- Dept of Medicine, Pulmonary and Critical Care Medicine, University of Vermont, Larner College of Medicine, Burlington, VT, USA.,These authors have contributed equally to this manuscript
| | - Shannon J Simpson
- Children's Lung Health, Telethon Kids Institute, School of Allied Health, Curtin University, Perth, Australia.,These authors have contributed equally to this manuscript
| | - Kenneth I Berger
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Peter Calverley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - Pedro L de Melo
- Dept of Physiology, Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ronald Dandurand
- Lakeshore General Hospital, Pointe-Claire, QC, Canada.,Montreal Chest Institute, Meakins-Christie Labs, Oscillometry Unit of the Centre for Innovative Medicine, McGill University Health Centre and Research Institute, and McGill University, Montreal, QC, Canada
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria - DEIB, Politecnico di Milano University, Milan, Italy
| | - Claude S Farah
- Dept of Respiratory Medicine, Concord Repatriation General Hospital, Sydney, Australia
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain.,CIBER de Enfermedades Respiratorias, Madrid, Spain
| | - Graham L Hall
- Children's Lung Health, Telethon Kids Institute, School of Allied Health, Curtin University, Perth, Australia
| | - Iulia Ioan
- Dept of Paediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Charles G Irvin
- Dept of Medicine, Pulmonary and Critical Care Medicine, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - David W Kaczka
- Depts of Anaesthesia, Biomedical Engineering and Radiology, University of Iowa, Iowa City, IA, USA
| | - Gregory G King
- Dept of Respiratory Medicine and Airway Physiology and Imaging Group, Royal North Shore Hospital, St Leonards, Australia.,Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
| | - Hajime Kurosawa
- Dept of Occupational Health, Tohoku University School of Medicine, Sendai, Japan
| | - Enrico Lombardi
- Paediatric Pulmonary Unit, Meyer Paediatric University Hospital, Florence, Italy
| | - Geoffrey N Maksym
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - François Marchal
- Dept of Paediatric Lung Function Testing, Children's Hospital, Vandoeuvre-lès-Nancy, France.,EA 3450 DevAH - Laboratory of Physiology, Faculty of Medicine, University of Lorraine, Vandoeuvre-lès-Nancy, France
| | - Ellie Oostveen
- Dept of Respiratory Medicine, Antwerp University Hospital and University of Antwerp, Belgium
| | - Beno W Oppenheimer
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine and André Cournand Pulmonary Physiology Laboratory, Belleuve Hospital, New York, NY, USA
| | - Paul D Robinson
- Woolcock Institute of Medical Research, Children's Hospital at Westmead, Sydney, Australia
| | - Maarten van den Berge
- Dept of Pulmonary Diseases, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, The University of Sydney, Sydney, Australia
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Bokov P, Gerardin M, Le Clainche L, Houdouin V, Delclaux C. Impulse oscillometry indices to detect an abnormal lung clearance index in childhood cystic fibrosis. Pediatr Pulmonol 2021; 56:3752-3757. [PMID: 34449977 DOI: 10.1002/ppul.25649] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/28/2021] [Accepted: 08/25/2021] [Indexed: 11/08/2022]
Abstract
The objective of our cross-sectional study was to assess the relationships between indices of multiple breath washout (MBW) and impulse oscillometry system (IOS) in cystic fibrosis in forty consecutive children (median age 8.1 years) in stable conditions and to evaluate whether cut-off values of IOS indices may help to avoid MBW, which is time-consuming. IOS measurements took a median duration of 3 min, while MBW measurements took a median duration of 49 min. Lung Clearance Index (LCI2.5% ) depicted significant linear correlations with z-scores of R5Hz, R5-20Hz, X5Hz, AX, and Fres (r2 = 0.27 to 0.51). Receiver-operator characteristic curves were constructed and showed that the best compromise was obtained with the z-score of Fres, with a cut-off value of -1.37 that had a sensitivity of 0.966, a specificity of 0.636, and a negative predictive value of 0.875. This z-score is useful for excluding increased LCI2.5% when below -1.37 using the reference set of Gochicoa et al. In conclusion, IOS measurement is easily and rapidly obtained in children and may be clinically useful for excluding increased LCI2.5% , thus allowing the time-consuming MBW test to be avoided.
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Affiliation(s)
- Plamen Bokov
- Université de Paris, AP-HP, Hôpital Robert Debré, Service de Physiologie Pédiatrique-Centre du Sommeil, INSERM NeuroDiderot, Paris, France
| | - Michele Gerardin
- AP-HP, Hôpital Robert Debré, Service de Pneumopédiatrie, Centre de Ressources et de Compétences de la Mucoviscidose, Paris, France
| | - Laurence Le Clainche
- AP-HP, Hôpital Robert Debré, Service de Pneumopédiatrie, Centre de Ressources et de Compétences de la Mucoviscidose, Paris, France
| | - Véronique Houdouin
- AP-HP, Hôpital Robert Debré, Service de Pneumopédiatrie, Centre de Ressources et de Compétences de la Mucoviscidose, INSERM UMR S 976, Paris, France
| | - Christophe Delclaux
- Université de Paris, AP-HP, Hôpital Robert Debré, Service de Physiologie Pédiatrique-Centre du Sommeil, INSERM NeuroDiderot, Paris, France
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6
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Forced Oscillation Technique for Monitoring the Respiratory Status of Children with Cystic Fibrosis: A Systematic Review. CHILDREN-BASEL 2021; 8:children8100857. [PMID: 34682122 PMCID: PMC8534643 DOI: 10.3390/children8100857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/13/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022]
Abstract
Spirometry is considered the gold standard method for monitoring lung function of patients with cystic fibrosis (CF) but it requires patients’ cooperation and therefore it is not useful for the majority of preschool-aged children. Oscillometry is an alternative modality for lung function monitoring that requires minimal cooperation and can be applied in children as young as 3 years of age. Furthermore, it generates lesser aerosol compared to spirometry, an issue that is of considerable importance in the COVID-19 era. The aim of this review was to present the existing clinical data regarding the application of oscillometry in children and adolescents with CF. The method seems to have acceptable feasibility and repeatability. However, there is conflicting data regarding the correlation of oscillometry values with the clinical symptoms of CF patients either in clinically stable or in exacerbation periods. Furthermore, it is not clear to what extent oscillometry measurements correlate with the spirometry indices. Based on current evidence, spirometry cannot be substituted by oscillometry in the monitoring of the respiratory status of children and adolescents with CF.
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8
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Lundblad LKA, Robichaud A. Oscillometry of the respiratory system: a translational opportunity not to be missed. Am J Physiol Lung Cell Mol Physiol 2021; 320:L1038-L1056. [PMID: 33822645 PMCID: PMC8203417 DOI: 10.1152/ajplung.00222.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Airway oscillometry has become the de facto standard for quality assessment of lung physiology in laboratory animals and has demonstrated its usefulness in understanding diseases of small airways. Nowadays, it is seeing extensive use in daily clinical practice and research; however, a question that remains unanswered is how well physiological findings in animals and humans correlate? Methodological and device differences are obvious between animal and human studies. However, all devices deliver an oscillated airflow test signal and output respiratory impedance. In addition, despite analysis differences, there are ways to interpret animal and human oscillometry data to allow suitable comparisons. The potential with oscillometry is its ability to reveal universal features of the respiratory system across species, making translational extrapolation likely to be predictive. This means that oscillometry can thus help determine if an animal model displays the same physiological characteristics as the human disease. Perhaps more importantly, it can also be useful to determine whether an intervention is effective as well as to understand if it affects the desired region of the respiratory system, e.g., the periphery of the lung. Finally, findings in humans can also inform preclinical scientists and give indications as to what type of physiological changes should be observed in animal models to make them relevant as models of human disease. The present article will attempt to demonstrate the potential of oscillometry in respiratory research, an area where the development of novel therapies is plagued with a failure rate higher than in other disease areas.
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Affiliation(s)
- Lennart K A Lundblad
- Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.,THORASYS Thoracic Medical Systems Inc., Montreal, Quebec, Canada
| | - Annette Robichaud
- SCIREQ Scientific Respiratory Equipment Inc., Montreal, Quebec, Canada
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9
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Rhoads E, Wall BL, Ren CL. Pediatric pulmonology year in review 2019: Physiology. Pediatr Pulmonol 2020; 55:2848-2852. [PMID: 32729952 DOI: 10.1002/ppul.24995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/02/2020] [Accepted: 07/05/2020] [Indexed: 11/07/2022]
Abstract
Pulmonary physiologic assessments are critical for the care and study of pediatric respiratory disease. In 2019, there were numerous contributions to this topic in Pediatric Pulmonology.
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Affiliation(s)
- Eli Rhoads
- Division of Pediatric Pulmonology, Allergy, and Sleep Medicine, Indiana University School of Medicine, Indianapolis, Indiana.,Riley Hospital for Children, Indianapolis, Indiana
| | - Brittany L Wall
- Division of Pediatric Pulmonology, Allergy, and Sleep Medicine, Indiana University School of Medicine, Indianapolis, Indiana.,Riley Hospital for Children, Indianapolis, Indiana
| | - Clement L Ren
- Division of Pediatric Pulmonology, Allergy, and Sleep Medicine, Indiana University School of Medicine, Indianapolis, Indiana.,Riley Hospital for Children, Indianapolis, Indiana
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10
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Correlation of Arterial CO 2 and Respiratory Impedance Values among Subjects with COPD. J Clin Med 2020; 9:jcm9092819. [PMID: 32878165 PMCID: PMC7564107 DOI: 10.3390/jcm9092819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/15/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a respiratory illness characterized by airflow limitation and chronic respiratory symptoms with a global prevalence estimated to be more than 10% in 2010 and still on the rise. Furthermore, hypercapnic subject COPD leads to an increased risk of mortality, morbidity, and poor QoL (quality of life) than normocapnic subjects. Series of studies showed the usefulness of the forced oscillation technique (FOT) to measure small airway closure. Traditional findings suggested that hypercapnia may not be the main treating targets, but recent findings suggested that blood stream CO2 may lead to a worse outcome. This study aimed to seek the relationship between CO2 and small airway closure by using FOT. Subjects with COPD (n = 124; hypercapnia 22 and normocapnia 102) were analyzed for all pulmonary function values, FOT values, and arterial blood gas analysis. Student’s t-test, Spearman rank correlation, and multi linear regression analysis were used to analyze the data. COPD subjects with hypercapnia showed a significant increase in R5, R20, Fres, and ALX values, and a greater decrease in X5 value than normocapnic patients. Also, multiple linear regression analysis showed R5 was associated with hypercapnia. Hypercapnia may account for airway closure among subjects with COPD and this result suggests treating hypercapnia may lead to better outcomes for such a subject group.
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