Lung Function Laboratory Research Articles

Pulmonary hypertension associated with lung disease

Pulmonary hypertension (PH) is amultifactorial pulmonary vascular disease. PH associated with pre-existing lung disease is common and classified as group3 in the clinical classification. Patients with chronic obstructive or interstitial lung disease are most likely to develop PH, with up to 20% of patients showing signs of PH. Distinguishing between the symptoms of the underlying lung disease and concomitant PH can be difficult. Clinical assessment, lung function tests, laboratory tests, and echocardiography can be helpful. The hemodynamic definition of PH has recently been changed. PH associated with lung disease is apre-capillary form by definition. A special sub-stratification in group3 is the differentiation of hemodynamic severity. Severe PH in group3 is defined as apulmonary vascular resistance (PVR) greater than 5Wood units (WU). This pulmonary vascular phenotype is characterized by rather mild to moderate impairment of lung function or lung parenchymal destruction but with severe pulmonary vascular disease or right heart strain. Currently, there are no specific PH medications approved for group3. However, the use of specific PH medications for the pulmonary vascular phenotype is being discussed in studies or on acase-by-case basis, while in patients with aPVR below 5WU treatment focuses on the underlying disease.

Type 2 cytokine genes as allergic asthma risk factors after viral bronchiolitis in early childhood.

Genome-wide association studies of asthma have identified associations with variants in type-2 related genes. Also, specific interactions between genetic variants and viral bronchiolitis in the development of asthma has been suggested. To conduct a gene-based analysis of genetic variants in type 2 cytokine related genes as risk factors for allergic asthma at school age, and further, to study their interaction with specific viral infections in early childhood. A prospectively investigated cohort of children with previous bronchiolitis and controls came for follow-up at school age. The research visit, blinded to viral exposure, included detailed lung function tests, laboratory investigation, and questionnaires. Allergic asthma was defined as typical symptoms plus objective variable airway obstruction, in addition to laboratory verified atopy (elevated eosinophil count or sensitization to an allergen). Targeted and complete sequencing was performed for nine type 2 cytokine candidate genes: IL4, 5, 13, 25, 33 and 37, IL17RB, CRLF2 and TSLP. At follow-up, there were 109 children with genetic data, 91 with a history of bronchiolitis (46% respiratory syncytial virus, 24% human rhinovirus, 15% human metapneumovirus and 14% mixed viral etiology) and 18 without. The median age was 9.4 years (range 6-13) and 41 (38%) had laboratory verified atopy. Twenty-one children (19%) met the definition of allergic asthma. After adjusting for age, sex and five viral categories, IL33 achieved nominal significance (p = 0.017) for a positive association with allergic asthma development. In the gene-virus interaction analysis, the variant set in IL17RB demonstrated a nominally significant positive interaction with human metapneumovirus infection (p=0.05). The results highlight the multifactorial nature of allergic asthma risk, with both viral infection and inherited genetic variants contributing to increasing risk. Results for IL33 and IL17RB were nominally significant and are potential candidate targets for designing therapeutics and early screening, but these results must be replicated in an independent study.

Indicaciones e interpretación de la espirometría y de la prueba de difusión

Spirometry and the measurement of carbon monoxide diffusion capacity are two basic tests in the diagnostic algorithm of most lung diseases given their widespread availability, simplicity, and low cost. They are also important in presurgical evaluations and the evaluation of disability, as well as in the fields of legal and occupational medicine. They are fundamental tests for establishing the prognosis of certain illnesses, such as interstitial lung diseases. They require trained nursing department staff to conduct them and they must be performed in lung function laboratories that meet a series of technical requirements. The current SARS-CoV-2 pandemic has made it necessary for scientific societies to create specific documents and protocols in order to safely conduct these tests.

Thick Mucus in ALS: A Mixed-Method Study on Associated Factors and Its Impact on Quality of Life of Patients and Caregivers.

In this explorative mixed-method pilot study, we set out to have a closer look at the largely under-recognized and under-investigated symptom of thick mucus in patients with ALS and its impact on patients and relatives. Thick mucus is a highly distressing symptom for both patients and caregivers. It complicates the use of non-invasive ventilation and is therefore an important prognostic factor of survival. Methods: In our preliminary study, we used a cross-sectional design, including ten ALS patients with thick mucus who were matched to ten ALS patients without thick mucus. Lung function tests and laboratory and sputum analysis were performed and questionnaires administered in order to determine associated factors of thick mucus accumulation. In a qualitative study using semi-structured interviews, we analysed the impact of thick mucus on patients and caregivers. Results: Reduced respiratory parameters as well as a higher degree of bulbar impairment were associated with the presence of thick mucus. Quality of life of patients and caregivers was strongly impaired by thick mucus accumulation. Conclusions: Thick mucus in patients with ALS has a strong impact on quality of life. Reduced cough flow and severely impaired bulbar function appear to be indicative parameters. We suggest that healthcare providers actively explore the presence of thick mucus in their patients and that it becomes included in commonly used screening tools.

Can static hyperinflation predict exercise capacity in COPD?

IntroductionThe diagnosis and severity assessment of COPD relies on spirometry, and in particular the FEV1. However, it has been proposed that hyperinflation and air-trapping are better predictors of exercise capacity and mortality than the FEV1. Research questionDoes static hyperinflation predict exercise capacity? MethodsWe conducted an observational prospective study. Patients with COPD referred to the lung function laboratory were consecutively recruited. Patients with hyperinflation (the experimental group) were compared to patients without hyperinflation (the control group). The sample sizes were determined assuming an effect size of 0.5 and a power of 0.80. ResultsWe recruited 124 participants, of whom 87% were male, the mean age was 66.1 ± 8.8 years. 67% were symptomatic (GOLD B or D). Airflow limitation was moderate to severe in the majority of patients (median FEV1 47%, IQR 38-65%) and 43% of patients had static hyperinflation. The median 6MWD was 479 meters (404-510) and peak workload in CPET was 64 watts (46-88) with peak VO2 1.12 L/min, 0.89-1.31 L/min. Patients with lower FEV1, DLCO and IC/TLC and higher RV/TLC had reduced exercise capacity in both 6MWT and CPET, measured as lower distance, greater desaturation and ∆Borg dyspnoea, and reduced workload, peak VO2 and peak VE and higher desaturation and ventilatory limitation (VE/MVV). An IC/TLC < 0.33 predicted reduced exercise performance (peak O2 <60%). Dyspnoea assessed by mMRC and QoL measured by CAT and CCQ were also worse in the hyperinflation in COPD patients. ConclusionIn COPD patients, IC/TLC and RV/TLC are valuable predictors of exercise performance in both 6MWT and CPET and PRO.

Early respiratory diagnosis: benefits of enhanced lung function assessment

IntroductionThe National Health Service for England Long Term Plan identifies respiratory disease as one of its priority workstreams. To assist with earlier and more accurate diagnosis of lung disease they...

Reference values of respiratory impedance with impulse oscillometry in healthy Chinese adults.

BackgroundImpulse oscillometry (IO) is a non-invasive pulmonary function test for measuring respiratory impedance. Available reference equations of IO indices for adults are limited. The aim of this study was to develop reference equations of IO indices for Chinese adults.MethodsIn a multicentral, cross-sessional study of IO in Chinese adults, IO data from healthy subjects were collected from 19 general hospitals across China between 2016 and 2018. Oscillometry measurements were conducted in accordance with recommendations of the European Respiratory Society (ERS). Multiple linear regression was performed to develop sex-specific reference equations of IO indices.ResultsIO measurements were performed in 1,318 subjects, of which 567 subjects were defined as healthy individuals with acceptable IO data and were included in the final analysis. Reference equations and limits of normal [lower limit of normal (LLN)/upper limit of normal (ULN)] of IO indices were developed separately for males and females. Height but not age was shown to be the most influential contributor to IO indices. The reference equations currently used in lung function laboratories predicted higher R5 and X5. Normal ranges of R5 and X5 recommended by the equipment manufacturer were clearly different from the ULN/LLN derived from the reference equations.ConclusionsReference equations of IO indices for Chinese adults from a wide region were provided in this study. It is necessary to update new IO reference equations and adopt ULN/LLN as normal ranges of IO indices.Trial RegistrationThis study was registered at www.clinicaltrials.gov as part of a larger study NCT03467880.

Lung function in children: a simple guide to performing and interpreting spirometry

<h2>Abstract</h2> Spirometry is the measurement of the volume and flow of air during expiration and inspiration. It is non-invasive and inexpensive and probably under-used in children. Whilst remaining a relatively simple test, it gives valuable information that can be used in the diagnosis and monitoring of respiratory conditions. Adequate spirometry requires good patient engagement, effort and technique. With practice, robust spirometry data can be collected in preschool children as young as 4 years of age. Increasing availability of portable spirometry equipment means that good quality data can be collected in a variety of clinical locations outside the lung function laboratory - even in the patient's own home. There are, however, a number of important considerations in both the performance and interpretation of spirometry. This review considers the equipment required, the basic techniques required and the essentials of interpretation of spirometry data.

Multiple breath washout quality control in the clinical setting.

Multiple breath washout (MBW) is increasingly used in the clinical assessment of patients with cystic fibrosis (CF). Guidelines for MBW quality control (QC) were developed primarily for retrospective assessment and central overreading. We assessed whether real-time QC of MBW data during the measurement improves test acceptability in the clinical setting. We implemented standardized real-time QC and reporting of MBW data at the time of the measurement in the clinical pediatric lung function laboratory in Bern, Switzerland, in children with CF aged 4-18 years. We assessed MBW test acceptability before (31 tests; 89 trials) and after (32 tests; 96 trials) implementation of real-time QC and compared agreement between reviewers. Further, we assessed the implementation of real-time QC at a secondary center in Zurich, Switzerland. Before the implementation of real-time QC in Bern, only 58% of clinical MBW tests were deemed acceptable following retrospective QC by an experienced reviewer. After the implementation of real-time QC, MBW test acceptability improved to 75% in Bern. In Zurich, after the implementation of real-time QC, test acceptability improved from 38% to 70%. Further, the agreement between MBW operators and an experienced reviewer for test acceptability was 84% in Bern and 93% in Zurich. Real-time QC of MBW data at the time of measurement is feasible in the clinical setting and results in improved test acceptability.

Current recommendations for pulmonary function testing during the COVID-19 pandemic

The article summarizes the experience of leading professional communities in organizing the work of lung function laboratories during the COVID-19 pandemic. Recommendations on the choice of methods, indications for pulmonary function testing and infection control measures aimed at minimizing the risk of cross-infection of medical staff and patients are presented.

ARTP statement on pulmonary function testing 2020

The Association for Respiratory Technology & Physiology (ARTP) last produced a statement on the performance of lung function testing in 1994. At that time the focus was on a practical...

Valores de referencia de la Global Lung Function Iniciative 2012 en un grupo de pacientes pediátricos asmáticos alérgicos

Resumen&#x0D; Propósito En 2012 Quanjer et.al. presentaron las ecuaciones globales de función pulmonar en pacientes entre 3 y 95 años. El objetivo del trabajo es conocer si el comportamiento espirométrico de pacientes con asma alérgico utilizando las tablas del Global Lung Function Iniciative 2012 -GLI son similares a los valores espirométricos de Hsu HK et.al. utilizada en nuestro laboratorio de función pulmonar para el diagnóstico.&#x0D; Material y Método Estudio descriptivo de tipo serie de casos, en pacientes con asma alérgico diagnosticados en el año 2018 y 2019; que cumplieron con los criterios de inclusión.&#x0D; Resultados Tres pacientes dieron valores de puntaje z para el VEF1 por debajo del límite inferior para normalidad y 6 pacientes dieron valores de puntaje z por debajo del límite inferior de la normalidad para la relación del VEF1/CVF. Comparado, con los valores de función pulmonar usados en nuestra unidad, que son los descritos por Hsu KH, et.al los resultaros fueron similares en ambas escalas obteniendo el mismo número de pacientes con patrones de obstrucción. Solo se encontró asociación positiva entre el nivel de la IgE y el valor del VEF1 (p=0.01) y entre el nivel de la IgE y el puntaje z para VEF1 (p=0.03).&#x0D; Conclusiones Los valores predictivos espirométricos de Hsu et.al se comportan similarmente a los de la Global Lung Function Iniciative, por lo que consideramos que cualquier de las dos tablas de valores son aplicables a nuestra población.

When to perform a bronchial challenge with mannitol?

&#x0D; &#x0D; &#x0D; Variable airflow limitation can be diagnosed by spirometry in asthmatic patients or provoked in a lung function laboratory by getting patients to in- hale substances that induce bronchoconstriction, so making it possible to detect and measure the airway hyperresponsiveness (AHR) frequently associated with the diagnosis of asthma [...]&#x0D; &#x0D; &#x0D;

Aligning Lung Function Equipment and Reference Values in Adults

Background: When introducing new equipment or reference equations into the lung function laboratory, systematic z-score deviations could arise due to local differences in population or equipment. Objective: To propose a workable method for aligning reference equations with lung function equipment. Method: Using two cases of equipment transition in our laboratory as a test case, we first performed lung function testing after the transition, on a control group of 40 normal young adults (20 male/20 female; 20–30 years old). For those indices with an average z-score in excess of ±0.5, adapted reference values were obtained by an offset or scaling factor on the M coefficient with the so-called lambda-mu-sigma (LMS) method recommended by the Global Lung Function Initiative, and the z-scores were computed again. Results: Following a transition involving instrumental dead space reduction, the lung clearance index was predictably reduced, resulting in a mean (±SD) z-score of –1.9 (±1.1) in the control group; by adapting the reference values with an offset on M, the z-score became –0.1 (±1.1). Applying the same method to a transition of standard lung function equipment, the z-scores became centered around zero in the control group, but also became properly aligned in a test group of 81 other subjects spanning a wider age range (20–80 years). Conclusions: We proposed and verified a method for aligning local equipment with reference values obtained elsewhere, or following a local change in equipment. The key is to measure a relatively small young adult group, identifying those lung function indices that need adaptation based on z-scores, in order to then obtain laboratory-specific reference values that can be applied over the entire age range.

Observational cross-sectional study on Symptoms Associated to Moisture DAmage at Workplace: the SAMDAW study protocol

IntroductionMoisture damage (MD) exposure at work has been shown to increase the risk of new onset asthma and exacerbation of asthma. However, most of the studies in this field have...

Editorial introductions

Editorial introductions

Substantial variation exists in spirometry interpretation practices for airflow obstruction in accredited lung function laboratories across Australia and New Zealand

Spirometry forms the foundation investigation for the diagnosis and monitoring of common pulmonary conditions. However, potential variation in spirometry interpretation for airflow obstruction may impact subsequent clinical management. To audit spirometry interpretation practices for airflow obstruction in Thoracic Society of Australia and New Zealand accredited laboratories. Thirty-nine accredited complex lung function laboratories were invited to participate in an online survey. The survey enquired about demographics, definition of lower limit of normal range for spirometry parameters, spirometric parameters used for identifying airflow obstruction, spirometric definition of airflow obstruction, definition of significant bronchodilator response and chosen spirometry reference equations. Thirty-six laboratories provided complete responses (response rate, 92%). To define the lower limit of normal, 26 of 36 used the 5th percentile, 7 of 36 used a fixed cut-off and 3 used other. Twenty-nine laboratories utilised forced expiratory volume in 1 s/forced vital capacity (FEV1 /FVC) as the sole parameter to identify airflow obstruction, 3 of 36 used FEV1 /FVC and FEF25-75% , and 4 used other. To define airflow obstruction, 25 of 36 laboratories used FEV1 /FVC < 5th percentile, 9 of 36 used a fixed cut-off (FEV1 /FVC < 0.7, 6/36; FEV1 /FVC < 0.8, 2/36; FEV1 /FVC < 0.75, 1/36) and 2 of 36 used other. Twenty-six laboratories defined a significant bronchodilator response as an increase of at least 200 mL and 12% in FEV1 and/or FVC, 9 of 36 used ≥200 mL and ≥ 12% increase in FEV1 only, and 1 used other criteria. Reference equations utilised for interpretation of spirometry data included: Quanjer 2012 Global Lung Initiative (16/36), the third National Health and Nutritional Examination Survey (8/36), European Community of Coal and Steel (8/36) and other (4/36). Significant heterogeneity in spirometry interpretation for airflow obstruction exists across Australian and New Zealand accredited lung function laboratories. Lack of standardisation may translate into clinically appreciable differences for the diagnosis and management of common respiratory conditions. Ongoing discussion regarding formal standardisation is required.

A Calibration Device to Compare Body Plethysmographs Among Pediatric Lung Function Laboratories.

Multi-center studies in specific airway resistance have shown significant inter laboratory variability. Comparison of plethysmographic equipment using a lung model easily transportable from one site to another should be of help to international normative studies. A resistor made of parallel capillary tubes – insuring adequate linearity within 1 L/sec – was connected to a glass bottle. Thermal time constants were measured while the bottle was empty and while stuffed with steel wool. In the latter, isothermal condition was estimated to occur only at very low frequency (around 0.01 Hz) and gas compression was polytropic up to 0.6 Hz. With the empty analog, adiabatic gas compression was estimated to occur at frequencies ≥0.2 Hz, and more accurate volume estimation was obtained. The empty analog volume and specific resistance measured in a body plethysmograph on different days indicated within 5% accuracy as well as intersession repeatability. It is concluded that a physical analog built out of simple material provides accurate measurements of specific resistance. The apparatus should be of help to compare plethysmographic equipments from different laboratories.

Elevated interleukin-6 and bronchiectasis as risk factors for acute exacerbation in patients with tuberculosis-destroyed lung with airflow limitation.

Patients with tuberculosis-destroyed lungs (TDLs), with airflow limitation, have clinical characteristics similar to those of patients with chronic obstructive pulmonary disease (COPD). Acute exacerbation is an important factor in the management of TDL. Therefore, the aim of this study was to investigate the factors associated with acute exacerbations in patients with stable TDL with airflow limitation. We evaluated the clinical characteristics, such as lung function, image findings, and serum laboratory findings, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin (IL)-6, in patients with TDL with chronic airflow limitation (n=94). We evaluated the correlation of these parameters with acute exacerbation. We found that patients with exacerbation were more likely to have bronchiectasis than those without exacerbation (patients with exacerbation, 66.7%; patients without exacerbation, 30.5%; P=0.001). CRP and IL-6 levels were significantly higher in patients with exacerbation than in those without exacerbation (P=0.001 and P<0.001, respectively). Bronchiectasis [OR, 3.248; 95% confidence interval (CI), 1.063-9.928; P=0.039] and elevated IL-6 levels (OR, 1.128; 95% CI, 1.013-1.257; P=0.028) were the most important parameters associated with acute exacerbation in patients with TDL with airflow limitation. Patients with bronchiectasis and high IL-6 levels may require more intensive treatment to prevent acute exacerbation.

Reference values for respiratory impedance measured by the forced oscillation technique in adult men and women.

The forced oscillation technique (FOT) is a particularly useful test of the mechanical properties of the respiratory system that has an increasingly important role in lung function laboratories. There is general agreement in the literature that thedetermination of reference values is of utmost importance in the clinical use of the FOT. Our aim was to present reference values for whole-breath FOT measurements, establish which anthropometric variables were more predictive of impedance parameters, and provide all the details to adequately adopt these reference equations in individual laboratories. We prospectively evaluated a randomly selected non-smoking sample of the adult Brazilian population (288 subjects, 144 males and 144 females aged 20-86 years). The volunteers were separated by sex and divided into six groups based on decade of age. Sex-specific linear prediction equations were developed by multiple regression analysis using age, body mass and height as explanatory variables. Age introduced a slight, but significant, reduction of resistance in men (P<.001) and women (P < .001). In general, significantly higher values of resistance were observed in females (P < .0001). Among the anthropometric variables analyzed, height was the best predictor for all parameters studied. This study provides an original frame of reference for the FOT in Brazilian males and females aged 20-86 years. Height was the best predictor of respiratory impedance parameters. Details contributing to an adequate adoption of these reference equations elsewhere by transference and verification are also provided.