Normal Lung Function and Mortality in World Trade Center Responders and National Health and Nutrition Examination Survey III Participants.

Rationale: Low FEV1 is a biomarker of increased mortality. The association of normal lung function and mortality is not well described. Objectives: To evaluate the FEV1-mortality association among participants with normal lung function. Methods: A total of 10,999 Fire Department of the City of New York (FDNY) responders and 10,901 Third National Health and Nutrition Examination Survey (NHANES III) participants, aged 18-65 years with FEV1 ⩾80% predicted, were analyzed, with FEV1 percent predicted calculated using Global Lung Function Initiative Global race-neutral reference equations. Mortality data were obtained from linkages to the National Death Index. Cox proportional hazards models estimated the association between FEV1 and all-cause mortality, controlling for age, sex, race/ethnicity, smoking history, and, for FDNY, work assignment. Cohorts were followed for a maximum of 20.3 years. Measurements and Main Results: We observed 504 deaths (4.6%) of 10,999 for FDNY and 1,237 deaths (9.4% [weighted]) of 10,901 for NHANES III. Relative to FEV1 ⩾120% predicted, mortality was significantly higher for FEV1 100-109%, 90-99%, and 80-89% predicted in the FDNY cohort. In the NHANES III cohort, mortality was significantly higher for FEV1 90-99% and 80-89% predicted. Each 10% higher predicted FEV1 was associated with 15% (hazard ratio, 0.85; 95% confidence interval, 0.80-0.91) and 23% (hazard ratio, 0.77; 95% confidence interval, 0.71-0.84) lower mortality for FDNY and NHANES III, respectively. Conclusions: In both cohorts, higher FEV1 is associated with lower mortality, suggesting higher FEV1 is a biomarker of better health. These findings demonstrate that a single cross-sectional measurement of FEV1 is predictive of mortality over two decades, even when FEV1 is in the normal range.

A prospective, open-label, randomized clinical trial to evaluate the efficacy and safety of remimazolam in patients undergoing EBUS-TBNA: REST trial design.

BACKGROUND: Remimazolam is safe and effective for moderate sedation during flexible bronchoscopy, but its safety and efficacy during endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) remains undetermined. The REST trial (NCT06275594) will be a prospective randomized study of remimazolam in patients undergoing EBUS-TBNA with conscious sedation. The primary aim is to evaluate whether remimazolam is safe and effective for moderate sedation during EBUS-TBNA compared to real-world midazolam and on-label midazolam. METHODS: The REST trial will recruit 330 patients from four university hospitals with mediastinal lesions suspected of being lung cancer who are eligible for EBUS-TBNA under moderate sedation. The participants will be randomized into groups using remimazolam, real-world midazolam, and on-label midazolam (US prescribing information dosage) to perform EBUS-TBNA for procedural sedation. The primary endpoint will be procedural success using composite measures. DISCUSSION: The REST trial will prospectively evaluate the efficacy and safety of remimazolam during EBUS-TBNA under moderate sedation. It will provide information for optimizing sedation modalities and contribute to practical benefits in patients undergoing EBUS-TBNA. TRIAL REGISTRATION: ClinicalTrials.gov (NCT06275594). Prospectively registered on 15 February 2024.

Telemedicine and Resource Utilization in Pulmonary Clinic.

BACKGROUND: Telemedicine use increased with the Covid-19 pandemic. The impact of telemedicine on resource use in pulmonary clinics is unknown. METHODS: This retrospective cohort study identified adults with pulmonary clinic visits at the University of Miami Hospital and Clinics (January 2018-December 2021). The primary exposure was telemedicine versus in-person visits. Standard statistics were used to describe the cohort and compare patients stratified by visit type. Multivariable logistic regression models evaluated the association of telemedicine with resource use (primarily, computed tomography [CT] orders placed within 7 days of visit). RESULTS: 21,744 clinic visits were included: 5,480 (25.2%) telemedicine and 16,264 (74.8%) in-person. In both, the majority were < 65-years-old, female, and identified as Hispanic white. Patients seen with telemedicine had increased odds of having CT scans ordered within 7 days (adjusted odds ratio [aOR] 1.34, [95% confidence interval 1.04-1.74]); and decreased odds of chest x-rays (aOR 0.37 [0.23-0.57]). Telemedicine increased odds of contact of any kind with our healthcare system within 30-days (aOR 1.56 [1.29-1.88]) and 90-days (aOR 1.39 [1.17-1.64]). Specifically, telemedicine visits had decreased odds of emergency department visits and hospitalizations (30 days: aOR 0.54 [0.38-0.76]; 90 days: aOR 0.68 [0.52-0.89]), but increased odds of phone calls and electronic health record inbox messages (30 days: aOR 3.44 [2.73-4.35]; 90 days: aOR 3.58 [2.95-4.35]). CONCLUSIONS: Telemedicine was associated with an increased odds of chest CT order with a concomitant decreased odds of chest x-ray order. Increased contact with the healthcare system with telemedicine may represent a larger time burden for outpatient clinicians.

Stressors, emotions, and social support systems among respiratory nurses during the Omicron outbreak in China: a qualitative study.

BACKGROUND: Respiratory nurses faced tremendous challenges when the Omicron variant spread rapidly in China from late 2022 to early 2023. An in-depth understanding of respiratory nurses' experiences during challenging times can help to develop better management and support strategies. The present study was conducted to explore and describe the work experiences of nurses working in the Department of Pulmonary and Critical Care Medicine (PCCM) during the Omicron outbreak in China. METHODS: This study utilized a descriptive phenomenological method. Between January 9 and 22, 2023, semistructured and individual in-depth interviews were conducted with 11 respiratory nurses at a tertiary hospital in Wuhan, Hubei Province. A purposive sampling method was used to select the participants, and the sample size was determined based on data saturation. The data analysis was carried out using Colaizzi's method. RESULTS: Three themes with ten subthemes emerged: (a) multiple stressors (intense workload due to high variability in COVID patients; worry about not having enough ability and energy to care for critically ill patients; fighting for anxious clients, colleagues, and selves); (b) mixed emotions (feelings of loss and responsibility; feelings of frustration and achievement; feelings of nervousness and security); and (c) a perceived social support system (team cohesion; family support; head nurse leadership; and the impact of social media). CONCLUSION: Nursing managers should be attentive to frontline nurses' needs and occupational stress during novel coronavirus disease 2019 (COVID-19) outbreaks. Management should strengthen psychological and social support systems, optimize nursing leadership styles, and proactively consider the application of artificial intelligence (AI) technologies and products in clinical care to improve the ability of nurses to effectively respond to future public health crises.

Molecular Accounting and Profiling of Human Respiratory Microbial Communities: Toward Precision Medicine by Targeting the Respiratory Microbiome for Disease Diagnosis and Treatment.

The wide diversity of microbiota at the genera and species levels across sites and individuals is related to various causes and the observed differences between individuals. Efforts are underway to further understand and characterize the human-associated microbiota and its microbiome. Using 16S rDNA as a genetic marker for bacterial identification improved the detection and profiling of qualitative and quantitative changes within a bacterial population. In this light, this review provides a comprehensive overview of the basic concepts and clinical applications of the respiratory microbiome, alongside an in-depth explanation of the molecular targets and the potential relationship between the respiratory microbiome and respiratory disease pathogenesis. The paucity of robust evidence supporting the correlation between the respiratory microbiome and disease pathogenesis is currently the main challenge for not considering the microbiome as a novel druggable target for therapeutic intervention. Therefore, further studies are needed, especially prospective studies, to identify other drivers of microbiome diversity and to better understand the changes in the lung microbiome along with the potential association with disease and medications. Thus, finding a therapeutic target and unfolding its clinical significance would be crucial.

Levels and predictors of patient satisfaction during flexible bronchoscopy procedures.

Background: Flexible bronchoscopy (FB) is a safe and commonly performed procedure in pulmonary medicine. Bronchoscopy literature mainly focusing on technical aspects. However, data on patients satisfaction and bronchoscopy is rare. Aim: To evaluate levels and factors affecting patient satisfaction with flexible bronchoscopy (FB). Subjects and Methods: This prospective study, conducted between June 2017 and May 2019 at King Abdulaziz University Hospital (Jeddah, Saudi Arabia), included all consecutive diagnostic bronchoscopies for adult patients. Patient willingness to return for another bronchoscopy (definitely not, probably not, unsure, probably would, or definitely would) was used as the indicator of satisfaction. Patients ranked their experiences with doctors, nurses, and process of care using a 5-choice scale (poor, fair, good, very good, or excellent). Results: A total of 351 patients participated in this study. Overall, patients were highly satisfied with their doctors, nurses, and process of care. However, only 34.1% of patients indicated that they would return for another FB if necessary. Predictors of return for FB were younger age (<65 years), university education, use of midazolam and higher doses of fentanyl >100 mcg, and inpatient setting. Logistic regression demonstrated that younger age (P = 0.005) and inpatient setting (P = 0.02) were significantly linked to willingness to return for bronchoscopy. Conclusions: Patient satisfaction with bronchoscopy was lower in our study compared to other studies, despite high ratings of doctors' and nurses' skills. Elderly patients and patients with outpatient bronchoscopies were less likely to return and should therefore be approached with extra care. Physicians can improve FB-related patient experiences by decreasing discomfort during bronchoscope insertion and by improving topical anesthesia.

Imaging in neonatal respiratory disease.

The purpose of this review is to describe the current state of the art in clinical imaging for NICU patients, divided into major areas that correspond to likely phenotypes of neonatal respiratory disease: airway abnormalities, parenchymal disease, and pulmonary vascular disease. All common imaging modalities (ultrasound, X-ray, CT, and MRI) are discussed, with an emphasis on modalities that are most relevant to the individual underlying aspects of disease. Some promising aspects of dynamic and functional imaging are included, where there may be future clinical applicability.

Crossover Patient Outcomes for Targeted Lung Denervation in Moderate to Severe Chronic Obstructive Pulmonary Disease: AIRFLOW-2.

BACKGROUND: Targeted Lung Denervation (TLD) is a potential new therapy for COPD. Radiofrequency energy is bronchoscopically delivered to the airways to disrupt pulmonary parasympathetic nerves, to reduce bronchoconstriction, mucus hypersecretion, and bronchial hyperreactivity. OBJECTIVES: This work assesses the effect of TLD on COPD exacerbations (AECOPD) in crossover subjects in the AIRFLOW-2 trial. METHOD: The AIRFLOW-2 trial is a multicentre, randomized, double-blind, sham-controlled crossover trial of TLD in COPD. Patients with symptomatic COPD on optimal medical therapy with an FEV1 of 30-60% predicted received either TLD or sham bronchoscopy in a 1:1 randomization. Those in the sham arm had the opportunity to cross into the treatment arm after 12 months. The primary end point was rate of respiratory adverse events. Secondary end points included adverse events, changes in lung function and health-related quality of life and symptom scores. RESULTS: Twenty patients were treated with TLD in the crossover phase and were subsequently followed up for 12 months (50% female, mean age 64.1 ± 6.9 years). After TLD, there was a trend towards a reduction in time to first AECOPD (hazard ratio 0.65, p = 0.28, not statistically significant) in comparison to sham follow-up period. There was also a reduction in time to first severe AECOPD in the crossover period (hazard ratio 0.38, p = 0.227, not statistically significant). Symptom scores and lung function showed stability. CONCLUSIONS: AIRFLOW-2 crossover data support that of the randomization phase, showing trends towards reduction in COPD exacerbations with TLD.

Evaluation of the synergistic impact of needle and forceps biopsy with electromagnetic navigation bronchoscopy: the CONFIDENT-ENB trial design.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) is an emerging advanced imaging-guided bronchoscopy technique for diagnosing peripheral lung lesions. However, the selection strategy for the optimal biopsy device and whether adopting a multi-tool strategy increases the diagnostic yield remains undetermined. The CONFIDENT-ENB trial (NCT05110131) is a prospective randomized study on ENB, performed in a least-invasive setting. The primary aim is to evaluate whether a combination of needle aspiration and forceps biopsy improves the diagnostic performance, and assess the comparative diagnostic value and discordance of the two devices. METHODS: The trial will recruit 142 participants with lung lesions suspected of malignancy who are eligible for an elective ENB procedure under moderate sedation. Participants will undergo ENB-guided needle aspiration and forceps biopsy in a randomized order without the use of any complementary techniques. All participants will be followed up subsequently for up to 12 months to conclude the final diagnosis of the biopsied lesions. Primary outcomes include the diagnostic yield and sensitivity of each biopsy modality and the diagnostic yield of the combined modalities. DISCUSSION: The CONFIDENT-ENB trial will prospectively evaluate the synergistic effectiveness and comparative accuracy of ENB-guided needle aspiration and forceps biopsy in a least-invasive setting. The results are expected to improve our understanding of the optimal tool-selection strategy for ENB. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05110131). Prospectively registered on 5 November 2021.

Prolonged mechanical ventilation after cardiac surgery: substudy of the Transfusion Requirements in Cardiac Surgery III trial.

PURPOSE: Prolonged mechanical ventilation (MV) is a major complication following cardiac surgery. We conducted a secondary analysis of the Transfusion Requirements in Cardiac Surgery (TRICTS) III trial to describe MV duration, identify factors associated with prolonged MV, and examine associations of prolonged MV with mortality and complications. METHODS: Four thousand, eight hundred and nine participants undergoing cardiac surgery at 71 hospitals worldwide were included. Prolonged MV was defined based on the Society of Thoracic Surgeons definition as MV lasting 24 hr or longer. Adjusted associations of patient and surgical factors with prolonged MV were examined using multivariable logistic regression. Associations of prolonged MV with complications were assessed using odds ratios, and adjusted associations between prolonged MV and mortality were evaluated using multinomial regression. Associations of shorter durations of MV with survival and complications were explored. RESULTS: Prolonged MV occurred in 15% (725/4,809) of participants. Prolonged MV was associated with surgical factors indicative of complexity, such as previous cardiac surgery, cardiopulmonary bypass duration, and separation attempts; and patient factors such as critical preoperative state, left ventricular impairment, renal failure, and pulmonary hypertension. Prolonged MV was associated with perioperative but not long-term complications. After risk adjustment, prolonged MV was associated with perioperative mortality; its association with long-term mortality among survivors was weaker. Shorter durations of MV were not associated with increased risk of mortality or complications. CONCLUSION: In this substudy of the TRICS III trial, prolonged MV was common after cardiac surgery and was associated with patient and surgical risk factors. Although prolonged MV showed strong associations with perioperative complications and mortality, it was not associated with long-term complications and had weaker association with long-term mortality among survivors. STUDY REGISTRATION: www. CLINICALTRIALS: gov (NCT02042898); registered 23 January 2014. This is a substudy of the Transfusion Requirements in Cardiac Surgery (TRICS) III trial.

RéSUMé: OBJET: La ventilation mécanique (VM) prolongée est une complication majeure après chirurgie cardiaque. Nous avons effectué une analyze secondaire de l'étude TRICS III sur les besoins de transfusion au cours de la chirurgie cardiaque pour décrire la durée de la VM, identifier les facteurs associés à une VM prolongée et examiner les associations de la VM prolongée avec la mortalité et les complications. MéTHODES: Quatre mille huit cent neuf participants subissant une chirurgie cardiaque dans 71 hôpitaux à travers le monde ont été inclus. La VM prolongée a été définie à partir de la définition de la Society of Thoracic Surgeons comme un événement durant 24 heures ou plus. Des associations ajustées de facteurs liés aux patients et à la chirurgie avec la VM prolongée ont été examinées en utilisant une régression logistique multifactorielle. Des associations de la VM prolongée avec des complications ont été évaluées en utilisant des rapports de cotes; les associations ajustées entre VM prolongée et mortalité ont été évaluées au moyen d'une régression multinominale. Les associations d'une VM de plus courte durée avec la survie et des complications ont été explorées. RéSULTATS: La VM prolongée est survenue chez 15 % (725/4 809) des participants. Une VM prolongée a été associée à des facteurs chirurgicaux indicateurs de complexité (comme une chirurgie cardiaque antérieure, la durée de la circulation extracorporelle et les tentatives de débranchement) et à des facteurs liés au patient (comme un état préopératoire critique, une défaillance ventriculaire gauche, une insuffisance rénale et une hypertension pulmonaire). La VM prolongée a été associée à des complications périopératoires, mais pas à des complications à long terme. Après ajustement pour le risque, la VM prolongée a été associée à la mortalité périopératoire; son association avec la mortalité à long terme des survivants a été plus faible. Les durées plus courtes de VM n'ont pas été associées à une augmentation du risque de mortalité ou à des complications. CONCLUSION: Dans cette étude auxiliaire de l'essai TRICS III, la VM prolongée a été fréquente après chirurgie cardiaque et a été associée à des facteurs de risque liés au patient et à la chirurgie. Bien que la VM prolongée ait présenté de fortes associations avec les complications périopératoires et la mortalité, elle n'a pas été associée avec des complications à long terme et était plus faiblement associée à la mortalité à long terme parmi les survivants. ENREGISTREMENT DE L'éTUDE: www.ClinicalTrials.gov (NCT02042898); enregistrée le 23 janvier 2014. Il s'agit d'une étude auxiliaire de l'étude TRICS III sur les besoins de transfusion en chirurgie cardiaque.

Pulmocrinology: Interplay of pulmonary and endocrine diseases.

The interplay between pulmonary and endocrine systems modify and influence the pathogenesis and manifestation of several disease processes. Endocrine dysfunctions predispose to numerous pulmonary disorders, including various respiratory infections. On the other hand, pulmonary conditions like chronic obstructive pulmonary disease and obstructive sleep apnoea can produce critical metabolic and endocrine derangements. Varied manifestations such as primary adrenal insufficiency, hypophysitis and hypercalcaemia can result from chronic granulomatous conditions like tuberculosis and sarcoidosis. Various endocrine consequences of coronavirus disease 2019 are also getting apparent during the pandemic. Tumours of the lung can secrete different hormones that give rise to several endocrine paraneoplastic syndromes. This review focuses on the clinically relevant interaction between these two diverse but interrelated systems. We suggest the portmanteau term "pulmocrinology" to delineate the multifaceted relationship evident in pathophysiology, clinical features and therapeutics of various pulmonary and endocrine disorders.

Joint Statement on the Role of Respiratory Rehabilitation in the COVID-19 Crisis: The Italian Position Paper.

Due to the exponential growth of the number of subjects affected by coronavirus disease 2019 (COVID-19), the entire Italian health care system had to respond promptly and in a very short time with the need of semi-intensive and intensive care units. Moreover, trained dedicated COVID-19 teams consisting of physicians were coming from different specialties (intensivists or pneumologists and infectiologists), while respiratory therapists and nurses have been recruited to work on and on without rest. However, due to still limited and evolving knowledge of COVID-19, there are few recommendations concerning the need in respiratory rehabilitation and physiotherapy interventions. The presentation of this paper is the result of a consensus promoted by the Italian societies of respiratory health care professionals who contacted pulmonologists directly involved in the treatment and rehabilitation of COVID-19. The aim was to formulate the more proper and common suggestions to be applied in different hospital settings in offering rehabilitative programs and physiotherapy workforce planning for COVID-19 patients. Two main areas of intervention were identified: organization and treatment, which are described in this paper to face the emergency.

[Apps in General Medicine : A topic for medical education?​]. / Apps in der Inneren Medizin : Ein Thema für das Medizinstudium?

BACKGROUND: Health-related apps can provide helpful resources for both doctors and patients. The selection of potentially useful apps and the appraisal of their quality are particularly important in the context of medicine as false or confusing app content may put patients at risk. AIM: In this article a brief overview of the topic is provided and the results of a pilot study, in which medical students tested and evaluated the quality of 143 health-related apps on the topics of cardiology and pulmonology are presented. MATERIAL AND METHODS: Using the semiautomated retrospective app store analysis (SARASA) method, a group of apps concerned with cardiology and pulmonology were identified from a pool of over 2,000,000 apps available in the Apple Store. As part of a practical exercise, 138 4th year medical students tested a total of 143 of these apps, subsequently evaluating them using a specially devised questionnaire. RESULTS: The most frequent target population among the tested apps was identified as patients and their carers and the primary purpose in the majority of cases was the provision of information. Despite this, at least one quarter of all apps tested required users to enter sensitive health-related information. The evaluations by the students portrayed a large range in terms of the quality of the apps tested. DISCUSSION: Health-related apps play a growing role in the management of illnesses in the field of internal medicine. Doctors must be aware of the benefits and limitations of using such apps and should be prepared during their medical studies for the challenge of advising patients on this topic.

Cost of asthma in children: A nationwide, population-based, cost-of-illness study.

BACKGROUND: Childhood asthma is very prevalent and costs can be high, especially in severe disease. This study aimed to estimate the cost of asthma in Portuguese children and the variations by level of asthma control. METHODS: A nationwide, population- and prevalence-based cost-of-illness study with a societal perspective was conducted. We measured direct and indirect costs using a bottom-up approach and a human capital method, respectively, for 208 children (<18 years), from two national repositories. Generalized linear modelling for analysis of asthma costs' determinants and sensitivity analysis to assess uncertainty were performed. RESULTS: The mean annualized asthma cost per child was €929.35 (95% CI, 809.65-1061.11): €698.65 (95% CI, 600.88-798.27) for direct costs and €230.70 (95% CI, 197.36-263.81) for indirect costs. Extrapolations for the Portuguese children amounted to €161 410 007.61 (95% CI, 140 620 769.55-184 293 968.55) for total costs. Direct costs represent 75.2% with the costliest domain (51.1% of total costs) being the healthcare service use: 20.7% for scheduled medical visits and 30.4% for acute asthma care-non-scheduled medical visits (7.9%, €12 766 203.20), emergency department visits (11.7%, €18 932 464.80) and hospitalizations (10.8%, €17 406 946.00). Children with partly controlled and uncontrolled asthma had higher mean costs per year (adjusted coefficients: 1.46 [95% CI, 1.12-1.90] and 2.25 [95% CI, 1.56-3.24], respectively). CONCLUSIONS: Costs of childhood asthma are high (0.9% of the healthcare expenditures in Portugal). Direct costs represented three-fourth of total costs, mainly related to the use of healthcare services for acute asthma care. Policies and interventions to improve asthma control and reduce acute use of healthcare services have the potential to reduce asthma costs.

Implementing flexible bronchoscopy in least developed countries according to international guidelines is feasible and sustainable: example from Phnom-Penh, Cambodia.

BACKGROUND: Flexible bronchoscopy is pivotal for the diagnosis of most respiratory diseases. A flexible bronchoscopy unit (FBU) was created in 2008 in the Preah Kossamak university hospital (Phnom Penh, Cambodia) through a cooperation program between a French and a Cambodian team. In 2009 we conducted an assessment of the compliance of the FBU to international standards and found that most of French and British guidelines were fully applied or adapted to local practice. The aim of the current work was to assess FBU again 6 years later, in order to determine if compliance to international guidelines was sustainable. METHODS: The 2015 evaluation was conducted identically to 2009. All recommendation items from the French and the British Thoracic Societies guidelines were assessed individually. Each recommendation was assigned a status expressing the level at which it was respected in Cambodia: applied, adapted, not applied and not evaluable. An endoscope microbial sampling was performed as recommended by the French Ministry of Health. RESULTS: Between 2009 and 2015, the pattern of international recommendations in the Cambodian FBU did not change. Notably the rates of applied French evaluable recommendations remained stable: respectively 58% vs 57%. Main changes in French guidelines occurred in adapted items that became applied (n = 5/15) while 4 previously adapted/applied items became not applied. Furthermore, all microbial analyses showed sterile results. CONCLUSIONS: Our results show that implementation of a high quality FBU in a least-developed country is feasible. In addition, the performance is maintained in the long-term.

Polynomial estimation of the smoothing splines for the new Finnish reference values for spirometry.

Background Discontinuity of spirometry reference values from childhood into adulthood has been a problem with traditional reference values, thus modern modelling approaches using smoothing spline functions to better depict the transition during growth and ageing have been recently introduced. Following the publication of the new international Global Lung Initiative (GLI2012) reference values also new national Finnish reference values have been calculated using similar GAMLSS-modelling, with spline estimates for mean (Mspline) and standard deviation (Sspline) provided in tables. The aim of this study was to produce polynomial estimates for these spline functions to use in lieu of lookup tables and to assess their validity in the reference population of healthy non-smokers. Methods Linear regression modelling was used to approximate the estimated values for Mspline and Sspline using similar polynomial functions as in the international GLI2012 reference values. Estimated values were compared to original calculations in absolute values, the derived predicted mean and individually calculated z-scores using both values. Results Polynomial functions were estimated for all 10 spirometry variables. The agreement between original lookup table-produced values and polynomial estimates was very good, with no significant differences found. The variation slightly increased in larger predicted volumes, but a range of -0.018 to +0.022 litres of FEV1 representing ± 0.4% of maximum difference in predicted mean. Conclusions Polynomial approximations were very close to the original lookup tables and are recommended for use in clinical practice to facilitate the use of new reference values.