The 1995 update of recommendations for a standard technique for measuring the single-breath carbon monoxide diffusing capacity (transfer factor)

Impact of Ongoing Treatment With Inhaled Corticosteroids During Specific Inhalation Challenges for Diagnosing Occupational Asthma

BACKGROUND

Specific inhalation challenge (SIC) tests are still the reference test for diagnosing sensitizer-induced occupational asthma (SIOA). The European Respiratory Society recommends the cessation of inhaled corticosteroids (ICS) 72 hours before SIC.

OBJECTIVE

To assess the effect of an ongoing ICS treatment during SIC on the maximum fall in forced expiratory volume in 1 second (FEV1), the change in methacholine provocative concentration of methacholine inducing a 20% fall in FEV1 (PC20), and sputum eosinophil counts after exposure to the suspected agent.

METHODS

We performed a retrospective analysis using a database of cases referred to our center for suspected SIOA from 1999 to 2022. The results of the SIC were compared between subjects treated with ICS during SIC and steroid-naïve subjects.

RESULTS

Six hundred and seventy-one individuals underwent SIC in the laboratory. Three hundred and eighteen were treated with ICS, whereas 353 were steroid naïve. The proportion of subjects with a positive SIC was greater among ICS-treated subjects (39. 6%) compared with steroid-naïve subjects (27.5%, P < .001). A treatment with ICS did not influence the outcome of the SIC. There was no difference in the change in PC20 or the percentage of sputum eosinophils after SIC between steroid-treated and steroid-naïve subjects.

CONCLUSIONS

An ongoing ICS treatment during an SIC did not affect the occurrence of an asthmatic reaction, the change in airway responsiveness, or eosinophilic inflammation after exposure to the suspected agent in subjects who have been treated with ICS for a long period of time.

Utility of routine pulmonary function test after autologous hematopoietic cell transplantation in lymphoma

This study aims to evaluate the predictive value of routine pulmonary function testing (PFT) at the 12-month mark post-autologous hematopoietic cell transplant (AHCT) in identifying clinically significant lung disease in lymphoma survivors. In 247 patients, 173 (70%) received BEAM (carmustine, etoposide, cytarabine, melphalan), and 49 (20%) received TBC (thiotepa, busulfan, cyclophosphamide) conditioning regimens. Abnormal baseline PFT was noted in 149 patients (60%). Thirty-four patients had a significant decline (reduction of >/= 20% in DLCO or FEV1 or FVC) in post-AHCT PFT, with the highest incidence in the CNS lymphoma group (39%). The incidence of clinically significant lung disease post-transplant was low at 2% and there was no association between abnormal pre- and 1-year post-transplant PFTs with the development of clinical lung disease. While this study illustrates the impact of treatment regimens on PFT changes, it did not demonstrate a predictive value of scheduled PFTs in identifying clinically significant post-AHCT lung disease.

Alveolar-capillary reserve during exercise in patients with chronic obstructive pulmonary disease

Background

Factors limiting exercise in patients with COPD are complex. With evidence for accelerated pulmonary vascular aging, destruction of alveolar-capillary bed, and hypoxic pulmonary vasoconstriction, the ability to functionally expand surface area during exercise may become a primary limitation.

Purpose

To quantify measures of alveolar-capillary recruitment during exercise and the relationship to exercise capacity in a cohort of COPD patients.

Methods

Thirty-two subjects gave consent (53% male, with mean ± standard deviation age 66±9 years, smoking 35±29 pack-years, and Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of 0-4: 2.3±0.8), filled out the St George's Respiratory Questionnaire (SGRQ) to measure quality of life, had a complete blood count drawn, and underwent spirometry. The intrabreath (IB) technique for lung diffusing capacity for carbon monoxide (IBDLCO) and pulmonary blood flow (IBQc, at rest) was also performed. Subsequently, they completed a cycle ergometry test to exhaustion with measures of oxygen saturation and expired gases.

Results

Baseline average measures were 44±21 for SGRQ score and 58±11 for FEV₁/FVC. Peak oxygen consumption (VO₂) was 11.4±3.1 mL/kg/min (49% predicted). The mean resting IBDLCO was 9.7±5.4 mL/min/mmHg and IBQc was 4.7±0.9 L/min. At the first workload, heart rate (HR) increased to 92±11 bpm, VO₂ was 8.3±1.4 mL/kg/min, and IBDLCO and IBQc increased by 46% and 43%, respectively, compared to resting values (p,0.01). The IBDLCO/Qc ratio averaged 2.0±1.1 at rest and remained constant during exercise with marked variation across subjects (range: 0.8-4.8). Ventilatory efficiency plateaued at 37±5 during exercise, partial pressure of mix expired CO₂/partial pressure of end tidal CO₂ ratio ranged from 0.63 to 0.67, while a noninvasive index of pulmonary capacitance, O₂ pulse × PetCO₂ (GxCap) rose to 138%. The exercise IBDLCO/Qc ratio was related to O₂ pulse (VO₂/HR, r=0.58, p<0.01), and subjects with the highest exercise IBDLCO/Qc ratio or the greatest rise from rest had the highest peak VO₂ values (r=0.65 and 0.51, respectively, p<0.05). Of the noninvasive gas exchange measures of pulmonary vascular function, GxCap was most closely associated with DLCO, DLCO/Qc, and VO₂ peak.

Conclusion

COPD patients who can expand gas exchange surface area as assessed with DLCO during exercise relative to pulmonary blood flow have a more preserved exercise capacity.

Reduced dynamic hyperinflation after LVRS is associated with improved exercise tolerance

INTRODUCTION

Dynamic hyperinflation (DH) after lung volume reduction surgery (LVRS) has not been well studied. It is not known if reductions in DH correlate with improvements in exercise performance post-LVRS.

METHODS

Forty-two upper-lobe predominant emphysema patients who underwent LVRS were analyzed. Inspiratory capacity was measured every 2 min during symptom-limited cardiopulmonary exercise test (CPET) and end-expiratory lung volumes (EELV) were calculated. The main measure of DH was EELV/TLC ratio matched at metabolic isotimes (based on the post-rehabilitation VCO2max).

RESULTS

Patients had very severe airflow obstruction (FEV1 28.3 ± 7.0% predicted), were hyperinflated (TLC 125 ± 17% predicted) and gas trapped (RV 198 ± 39% predicted). Compared to the post-rehab baseline, dynamic hyperinflation (EELV/TLC) was significantly reduced after LVRS at 6, 12, 24, and 36 months. There were also increases in inspiratory reserve volume at matched isotimes after surgery. Patients adopted a slower, deeper breathing pattern during exercise after LVRS, which strongly correlated to reductions in DH. There were significant correlations between reductions in DH (EELV/TLC @50% VCO2max) and improvements in 6 min walk distance (Pearson r = -0.411, p = 0.02, n = 33) and maximal watts on CPET (Spearman r = -0.536, p = 0.001, n = 33) when comparing post-rehabilitation and 6 month post-LVRS values.

CONCLUSION

Dynamic hyperinflation during exercise was reduced after LVRS (up to 3 years) and there was a strong association between alterations in breathing pattern and reduced DH after LVRS. This is the first study to demonstrate that reductions in DH correlated with improved exercise performance following LVRS.

Risk factors and comorbidities in the preclinical stages of chronic obstructive pulmonary disease

RATIONALE

There is little information about comorbidities and their risk factors in the preclinical stages of chronic obstructive pulmonary disease (COPD).

OBJECTIVES

This study aims to investigate the prevalence of premorbid risk factors and comorbid diseases and its association with daily physical activity in subjects detected with COPD by spirometry screening.

METHODS

Sixty subjects with preclinical COPD (63 ± 6 yr; 68% [n = 41] male) were compared with 60 smoking control subjects (62 ± 7 yr; 70% [n = 42] male) and 60 never-smoking control subjects (62 ± 6 yr; 57% [n = 34] male). Comorbidities (cardiovascular, metabolic, and musculoskeletal disease) and daily physical activity (by multisensor activity monitor) were measured objectively.

MEASUREMENTS AND MAIN RESULTS

The prevalence of premorbid risk factors and comorbid diseases was significantly higher in preclinical COPD compared with age-matched never-smoking control subjects, but was similar to smoking control subjects not suffering from COPD. In preclinical COPD and smoking control subjects, the combination of cardiovascular disease and musculoskeletal disease was the most prevalent (15% [n = 9] and 12% [n = 7], respectively). In a multivariate logistic regression analysis, physical inactivity and smoking were found to be independent risk factors for having greater than or equal to two comorbidities.

CONCLUSIONS

Premorbid risk factors and comorbid diseases were more prevalent in the preclinical stages of COPD and smokers without COPD. Physical inactivity and smoking were more strongly associated with the presence of comorbidities compared with airflow obstruction. Clinical trial registered with www.clinicaltrials.gov (NCT 01314807).

Heterogeneity of lung volume reduction surgery outcomes in patients selected by use of evidence-based criteria

BACKGROUND

Despite its benefit, lung volume reduction surgery (LVRS) is underused, partially because of the heterogeneous responses and lack of recent outcomes data.

METHODS

Data from 59 consecutive emphysema patients who underwent LVRS were analyzed. The proportion of patients responding based on 6-minute walk distance (6-MWD), exercise capacity (watts), and forced expiratory volume in 1 second (FEV1) were calculated. Baseline variables were correlated with improvements in 6-MWD, maximal watts, and FEV1.

RESULTS

Eighty-eight percent of patients responded to LVRS, with a higher proportion of FEV1 and 6-MWD responders in our cohort compared with similar patients from the National Emphysema Treatment Trial. Significant associations existed between lower baseline 6-MWD and increased 6-MWD after operation (r = -0.423), more extensive emphysema and increased FEV1 (r = 0.491), and hyperinflation and increased maximal watts (r = 0.438). The probability of survival was 0.93 at 90 days, 0.90 at 1 year, and 0.80 (3 years). The lowest exercise group (<20 watts on baseline testing) had an increased risk for death (RR 13.3, p = 0.001).

CONCLUSIONS

There were durable improvements in FEV1 and exercise capacity in patients meeting the National Emphysema Treatment Trial criteria. Survival was comparable to that in similar patients from the National Emphysema Treatment Trial; response rates were higher in our cohort for FEV1 and 6-MWD. Those with lower 6-MWD, more emphysema, and more hyperinflation at baseline were most likely to respond to LVRS. Those with lowest exercise capacity at baseline may have a higher risk of death after LVRS.

Genomic copy number determines functional expression of {beta}-defensin 2 in airway epithelial cells and associates with chronic obstructive pulmonary disease

RATIONALE

Copy number variations of the cluster of beta-defensin genes have been associated with psoriasis and inflammatory bowel disease. Controversy still exists on whether the beta-defensins genes determine susceptibility for chronic obstructive pulmonary disease (COPD).

OBJECTIVES

We investigated whether genomic copy number variations of the beta-defensin gene cluster have a functional role in airway epithelial cells and associate with the presence of COPD.

METHODS

Baseline and inflammatory induced transcript expression of DEFB4 was studied in nasal epithelial cell cultures and its effect on Pseudomonas aeruginosa inhibition was assessed. Subsequently, relevant functional cut-offs for copy numbers were used to explore associations with COPD in two independent case-control studies.

MEASUREMENTS AND MAIN RESULTS

Copy number variation in the beta-defensin encoding genes correlated with baseline mRNA DEFB4 expression levels (R(2) = 0.96; P = 0.02), with a plateau effect from five copies or more. Only when higher copy numbers of beta-defensin genes were present, transcription was significantly up-regulated by tumor necrosis factor-alpha (P < 0.0001), which resulted in better antimicrobial activity in vitro. When comparing healthy smokers with COPD patients, a copy number greater than or equal to 5 was associated with increased risk for COPD with an adjusted odds ratio of 1.8 (confidence interval, 1.1-2.8; P = 0.02), which was confirmed by a second independent case-control study.

CONCLUSIONS

Genomic copy number variation of beta-defensin encoding genes has a functional role in airway epithelial cells, which may contribute to the pathogenesis of COPD.

The 15q24/25 susceptibility variant for lung cancer and chronic obstructive pulmonary disease is associated with emphysema

RATIONALE

Genome-wide association studies have identified genetic variants in the nicotinic acetylcholine receptor (nAChR) on chromosome 15q24/25 as a risk for nicotine dependence, lung cancer, and chronic obstructive pulmonary disease (COPD). Assessment of bronchial obstruction by spirometry, typically used for diagnosing COPD, fails, however, to detect emphysema.

OBJECTIVES

To determine the association of the 15q24/25 locus with emphysema.

METHODS

The rs1051730 variant on 15q24/25 was genotyped in two independent white cohorts of 661 and 456 heavy smokers. Participants underwent pulmonary function tests and computed tomography (CT) of the chest, and took questionnaires assessing smoking behavior and health status.

MEASUREMENTS AND MAIN RESULTS

The rs1051730 A-allele correlated with reduced FEV(1) and with increased susceptibility for bronchial obstruction with a pooled odds ratio (OR) of 1.33 (95% confidence interval [CI] = 1.11-1.61; P = 0.0026). In both studies a correlation between the rs1051730 A-allele and lung diffusing capacity (Dl(CO)) and diffusing capacity per unit alveolar volume (Kco) was observed. Consistently, the rs1051730 A-allele conferred increased risk for emphysema as assessed by CT (P = 0.0097 and P = 0.019), with a pooled OR of 1.39 (CI = 1.15-1.68; P = 0.00051). Visual emphysema scores and scores based on densities quantified on CT were more pronounced in A-allele carriers, indicating that rs1051730 correlates with the severity of emphysema.

CONCLUSIONS

The 15q24/25 locus in nAChR is associated with the presence and severity of emphysema. This association was independent of pack-years smoking, suggesting that nAChR is causally involved in alveolar destruction as a potentially shared pathogenic mechanism in lung cancer and COPD.

An open-circuit method for determining lung diffusing capacity during exercise: comparison to rebreathe

To avoid limitations associated with the use of single-breath and rebreathe methods for assessing the lung diffusing capacity for carbon monoxide (DlCO) during exercise, we developed an open-circuit technique. This method does not require rebreathing or alterations in breathing pattern and can be performed with little cognition on the part of the patient. To determine how this technique compared with the traditional rebreathe (DlCO,RB) method, we performed both the open-circuit (DlCO,OC) and the DlCO,RBmethods at rest and during exercise (25, 50, and 75% of peak work) in 11 healthy subjects [mean age = 34 yr (SD 11)]. Both DlCO,OCand DlCO,RBincreased linearly with cardiac output and external work. There was a good correlation between DlCO,OCand DlCO,RBfor rest and exercise (mean of individual r2= 0.88, overall r2= 0.69, slope = 0.97). DlCO,OCand DlCO,RBwere similar at rest and during exercise [e.g., rest = 27.2 (SD 5.8) vs. 29.3 (SD 5.2), and 75% peak work = 44.0 (SD 7.0) vs. 41.2 ml·min−1·mmHg−1(SD 6.7) for DlCO,OCvs. DlCO,RB]. The coefficient of variation for repeat measurements of DlCO,OCwas 7.9% at rest and averaged 3.9% during exercise. These data suggest that the DlCO,OCmethod is a reproducible, well-tolerated alternative for determining DlCO, particularly during exercise. The method is linearly associated with cardiac output, suggesting increased alveolar-capillary recruitment, and values were similar to the traditional rebreathe method.

Impaired Respiratory and Skeletal Muscle Strength in Patients Prior to Hematopoietic Stem-Cell Transplantation

STUDY OBJECTIVES

The primary aim was to determine if respiratory and skeletal muscle strength and submaximal exercise capacity were reduced in subjects prior to sibling- or unrelated-donor hematopoietic stem-cell transplantation (HSCT).

DESIGN

Prospective observational study.

SETTING

Tufts-New England Medical Center, a tertiary referral center in Boston, MA.

PATIENTS

All patients (n = 56) undergoing either sibling- or unrelated-donor HSCT from January 1, 2002, to December 31, 2002.

MEASUREMENTS

Demographic data, chemotherapy burden, pulmonary function tests (PFTs), maximal inspiratory muscle strength (PImax), maximal expiratory muscle strength (PEmax), dominant hand grip strength (GS), 6-min walk test (6MWT), and survival as of May 21, 2004.

RESULTS

PImax was reduced to < 80% predicted in 42% of subjects and to < 60% predicted in 18% of subjects. PEmax was reduced to < 80% predicted in 89% of subjects and to < 60% of predicted in 80% of subjects. A significant correlation was observed between PImax and PEmax (r = 0.65, p < 0.0001). GS was reduced to < 80% predicted in 39% of subjects and < 60% predicted in 15% of subjects. The 6MWT was reduced to < 80% predicted in 58% of subjects and to < 60% predicted in 9.6% of subjects. Diffusing capacity of the lung for carbon monoxide (Dlco) was the only PFT that was significantly correlated with 6MWT distance (r = 0.44, p = 0.015). The mean calculated load of chemotherapy was 14.8 +/- 16.5 U (+/- SD). The mean time elapsed from date of hematologic diagnosis to date of HSCT was 874 +/- 1,109 days. The median survival of the cohort was 374 days (95% confidence interval, 177 to 665 days). Respiratory or skeletal muscle strength, 6MWT distance, or calculated burden of chemotherapy did not predict survival.

CONCLUSIONS

Respiratory and skeletal muscle strength and submaximal exercise capacity are reduced in a significant percentage of patients prior to undergoing HSCT. These observations may help explain musculoskeletal weakness that has been reported in the posttransplant period.

Guidelines in pulmonary medicine: a 25-year profile

OBJECTIVE

We attempted to identify clinical practice guideline and pathway articles in the area of pulmonary medicine published in peer-reviewed journals since 1974.

DESIGN

Review.

DATA SOURCES

MEDLINE, the Cochrane Database, Best Evidence, and Abstracts of Clinical Care Guidelines from January 1974 to December 1998.

STUDY SELECTION

All articles contained relevant search terms for pulmonary topics and were included irrespective of setting (primary or specialty, inpatient or outpatient). Controlled and uncontrolled trials as well as observational studies and consensus opinion/statements were all identified. The articles were stratified by design as well as by pulmonary topic.

DATA EXTRACTION

Limited data on study type, study focus, year of publication, and results of study were abstracted.

RESULTS

Our criteria yielded 271 articles, including 115 consensus statements and expert opinion guidelines; 30 controlled studies, meta-analyses, or systematic reviews; and 126 uncontrolled trials and observational studies. Of these, 82 articles (30.3%) related to asthma, 46 articles (17.0%) related to COPD, and 36 articles (13.3%) related to pneumonia. In addition, we tracked the increasing publication of all guideline-related pulmonary articles; randomized, controlled trials (RCTs); systematic reviews; and consensus statements by year for the past 25 years.

CONCLUSION

Pulmonary guidelines are increasingly published in peer-reviewed journals, but few are tested clinically in RCTs. There is continued reliance on consensus statements and expert opinion. Pulmonary guideline publications have continued to dramatically increase in number and in importance since 1974, both on the local level and internationally.