DLCO In Patients Research Articles

Usefulness of Transbronchial Lung Cryobiopsy When Starting Antifibrotic Treatment and Predicting Progressive Fibrosing Interstitial Lung Disease: Descriptive Research.

Although transbronchial lung cryobiopsy (TBLC) is widely used in diagnostic algorithms for various interstitial lung diseases (ILDs), its real-world utility in the therapeutic decision-making strategy for ILD patients remains unclear, in particular, when judging the time to start antifibrotic agents. We analyzed medical records of 40 consecutive patients with idiopathic or fibrotic hypersensitivity pneumonitis who underwent TBLC. A TBLC-based usual interstitial pneumonia (UIP) score was used to assess three morphologic descriptors: patchy fibrosis, fibroblastic foci, and honeycombing. In our 40 patients with ILD, the most frequent radiological feature was indeterminate for UIP (45.0%). Final diagnosis included idiopathic pulmonary fibrosis (22.5%), fibrotic nonspecific interstitial pneumonia (5.0%), fibrotic hypersensitivity pneumonitis (35.0%), and unclassifiable ILD (37.5%). Linear mixed-effects analysis showed that declines in the slopes of %FVC and %DLCO in patients with TBLC-based UIP "Score ≥ 2" were significantly steeper than those of patients with "Score ≤ 1." During follow-up of patients with Score ≥ 2 (n = 24), more than half of them (n = 17) received an antifibrotic agent, with most patients (n = 13) receiving early administration of the antifibrotic agent within 6 months after the TBLC procedure. TBLC-based UIP Score ≥ 2 indicated the increased possibility of a progressive fibrosis course that may prove helpful in predicting progressive pulmonary fibrosis/progressive fibrosing ILD even if disease is temporarily stabilized due to anti-inflammatory agents. Patients may benefit from early introduction of antifibrotic agents by treating clinicians.

Adjusting diffusing capacity for anemia in patients undergoing allogeneic HCT: a comparison of two methodologies

BackgroundDiffusing capacity (DLCO) measurements are affected by hemoglobin. Two adjustment equations are used: Cotes (recommended by ATS/ERS) and Dinakara (used in the hematopoietic stem cell transplantation comorbidity index [HCT-CI]). It is unknown how these methods compare, and which is better from a prognostication standpoint. Study designThis is a retrospective cohort of 1273 adult patients who underwent allogeneic HCT, completed a pre-transplant DLCO and had a concurrent hemoglobin measurement. Non-relapse mortality was measured using competing risk analysis. ResultsPatients had normal spirometry (FEV1 99.7% [IQR: 89.4–109.8%; FVC 100.1% [IQR: 91.0-109.6%] predicted), left ventricular ejection fraction (57.2[6.7]%) and right ventricular systolic pressure (30.1[7.0] mmHg). Cotes-DLCO was 85.6% (IQR: 76.5-95.7%) and Dinakara-DLCO was 103.6% (IQR: 90.7-117.2%) predicted. For anemic patients (Hb<10g/dL), Cotes-DLCO was 84.2% (IQR: 73.9–94.1%) while Dinakara-DLCO 111.0% (97.3–124.7%) predicted. Cotes-DLCO increased HCT-CI score for 323 (25.4%) and decreased for 4 (0.3%) patients. Cotes-DLCO was superior for predicting non-relapse mortality: for both mild (66-80% predicted, HR 1.55 [95%CI: 1.26-1.92, p < 0.001]) and moderate (<65% predicted, HR 2.11 [95%CI: 1.55-2.87, p<0.001]) impairment. In contrast, for Dinakara-DLCO, only mild impairment (HR 1.69 [95%CI 1.26-2.27, p < 0.001]) was associated with lower survival while moderate impairment was not (HR 1.44 [95%CI: 0.64-3.21, p = 0.4]). In multivariable analyses, after adjusting for demographics, hematologic variables, cardiac function and FEV1, Cotes-DLCO was predictive of overall survival at 1-year (OR 0.98 [95%CI: 0.97-1.00], p = 0.01), but Dinakara-DLCO was not (OR 1.00 [95%CI: 0.98-1.00], p = 0.20). ConclusionThe ERS/ATS recommended Cotes method likely underestimates DLCO in patients with anemia, whereas the Dinakara (used in the HCT-CI score) overestimates DLCO. The Cotes method is superior to the Dinakara method score in predicting overall survival and relapse-free survival in patients undergoing allogeneic HCT.

Pulmonary circulation abnormalities in post-acute COVID-19 syndrome: dual-energy CT angiographic findings in 79 patients.

To evaluate the frequency and pattern of pulmonary vascular abnormalities in the year following COVID-19. The study population included 79 patients remaining symptomatic more than 6months after hospitalization for SARS-CoV-2 pneumonia who had been evaluated with dual-energy CT angiography. Morphologic images showed CT features of (a) acute (2/79; 2.5%) and focal chronic (4/79; 5%) PE; and (b) residual post COVID-19 lung infiltration (67/79; 85%). Lung perfusion was abnormal in 69 patients (87.4%). Perfusion abnormalities included (a) perfusion defects of 3 types: patchy defects (n = 60; 76%); areas of non-systematized hypoperfusion (n = 27; 34.2%); and/or PE-type defects (n = 14; 17.7%) seen with (2/14) and without (12/14) endoluminal filling defects; and (b) areas of increased perfusion in 59 patients (74.9%), superimposed on ground-glass opacities (58/59) and vascular tree-in-bud (5/59). PFTs were available in 10 patients with normal perfusion and in 55 patients with abnormal perfusion. The mean values of functional variables did not differ between the two subgroups with a trend toward lower DLCO in patients with abnormal perfusion (74.8 ± 16.7% vs 85.0 ± 8.1). Delayed follow-up showed CT features of acute and chronic PE but also two types of perfusion abnormalities suggestive of persistent hypercoagulability as well as unresolved/sequelae of microangiopathy. Despite dramatic resolution of lung abnormalities seen during the acute phase of the disease, acute pulmonary embolism and alterations at the level of lung microcirculation can be identified in patients remaining symptomatic in the year following COVID-19. • This study demonstrates newly developed proximal acute PE/thrombosis in the year following SARS-CoV-2 pneumonia. • Dual-energy CT lung perfusion identified perfusion defects and areas of increased iodine uptake abnormalities, suggestive of unresolved damage to lung microcirculation. • This study suggests a complementarity between HRCT and spectral imaging for proper understanding of post COVID-19 lung sequelae.

Relationship Between Novel Parameters of Six-Minute Walk test and Respiratory Parameters in Patients with Interstitial Lung Disease

Background and Aim: The 6-minute walk test (6MWT) is used to measure exercise capacity and assess prognosisin interstitial lung disease (ILD). In this study we aim to evaluate the correlation of outcomes of 6MWT withspirometry variables and DLCO in patients with interstitial lung diseases thereby corroborating 6MWT as reliablemarker of functional assessment of ILD.Material and Methods: It is a hospital based descriptive observational study conducted over a period of oneyear. The study population comprises of 100 patients of interstitial lung disease who attended pulmonary clinic atTertiary care Hospital of India. The information on sociodemographic status including age, sex, religion, occupationand residential place were noted. Further clinical assessment, lab investigations, radiographs, pulmonary functiontests and 6 minute walk test were done the data was then subjected to statistical analysis.Results: The percentage predicted mean values for FEV1 and FVC are 1.90 (0.75) and 1.50 (0.60). Out of all 100patients, 6MWD had a statistically significant negative correlation with age and statistically significant positivecorrelation with the height of the patient. Also 6MWD had positive correlation with weight (r-0.02) but thus cantcorrelation was not statistically significant. Borg scale dyspnoea had non-significant correlation with age, heightand weight but had a statistically negative correlation with FVC and DLCO while it had a statistically significantpositive correlation with FEV1.Conclusion: The conclusion drawn from our study is to emphasize the importance of six minute walk test inpatients of ILD by virtue of its strong correlation with many of the objective parameters for detecting the functionalstatus like spirometry variables and DLCO.

The evaluation of DLCO changes in patients with relatively higher lung shunt fractions receiving TARE.

Transarterial radioembolization (TARE) with Yttrium-90 (90Y) labeled microspheres is an effective locoregional treatment option for patients with primary and metastatic liver cancer. However, TARE is also associated with radiation-induced lung injury due to hepatopulmonary shunting. If a large proportion of the injected radionuclide microspheres (more than 15%) is shunted, a rare but lethal complication may develop: radiation-induced pneumonitis (RP). Diffusion capacity of the lungs for carbon monoxide (DLCO) is a valuable test to assess lung function and a decrease in DLCO may indicate an impairment in gas exchange caused by the lung injury. Some previous researches have been reported the most consistent changes in pulmonary function tests after external beam radiotherapy are recorded with DLCO. This study aimed to examine the changes in DLCO after TARE with glass microspheres in newly treated and retreated patients with relatively higher lung shunt fractions. We prospectively analyzed forty consecutive patients with liver malignancies who underwent lobar or superselective TARE with 90Y glass microspheres. DLCO tests were performed at baseline and on days 15, 30, and 60 after the treatment. All patients were followed up clinically and radiologically for the development of RP. A statistically significant decrease was found in the DLCO after the first treatment (81.4 ± 13.66 vs. 75.25 ± 13.22,p = 0.003). The frequency of the patients with impaired DLCO at baseline was significantly increased after the first treatment (37.5 vs 57.5% p < 0.05). In the retreated group (n = 8), neither the DLCO (71.5 ± 10.82 vs. 67.50 ± 11.24,p = 0.115) nor the frequency of patients with impaired DLCO (25 vs 25%, p = 1) did not significantly change. Also, the change in DLCO values did not significantly correlate with lung shunt fraction, administered radiation dose, and absorbed lung dose after the first and second treatments (p > 0.05 for all). None of the patients developed RP. Our study showed that a significant reduction in DLCO after TARE may occur in patients with relatively higher lung shunt fractions. Further studies with larger sample sizes are needed to better investigate the changes in DLCO in patients with high lung shunt fractions.

Natural Course of the Diffusing Capacity of the Lungs for Carbon Monoxide in COPD: Importance of Sex

The value of the single-breath diffusing capacity of the lungs for carbon monoxide (Dlco) relates to outcomes for patients with COPD. However, little is known about the natural course of Dlco over time, intersubject variability, and factors that may influence Dlco progression. What is the natural course of Dlco in patients with COPD over time, and which other factors, including sex differences, could influence this progression? We phenotyped 602 smokers (women, 33%), of whom 506 (84%) had COPD and 96 (16%) had no airflow limitation. Lung function, including Dlco, was monitored annually over 5 years. A random coefficients model was used to evaluate Dlco changes over time. The mean (± SE) yearly decline in Dlco %in patients with COPD was 1.34%± 0.015%/y. This was steeper compared with non-COPD control subjects (0.04%± 0.032%/y; P= .004). Sixteen percent of the patients with COPD, vs4.3%of the control subjects, had a statistically significant Dlco %slope annual decline (4.14%/y). At baseline, women with COPD had lower Dlco values (11.37%± 2.27%; P< .001) in spite of a higher FEV1 %than men. Compared with men, women with COPD had a steeper Dlco annual decline of 0.89%± 0.42%/y (P= .039). Patients with COPD have an accelerated decline in Dlco compared with smokers without the disease. However, the decline is slow, and a testing interval of 3 to 4 years may be clinically informative. The lower and more rapid decline in Dlco values in women, compared with men, suggests a differential impact of sex in gas exchange function. ClinicalTrials.gov; No.: NCT01122758; URL: www.clinicaltrials.gov.

A STUDY OF INTERSTITIAL LUNG DISEASE ASSOCIATED WITH RHEUMATOID ARTHRITIS

BACKGROUND: Rheumatoid Arthritis (RA) is a common systemic disease that manifests as inflammatory arthritis of multiple joints and produces a wide variety of extra-articular manifestations. Interstitial Lung Disease (ILD) is one of the important pulmonary manifestation of RA like other Connective Tissue Disease(CTD). However RA-ILD differs from CTD-ILD in terms of histopathology and prognosis. OBJECTIVES: To study the clinical features, laboratory profile, radiological patterns, pulmonary function tests including spirometry and DLCO in patients with RA-ILD. MATERIALS AND METHODS: This study was a cross sectional study carried out in the department of Respiratory Medicine at MMIMSR,Mullana, Haryana. A total of 10 patients were included in the study after verifying inclusion and exclusion criteria. After complete history and investigations details were documented in a proforma. RESULTS: A total of 10 patients comprising of 3 males and 7 females with a mean age of 56.5 years were included. Dry cough (100%) was the most common presenting complaints followed by excertional dyspnoea (80%). Among the 10 patients 8 were smokers. Bilateral basal Velcro creps was the most common feature (70%) followed by clubbing(20%).In HRCT the most common pattern was UIP (typical UIP-10%, probable UIP-70%) followed by Non-IPF pattern (20%). Spirometry showed restrictive pattern in all cases. DLCO was severely reduced in typical UIP pattern. CONCLUSION: HRCT chest is the most sensitive tool for early diagnosis of ILD, while DLCO is most sensitive for monitoring the prognosis. RA-ILD can be prevented and treated at an early state.

Comparison between quantitative computed tomography, scintigraphy, and anatomical methods for prediction of postoperative FEV1 and DLCO: effects of chronic obstructive pulmonary disease status and resected lobes.

BackgroundPostoperative assessment of pulmonary function is important for estimating the risk of thoracic surgery and long-term disability following pulmonary resection, including predicted postoperative (ppo) forced expiratory volume (FEV) in one second (ppoFEV1) and percent predicted lung diffusion capacity for carbon monoxide (ppo%DLCO) estimation. The ppo values were compared using four different estimation methods between chronic obstructive pulmonary disease (COPD) and non-COPD patients and according to the resected lobe.MethodsThis prospective study included 59 eligible patients requiring single lobectomy and succeeded in performing pulmonary function tests at 3 and 12 months after lobectomy. The ppoFEV1 and ppo%DLCO were compared with poFEV1 and po%DLCO obtained at 3 and 12 months after lobectomy. The ppo values were estimated using the four usual methods: the 19-segment anatomical technique (S), perfusion scintigraphy (Q), quantitative CT (CT), and quantitative CT with low attenuation volume (CTLAV) subtraction.ResultsFor non-COPD and COPD patients, the smallest mean difference between ppo and po values was observed by S for FEV1 and %DLCO. Based on the resected lobe, the smallest mean difference was observed by (I) Q for right upper lobectomy (RUL) excluding %DLCO at 12 months by S, (II) S for left upper lobectomy (LUL), (III) CT and CTLAV for right lower lobectomy (RLL), and (IV) CT and CTLAV for left lower lobectomy (LLL) at 12 months. The ppo values calculated by S for RUL (FEV1 at 3 and 12 months and %DLCO at 3 months) and by all four methods for LLL (FEV1 and %DLCO at 3 months) were smaller than the po values.ConclusionsThe S method is adequate for calculating ppoFEV1 and ppo%DLCO when patients are classified as non-COPD and COPD. However, S sometimes overestimates the ppoFEV1 and ppo%DLCO when patients are classified according to the resected lobe. The CTLAV method may be the method of choice instead of S for calculating ppoFEV1 and ppo%DLCO in patients who undergo lung lobectomy despite the presence or absence of airflow limitation.

Autoantibody status is not associated with change in lung function or survival in patients with idiopathic pulmonary fibrosis.

A proportion of patients with idiopathic pulmonary fibrosis (IPF) have autoantibodies directed against intracellular targets. This study aimed to determine the relationship between serologic status, lung function decline and survival. IPF patients assessed for antinuclear antibody (ANA) and related antigen-specific serology detected by addressable laser bead immunoassay (ALBIA) were included. Demographics, serial pulmonary function tests and survival were compared between patients with and without autoantibodies. Linear mixed models were used to estimate changes in forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLCO) over time. Cox-proportional hazards models were used to compare survival, adjusted for a composite score including age, sex and baseline lung function. Of 61 included patients, the mean baseline age was 70 years (SD=9), 77% were male, and 87% were Caucasian. Either ANA or antigen-specific serology by ALBIA was positive in 25 (41%) during follow-up. ANA was detected in 23 (38%), and specific autoantibodies by ALBIA in 6 (10%). There was no difference in age, sex, race, smoking status, anti-fibrotic use or baseline FVC or DLCO in patients with and without autoantibodies. There was no association between autoantibody status and survival (HR=1.18, 95% CI 0.61, 2.29), rate of decline in FVC or DLCO (difference in FVC=4.2mL/year, p=0.82; difference in DLCO=4.6*10-4 mL/min/mmHg/year, p = 0.20). These data suggest that autoantibodies are common in IPF and that patients with a subset of autoantibodies, but without features of autoimmunity, demonstrate similar disease behaviour to those without autoantibodies.

Independent Prognostic Value of Pulmonary Diffusing Capacity in Nonsmoking Patients with Chronic Heart Failure.

The diffusing capacity of the lung for carbon monoxide (DLCO) is indicative of the alveolar-capillary membrane function. A reduced DLCO is associated with poor prognosis in chronic heart failure (HF). However, the significance of DLCO as an independent prognostic predictor has not been established. Here, we aimed to determine the prognostic value of DLCO in patients with chronic HF.We enrolled 214 patients (139 females, mean age: 63 ± 16 years, left ventricular ejection fraction [LVEF]: 45 ± 21%) with stable chronic HF who underwent pulmonary function tests. Only never smokers were included in the analysis because smoking can decrease DLCO.During a median follow-up period of 2.1 years, 52 patients (24.3%) experienced cardiac events, including unplanned HF admissions, left ventricular assist device (LVAD) implantations, all-cause deaths, and cardiopulmonary arrests (CPAs). The median percent predicted DLCO (%DLCO) was 87.3%. In a Cox regression analysis, a %DLCO of ≤87.3% was independently associated with the cardiac events, even after adjusting for age, sex, systolic blood pressure (SBP), LVEF, anemia, brain natriuretic peptide, estimated glomerular filtration rate (eGFR), and prior HF admission (hazard ratio [HR]: 1.87, 95% confidence interval: 1.03-3.53, P = 0.030).A reduced DLCO is an independent predictor of poor prognosis in nonsmoking patients with chronic HF.

Performance of Forced Vital Capacity and Lung Diffusion Cutpoints for Associated Radiographic Interstitial Lung Disease in Systemic Sclerosis

Forced vital capacity (FVC) and DLCO are used for screening of systemic sclerosis-associated interstitial lung disease (SSc-ILD). The study purpose was to determine the sensitivity, specificity, and negative predictive value (NPV) (proportion of true negative screening tests) of FVC and DLCO thresholds for SSc-ILD on chest high-resolution computed tomography (HRCT) scans. Patients fulfilling American College of Rheumatology 2013 SSc criteria with a chest HRCT scan and pulmonary function tests (PFT) were studied. A thoracic radiologist quantified radiographic ILD. Optimal FVC and DLCO % predicted thresholds for ILD were identified using receiver-operating characteristic curves. The FVC and DLCO combinations with greatest sensitivity and specificity were also determined. Subanalysis was performed in patients with positive Scl-70 autoantibodies. The study included 265 patients. Of 188 (71%) with radiographic ILD, 59 (31%) had "normal" FVC (≥ 80% predicted), and 65 out of 151 (43%) had "normal" DLCO (≥ 60% predicted). FVC < 80% (sensitivity 0.69, specificity 0.73), and DLCO < 62% (sensitivity 0.60, specificity 0.70) were optimal thresholds for radiographic SSc-ILD. All FVC and DLCO threshold combinations evaluated had NPV < 0.70. The NPV for radiographic ILD for FVC < 80% was lower in patients with positive Scl-70 autoantibody (NPV = 0.05) compared to negative Scl-70 autoantibody (NPV = 0.57). Radiographic ILD is prevalent in SSc despite "normal" PFT. No % predicted FVC or DLCO threshold combinations yielded high NPV for SSc-ILD screening. "Normal" FVC and DLCO in patients with SSc, especially those with positive Scl-70 autoantibodies, should not obviate consideration of HRCT for ILD evaluation.

A COMPARATIVE EVALUATION OF DLCO IN PATIENTS OF ACOS, ASTHMA, AND COPD

A COMPARATIVE EVALUATION OF DLCO IN PATIENTS OF ACOS, ASTHMA, AND COPD

Isolated decrease of the lung diffusing capacity in patients with systemic sclerosis without pulmonary arterial hypertension: a long-term prospective study

The objective of this 5year prospective study was to investigate a clinical role of isolated decrease of DLCO in patients with systemic sclerosis (SS) without pulmonary arterial hypertension (PAH).Methods. We selected 48 out of 142 patients with SS: 35 (73%) with limited SS and 13 (27%) with diffuse SS. The average length of the disease was 12.9 ± 7.9 years. Inclusion criteria were DLCO &lt; 80% pred., forced vital capacity (FVC) ≥ 80% pred. and systolic pulmonary artery pressure (PAP) ≤ 35 mm Hg according to echocardiographic examination (echoCG). High resolution computed tomography (HRCT), spirometry, DLCO measurement, and echoCG were obtained at baseline and after 4.7 ± 1 year of follow up. All patients were treated with standard therapy.Results. CT signs of interstitial lung disease (ILD) were found in 43 (89.6%) patients at baseline and newly developed in 3 other patients during the followup. During the followup, lung CT improved in 5 (10.4%) patients and progressed in 15 (31.3%) patients. Over 5 years, FVC did not change significantly (97.6 ± 10.7% and 100.8 ± 18.9%; р = 0.15), while DLCO significantly decreased both in limited and diffuse SS groups (59.8 ± 13.5% and 56.3 ± 12%; р = 0.006). Mean PAP values remained within normal range in majority of patients. Clinically significant FVC reduction (≥ 10%) was found in 5 patients; of them, CT signs of ILD at baseline were seen in 3 patients and newly developed during the followup in 2 others. Clinically significant DLCO reduction (≥ 10%) was documented in 11 (23%) patients, all had CT signs of ILD at baseline, although CT progression during the followup was noted only in six of them. Contemporary deterioration in FVC, DLCO and CT was found in 3 patients.Conclusion. Clinical course of ILD in SS patients with isolated DLCO reduction and without PAH was relatively benign, with respiratory volumes being preserved within normal range for long time. Comparison of radiological and functional changes in a prospective study has suggested that DLCO is a more sensitive tool to determine ILD progression compared to HRCT. Regular DLCO measurements could be used as a reliable tool for monitoring of ILD associated with SS.

Can the measurement of pulmonary diffusing capacity for nitric oxide replace the measurement of pulmonary diffusing capacity for carbon monoxide?

Pulmonary diffusing capacity for carbon monoxide (DLCO) has been an important pulmonary function test used since the 1950’s. It measures the uptake of CO from the alveolar space into pulmonary capillary blood, following the same path as oxygen. It’s used to evaluate/follow the progress of various lung diseases. In the eighties, a new test was developed similar to the DLCO test: pulmonary diffusing capacity for nitric oxide (DLNO). About 81–90% of the variance in DLNO is shared by DLCO in patients with cardiopulmonary disease and in healthy subjects. When DLNO is abnormally low, so is DLCO, and when DLNO is normal, so is DLCO (Kappa Statistic=0.69, n=251). The probability that DLNO and DLCO will be abnormally low when a cardiopulmonary disease is present (sensitivity) is 79% and 68%, respectively. The DLNO test avoids many technical issues associated with the measurement of DLCO: (1) DLNO is relatively unaffected by inspired oxygen concentration or ambient pressure, (2) DLNO is unaffected by carboxyhemoglobin, (3) DLNO is minimally affected by hemoglobin (Hb) concentration, thus correcting for Hb is not needed. (4) DLNO is more affected by lung volume compared to DLCO, thus DLNO divided by alveolar volume (KNO) is a better measure than KCO in those with restrictive lung disease, and (5) DLNO is a more stable measure over time compared to DLCO. Therefore, DLNO has several advantages over DLCO in the management of patients and could replace the DLCO test in most cases moving forward.

Use of Mycophenolate Mofetil or Azathioprine for the Management of Chronic Hypersensitivity Pneumonitis

The treatment of chronic hypersensitivity pneumonitis (cHP) often includes systemic oral corticosteroids, but the optimal pharmacologic management remains unclear. The morbidity associated with prednisone has motivated the search for alternative therapies. We aimed to determine the effect of treatment with mycophenolate mofetil (MMF) or azathioprine (AZA) on lung function in patients with cHP. Patients with cHP treated with either MMF or AZA were retrospectively identified from four interstitial lung disease centers. Change in lung function before and after treatment initiation was analyzed using linear mixed-effects modeling (LMM), adjusting for age, sex, smoking history, and prednisone use. Seventy patients were included: 51 were treated with MMF and 19 with AZA. Median follow-up after treatment initiation was 11months. Prior to treatment initiation, FVC and diffusion capacity of the lung for carbon monoxide (Dlco) %predicted were declining at a mean rate of 0.12%(P< .001) and 0.10%(P< .001) per month, respectively. Treatment with either MMF or AZA was not associated with improved FVC (0.5%at 1 year; P= .46) but was associated with a statistically significant improvement in Dlco of 4.2%(P< .001) after 1 year of treatment. Results were similar in the subgroup of patients treated with MMF for 1 year; the FVC increased nonsignificantly by 1.3%(P= .103) and Dlco increased by 3.9%(P< .001). Treatment with MMF or AZA is associated with improvements in Dlco in patients with cHP. Prospective randomized trials are needed to validate their effectiveness for cHP.

Effect of Obesity on Diffusing Capacity of Lung for Carbon Monoxide: Quality Improvement Project

SESSION TITLE: Pulmonary Physiology Posters SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM PURPOSE: Various reference equations are available to determine predicted values for the diffusing capacity of the lung for carbon monoxide (DLCO). Most were derived many years ago from reference populations with a lower the prevalence of obesity than is seen in contemporary patients. We conducted this study to evaluate the effect of elevated body mass index (BMI) on the predicted value for DLCO in patients without known lung disease. METHODS: A retrospective analysis of pulmonary function tests (PFTs) of patients with BMI > 30 and age >18 years was performed. We excluded patients with obstructive and restrictive lung disease defined as FEV1/FVC <0.7% and FVC<80% predicted or unacceptable study as per ATS guidelines. DLCO was determined by the single breath method with predicted values derived by Burrows and Roca reference equations. RESULTS: Analyses were carried out on 359 patients, 178 males and 181 females. The mean age, BMI and measured DLCO for males was 56 +15.4 years, 34.7+3.95 kg/m2and 22.2+5.98 ml/mmHg/min, and for females 55+15.3 years, 36.8+5.16 kg/m2 and 16.4+3.65 ml/mmHg/min. The measured DLCO declined with increasing age regardless of sex.. Females had significantly higher BMIs than males whereas the latter had significantly higher DLCO actual than females. We found a decline in DLCO measured with increasing age regardless of sex (ANOVA, p< 0.001) whereas an effect of BMI was not significant. Reference equations for predicted DLCO (Burrows and Roca) were examined; these gave estimates that were larger than DLCO measured regardless of gender. ANCOVA was performed on DLCO predicted: a significant effect of age was noted and the effect of BMI was now found to be highly significant (p < 0.001). CONCLUSIONS: DLCO predicted (Burrows and Roca) appeared to be larger than DLCO measured in patients with BMI> 30. This may lead to unnecessary diagnostic testing; hence, predicted DLCO should be cautiously interpreted in this cohort of patients. CLINICAL IMPLICATIONS: Physicians should cautiously interpret DLCO values predicted by Burrows and Roca equations in patients with BMI ≥ 30. DISCLOSURE: The following authors have nothing to disclose: Alexander Blood, Anup Singh, Annamaria Iakovou, Anthony Sica, Harly Greenberg, Arunabh Talwar No Product/Research Disclosure Information

Measurement of CO diffusion capacity (II): Standardisation and quality criteria

The diffusion capacity is the technique that measures the ability of the respiratory system for gas exchange, thus allowing a diagnosis of the malfunction of the alveolar-capillary unit. The most important parameter to assess is the CO diffusion capacity (DLCO). New methods are currently being used to measure the diffusion using nitric oxide (NO). There are other methods for measuring diffusion, although in this article the single breath technique is mainly referred to, as it is the most widely used and best standardized. Its complexity, its reference equations, differences in equipment, inter-patient variability and conditions in which the DLCO is performed, lead to a wide inter-laboratory variability, although its standardization makes this a more reliable and reproductive method. The practical aspects of the technique are analyzed, by specifying the recommendations to carry out a suitable procedure, the calibration routine, calculations and adjustments. Clinical applications are also discussed. An increase in the transfer of CO occurs in diseases in which there is an increased volume of blood in the pulmonary capillaries, such as in the polycythemia and pulmonary hemorrhage. There is a decrease in DLCO in patients with alveolar volume reduction or diffusion defects, either by altered alveolar-capillary membrane (interstitial diseases) or decreased volume of blood in the pulmonary capillaries (pulmonary embolism or primary pulmonary hypertension). Other causes of decreased or increased DLCO are also highlighted.

Medición de la difusión de CO (II): estandarización y criterios de calidad

The diffusion capacity is the technique that measures the ability of the respiratory system for gas exchange, thus allowing a diagnosis of the malfunction of the alveolar-capillary unit. The most important parameter to assess is the CO diffusion capacity (DLCO). New methods are currently being used to measure the diffusion using nitric oxide (NO). There are other methods for measuring diffusion, although in this article the single breath technique is mainly referred to, as it is the most widely used and best standardized.Its complexity, its reference equations, differences in equipment, inter-patient variability and conditions in which the DLCO is performed, lead to a wide inter-laboratory variability, although its standardization makes this a more reliable and reproductive method.The practical aspects of the technique are analyzed, by specifying the recommendations to carry out a suitable procedure, the calibration routine, calculations and adjustments. Clinical applications are also discussed. An increase in the transfer of CO occurs in diseases in which there is an increased volume of blood in the pulmonary capillaries, such as in the polycythemia and pulmonary hemorrhage. There is a decrease in DLCO in patients with alveolar volume reduction or diffusion defects, either by altered alveolar-capillary membrane (interstitial diseases) or decreased volume of blood in the pulmonary capillaries (pulmonary embolism or primary pulmonary hypertension). Other causes of decreased or increased DLCO are also highlighted.

Long-term follow-up of whole lung lavage in patients with pulmonary alveolar proteinosis.

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by intra-alveolar accumulation of lipid and proteinaceous material. While a small subset of patients with PAP spontaneously improve or even undergo disease remission, the majority of patients develop persistent or progressive disease. Numerous therapies have been used to treat PAP over the years; however, at present, whole lung lavage (WLL) remains the gold standard treatment for PAP. In the present study, data were accumulated from a cohort of patients with PAP (n=11) between 2003 and 2011 at the Wuxi People’s Hospital Affiliated to Nanjing Medical University. The disease affected males and females with a ratio of 2.7:1 and all the males were current or previous smokers. The disease severity score (DSS) of the patients was mainly distributed in DSS 4 or DSS 5. All the patients underwent WLL at least once, with one patient undergoing WLLs twice and another patient three times. The clinical features, arterial blood gas and pulmonary function of the patients, were assessed prior to and following the lavage. WLL resulted in a significant improvement in symptoms, radiographic features, PaO2, D(A-a)O2 and DLCO in patients with PAP, while pulmonary ventilation function did not significantly improve. WLL appears to be an effective approach for the treatment of PAP and leads to an improvement in survival rate.

Increased Serum Pentraxin 3 in Patients with Systemic Sclerosis

To determine serum concentrations of pentraxin 3 (PTX3) and its clinical associations in patients with systemic sclerosis (SSc). Serum PTX3 levels from 45 patients with diffuse cutaneous SSc (dSSc), 46 with limited cutaneous SSc (lSSc), and 20 healthy controls were examined by ELISA. PTX3 expression in the sclerotic skin from SSc patients was evaluated immunohistochemically. Normal and SSc fibroblasts were cultured and PTX3 levels in the culture medium were also examined by ELISA. Serum PTX3 levels were elevated in patients with SSc relative to controls. PTX3 levels in dSSc patients were significantly higher than in controls and lSSc patients. PTX3 expression in the sclerotic skin from SSc patients was more intense relative to normal skin. Elevation of serum PTX3 levels was associated with more frequent presence of pulmonary fibrosis, cardiac disease, and pitting scar/ulcer and increased serum immunoglobulin levels and erythrocyte sedimentation rates. PTX3 levels correlated positively with modified Rodnan total skin thickness score, and negatively with percentage vital capacity and percentage DLCO in patients with SSc. PTX3 levels also correlated positively with serum levels of 8-isoprostane, a marker of oxidative stress, and hyaluronan, recently identified as an endogenous ligand for Toll-like receptors. PTX3 production from cultured SSc fibroblasts was increased by stimulation with hyaluronan. These results suggest that elevated serum PTX3 levels are associated with the disease severity of SSc.