Single-breath Method Research Articles

Impact of a 12-week high-intensity interval training intervention on cardiac structure and function after COVID-19 at 12-month follow-up.

In patients previously hospitalised for COVID-19, a 12-week high-intensity interval training (HIIT) intervention has previously been shown to increase left ventricular mass (LVM) immediately after the intervention. In the present study, we examined the effects of the same HIIT scheme on LVM, pulmonary diffusing capacity, symptom severity and functional capacity at 12-month follow-up. In this investigator-blinded, randomised controlled trial, 12weeks of a supervised HIIT scheme (4×4min, three times a week) was compared to standard care (control) in patients recently discharged from hospital due to COVID-19. At inclusion and at 12-month follow-up, LVM was assessed by cardiac magnetic resonance imaging (cMRI, primary outcome), while pulmonary diffusing capacity for carbon monoxide (DLCOc, secondary outcome) was examined by the single-breath method. Symptom severity and functional status were examined by the Post-COVID-19 Functional Scale (PCFS) and King's Brief Interstitial Lung Disease (KBILD) questionnaire score. Of the 28 patients assessed at baseline, 22 completed cMRI at 12-month follow-up (12.4±0.6months after inclusion). LVM was maintained in the HIIT but not the standard care group, with a mean between-group difference of 9.68 [95% CI: 1.72, 17.64] g (P=0.0182). There was no differences in change from baseline to 12-month follow-up between groups in DLCOc % predicted (-2.45 [-11.25, 6.34]%; P=0.578). PCFS and KBILD improved similarly in the two groups. In individuals previously hospitalised for COVID-19, a 12-week supervised HIIT scheme resulted in a preserved LVM at 12-month follow-up but did not affect pulmonary diffusing capacity or symptom severity.

Hypercapnia and lung function parameters in chronic obstructive pulmonary disease

BackgroundIn advanced chronic obstructive pulmonary disease (COPD), hypercapnia may occur due to severe bronchial obstruction with lung hyperinflation. Non-invasive ventilation (NIV) provides the standard of care intended to achieve physiological PCO2 levels, thereby reducing overall mortality. The present study aimed to evaluate pulmonary function parameters derived from spirometry (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV1]), body plethysmography (residual volume [RV], total lung capacity [TLC]), and lung diffusion capacity for carbon monoxide (single-breath method [DCO-SB], alveolar-volume corrected values [DCO-VA]) as predictors of chronic hypercapnia in patients with advanced COPD.MethodsThis monocentric, retrospective observational study included 423 COPD patients. Receiver operating characteristic (ROC) curve analysis and cross-validation were used to assess lung function parameters’ diagnostic accuracy for predicting chronic hypercapnia, with the resulting performance expressed as area under the ROC curve (AUROC). We performed univariable and multivariable binary logistic regression analysis to determine if these parameters were independently associated with chronic hypercapnia, with probabilities reported as odds ratios [OR] with 95% confidence intervals [95%CI].ResultsFVC% (AUROC 0.77 [95%CI 0.72–0.81], P < 0.01) and FEV1% (AURIC 0.75 [95%CI 0.70–0.79], P < 0.01) exhibited reasonable accuracy in the prediction of chronic hypercapnia, whereas lung diffusion capacity performed poorly (AUROC 0.64 [95%CI 0.58–0.71] for DCO-SB%, P < 0.01). FVC% (OR 0.95 [95%CI 0.93–0.97], P < 0.01) and FEV1% (OR 0.97 [95%CI 0.94–0.99], P = 0.029) were the only parameters associated independently with chronic hypercapnia in logistic regression analysis. FVC and FEV1 thresholds that best separated hypercapnic from normocapnic subjects reached 56% and 33% of predicted values.ConclusionsRoutinely collected pulmonary function parameters, particularly FVC% and FEV1%, may predict chronic hypercapnia during COPD progression.

Effect of Ultramarathon Trail Running at Sea Level and Altitude on Alveolar-Capillary Function and Lung Diffusion.

Endurance exercise at altitude can increase cardiac output and pulmonary vascular pressure to levels that may exceed the stress tolerability of the alveolar-capillary unit. This study examined the effect of ultramarathon trail racing at different altitudes (ranging from <1000 m to between 1500 and 2700 m) on alveolar-capillary recruitment and lung diffusion. Cardiac and lung function were examined before and after an ultramarathon in 67 runners (age: 41 ± 9 yr, body mass index: 23 ± 2 kg·m -2 , 10 females), and following 12-24 h of recovery in a subset ( n = 27). Cardiac biomarkers (cTnI and BNP) were assessed from whole blood, whereas lung fluid accumulation (comet tails), stroke volume (SV), and cardiac output ( Q ) were quantified via echocardiography. Lung diffusing capacity for carbon monoxide (DLco) and its components, alveolar membrane conductance (Dm) and capillary blood volume (Vc), were determined via a single-breath method at rest and during three stages of submaximal semirecumbent cycling (20, 30, and 40 W). Average race time was 25 ± 12 h. From pre- to post-race, there was an increase in cardiac biomarkers (cTnI: 0.04 ± 0.02 vs 0.13 ± 0.03 ng·mL -1 , BNP: 20 ± 2 vs 112 ± 21 pg·mL -1 ; P < 0.01) and lung comet tails (2 ± 1 vs 7 ± 6, P < 0.01), a decrease in resting and exercise SV (76 ± 2 vs 69 ± 2 mL, 40 W: 93 ± 2 vs 88 ± 2 mL; P < 0.01), and an elevation in Q at rest (4.1 ± 0.1 vs 4.6 ± 0.2 L·min -1 , P < 0.01; 40 W: 7.3 ± 0.2 vs 7.4 ± 0.3 L·min -1 , P = 0.899). Resting DLco and Vc decreased after the race ( P < 0.01), whereas Dm was unchanged ( P = 0.465); however, during the three stages of exercise, DLco, Vc, and Dm were all reduced from pre- to post-race (40 W: 36.3 ± 0.9 vs 33.0 ± 0.8 mL·min -1 ·mm Hg -1 , 83 ± 3 vs 73 ± 2 mL, 186 ± 6 vs 170 ± 7 mL·min -1 ·mm Hg -1 , respectively; P < 0.01). When corrected for alveolar volume and Q , DLco decreased from pre- to post-race ( P < 0.01), and changes in DLco were similar for all ultramarathon events ( P > 0.05). Competing in an ultramarathon leads to a transient increase in cardiac injury biomarkers, mild lung-fluid accumulation, and impairments in lung diffusion. Reductions in DLco are predominantly caused by a reduced Vc and possible pulmonary capillary de-recruitment at rest. However, impairments in alveolar-capillary recruitment and Dm both contribute to a fall in exertional DLco following an ultramarathon. Perturbations in lung diffusion were evident across a range of event distances and varying environmental exposures.

Pulmonary diffusing capacity for carbon monoxide and nitric oxide after COVID-19: A prospective cohort study (the SECURe study).

Many patients exhibit persistently reduced pulmonary diffusing capacity after coronavirus disease 2019 (COVID-19). In this study, dual test gas diffusing capacity for carbon monoxide and nitric oxide (DL,CO,NO) metrics and their relationship to disease severity and physical performance were examined in patients who previously had COVID-19. An initial cohort of 148 patients diagnosed with COVID-19 of all severities between March 2020 and March 2021 had a DL,CO,NO measurement performed using the single-breath method at 5.7months follow-up. All patients with at least one abnormal DL,CO,NO metric (n=87) were revaluated at 12.5months follow-up. The DL,CO,NO was used to provide the pulmonary diffusing capacity for nitric oxide (DL,NO), the pulmonary diffusing capacity for carbon monoxide (DL,CO,5s), the alveolar-capillary membrane diffusing capacity and the pulmonary capillary blood volume. At both 5.7 and 12.5months, physical performance was assessed using a 30 s sit-to-stand test and the 6min walk test. Approximately 60% of patients exhibited a severity-dependent decline in at least one DL,CO,NO metric at 5.7months follow-up. At 12.5months, both DL,NO and DL,CO,5s had returned towards normal but still remained abnormal in two-thirds of the patients. Concurrently, improvements in physical performance were observed, but with no apparent relationship to any DL,CO,NO metric. The severity-dependent decline in DL,NO and DL,CO observed at 5.7months after COVID-19 appears to be reduced consistently at 12.5months follow-up in the majority of patients, despite marked improvements in physical performance.

Dual Test Gas Pulmonary Diffusing Capacity Measurement During Exercise in Humans Using the Single-Breath Method.

The combined single-breath measurement of the diffusing capacity of carbon monoxide (DL,CO) and nitric oxide (DL,NO) is a useful technique to measure pulmonary alveolar-capillary reserve in both healthy and patient populations. The measurement provides an estimate of the participant's ability to recruit and distend pulmonary capillaries. The method has recently been reported to exhibit a high test-retest reliability in healthy volunteers during exercise of light to moderate intensity. Of note, this technique permits up to 12 repeated maneuvers and only requires a single breath with a relatively short breath-hold time of 5 s. Representative data are provided showing the gradual changes in DL,NO and DL,CO from rest to exercise at increasing intensitiesof up to 60% of maximal workload. The measurement of diffusing capacity and evaluation of alveolar-capillary reserve is a useful tool to evaluate the lung's ability to respond to exercise both in the healthy population as well as in patient populations such as those with chronic lung disease.

Evaluation of the Relationship Between Pulmonary Perfusion Via Chest Digital Dynamic Radiography System and Diffusing Capacity Test.

Non-invasive, visual, and quantitative in vivo evaluation of pulmonary blood flow is helpful in assessing gas exchange at the alveolar level. A chest digital dynamic radiography system (CDDR) has the potential to visually and quantitatively express pulmonary haemodynamics using temporal changes in radiographic transparency synchronised with the heartbeat. The lung-diffusing capacity (DLCO) test involves membranous factors comprising the alveolar membrane, interstitium, and vascular walls. Additionally, DLCO includes pulmonary blood flow factors defined by pulmonary capillary blood flow and haemoglobin levels. In individuals lacking an alveolar septum, interstitial abnormalities or anaemia leading to changes in DLCO may reflect changes in the pulmonary blood flow. Here, we investigated the usefulness of CDDR in evaluating pulmonary blood flow by comparing it with DLCO.For pulmonary blood flow, we extracted and visualised signal changes in the lung field synchronised with heart rate during CDDR imaging and created a maximum intensity projection (MIP). The DLCO was measured using the single-breath method. Among the patients who underwent CDDR, 10 with FEV/FVC (FEV1.0%)>70% and 16 with COPD (FEV1.0%<70%) without noticeable interstitial changes were included, with a cutoff=70%/predicted value. MIP was compared as a pulmonary blood flow evaluation method in the DLCO≥70% group (control group: n=15) and the DLCO<70% group (decreased DLCO group: n=11). The mean and median values of MIP in the reduced group were lower than those in the control group (p<0.05).Pulmonary blood flow evaluated using CDDR may be able to assess pulmonary circulatory disturbances visually and quantitatively, as indicated by decreased pulmonary diffusion capacity in patients with negligible pulmonary interstitial changes and anaemia.

Gas Exchange in Patients with Pulmonary Tuberculosis: Relationships with Pulmonary Poorly Communicating Fraction and Alveolar Volume

Tuberculosis-related lung damage is very different. Lung ventilation disorders have been studied in patients with pulmonary tuberculosis (TB) during the active process and after treatment, but the main causes of gas exchange changes have not been sufficiently studied. Investigation of diffusing lung capacity in combination with bodyplethysmography is useful for the interpretation of pulmonary gas exchange disorders. The aim was to determine the relationship of gas exchange with the value of alveolar volume (VA) and pulmonary poorly communicating fraction (PCF) in patients with pulmonary TB. A total of 292 patients (117/175 M/W) with verified pulmonary TB with smoking age less than 10 packs-years underwent spirometry, bodyplethysmography, and DLCO by the single-breath method. PCF was estimated calculating the difference between total lung capacity (TLC) and VA (% TLC). Patients with low DLCO had statistically significantly lower spirometric values (FVC, FEV1, FEV1/FVC, MMEF), lower TLC, higher airway resistance, RV/TLC, air-trapping volume, and PCF. The patients with low level of DLCO were divided into four groups depending on level VA and PCF. In most patients with infiltrative tuberculosis (50%), the leading syndrome of the DLCO decrease was alveolar-capillary damage. In patients with tuberculomas, the syndromes of alveolar capillary damage and pulmonary ventilation inhomogeneity were with the same frequency (43%). In patients with disseminated tuberculosis, the most frequent syndrome of the DLCO decrease was pulmonary ventilation inhomogeneity (33%), then alveolar-capillary damage (29%) and mixed (24%). In patients with cavernous tuberculosis, the leading syndrome of the DLCO decrease was mixed (39%), then alveolar capillary damage (25%) and pulmonary ventilation inhomogeneity (23%). The syndrome of gas exchange surface reduction in patients with disseminated and cavernous tuberculosis was less common (14%). In conclusion, an additional evaluation of the combination of PCF and VA increases the amount of clinical information obtained using the diffusion lung capacity measurements, since it allows identifying various syndromes of gas exchange impairment. The leading causes of diffusing capacity impairment vary by different types of pulmonary TB.

A single-breath-hold protocol for hyperpolarized 129 Xe ventilation and gas exchange imaging.

Hyperpolarized 129 Xe MRI (Xe-MRI) is increasingly used to image the structure and function of the lungs. Because 129 Xe imaging can provide multiple contrasts (ventilation, alveolar airspace size, and gas exchange), imaging often occurs over several breath-holds, which increases the time, expense, and patient burden of scans. We propose an imaging sequence that can be used to acquire Xe-MRI gas exchange and high-quality ventilation images within a single, approximately 10 s, breath-hold. This method uses a radial one-point Dixon approach to sample dissolved 129 Xe signal, which is interleaved with a 3D spiral ("FLORET") encoding pattern for gaseous 129 Xe. Thus, ventilation images are obtained at higher nominal spatial resolution (4.2 × 4.2 × 4.2 mm3 ) compared with gas-exchange images (6.25 × 6.25 × 6.25 mm3 ), both competitive with current standards within the Xe-MRI field. Moreover, the short 10 s Xe-MRI acquisition time allows for 1 H "anatomic" images used for thoracic cavity masking to be acquired within the same breath-hold for a total scan time of about 14 s. Images were acquired using this single-breath method in 11 volunteers (N = 4 healthy, N = 7 post-acute COVID). For 11 of these participants, a separate breath-hold was used to acquire a "dedicated" ventilation scan and five had an additional "dedicated" gas exchange scan. The images acquired using the single-breath protocol were compared with those from dedicated scans using Bland-Altman analysis, intraclass correlation (ICC), structural similarity, peak signal-to-noise ratio, Dice coefficients, and average distance. Imaging markers from the single-breath protocol showed high correlation with dedicated scans (ventilation defect percent, ICC = 0.77, p = 0.01; membrane/gas, ICC = 0.97, p = 0.001; red blood cell/gas, ICC = 0.99, p < 0.001). Images showed good qualitative and quantitative regional agreement. This single-breath protocol enables the collection of essential Xe-MRI information within one breath-hold, simplifying scanning sessions and reducing costs associated with Xe-MRI.

Relationships of computed tomography-based small vessel indices of the lungs with ventilation heterogeneity and high transfer coefficients in non-smokers with asthma.

Background: The mechanism of high transfer coefficients of the lungs for carbon monoxide (Kco) in non-smokers with asthma is explained by the redistribution of blood flow to the area with preserved ventilation, to match the ventilation perfusion. Objectives: To examine whether ventilation heterogeneity, assessed by pulmonary function tests, is associated with computed tomography (CT)-based vascular indices and Kco in patients with asthma. Methods: Participants were enrolled from the Hokkaido-based Investigative Cohort Analysis for Refractory Asthma (Hi-CARAT) study that included a prospective asthmatic cohort. Pulmonary function tests including Kco, using single breath methods; total lung capacity (TLC), using multiple breath methods; and CT, were performed on the same day. The ratio of the lung volume assessed using single breath methods (alveolar volume; VA) to that using multiple breath methods (TLC) was calculated as an index of ventilation heterogeneity. The volume of the pulmonary small vessels <5mm2 in the whole lung (BV5 volume), and number of BV5 at a theoretical surface area of the lungs from the plural surface (BV5 number) were evaluated using chest CT images. Results: The low VA/TLC group (the lowest quartile) had significantly lower BV5 number, BV5 volume, higher BV5 volume/BV5 number, and higher Kco compared to the high VA/TLC group (the highest quartile) in 117 non-smokers, but not in 67 smokers. Multivariable analysis showed that low VA/TLC was associated with low BV5 number, after adjusting for age, sex, weight, lung volume on CT, and CT emphysema index in non-smokers (not in smokers). Conclusion: Ventilation heterogeneity may be associated with low BV5 number and high Kco in non-smokers (not in smokers). Future studies need to determine the dynamic regional system in ventilation, perfusion, and diffusion in asthma.

Design and Verification of Lung Diffusion Function Detection System

A lung diffusion function detection system is designed. Firstly, the controllable collection of air, test gas source and calibration gas source was based on single-breath method measurement principle. Secondly, pulmonary diffusing capacity for carbon monoxide (DlCO) was calculated by gas concentration measured by the non-dispersive infrared sensor to measure, the gas flow measured by the differential pressure sensor, and the temperature, humidity and atmospheric pressure sensors to test and evaluate the quantitative detection and evaluation of lung diffusion function. Moreover, a preliminary verification of the lung diffusion function detection system was implemented, and the results showed that the error of the lung carbon monoxide diffusion and the alveolar volume did not exceed 5%. Therefore, the system has high accuracy and is of great value for early screening and accurate assessment of COPD.

Changes in Cough Reflex Sensitivity in Children After Removal of Hypertrophied Adenoid Tissue.

PurposeThe co-occurrence of adenoids and chronic cough is common in children. The goal of this research was to specify changes in cough reflex sensitivity as a result of adenoid tissue removal.Patients and MethodsThe sample group consisted of 17 children (six boys and 11 girls, aged 4–12 years, mean age 6.24 years), all of them possessing symptoms of chronic cough and adenoids, confirmed by nasal fiberoptic endoscopy. This sample group underwent cough reflex sensitivity assessment, which took place both prior to and after endoscopic adenoidectomy. The definition of the cough reflex sensitivity is the lowest capsaicin concentration that caused two (C2) or five (C5) coughs. Capsaicin aerosol in ascending concentrations (from 0.61 to 1250 µmol/L) was inhaled by a single-breath method (KoKo DigiDoser), with the addition of an inspiratory flow regulator valve (RIFR).ResultsConcentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Cough sensitivity (geometric mean with 95% CI) for C2 was 31.86 (12.98–78.18) µmol/L preoperatively and 11.97 (6.16–23.26) µmol/L postoperatively (P=0.064). Cough sensitivity for C5 was 234.91 (97.19–567.77) µmol/L preoperatively and 69.13 (29.08–164.35) µmol/L postoperatively (P=0.022). The children’s pulmonary function was within the normal range.ConclusionIn our study, adenoidectomy significantly increased cough reflex sensitivity in non-atopic children suffering from chronic cough.

Impact of Emphysema Subtypes and Volume on Lung Ventilation and Gas Exchange Functions as Evidenced by Computed Tomography

Objective: to characterize the relationship between the subtype and volume of pulmonary emphysema on the indicators of lung ventilation and gas exchange functions. Material and methods. The data of radiation and functional studies were analyzed in 50 patients. The inclusion criteria were chronic obstructive pulmonary disease and emphysema, which had been diagnosed by computed tomography (CT) and confirmed by two radiologists; comprehensive pulmonary function studies, including spirometry and body plethysmography, were performed; diffusion capacity was measured using a single-breath method, involving inhalation of carbon monoxide, and a breath hold. Patients with primary pulmonary emphysema, any history of pulmonary surgery, and emphysema concurrent with other lung X-ray syndromes (consolidation, cavity) were excluded. CT was performed with a 1-mm thick slice and standard scanning parameters on Toshiba tomographs (Japan). Pulmonary function was tested using a MasterScreen Body Diffusion expert diagnostic unit (VIASYS Healthcare, Germany) in accordance with the criteria for correct pulmonary functional tests proposed by a joint group of experts from the American Thoracic Society and the European Respiratory Society. Volumetric analysis of emphysema was performed using the Lung Volume Analysis software package (Toshiba, Japan). In the study, there was a predominance of male patients (n = 42 (84%)), mainly in the 61-70 age group. Results. The isolated type of emphysema was rare: centrilobular and paraseptal emphysemas were seen in 3 (6%) and 2 (4%) patients, respectively. The mixed type of emphysema was detected in 90% of cases; 33 (66%) patients having a predominant centrilobular component constituted a large proportion. It was determined that as the volume of emphysema increased, the patency of the airways worsened, the static pulmonary volumes increased, the lungs were hyperinflated, pulmonary gas exchange worsened, the bronchial resistance slightly increased during calm breathing. No statistically significant results were found from the point of view of correlations between the volume of emphysema and other parameters of pulmonary function. Conclusion. An increase in the volume of emphysema deteriorates pulmonary function; the greatest contribution to the overall picture is made by the patients with a mixed type of emphysema with a predominance of the centrilobular component.

Post-COVID-19 pulmonary function tests in young health care workers in South Indian population – An observational study

Background: The risk of exposure to COVID-19 pandemic was substantially higher in frontline young health care workers. Due to repeated exposure while treating patients, the viral load is exponentially higher than the other population. Lungs being the earliest organ to be affected carry more risk of long-term morbidity. Thus, pulmonary function tests (PFTs) on post-COVID young health care workers provide a better view on the impact, recovery and residual effects. Aim and Objectives: The objectives of the study are as follows: (i) To assess the PFT in study group who have recovered from COVID-19 within the past 3 months; (ii) to compare their lung function with that of health care workers who have not been infected by COVID-19; and (iii) to determine obstructive, restrictive or mixed pulmonary changes if any in health care workers after 3 months of recovery. Materials and Methods: This study involving 50 young health care workers was done in the department of pulmonary medicine for a period of 4 months between January and April 2021. The study (mild COVID-19 positive) control group involved 25 participants each. PFT and diffusing capacity of lung for carbon monoxide (DLCO) were measured using computerized spirometer and single breath method. Results were analyzed using Shapiro–Wilk test, Independent sample t test, and Chi-square test. Results: A statistically significant difference was observed among the subjects of case and control group with respect to the level of FEV1 (P &lt; 0.05), FEV1/Forced vital capacity (FVC) (P &lt; 0.01), and FEF. FVC, Peak expiratory flow (PEF), forced expiratory time, DLCO, and peak inspiratory flow (PIF) were not statistically different between the study and control group. (P &gt; 0.05).The 3-month post recovery values were high in males when compared to females, except for PIF, PEF and FEV1%. Conclusion: PFT and DLCO values were normal in young health care workers after 3 months of COVID-19 infection except for a decrease in FEF 25–75%.

Dynamic diffusion lung capacity of carbon monoxide (DLCO) as a predictor of pulmonary microangiopathy and its association with extra pulmonary microangiopathy in patients with type II diabetes mellitus

Background and aimLung as a target end organ for microvascular disease often remains underdiagnosed. This study aims to assess occurrence of pulmonary microangiopathy among Type 2 diabetes mellitus (T2DM) using dynamic diffusion lung capacity of carbon monoxide (DLCO). MethodsA total of 120 participants aged >18 years were enrolled in this study. Group 1 comprised T2DM with microangiopathy (n = 40), group 2 include T2DM without microangiopathy (n = 40), group 3 were healthy controls (n = 40). Individuals with underlying lung disease, smoking history, heart failure, urinary tract infection, macrovascular complications of diabetes, microalbuminuria due to other causes were excluded from the study. Using electronic spirometry, Forced Expiratory Volume in first second (FEV1), Forced Vital Capacity (FVC) was measured and FEV1/FVC ratio calculated. DLCO (%predicted) using single breath method was measured in sitting position followed by supine position and delta DLCO was calculated. DLCO measured was compared between the three groups. ResultsDLCO (median [IQR]) in sitting (78 [70–82.75]) and supine position (70 [62–84]) among group one was significantly decreased when compared to other two groups (p value < 0.001, p value < 0.001 respectively). Delta DLCO (median, [IQR]) among patients with diabetic microangiopathy (−6 [-8 to −2]) was significant on comparison with group two (4[2,6]) and control group (5[4,6]) (p < 0.001). Negative delta DLCO reflecting pulmonary microangiopathy was significantly associated with extrapulmonary microangiopathy (p value = 0.027). ConclusionPostural variation in DLCO is a useful non-invasive test for identifying pulmonary microangiopathy among T2DM patients. Presence of pulmonary microangiopathy has significant association with diabetic nephropathy and retinopathy.

Correlation between Measurement of Lung Diffusion Capacity Using Single Breath Methods (DLCO-SB) and COPD Group in Persahabatan Hospital Jakarta

Background: This was a preliminary study to measure DLCO-SB on COPD patients in Persahabatan Hospital to understand the prevalence of DLCO reduction among COPD patients.Methods: This was a cross sectional study of COPD patients who attended COPD-Asthma clinic in Persahabatan Hospital Jakarta. Spirometry and DLCO-SB were performed consecutively during May–July 2015. Comorbidities were also recorded.Results: Spirometry and DLCO-SB measurements were conducted on 65 COPD subjects of which 10.8% subjects were in COPD Group A, 29.2% Group B, 32.3% Group C and 27.7% Group D. The mean age was 64.15; mean FEV1% was 46.05%, mean DLCO measured was 19.42 ml/min/mmHg and the mean DLCO% was 72.00%. The proportion of DLCO decline among COPD patients was 56.92%. There were significant correlations between COPD group, GOLD COPD grade, FEV1, BMI and comorbidities with the DLCO value results. There were no significant correlation between DLCO value with sex, age, smoking history, Brinkmann Index, obstructive-restrictive criteria, comorbidities and length of COPD period. Conclusion: The proportion of DLCO decline among COPD patients was 56.92%. There were significant correlations between COPD group, GOLD COPD grade, FEV1, BMI and previous TB history with the results of DLCO.

Relationship between cough reflex sensitivity and body mass index in children with chronic cough - a pilot study.

Obesity is characterized by chronic, low-grade systemic inflammation. Obesity may also be associated with chronic cough. The aim of this pilot study was to clarify relation of cough reflex sensitivity and body mass index (BMI) in children with chronic cough. Altogether 41 children having symptoms of chronic cough were submitted to cough reflex sensitivity measurement. We assessed the relation of cough reflex sensitivity (CKR) due to BMI. Cough reflex sensitivity was defined as the lowest capsaicin concentration which evoked two (C2) or five (C5) coughs. Capsaicin aerosol in doubling concentrations (from 0.61 to 1250 micromol/l) was inhaled by a single breath method (KoKo DigiDoser; nSpire heath Inc, Louisville, CO, USA), modified by the addition of an inspiratory flow regulator valve (RIFR; nSpire heath Inc, Louisville, CO, USA). BMI was calculated. Pulmonary function was within normal range. Concentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Children (22 boys and 19 girls, mean age 6.8 years) cough reflex sensitivity (median, with the Inter-Quartile Range) for C2 was 19.5 (73.4) micromol/l; for C5 it was 78.1 (605.5) micromol/l. We have noticed statistically significant relation of the cough reflex sensitivity (C5) and body mass index (P<0.0001); however, the effect size was small, R2=0.03. Increase of body mass index in one unit is associated with -34.959 micromol/l decrease of C5. We did not find a statistically significant relation between C2 and BMI (P=0.41). The median value of CKR (C2) in boys is not statistically significantly different than the median value of CKR (C2) in girls (P-value 0.5). The median value of CKR (C5) in boys is not statistically significantly different than the median value of CKR (C5) in girls (P-value 0.5). Increase of body mass index in children suffering from chronic cough relates to decrease of cough reflex sensitivity (C5 value).

Cough reflex sensitivity and fractional exhaled nitric oxide in children with asthma.

Individual studies have suggested the utility of fractional exhaled nitric oxide (FeNO) measurement in detecting cough-variant asthma and eosinophilic bronchitis in patients with chronic cough. The aim of this study was to clarify a correlation of cough reflex sensitivity and fractional exhaled nitric oxide in asthmatic children. 25 children with asthma and 15 controls were submitted to cough reflex sensitivity measurement - capsaicin aerosol in doubling concentrations (from 0.61 to 1250 micromol/l) was inhaled by a single breath method. Concentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Fractional exhaled nitric oxide (FeNO) measurement was included. Asthmatic children' (11 boys and 14 girls, mean age 9+/-1 years) and control group (unconfirmed diagnosis of asthma) (6 boys and 9 girls, mean age 8+/-1 years) were included into the study. FeNO vs. C2 in asthma (Spearman´s rank correlation: -0.146, p=0.49); FENO vs. C5 in asthma (Spearman´s rank correlation: -0.777, p=0.71). We found that there is no correlation between cough reflex sensitivity and fractional exhaled nitric oxide either in children with asthma or in the control group.

Lung capacity and alveolar gas diffusion in aquatic athletes: Implications for performance and health

The diffusion capacity of carbon monoxide (DLCO) provides a measure of gas transfer in the lungs. Endurance training does not increase lung volumes or diffusion in land-based athletes. However swimmers have larger lungs and better diffusion capacity than other matched athletes and controls. The aim of this study was to evaluate pulmonary alveoli-capillary diffusion and lung volumes in elite aquatic athletes, specifically swimmers, artistic swimmers and water polo players. The participants were 64 international level aquatic athletes including 31 swimmers (11 female and 20 male), 12 artistic swimmers (only female), and 21 water polo players (10 female and 11 male). The single-breath method was used to measure DLCO and pulmonary parameters. The main finding of this study is that DLCO is high in aquatic athletes, clearly above their reference values, both in females (33.4 ± 9.4 mL min−1·mmHg−1; 135%) and males (48.0 ± 5.83 mL min−1·mmHg−1; 148%). There was no difference in DLCO between female swimmers, artistic swimmers and water polo players (34.7 ± 8.3 to 33.4 ± 4.0 to 32.1 ± 5.6 mL min−1·mmHg−1), but male swimmers had a higher DLCO compared to water polo players (50.4 ± 5.3 to 43.4 ± 7.0, p = 0.014). Aquatic athletes have larger lungs and better diffusion capacity than the percentage predicted by age and height. Therefore, swimming-based sports could help to improve pulmonary function in many different segments of the population.

Swimming exercise transiently decrease lung diffusing capacity in elite swimmers.

Swimmers have larger lungs and a higher diffusion capacity than other athletes, but it remains unknown whether swimming exercise changes lung diffusing properties. This study aimed to evaluate modifications in pulmonary alveolar-capillary diffusion after swimming exercise. The participants were 21 elite level swimmers, including 7 females and 14 males, with a training volume of 45-70 kilometers of swimming per week. The single-breath method was used to measure the lung diffusing capacity for carbon monoxide (DLCO and the transfer coefficient of the lungs for carbon monoxide (K<inf>CO</inf>) before and after 10 training sessions over 4 weeks along 207 pre- to postevaluations. Swimming training consistently decreased lung diffusion capacity during the follow-up period, both DL<inf>CO</inf> (44.4±8.1 to 43.3±8.9 mL·min-1·mmHg-1, P=0.047, ŋ2<inf>p</inf>=0.55) and K<inf>CO</inf> (5.92±0.79 to 5.70±0.81 mL·min-1·mmHg-1·L-1, P=0.003, ŋ2<inf>p</inf>=0.75). Elite swimmers experience a subclinical impairment in lung diffusing capacity after swimming exercise, but the stress caused by swimming on the lungs and the acute reduction in DL<inf>CO</inf> does not lead to physiological dysfunction.

Changes in Lung Diffusing Capacity of Elite Artistic Swimmers During Training.

Artistic swimmers (AS) are exposed to repeated apnoeas in the aquatic environment during high intensity exercise provoking specific physiological responses to training, apnoea, and immersion. This study aimed to evaluate the changes in lung diffusing capacity in AS pre-, mid- and post-training in a combined session of apnoeic swimming, figures and choreography. Eleven elite female AS from the Spanish national team were the study's participants. The single-breath method was used to measure lung diffusing capacity for carbon monoxide (DLCO) and one-way repeated measures ANOVA was utilized to evaluate the statistical analysis. Basal values of DLCO were higher than normal for their age and height (33.6±4.9 mL·min-1·mmHg-1; 139±19%) and there were a significant interaction between DLCO and AS training (ŋ2 p=0.547). After the apnoeic swimming (mid-training) there was an increase in DLCO from basal to 36.7±7.3 mL·min-1·mmHg-1 (p=0.021), and after the figures and choreography (post-training) there was a decrease compared to mid-training (32.3±4.6 mL·min-1·mmHg-1, p=0.013). Lung diffusing capacity changes occur during AS training, including a large increase after apnoeic swimming. There were no differences in lung diffusing capacity from pre- to post-training, although large inter-individual variability was observed.