Complete Pulmonary Function Tests Research Articles

Pulmonary function tests in obese people candidate to bariatric surgery

Obesity is considered one of the most serious public health problems of the modern world. Because it alters the relationship between the lungs, chest wall and diaphragm, it is to be expected that it impacts on the respiratory function. In Portugal, there is not much data about the relationship between obesity and pulmonary function.The aim of this study was to characterize respiratory function in morbidly obese patients and to evaluate whether weight loss in patients submitted to bariatric surgery affects pulmonary function tests (PFT).We conducted a retrospective study with 36 morbidly obese patients submitted to bariatric surgery, with a mean age of 40.6 years, 64% female and with a mean body mass index (BMI) of 49.7kg/m2. All patients were clinical and functionally evaluated before surgery and after their weight had stabilized following surgery. They underwent a complete pulmonary function testing with spirometry, lung volumes, carbon monoxide diffusing capacity (DLCO), maximum respiratory pressures and arterial blood gases analysis. Prior to surgery almost all the patients had functional respiratory changes, 34 had a decrease in functional residual capacity (FRC) 6 of whom a restrictive syndrome. Only 2 patients did not show any functional or arterial blood gas change. After bariatric surgery, BMI decreased to 34kg/m2 and there was a significant improvement in almost all functional parameters with resolution of restrictive disorders. Nevertheless, in 13 patients the FRC remained decreased.After weight loss, the only correlation found was between reduction of BMI and increased FRC (r=−0.371; p=0.028). This study suggests a relationship between obesity and pulmonary restriction and a positive impact of bariatric surgery in PFT.

Effect of Bisoprolol on Respiratory Function and Exercise Capacity in Chronic Obstructive Pulmonary Disease

Cardioselective β blockers are considered to have little impact on lung function at rest in patients with chronic obstructive pulmonary disease (COPD). However, their effects on dynamic hyperinflation, an important mechanism contributing to symptoms and exercise tolerance in patients with COPD, have not been evaluated. Twenty-seven patients with moderate to severe COPD (forced expiratory volume in 1 second 52 ± 13% predicted) completed pulmonary function tests, echocardiography, maximal exercise tests, and cycle endurance tests at baseline. Inspiratory capacity was measured at 2-minute intervals during the cycle endurance test to quantify dynamic hyperinflation. Pulmonary function and cycle endurance testing were repeated after 14 days of bisoprolol 10 mg/day and 14 days of placebo in a randomized, double-blind, placebo-controlled, crossover trial. The extent of dynamic hyperinflation at peak isotime exercise with bisoprolol and placebo was compared. Peak isotime was defined as the latest time point that was reached during the 2 cycle endurance tests. Changes in inspiratory capacity from rest to peak isotime were different with bisoprolol compared to placebo (-0.50 ± 0.35 vs -0.41 ± 0.33 L, p = 0.01). Exercise duration tended to be lower with bisoprolol compared to placebo (305 ± 125 vs 353 ± 172 seconds, p = 0.11). The magnitude of change in exercise duration between the bisoprolol and placebo conditions was correlated with the magnitude of change in inspiratory capacity (r = 0.57, p <0.01). In conclusion, bisoprolol was associated with modest worsening dynamic hyperinflation, whereas exercise duration remained unchanged in patients with moderate to severe COPD. The magnitude of these effects was small and should not contraindicate the use of bisoprolol in patients with COPD.

Pulmonary Function and Incident Bronchitis and Asthma in Children: A Community-Based Prospective Cohort Study

BackgroundPrevious studies revealed that reduction of airway caliber in infancy might increase the risks for wheezing and asthma. However, the evidence for the predictive effects of pulmonary function on respiratory health in children was still inconsistent.MethodsWe conducted a population-based prospective cohort study among children in 14 Taiwanese communities. There were 3,160 children completed pulmonary function tests in 2007 and follow-up questionnaire in 2009. Poisson regression models were performed to estimate the effect of pulmonary function on the development of bronchitis and asthma.ResultsAfter adjustment for potential confounders, pulmonary function indices consistently showed protective effects on respiratory diseases in children. The incidence rate ratios of bronchitis and asthma were 0.86 (95% CI 0.79–0.95) and 0.91 (95% CI 0.82–0.99) for forced expiratory volume in 1 second (FEV1). Similar adverse effects of maximal mid-expiratory flow (MMEF) were also observed on bronchitis (RR = 0.73, 95% CI 0.67–0.81) and asthma (RR = 0.85, 95% CI 0.77–0.93). We found significant decreasing trends in categorized FEV1 (p for trend = 0.02) and categories of MMEF (p for trend = 0.01) for incident bronchitis. Significant modification effects of traffic-related air pollution were noted for FEV1 and MMEF on bronchitis and also for MMEF on asthma.ConclusionsChildren with high pulmonary function would have lower risks on the development of bronchitis and asthma. The protective effect of high pulmonary function would be modified by traffic-related air pollution exposure.

Função pulmonar em doentes obesos submetidos a cirurgia bariátrica

Obesity is considered one of the most serious public health problems of the modern world. Because it alters the relationship between the lungs, chest wall and diaphragm, it is to be expected that it impacts on the respiratory function. In Portugal, there is not much data about the relationship between obesity and pulmonary function.The aim of this study was to characterize respiratory function in morbidly obese patients and to evaluate whether weight loss in patients submitted to bariatric surgery affects pulmonary function tests (PFT).We conducted a retrospective study with 36 morbidly obese patients submitted to bariatric surgery, with a mean age of 40.6 years, 64% female and with a mean body mass index (BMI) of 49.7 kg/m2. All patients were clinical and functionally evaluated before surgery and after their weight had stabilized following surgery. They underwent a complete pulmonary function testing with spirometry, lung volumes, carbon monoxide diffusing capacity (DLCO), maximum respiratory pressures and arterial blood gases analysis. Prior to surgery almost all the patients had functional respiratory changes, 34 had a decrease in functional residual capacity (FRC) 6 of whom a restrictive syndrome. Only 2 patients did not show any functional or arterial blood gas change. After bariatric surgery, BMI decreased to 34 kg/m2 and there was a significant improvement in almost all functional parameters with resolution of restrictive disorders. Nevertheless, in 13 patients the FRC remained decreased.After weight loss, the only correlation found was between reduction of BMI and increased FRC (r = −0.371; p = 0.028). This study suggests a relationship between obesity and pulmonary restriction and a positive impact of bariatric surgery in PFT.

High-intensity training improves airway responsiveness in inactive nonasthmatic children: evidence from a randomized controlled trial

the relationship between physical activity and airway health in children is not well understood. The purpose of this study was to determine whether 8 wk of high-intensity exercise training would improve airway responsiveness in prepubescent, nonasthmatic, inactive children. 16 healthy, prepubescent children were randomized [training group (TrG) n = 8, control group (ConG) n = 8]. Prior to and following 8 wk of training (or no training), children completed pulmonary function tests (PFTs): forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), forced expiratory flow at 25-75% of vital capacity (FEF(25-75)), and exhaled nitric oxide (FENO). Children completed an incremental cycle Vo(2max) test, eucapnic voluntary hyperventilation (EVH), anthropometric tests, and blood tests to determine fasting blood glucose, total cholesterol, HDL, LDL, and triglycerides. Body fat percentage was determined using dual-energy X-ray absorptiometry pretraining and bioelectrical impedance pre- and posttraining. there were no differences (P > 0.05) in anthropometric measures or PFTs between TrG and ConG at baseline. In the TrG, there was a significant increase in Vo(2max) (∼24%) and a decrease in total cholesterol (∼13%) and LDL cholesterol (∼35%) following training. There were improvements (P < 0.05) in ΔFEV(1) both postexercise (pre: -7.60 ± 2.10%, post: -1.10 ± 1.80%) and post-EVH (pre: -6.71 ± 2.21%, post: -1.41 ± 1.58%) with training. The ΔFEF(25-75) pre-post exercise also improved with training (pre: -16.10 ± 2.10%, post: -6.80 ± 1.80%; P < 0.05). Lower baseline body fat percentages were associated with greater improvements in pre-post exercise ΔFEV(1) following training (r = -0.80, P < 0.05). these results suggest that in nonasthmatic prepubescent children, inactivity negatively impacts airway responsiveness, which can be improved with high-intensity training. Excess adiposity, however, may constrain these improvements.

What Is the Clinical Value of Lung Volumes?

Lung volumes are considered part of a complete pulmonary function test, but their value for enhancing clinical decision making is unknown. Unlike spirometry and diffusing capacity of the lung for carbon monoxide (D(LCO)), which do contribute to confirming or excluding a diagnosis, there are few clear indications when lung volumes are discriminatory. Confirming "restriction" when vital capacity (VC) or FVC is reduced is perhaps the most important. A restrictive pattern can have many etiologies, and clinicians often use VC or FVC as a primary index of lung volume. This makes "physiologic" sense because, in healthy subjects, and in patients with true restriction, VC comprises most of the total lung capacity (TLC). Mixed obstruction-restriction and the nonspecific pattern (ie, reduced FVC and FEV(1), normal FEV(1)/FVC and TLC) require measuring TLC to confirm the underlying physiology. In obesity, VC and TLC may remain within normal limits, but functional residual capacity (FRC) can exponentially decrease. Increased lung volumes, particularly residual volume (RV), are commonly observed in airway obstruction. TLC may be normal, but is frequently increased in the late stages of COPD. Hyperinflation and air-trapping are terms commonly used to reflect these changes, but are not well standardized. The variability of lung volumes related to degree of obstruction suggests that measuring gas-trapping may be needed to monitor therapy. Changes in inspiratory capacity, RV, or FRC may be important gauges of response to bronchodilators or other hyperinflation-reducing therapies. How lung volumes are measured may be important, especially in patients who have moderate or severe airway obstruction. Body plethysmography is often considered more accurate than gas dilution methods in the presence of obstruction. However, the differences between techniques are not completely understood. Newer approaches such as computed tomography, although not suitable for routine testing, may help to delineate the true underlying physiology.

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Authors' Response

Evaluation of Pulmonary Function and Exercise Performance by Cardiopulmonary Exercise Testing Before and After Lung Transplantation

Detailed description of functional exercise outcomes before and after lung transplantation is lacking. The objective of this study was to describe and compare posttransplant improvement in lung function and peak exercise parameters in patients with advanced lung disease. The study included 153 patients who underwent lung transplantation over 7 years who had complete cardiopulmonary exercise testing (CPET) and pulmonary function tests (PFTs) before and after lung transplantation. CPET and PFT within 30 months pretransplant and posttransplant were compared. Pulmonary function markedly improved posttransplant as FVC increased 67%, maximum voluntary ventilation increased 91%, and FEV(1) increased 136%. However, peak oxygen consumption increased only 19%, peak CO(2) production increased 50%, and peak work increased 78%. Although transplant recipients had a 1.5- to 2.0-fold increase in exercise capacity posttransplant, peak exercise capacity remained at 50% of the predicted normal, suggesting a maximal limitation. Subgroup stratification into quartiles based on pretransplant exercise capacity revealed the greatest exercise benefit to be in the lowest functional pretransplant groups. Lung transplant recipients have an increase in exercise capacity that does not match the improvement in lung function, indicating that poor strength, deconditioning, or other peripheral factors play a significant role in the limitation of exercise benefit posttransplantation. Further elucidation of the mechanisms of exercise limitation may allow for improved exercise outcomes posttransplant.

Comorbid Trends in World Trade Center Cough Syndrome and Probable Posttraumatic Stress Disorder in Firefighters

We describe the relationship between World Trade Center (WTC) cough syndrome symptoms, pulmonary function, and symptoms consistent with probable posttraumatic stress disorder (PTSD) in WTC-exposed firefighters in the first year post-September 11, 2001 (baseline), and 3 to 4 years later (follow-up). Five thousand three hundred sixty-three firefighters completed pulmonary function tests (PFTs) and questionnaires at both times. Relationships among WTC cough syndrome, probable PTSD, and PFTs were analyzed using simple and multivariable models. We also examined the effects of cofactors, including WTC exposure. WTC cough syndrome was found in 1,561 firefighters (29.1%) at baseline and 1,186 (22.1%) at follow-up, including 559 with delayed onset (present only at follow-up). Probable PTSD was found in 458 firefighters (8.5%) at baseline and 548 (10.2%) at follow-up, including 343 with delayed onset. Baseline PTSD symptom counts and probable PTSD were associated with WTC cough syndrome at baseline, at follow-up, and in those with delayed-onset WTC cough syndrome. Similarly, WTC cough syndrome symptom counts and WTC cough syndrome at baseline were associated with probable PTSD at baseline, at follow-up, and in those with delayed-onset probable PTSD. WTC arrival time and work duration were cofactors of both outcomes. A small but consistent association existed between pulmonary function and WTC cough syndrome, but none with PTSD. The study showed a moderate association between WTC cough syndrome and probable PTSD. The presence of one contributed to the likelihood of the other, even after adjustment for shared cofactors such as WTC exposure.

Using Spirometry to Rule Out Restriction in Patients with Concomitant Low Forced Vital Capacity and Obstructive Pattern

Background:Different formulas have been proposed to exclude restriction based on spirometry, however none of them have specifically tested the patients whose spirometry show both obstruction and a low forced vital capacity (FVC).Study Objective:The study was designed to create an algorithm that would better predict the absence of restriction in such patients.Design:Retrospective analysis of prospectively collected data.Methods:A cohort of consecutive adults that underwent complete pulmonary function testing from 2002-2004 was analyzed. The data was randomly split into two groups to allow for derivation and then validation of a predictive formula. Patients were randomly assigned into either a “derivation” or “validation” group. In the derivation group, stepwise logistic regression was used to determine a formula and optimal cut-off value for the variable with the best discriminative capacity. The formula was applied subsequently to the validation group to test the results and compared to previously published formula.Results:The study group contained 766 patients. We determined that the variable with the highest association with TLC was [(FEV1/FVC) % predicted/FVC % predicted]. A value of ≥1.11 was found to be the maximal cutoff to predict the absence of restriction.The formula was applied to a validation group (n=397) and performed better than prior published algorithm with a sensitivity, specificity, positive predictive value and negative predictive value of 95%, 44%, 22%, and 98%, respectively.Conclusion:Our formula performs superior to the previously published algorithms in patients with concomitant low FVC and obstruction to exclude restriction.

High-Intensity Interval Training Improves Airway Health in Inactive Non-asthmatic Children

PURPOSE: The relationship between physical activity and airway health in children is not well understood. The purpose of this study was to determine whether eight weeks of high-intensity exercise training would improve the airway health of inactive, non-asthmatic prepubescent children. METHODS: Sixteen healthy, prepubescent children were tested (training group [TrG] n=8, control group [ConG] n=8). Subjects wore accelerometers for seven days prior to the 8-week training period to determine activity level. Prior to and following eight weeks of training (or no training), subjects completed pulmonary function tests (PFTs) including forced expiratory flow in 1-sec (FEV1), forced vital capacity, forced expiratory flow at 25-75% of vital capacity (FEF25-75), exhaled nitric oxide (eNO), and impulse oscillometry (IOS). Subjects also completed an incremental cycle VO2max test, eucapnic voluntary hyperventilation (EVH), anthropometric tests, and blood tests to determine fasting blood glucose, total cholesterol, HDL, LDL, and triglycerides. Body composition was determined using dual-energy x-ray absorptiometry (DXA) pre-training and bioelectrical impedance analysis (BIA) pre- and post-training. RESULTS: There were no differences (p>0.05) in anthropometric measures or PFTs between TrG and ConG at baseline. In the TrG, there was a significant increase in VO2max (∼24%), and a decrease in total cholesterol (∼13%) and LDL cholesterol (∼35%) following training. Additionally, we found improvements (p<0.05) in ΔFEV1 both post-exercise (pre: -7.60±2.10%, post: -1.10±1.80%) and post-EVH (pre: -6.71±2.21%, post: -1.41±1.58%) with training. The change in FEF25-75 pre-post exercise also improved with training (pre: -16.10±2.10%, post: -6.80±1.80%; p<0.05). Lower baseline body-fat percentages were associated with greater improvements in ΔFEV1 following training, and controlling for VO2max lean body mass did not change this association (r=-0.80, p<0.05). CONCLUSION: These results suggest that physical inactivity negatively impacts airway health in non-asthmatic prepubescent children, which can be improved with high-intensity training. However, increased body fat may constrain these improvements.

441 Possible Disease Markers in BAL Fluid of BOS Patients

Purpose: Cardiopulmonary exercise testing (CPET) is a known predictor of all cause mortality in heart failure, emphysema and normal populations but has not been used post lung transplant (LnTx). We hypothesize that CPET at 1 year post LnTx is a predictor of all cause mortality, conditioned on one-year survival. Methods and Materials: An IRB approved retrospective chart review was done of all LnTx between 7/01 and 6/09 at the Columbia University Medical Center (CUMC). Initial CPET performed post LnTx with complete pulmonary function test (PFT) data 1 to 2 1⁄2 years post transplant were included for analysis. Peak watts percent predicted (PW%) and FEV1 percent predicted (FEV1%) were used. Date of death was obtained from the Social Security Index Database. Cause of death was from the final note in transplant chart.

Diaphragm Fatigue after Submaximal Exercise with Chest Wall Restriction

We asked whether submaximal exercise with chest wall restriction (CWR), as a model of restrictive pulmonary disease, would result in fatigue of the diaphragm in healthy humans. To address this question, we used cervical magnetic stimulation of the phrenic nerves along with measures of transdiaphragmatic pressure. Seven healthy young men (30 ± 7 yr) completed pulmonary function tests and a maximal cycle exercise test. On a separate day, baseline measures of diaphragm contractility were obtained followed by cycle exercise at 45% of maximum intensity for 10 min with no restriction (NCWR). Diaphragm contractility was assessed again at 10 and 30 min after exercise. One hour later, inelastic straps were applied to reduce forced vital capacity by 40% followed by exercise at the same intensity. Diaphragm contractility was reassessed at 10 and 30 min after exercise. During exercise, the work of breathing, respiratory pressures, ventilatory parameters, and perceptions of respiratory and leg discomfort were recorded. The work of breathing and dyspnea ratings were greater during CWR exercise compared with NCWR (P < 0.05). The CWR condition had reductions in diaphragm contractility 10 min after exercise using nonpotentiated (-20.2% ± 15.3%) or potentiated twitches (-23.3% ± 12.4%, P < 0.05). There were no differences after exercise for NCWR (P > 0.05). The reduction in diaphragm contractility was correlated with the inspiratory elastic work of breathing (r2 = 0.74, P < 0.05). We conclude that fatigue of the diaphragm occurs under restricted conditions and likely contributes to poor exercise tolerance in patients with restrictive disease.

Carnitine Deficiency in Chronic Obstructive Pulmonary Disease Patients

Chronic Obstructive Pulmonary Disease (COPD) is increasingly recognized as a systemic disease characterized by progressive airflow limitation as well as respiratory and peripheral muscle weakness. Deficiency in the levels of carnitine “an essential nutrient for optimal muscle function” has been associated with peripheral and respiratory muscle weakness in other diseases, but has not yet been examined in COPD patients. The aim of this study was to investigate whether plasma acyl carnitine fractions were reduced in patients with COPD, and examine if the deficiency correlated with COPD severity. Patients and methods: A prospective case control study to compare acyl carnitine levels and other parameters in 81 COPD patients treated at the Pulmonology Department, King Fahad Specialist Hospital Dammam, with 48 age and sex matched healthy controls. All subjects participating in the study underwent a complete physical examination and detailed pulmonary function tests (PFTs). Blood samples were taken for acyl carnitine profiles as well as a panel of other tests including albumin, total protein, Iron, CRP and pre-albumin. Acyl carnitine profile was determined using LC-MS/MS analysis. Results: COPD patients had significantly lower total carnitine levels compared to controls (43.9±6.5 and 22.7±11.9 respectively). Furthermore there was a significantly greater reduction in carnitine levels in patients with very severe COPD compared to patients with mild COPD. Conclusion: Our study demonstrated a significant deficiency in carnitine levels in COPD patients, and the degree of deficiency correlated with the severity of COPD.

Correlation of pulmonary function variables with hemodynamic measurements in patients with pulmonary arterial hypertension

A reduced diffusing capacity of the lung for carbon monoxide (DLCO) measured during a pulmonary function test can suggest pulmonary arterial hypertension (PAH). The DLCO has been reported to weakly correlate with pulmonary hemodynamics. To determine whether the relationship between the DLCO and pulmonary arterial pressures can be strengthened by normalizing the DLCO to spirometric variables. Patients were seen at a tertiary care referral center. Consecutive subjects who underwent right heart catheterization (RHC) for the evaluation of suspected PAH from 01 January 1991 through 01 October 2006 were identified. Pulmonary function testing (PFT) data performed within 60 days of the RHC was collected. Spearman rank correlation between PFT and RHC variables was calculated. One hundred thirty-eight patients who had an RHC performed had complete PFTs available. No significant correlation was identified between the mean pulmonary artery pressure and the pulmonary vascular resistance against the DLCO, nor the DLCO when normalized to: forced expiratory volume in 1 s, forced vital capacity, total lung capacity or alveolar volume. Spirometric subgroups were identified by standard definitions of restrictive and/or obstructive ventilatory defects. Clinical subgroups were classified based on the clinically diagnosed cause of the patient's PAH. Again, no significant correlation was identified between the PFT variables and RHC measurements in these stratified subgroups. In patients with suspected PAH, invasive hemodynamic measurements of PAH do not correlate with PFT variables, even when corrected for spirometric volumes, and regardless of the subgroup of ventilatory physiology or clinical diagnosis.

Impact of preoperative smoking status on postoperative complication rates and pulmonary function test results 1-year following pulmonary resection for non-small cell lung cancer

There is a lack of evidence in the literature regarding the impact of preoperative smoking status on pulmonary function test (PFT) results 1 year after resection for non-small cell lung cancer (NSCLC). Furthermore, there is disagreement in the literature regarding the impact of preoperative smoking cessation on postoperative complication rates. We performed a single-institution retrospective review of all NSCLC patients who underwent resection from April 2000 through April 2006. Timing of smoking cessation was stratified as follows: smoking cessation more than a month before surgery (Distant Smokers), smoking cessation within a month before surgery (Recent Smokers), and failure to achieve smoking cessation before surgery (Current Smokers). During the study period, 213 patients underwent NSCLC resection, 121 of whom (all males; mean age, 67.4 years) completed pre- and postoperative PFTs. After adjusting for potential confounding covariates (age, type of resection, and use of radiation therapy), we noted no significant difference ( p > 0.40) between groups after resection with regard to either relative (−12.20 ± 15.77 L [Distant Smokers], −15.38 ± 19.38 L [Recent Smokers], −9.61 ± 15.54 L [Current Smokers]) or absolute changes in percent predicted forced expiratory volume in 1 s (−0.14 ± 0.20 L [Distant Smokers], −0.18 ± 0.19 L [Recent Smokers], −0.12 ± 0.20 L [Current Smokers]). Because 92 patients did not complete postoperative PFTs, we performed a stratified analysis to assess for selection bias; as compared with those who completed PFTs, baseline PFT results did not significantly differ. We found no significant differences between the 3 groups with regard the overall rate of postoperative complications or the rate of any specific postoperative complication. In conclusion, smoking cessation immediately before NSCLC resection does not significantly impact postoperative pulmonary complication rates or 1-year postoperative PFT results and therefore should not be a reason to delay surgical resection.

The Effects of N-Acetylcysteine on Respiratory Muscle Fatigue During Heavy Exercise

Diaphragmatic fatigue is known to limit endurance performance during heavy exercise. Previous reports have shown that diaphragmatic fatigue is reduced in rats with N-acetylcysteine (NAC; a nonspecific antioxidant) infusion suggesting that oxidative stress contributes to this fatigue. However, it is not know if oral supplementation of NAC will reduce respiratory muscle fatigue during heavy exercise in humans. PURPOSE: To determine the effect of an acute oral dose of NAC on respiratory muscle fatigue during whole body heavy exercise. METHODS: Eight healthy men (22+2 yrs; VO2peak: 43+5 ml/kg/min) initially completed baseline pulmonary function tests followed by an incremental cycle VO2peak test. Subjects then performed a randomized, double blind crossover study where subjects were given either placebo (PLA) or NAC (1800 mg) 45 min prior to a constant load (85% VO2peak), discontinuous, 30 minute cycle exercise test. Tests were separated by one week. Maximum pressures (inspiratory, PImax; expiratory, PEmax) and venous blood samples (lactate and total glutathione) were made prior to- and following each 5-min of exercise. RESULTS: There was no difference (p>0.05) in PImax between NAC (127.9+34.1 cmH2O) or PLA (134.1+28.1 cmH2O) at rest. During exercise, PImax was significantly lower (~14%) in 6 of 8 subjects with PLA compared to NAC at minutes 25 and 30; whereas with NAC, PImax did not change (p>0.05) from rest throughout exercise indicating no respiratory muscle fatigue. There was no difference (p>0.05) in PEmax, plasma glutathione, lactate, VO2, VE, or HR between PLA and NAC at rest or during exercise. CONCLUSIONS: These results suggest that an acute dose of NAC reduces respiratory muscle fatigue during high intensity exercise but does not alter other ventilatory or metabolic indices. These data indicate that NAC's affect on respiratory muscles may favorably influence endurance exercise performance. Support from Kansas State University Research Grant

Long-term follow-up of living-donor single lobe transplantation for idiopathic pulmonary arterial hypertension in a child

Long-term follow-up of living-donor single lobe transplantation for idiopathic pulmonary arterial hypertension in a child

Chronic obstructive pulmonary disease and inhaled steroids alter surfactant protein D (SP-D) levels: a cross-sectional study

BackgroundSurfactant protein D (SP-D), an innate immune molecule, plays an important protective role during airway inflammation. Deficiency of this molecule induces emphysematous changes in murine lungs, but its significance in human COPD remains unclear.MethodsWe collected bronchoalveolar lavage fluid from 20 subjects with varying degrees of COPD (8 former smokers and 12 current smokers) and 15 asymptomatic healthy control subjects (5 never smokers, 3 remote former smokers, and 7 current smokers). All subjects underwent a complete medical history and pulmonary function testing. SP-D was measured by Enzyme-Linked ImmunoSorbent Assay. Statistical analysis was performed using nonparametric methods and multivariable linear regression for control of confounding. The effect of corticosteroid treatment on SP-D synthesis was studied in vitro using an established model of isolated type II alveolar epithelial cell culture.ResultsAmong former smokers, those with COPD had significantly lower SP-D levels than healthy subjects (median 502 and 1067 ng/mL, respectively, p = 0.01). In a multivariable linear regression model controlling for age, sex, race, and pack-years of tobacco, COPD was independently associated with lower SP-D levels (model coefficient -539, p = 0.04) and inhaled corticosteroid use was independently associated with higher SP-D levels (398, p = 0.046). To support the hypothesis that corticosteroids increase SP-D production we used type II alveolar epithelial cells isolated from adult rat lungs. These cells responded to dexamethasone treatment by a significant increase of SP-D mRNA (p = 0.041) and protein (p = 0.037) production after 4 days of culture.ConclusionAmong former smokers, COPD is associated with lower levels of SP-D and inhaled corticosteroid use is associated with higher levels of SP-D in the lung. Dexamethasone induced SP-D mRNA and protein expression in isolated epithelial cells in vitro. Given the importance of this molecule as a modulator of innate immunity and inflammation in the lung, low levels may play a role in the pathogenesis and/or progression of COPD. Further, we speculate that inhaled steroids may induce SP-D expression and that this mechanism may contribute to their beneficial effects in COPD. Larger, prospective studies are warranted to further elucidate the role of surfactant protein D in modulating pulmonary inflammation and COPD pathogenesis.

Low Level of Exposure to Pesticides Leads to Lung Dysfunction in Occupationally Exposed Subjects

Pesticides may contribute to adverse respiratory health effects among farmers and have been considered one causal factor for the rise in asthma prevalence. This cross-sectional study was conducted to evaluate potential respiratory function abnormalities following long-term pesticide exposure by means of a complete pulmonary function testing, including spirometry, lung volumes, and diffusing capacity for carbon monoxide. The study population was comprised by workers from a prominent intensive agriculture area of southern Spain that relied on pesticides for the control of plagues. Eighty-nine pesticide sprayers of plastic greenhouse farming and a control group of 25 nonspraying control farmers from the same area were interviewed by a general practitioner asking about sociodemographic factors, occupational exposure, and clinical symptoms by using a structured questionnaire. Multiple regression analyses showed a relationship of short-term exposure to pesticides (as indicated by a drop in serum cholinesterase > 25% of baseline levels) with reduced forced expired volume in 1 s, and of long-term exposure (as indicated by a cumulative pesticide exposure index) with reduced forced expiratory flow rate. Exposure to bipyridilium-class herbicides was a determinant of a fall in the diffusing capacity of the lungs, and neonicotinoid insecticides showed a relationship with lower pulmonary volumes (total lung capacity, residual volume, and functional residual capacity), suggestive of restrictive lung disease, and with an increased risk of reporting irritative symptoms.