Slow Vital Capacity Research Articles

Evaluation of Airway resistance and Spirometry in Petrol Pump Workers: A Crossectional study

Background: The rapidly increasing number of automobiles in most cities has led to an increase in air-pollution and has become a cause of grave concern. Air pollutants derived from automobile exhaust and fuel vapours have become a major health hazard for certain groups of our society by virtue of their occupation. Objective: To evaluate the airway resistance and spirometry parameters of petrol-pump workers. Design: The present study was carried out on 40 male petrol pump workers in the age-group of 20-40 years who were working at petrol-pumps for more than 5 years. Spirometry parameters such as Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Forced Expiratory Flow [FEF(25-75%)], Slow Vital capacity (SVC), Maximum Voluntary Ventilation (MVV) and Plethysmography parameters like Airway Resistance (Raw) were recorded on a whole body Plethysmograph (Elite Dx model, Med graphics ,USA ). The results were compared with that of the controls. Results: FVC, FEV1, FEF (25-75%), SVC, and MVV showed a significant decline whereas Raw was increased in petrol pump workers as compared to controls. Conclusions: Petrol pump workers have significantly lower lung functions as measured by spirometry & airway resitance is significantly raised in them as compared to controls.

Impact of asymptomatic idiopathic scoliosis on pulmonary function

Background: Scoliosis is considered as one of the commonest spinal deformity to affect the pulmonary functions because of its ability to alter the respiratory mechanics. Its advancement with age proves fatal because of complications such as respiratory failure. Even though idiopathic scoliosis is also prevalent in India, the data regarding pulmonary function status of these individuals are scant. This necessitates a study on pulmonary functions in Idiopathic Scoliosis. Aims & Objective: To study the pulmonary functions in individuals with idiopathic scoliosis and to compare the same with age and sex matched normal individuals. Materials and Methods: In this study pulmonary functions such as slow vital capacity parameters and forced vital capacity parameters were studied in thirty individuals with Idiopathic Scoliosis in the age group of 15- 30 years. These parameters were compared with those recorded in equal number of age and sex matched apparently normal healthy individuals using unpaired t test. Results: A significant reduction was observed in lung function parameters such as vital capacity, tidal volume, inspiratory/expiratory reserve volumes, inspiratory capacity, forced vital capacity(FVC) and forced expiratory volume in first second (FEV1). However the ratio between FEV1 and FVC were within normal limits in both the groups and did not show any significant change. Conclusion: Observations of the present study is suggestive of a restrictive pattern of impairment in Scoliosis, which is mainly because of alteration in respiratory mechanics. These pulmonary deficits may not be evident as they are symptomless. However in future these may tip the balance towards respiratory complications. So study of pulmonary functions in scoliotics may give an idea regarding the extent of detriment of lung function and hence will be useful in planning the treatment options for Scoliosis.

Dexpramipexole effects on functional decline and survival in subjects with amyotrophic lateral sclerosis in a Phase II study: Subgroup analysis of demographic and clinical characteristics

Our objective was to explore treatment effects in patient subgroups using post hoc analyses of data from part 2 of the dexpramipexole Phase II study. Subjects with amyotrophic lateral sclerosis (ALS) received dexpramipexole 300 mg/day or 50 mg/day for 24 weeks. Treatment effects on the slope of the revised ALS Functional Rating Score (ALSFRS-R) and Combined Assessment of Function and Survival (CAFS) were evaluated in dichotomized subgroups: riluzole use, gender, site of symptom onset. Other subgroups were dichotomized using median baseline values for age, ALSFRS-R, slow vital capacity, symptom duration, diagnostic delay, and progression rate. Results showed that there was a 21% reduction in ALSFRS-R decline favoring the 300-mg vs. 50-mg arm (p = 0.177); mean CAFS ranking was significantly higher in the 300-mg vs. 50-mg arm (52.4 vs. 41.1; p = 0.046). Trends were recapitulated in virtually all subgroups. Generally, ALSFRS-R decline was reduced and CAFS rankings were higher in the 300-mg vs. 50-mg arm across subgroups. CAFS rankings were significantly higher in the 300-mg vs. 50-mg arm among subjects with ALSFRS-R scores ≤35, symptom duration <18.7 months, or progression rate ≥ 0.7 points/month (p < 0.03). In conclusion, the observed benefit of 300- vs. 50-mg dexpramipexole on functional decline and survival was generally consistent among subjects regardless of baseline characteristics.

Using Statistical Techniques to Predict Dynamic Arterial PCO2in Patients With COPD During Maximum Exercise

P(aCO(2)) as measured during exercise in patients with COPD is poorly predicted (predicted P(aCO(2))) from lung function testing and some noninvasive measurements, such as end-tidal P(CO(2)) (P(ETCO(2))). We performed a number of statistical techniques on P(ETCO(2)) and its interaction with other physiologic variables during exercise testing, in order to improve our ability to predict P(aCO(2)). The estimated P(aCO(2)) as determined from these techniques may therefore be used to contrast the P(ETCO(2)) readings that are measured during an incremental exercise test on a breath-by-breath basis (ie, P(aCO(2)) - P(ETCO(2))), and to identify exercise-induced hypercapnia. Forty-seven men with COPD underwent both pulmonary function testing and incremental exercise testing until limited by symptoms. Arterial blood gases and exercise physiological measurements were performed during maximal exercise testing. The prediction equations for P(aCO(2)) were generated using regression techniques with the leave-one-out cross-validation technique. Forty-one patients were included in the final analysis after 6 patients were excluded due to inadequate data collection. The best prediction equation we found was: predicted P(aCO(2)) = 23.71 + P(ETCO(2)) × (0.9-0.01 × D(LCO) -0.04 × V(T)) - 2.61 × SVC - 0.04 × MEP, where D(LCO) is diffusing capacity for carbon monoxide in mL/min/mm Hg, V(T) is tidal volume in L, SVC is slow vital capacity in L, and MEP is maximum expiratory pressure in cm H(2)O. The difference between the measured and predicted P(aCO(2)) at each time point was not statistically significant (all P > .05). The standard errors of the estimated P(aCO(2)) at each time point were 0.91-1.12 mm Hg. A validated mixed-model regression derived equation yields a predicted P(aCO(2)) trend during exercise that can be helpful when interpreting exercise testing to determine P(aCO(2)) - P(ETCO(2)) and exercise-induced hypercapnia.

Pulmonary function in patients with hereditary motor and sensory neuropathy: A comparison of patients with and without spinal deformity

We assessed pulmonary function in hereditary motor and sensory neuropathy. Fourteen neuropathy patients without spinal deformity (group 1), 14 with spinal deformity (group 2), and 16 individuals with idiopathic spinal deformity (group 3) matched to group 2 for age, height and Cobb angle, were included. Hereditary motor and sensory neuropathy severity was measured with Charcot-Marie-Tooth Neuropathy Score. All participants exhibited mild decrease in maximal inspiratory pressure at the mouth. One-way analysis of variance yielded significant main effects for lung volumes - slow vital capacity, forced expiratory volume in 1s, and total lung capacity (p's<.01), attributable to greater volumes in group 1 compared to groups with spinal deformity - and transfer factor for carbon monoxide (p=.013), reflecting differences between groups 1 vs. 2. Slow vital capacity and total lung capacity correlated with maximal inspiratory pressure at the mouth in group 2, whereas slow vital capacity correlated with muscle work in group 3 (p's<.05). Decreased lung volume may be due to impaired respiratory muscle strength in hereditary motor and sensory neuropathy with spinal deformity and due to spinal deformity in idiopathic patients.

A Randomized, Double Blind, Placebo-Controlled Trial of Pioglitazone in Combination with Riluzole in Amyotrophic Lateral Sclerosis

BackgroundPioglitazone, an oral anti-diabetic that stimulates the PPAR-gamma transcription factor, increased survival of mice with amyotrophic lateral sclerosis (ALS).Methods/Principal FindingsWe performed a phase II, double blind, multicentre, placebo controlled trial of pioglitazone in ALS patients under riluzole. 219 patients were randomly assigned to receive 45 mg/day of pioglitazone or placebo (one: one allocation ratio). The primary endpoint was survival. Secondary endpoints included incidence of non-invasive ventilation and tracheotomy, and slopes of ALS-FRS, slow vital capacity, and quality of life as assessed using EUROQoL EQ-5D. The study was conducted under a two-stage group sequential test, allowing to stop for futility or superiority after interim analysis. Shortly after interim analysis, 30 patients under pioglitazone and 24 patients under placebo had died. The trial was stopped for futility; the hazard ratio for primary endpoint was 1.21 (95% CI: 0.71–2.07, p = 0.48). Secondary endpoints were not modified by pioglitazone treatment. Pioglitazone was well tolerated.Conclusion/SignificancePioglitazone has no beneficial effects on the survival of ALS patients as add-on therapy to riluzole.Trial RegistrationClinicaltrials.gov NCT00690118.

Health hazards among workers in plastic industry

Styrene is a basic building block for manufacturing thousands of products throughout the world. The present study aimed to (1) detect the presence of styrene and/or its metabolites in the workers in one of the Egyptian plastic factories; (2) demonstrate some common health effects of styrene exposure among the same group by some laboratory investigations and compare them with the unexposed healthy individuals; and (3) correlate the duration of styrene exposure and its level in the blood with the severity of the demonstrated health effects. This study was conducted in one of Egyptian plastic factories. The exposed group was 40 male workers, ranging in age from 18 to 33 years (23.20 ± 4.09), working 12 h/day with 1 day off, and working without any protective equipment. A control group of 50 unexposed healthy males matched with the exposed group for age (21-35 yrs (23.40 ± 4.05)), sex, socioeconomic status, and smoking habit is selected. Written individual consent is obtained from all participants followed by (a) a full medical and occupational history and full clinical examination; (b) ventilatory function tests: forced vital capacity (FVC), slow vital capacity, forced expiratory volume in the 1st second (FEV₁)%, FEV₁/FVC%, peak expiratory flow, and mid-expiratory flow 25-75%; (c) analyses of β₂ microglobulin; blood styrene level; and urinary mandelic acid; and (d) cytogenetic study. The study results showed a statistically significant difference between the exposed and the control groups as regard the blood styrene level, urinary mandelic acid level, β₂ microgloblin in urine, and chromosomal study. The study also showed a statistically significant correlation between the duration of styrene exposure and ventilatory function parameters, also between the duration of styrene exposure and some detectable chromosomal aberrations. Our study recommends the implementation of preemployment and periodic medical examinations and health education programs using personal protective equipments and following the recommended allowable concentrations of styrene exposure.

A Study To Evaluate Safety and Tolerability of CK-2017357 (CK-357) in Patients with Amyotrophic Lateral Sclerosis Using a Twice-Daily, Dose-Titration Regimen (P04.155)

Objective: The primary objective of this study was to determine the safety and tolerability of CK-357 as the dose was increased over 3 weeks in ALS patients taking concomitant riluzole at a dose half that normally prescribed. Measures of strength, endurance, and function were obtained to pilot assessments for a planned efficacy study. Background CK-357 is an orally bioavailable fast skeletal muscle troponin activator that increases the force response of muscle to neuronal input. In a single-dose Evidence of Effect Phase 2a study, both patient- and investigator global assessments reflected dose-related improvement; and gains were noted in some measures of respiratory function and muscle fatigue. Additionally, small strength improvements were observed in some muscles 24 hours post-dose. Plasma riluzole levels were increased approximately 2 to 3-fold after a single dose of CK-357. Design/Methods: Eligible patients had a Slow Vital Capacity (SVC) of greater than 50% of predicted, and diminished but measurable grip strength in at least one hand. All 24 enrolled patients took 50 mg riluzole each morning. Patients were randomized to receive placebo or CK-357 tablets, administered twice daily. The dose of CK-2017357 was increased at weekly intervals starting at 125 mg BID, increasing to 250 mg BID (500 mg total daily dose) over a 3-week period. Safety and efficacy measures were collected prior to and at the end of dosing, and one week after study drug was discontinued. Clinical outcome measures included ALSFRS-R, strength of selected muscle groups, submaximal handgrip endurance, respiratory function (SVC, Sniff Nasal Inspiratory Pressure, and Maximum Voluntary Ventilation), nocturnal pulse oximetry, and Timed Up-and-Go test. Results: Demographic data, safety and tolerability information, and outcomes data will be presented. Conclusions: This study will provide information to aid in dose selection for future Phase 3 studies of CY-2017357 in ALS. Supported by: Cytokinetics, Inc. Disclosure: Dr. Shefner has received personal compensation for activities with Biogen Idec, GlaxoSmithKline, Cytokinetics, Inc., and Trophos. Dr. Shefner has received personal compensation in an editorial capacity for UpToDate. Dr. Shefner has received research support from the National Institutes of Health, the ALS Association, the ALS Therapy Alliance, GlaxoSmithKline, Neuralstem, Isis Pharmaceuticals, Biogen Idec, Cytokinetics, Inc., and Sanofi Pharmaceuticals. Dr. Andrews has received personal compensation for activities with AVANIR. Dr. Bedlack has received personal compensation for activities with Pfizer Inc, Athena Diagnostics, Eli Lilly & Company, UCB Pharma and Guidepoint Pharmacy as a speaker and/or consultant. Dr. Berry has nothing to disclose. Dr. Goslin has nothing to disclose. Dr. Jackson has received personal compensation for activities with Avanir Pharmaceuticals.Dr. Jackson has received research support from Knopp Pharmaceuticals, Biogen Idec and Cytokinetics. Dr. Kissel has nothing to disclose. Dr. Lange has nothing to disclose. Dr. Licht has received research support from Avanir Pharmaceuticals. Dr. Mozaffar has nothing to disclose. Dr. Pestronk has received personal compensation or activities with Athena Diagnostics.Dr. Pestronk has received (royalty or license fee or contractual rights) payments from Athena Diagnostics.Dr. Pestronk holds stock and/or stock options in Johnson & Johnson.Dr. Pestronk has received research support from Knopp, ISIS, Sanofi-Aventis, and Prosensa. Dr. Rosenfeld has received personal compensation for activities with Avanir Pharmaceuticals, Cytokinetics, Gerson Lehrman Group and Guidepoint Global as a speaker and consultant. Dr. Wolff has received personal compensation for activities with Cytokinetics, Inc as an employee. Dr. Wolff holds stock and/or stock options in Cytokinetics, Inc which sponsored research in which Dr. Wolff was involved as an investigator. Dr. Wolff holds stock and/or stock options in Cytokinetics, Inc. Dr. Wolff has received research support from Cytokinetics, Inc. Dr. Lee has received personal compensation for activities with Cytokinetics as an employee. Dr. Masonek has received personal compensation for activities with Cytokinetics, Inc., as an employee. Dr. Jones has received personal compensation for activities with Cytokinetics, Inc. as an employee. Dr. Meng has received personal compensation for activities with Cytokinetics, Inc., as an employee. Dr. Cedarbaum has received personal compensation for activities with Cytokinetics, Inc. as an employee.

Lungenfunktionsdiagnostik der kleinen Atemwege

In the recent years growing interest has focused on the involvement of the distal airways (internal diameter < 2 mm) in obstructive lung diseases and other pulmonary conditions. Inflammation in the small airways seems to play a major role in severe and uncontrolled asthma as a major determinant of airflow obstruction. Thus, small airways represent an important target for inhalation therapy. Currently there is no accepted single lung function parameter to detect small airway dysfunction. Various invasive and non-invasive techniques have been described. In future, non-invasive lung function testing will gain more importance. Using spirometry or body plethysmography, lung function parameters such as the ratio of forced vital capacity to slow vital capacity (FVC/SVC) and the residual volume (RV) can provide information about air trapping in small airway disease. Recent data show that techniques such as impulse oscillometry, nitrogen washout testing and analysis of exhaled nitric oxide are promising tools to assess involvement of the small airways. Impulse oscillometry is a sensitive method to calculate peripheral airway resistance, nitrogen washout allows one to detect air trapping and inhomogeneous ventilation in the distal lung, and the alveolar nitric oxide concentration represents a marker of peripheral inflammation. Further studies are needed to validate these functional tests or their combination for diagnosis and assessment of treatment response in pulmonary diseases involving small airways.

Nasal versus oronasal raised volume forced expirations in infants—A real physiologic challenge

Raised volume rapid thoracoabdominal compression (RTC) generates forced expiration (FE) in infants typically from an airway opening pressure of 30 cm H(2)O (V(30)). We hypothesized that the higher nasal than pulmonary airway resistance limits forced expiratory flows (FEF(%)) during (nasal) FE(n), which an opened mouth, (oronasal) FE(o), would resolve. Measurements were performed during a brief post-hyperventilation apnea on 12 healthy infants aged 6.9-104 weeks. In two infants, forced expiratory (FEFV) flow volume (FV) curves were generated using a facemask that covered the nose and a closed mouth, then again with a larger mask with the mouth opened. In other infants (n = 10), the mouth closed spontaneously during FE. Oronasal passive expiration from V(30) generated either the inspiratory capacity (IC) or by activating RTC before end-expiration, the slow vital capacity ((j) SVC). Peak flow (PF), FEF(25), FEF(50), FEF(25-75), FEV(0.4), and FEV(0.5) were lower via FE(n) than FE(o) (P < 0.05), but the ratio of expired volume at PF and forced vital capacity (FVC) as percent was higher (P < 0.05). FEF(75), FEF(85), FEF(90), FVC as well as the applied jacket pressures were not different (P > 0.05). FEFV curves generated via FE(o) exhibited higher PF than FV curves of IC (P < 0.05); PF of those produced via FE(n) were not different from FV curves of IC (P > 0.05) but lower than those of (j) SVC (P < 0.05). In conclusion, the higher nasal than pulmonary airways resistance unequivocally affects the FEFV curves by consistently reducing PF and decreases mid-expiratory flows. A monitored slightly opened mouth and a gentle anterior jaw thrust are physiologically integral for raised volume RTC in order to maximize the oral and minimize nasal airways contribution to FE so that flow limitation would be in the pulmonary not nasal airways.

Respiratory Expulsive Efforts Evoked by Maximal Lung Emptying

Some patients exhibit cough-like expiratory efforts ("deflation cough") during slow vital capacity (SVC) and/or FVC maneuver. The cause and motor features of these expulsive efforts are unknown. Of 1,720 consecutive patients, 43 displayed deflation cough during SVC or FVC, and 18 agreed to participate in additional examinations involving radiologic and clinical assessments. Variables of the motor pattern of deflation cough, as well as its intensity and frequency, were recorded by means of a pneumotachograph; the "integrated" surface abdominal electromyographic activity (IEMG) was recorded as well. On different occasions, participants were randomly administered either an antacid or salbutamol or matched placebos. Comparisons between deflation cough variables prior to and after drug administration were performed by means of the analysis of variance and post hoc tests. Fourteen patients (77.8%) were affected by a respiratory disease, and all of them also reported esophageal and/or extraesophageal symptom(s) of reflux. In control conditions, maximal lung emptying was consistently accompanied by the appearance of deflation cough. Peak IEMG and peak expiratory flow rates of deflation cough correlated (r = 0.53, P < .05). Inhaled agents had no effect. Antacid abolished deflation cough in 11 patients, reduced its frequency in four, and was ineffective in three. Matched placebo was significantly less effective. All patients with deflation cough present symptoms of gastroesophageal reflux; acidic reflux, possibly evoked by the efforts of lung emptying, may be the causative factor. Receptors sensitive to lung collapse may also contribute to deflation cough when antacid administration fails.

Cardiac abnormalities in a follow-up study on carriers of Duchenne and Becker muscular dystrophy

Cardiac involvement has been reported in carriers of dystrophin mutations giving rise to Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). The progress of these abnormalities during long-term follow-up is unknown. We describe the long-term follow-up of dilated cardiomyopathy (DCM) in DMD/BMD carriers. A long-term follow-up study was performed among Dutch DMD/BMD carriers first analyzed in 1995. A cardiac history was taken, and all carriers were assigned a functional score to assess skeletal muscle involvement. Electrocardiography and M-mode and 2-D echocardiography were performed. DCM was defined as an enlarged left ventricle with a global left ventricle dysfunction or fractional shortening less than 28%. Slow vital capacity of the lung was measured by a hand-held spirometer. Ninety-nine carriers were monitored with a median follow-up of 9 years (range 7.0-10.6 years). Eleven carriers with DCM (10 DMD, 1 BMD) were identified. Nine of them developed DCM in the follow-up period. One of the patients with DCM reported in the 1995 study died of cardiac failure at age 57 years. DCM was more frequently found in carriers who were functionally symptomatic. Cardiac abnormalities in DMD/BMD carriers are progressive, as in patients with DMD/BMD.

Exhaled breath temperature in healthy children is influenced by room temperature and lung volume

Exhaled breath temperature (EBT) has been proposed for the non-invasive assessment of airway inflammation. Previous studies have not examined the influence of room temperature or lung size on the EBT. This study aimed to address these issues in healthy children. We assessed the effects of room temperature and lung volume in 60 healthy children aged 9-11 years (mean age 10.3 years, 33 male). Static lung volumes were assessed using multiple breath nitrogen washout. Questionnaire and skin prick tests were also used to establish respiratory health in the children. We obtained the EBT parameters of slope, end plateau temperature (PLET) and normalized plateau temperature (nPLET; plateau temperature minus inspired air temperature), and ascertained physiological factors influencing EBT. End plateau temperature was shown to be proportionally affected by room temperature (r = 0.532, P < 0.001) whereas slope and nPLET decreased with increasing room temperature (r = -0.392 P < 0.02 and r = -0.507 P = 0.002). After adjusting for room temperature, height and age, the total lung capacity (r(2) = 0.435, P = 0.006) and slow vital capacity (SVC; r(2) = 0.44, P = 0.005) were found to be the strongest predictors of end PLET in healthy children. When all factors were included in a multiple regression model, SVC and room temperature were the only predictors of plateau and nPLET. Slope was only influenced by room temperature. Exhaled breath temperature measurements are highly feasible in children with a 95% success rate in this healthy population. Room temperature and SVC significantly influence EBT variables in healthy children. Further studies are required to investigate the ability of EBT to assess airway inflammation in children with respiratory disease. Pediatr. Pulmonol. 2011; 46:1062-1068. © 2011 Wiley Periodicals, Inc.

Recombinant human acid alpha-glucosidase (rhGAA) in adult patients with severe respiratory failure due to Pompe disease

Pompe disease is a rare metabolic myopathy caused by lysosomal α-glucosidase deficiency. Pompe disease ranges from a rapidly progressive course when symptoms present in infancy to a more slowly progressive rate when symptoms present in childhood or adulthood. This open-label prospective exploratory study investigated the effect of 12 months of recombinant enzyme replacement therapy in 5 adult patients who had already advanced to a very severe stage of Pompe disease. Muscular and respiratory function, quantitative muscle testing and spirometry were assessed. Four patients were tracheostomized. Respiratory parameters did not deteriorate. A moderate improvement in sitting/supine slow vital capacity in 2 patients (from 7% to 11% and 28% to 32% of predicted) and reductions of ventilation support in 2 patients was observed. Three patients, wheelchair bound at baseline, improved sitting and proximal motor function; 2 patients improved in their ability to stand and transfer. The treatment was well tolerated. Alglucosidase alfa may stabilize or even slightly improve muscle strength and respiratory function among patients with severe Pompe disease.

Respiratory pattern in an adult population of dystrophic patients

We studied respiratory function and Chest Wall kinematics in a large population of adult patients affected by slow course muscular dystrophies such as Limb-Girdle Muscular Dystrophy (LGMD, n = 38), Becker Muscular Dystrophy (BMD, n = 20) and Facio-Scapulo Humeral Dystrophy (FSHD, n = 30), through standard spirometry and through the Optoelectronic Plethysmography, to measure the thoraco-abdominal motion during Quiet Breathing and Slow Vital Capacity maneuvers. Within the restrictive pulmonary syndrome characterizing LGMD and FSHD, several different thoraco-abdominal patterns compared to those of healthy subjects were present in the more advanced stages of the disease. These differences were present in the seated position, during the execution of a maximal maneuver such as Slow Vital Capacity. A global respiratory (both inspiratory and expiratory) muscle involvement was more pronounced in the LGMD and FSHD than in the BMD patients, and a significant reduction of abdominal contribution in wheelchair bound patients was observed. In conclusion, OEP technique is able to reveal mild initial modifications in the respiratory muscles in FSHD and LGMD patients, which could be helpful for functional and new therapeutic strategy evaluation.

Effects of emphysema on oxygen uptake during maximal exercise in COPD

The objective of the study is to assess the effects of emphysema on peak oxygen uptake ([Formula: see text]) during a cardiopulmonary exercise test in patients with chronic obstructive pulmonary disease (COPD). We measured [Formula: see text] and oxygen pulse in 80 patients with stable COPD exercising maximally. Oxygen saturation was measured by pulse oximetry (SpO(2)), and the ventilatory response assessed by the ratio of tidal volume (V (T)) at peak to slow vital capacity (SVC) at baseline, and by the percent increase of peak V (T) over baseline. Computed tomography imaging (CT scan) served as the reference diagnostic standard for emphysema. Based on the panel-grading (PG) method, emphysema was rated absent or mild (PG≤30, n=54), or moderate to severe (PG>30, n=26). Multiple quantile regression was applied to estimate the effects of PG>30 on [Formula: see text]. At peak exercise, the patients with PG>30 had significantly lower [Formula: see text], oxygen pulse and SpO(2), and featured a blunted ventilatory response with respect to those with PG≤30 (p<0.001). With multiple quantile regression, the effects of PG>30 on [Formula: see text] were only partially explained by the degree of lung hyperinflation, a substantial component being imputable to impairment of lung diffusing capacity. In conclusion, chronic obstructive pulmonary disease patients with moderate to severe emphysema feature significantly lower exercise tolerance than those with no or mild emphysema. Our findings underscore the need of tailoring therapeutic interventions for COPD to the predominant clinical phenotype to improve exercise capacity.

Regional ventilation distribution determined by electrical impedance tomography: Reproducibility and effects of posture and chest plane

Reliable assessment of regional lung ventilation and good reproducibility of electrical impedance tomography (EIT) data are the prerequisites for the future application of EIT in a clinical setting. The aims of our study were to determine (i) the reproducibility of repeated EIT measurements and (ii) the effect of the studied transverse chest plane on ventilation distribution in different postures. Ten healthy adult subjects were studied in three postures on two separate days. EIT and spirometric data were obtained during tidal breathing and slow vital capacity (VC) manoeuvres. EIT data were acquired in two chest planes at 13 scans/s. Reproducibility of EIT findings was assessed by Bland-Altman analysis and Pearson correlation in 16 regions of interest in each plane. Regional ventilation distribution during tidal breathing and deep expiration was determined as fractional ventilation in four quadrants of the studied chest cross-sections. Our study showed a good reproducibility of EIT measurements repeated after an average time interval of 8 days. Global tidal volumes and VCs determined by spirometry on separate days were not significantly different. Regional ventilation in chest quadrants assessed by EIT was also unaffected. Posture exerted a significant effect on ventilation distribution among the chest quadrants during spontaneous breathing and deep expiration in both planes. The spatial distribution patterns in the two planes were not identical. We conclude that regional EIT ventilation findings are reproducible and recommend that the EIT examination location on the chest is carefully chosen especially during repeated measurements and follow-up.

Efeitos de um programa de reabilitação pulmonar sobre mecânica respiratória e qualidade de vida de mulheres obesas

INTRODUÇÃO: A obesidade é uma doença metabólica caracterizada por uma etiologia multifatorial que propicia o acúmulo de gordura levando a quadros de morbidade e mortalidade. OBJETIVO: Verificar os efeitos de um programa de reabilitação pulmonar sobre a mecânica respiratória, a capacidade funcional e a qualidade de vida de 20 mulheres obesas sedentárias com idade média de 48,75 ± 13,71 e IMC de 34,54 ± 3,85 kg/m². MATERIAIS E MÉTODOS: As voluntárias foram entrevistadas usando o questionário SF-36 como instrumento para determinar qualidade de vida, seguido da mensuração da massa corporal, estatura, cirtometria tóraco-abdominal, volume minuto e corrente, capacidade vital lenta, pressão inspiratória e expiratória máxima. A comparação dos resultados pré e pós-programa de reabilitação pulmonar foi pelo teste t de Student pareado, observando-se um valor p &lt; 0,05. RESULTADOS: Os resultados após o programa foram estatisticamente significativos (p &lt; 0,05) para o volume minuto de 11008,30 ± 5035,53 mL (p = 0,001), volume corrente de 758,70 ± 345,78 mL (p = 0,023), capacidade vital lenta com 2632,95 ± 852,25 mL (p = 0,001), pressão inspiratória máxima com - 69,75 ± 21,37 cmH2O (p = 0,045) e pressão expiratória máxima com 74,50 ± 28,23 cmH2O (p = 0,000) e na percepção da qualidade de vida em seu estado geral de saúde 76,5 ± 14,04 (p = 0,033), aspectos sociais 83,1 ± 18,71 (p = 0,031), aspectos emocionais 88,4 ± 19,52 (p = 0,042) e na saúde mental 83,4 ± 14,81 (p = 0,049). CONCLUSÃO: O programa de reabilitação pulmonar proposto promoveu efeitos positivos melhorando a mecânica respiratória e a qualidade de vida das mulheres obesas sedentárias.

Pulmonary functions in patients with diabetes mellitus

Background:A reduction in lung capacity has been reported previously among diabetics. According to WHO estimates, Pakistan is currently eighth in the prevalence of diabetes mellitus (DM) and will become fourth by the year 2025 with over 15 million individuals. This study was designed to see the impairment of lung functions on spirometry in DM patients.Objective:Our aim was to investigate the pulmonary functions tests of Pakistani patients with DM.Materials and Methods:Between January to July 2004, 128 subjects who were never-smokers and had no acute or chronic pulmonary disease were recruited. Sixty-four of these subjects had DM and 64 were healthy matched controls. All underwent screening with detailed history, anthropometry, lipid profile, and spirometric measurements at the Aga Khan University Hospital, Karachi, Pakistan.Results:The mean age of diabetics and matched control were 54.3±9 and 54.0±8 (P<0.87) years, respectively. Diabetes patients showed a significant reduction in the forced vital capacity (FVC) [mean difference (95% CI) – 0.36 (–0.64, –0.07) P<0.01], forced expiratory volume in one second (FEV1) [– 0.25(–0.50, –0.003) P<0.04], and slow vital capacity (SVC) [– 0.28(–0.54, –0.01) P<0.04], relative to nondiabetic controls. There was no significant difference noted in the forced expiratory ratio and maximum mid-expiratory flow between the groups. There was also a significant higher level of triglycerides noted among diabetics (P<0.001).Conclusion:Diabetic patients showed impaired lung function independent of smoking. This reduced lung function is likely to be a chronic complication of diabetes mellitus.

Exhaled Nitric Oxide: Offline Tidal Breathing Measurements Are Feasible in Children and Correlate with Online Single Breath Measurements

Fractional exhaled nitric oxide (FENO) measurements are useful in monitoring airway inflammation. Online and offline sampling techniques are well standardized. However, young children are often unable to perform slow vital capacity maneuvers. The aim of this study was to compare a simplified mobile offline tidal breathing method with an online single breath measurement. We performed online and offline FENO measurements in children between 5 and 16 years with respiratory disease. Online measurements were performed by a slow vital capacity maneuver; offline measurements were performed by collecting exhaled air in Mylar balloons during tidal breathing. In 59 children (5.3–16.7 years) able to perform both techniques, a good correlation (0.9348) between offline tidal breathing and online single breath measurement was found over a wide range of values. Offline tidal breathing values correspond to online values. Online single breath FENO values can be predicted from offline tidal breathing FENO values. Offline tidal breathing measurements are highly correlated with online single breath values in children.