Thoracic Gas Volume Research Articles

Lung volumes and respiratory mechanics in elastase-induced emphysema in mice

Absolute lung volumes such as functional residual capacity, residual volume (RV), and total lung capacity (TLC) are used to characterize emphysema in patients, whereas in animal models of emphysema, the mechanical parameters are invariably obtained as a function of transrespiratory pressure (Prs). The aim of the present study was to establish a link between the mechanical parameters including tissue elastance (H) and airway resistance (Raw), and thoracic gas volume (TGV) in addition to Prs in a mouse model of emphysema. Using low-frequency forced oscillations during slow deep inflation, we tracked H and Raw as functions of TGV and Prs in normal mice and mice treated with porcine pancreatic elastase. The presence of emphysema was confirmed by morphometric analysis of histological slices. The treatment resulted in an increase in TGV by 51 and 44% and a decrease in H by 57 and 27%, respectively, at 0 and 20 cmH(2)O of Prs. The Raw did not differ between the groups at any value of Prs, but it was significantly higher in the treated mice at comparable TGV values. In further groups of mice, tracheal sounds were recorded during inflations from RV to TLC. All lung volumes but RV were significantly elevated in the treated mice, whereas the numbers and size distributions of inspiratory crackles were not different, suggesting that the airways were not affected by the elastase treatment. These findings emphasize the importance of absolute lung volumes and indicate that tissue destruction was not associated with airway dysfunction in this mouse model of emphysema.

The bimodal quasi-static and dynamic elastance of the murine lung

The double sigmoidal nature of the mouse pressure-volume (PV) curve is well recognized but largely ignored. This study systematically examined the effect of inflating the mouse lung to 40 cm H2O transrespiratory pressure (Prs) in vivo. Adult BALB/c mice were anesthetized, tracheostomized, and mechanically ventilated. Thoracic gas volume was calculated using plethysmography and electrical stimulation of the intercostal muscles. Lung mechanics were tracked during inflation-deflation maneuvers using a modification of the forced oscillation technique. Inflation beyond 20 cm H2O caused a shift in subsequent PV curves with an increase in slope of the inflation limb and an increase in lung volume at 20 cm H2O. There was an overall decrease in tissue elastance and a fundamental change in its volume dependence. This apparent "softening" of the lung could be recovered by partial degassing of the lung or applying a negative transrespiratory pressure such that lung volume decreased below functional residual capacity. Allowing the lung to spontaneously recover revealed that the lung required approximately 1 h of mechanical ventilation to return to the original state. We propose a number of possible mechanisms for these observations and suggest that they are most likely explained by the unfolding of alveolar septa and the subsequent redistribution of the fluid lining the alveoli at high transrespiratory pressure.

Validity of Predicted Thoracic Gas Volumes in Determining Body Composition During Air Displacement Plethysmography in Collegiate Athletes

Physical assessments are of increasing value in the development of peak conditioning in athletes. However, time constraints may often limit which assessment is performed. Measuring thoracic gas volume is an option provided during air displacement plethysmography (ADP), but adds time to the body composition (BC) assessment. Predicting lung volume may save time as less testing is required. However, what remains in question is the accuracy of using predicted lung volume in determining BC in athletes. PURPOSE: The aim of this study was to assess the validity of using predicted thoracic gas volume in determining BC during ADP in collegiate athletes. METHODS: Thirty-one subjects (5 males, 26 females) from 3 collegiate teams underwent BC procedures using ADP with the subject characteristics being height (m): 1.78 ± 0.08, body mass (kg): 78.66 ± 14.27, and BMI (kg/m2): 24.85 ± 3.70. Percent fat free mass (FFM) and percent fat mass (FM) were calculated from the assessment using predicted and measured lung volumes. Paired t-tests were used to compare the means of FFM and FM using predicted and measured measurements. A Pearson correlation coefficient calculated the relationship between subjects' predicted and measured body composition. RESULTS: A paired t-test revealed no significant difference between the mean measurements, p > 0.05. A Pearson correlation coefficient revealed a strong correlation between predicted and measured body composition in all subjects with r = 0.981, p = 0.001. CONCLUSION: Using the predicted lung volume provides a valid FFM and FM during BC testing during ADP in collegiate athletes. Time and effort may be saved by not measuring lung volume directly during ADP.Body Composition Values determined by Predicted and Measured Thoracic Lung Volumes.

High tidal volume ventilation in infant mice

Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.

Absence of cholinergic airway tone in normal BALB/c mice

Basal airway smooth muscle (ASM) tone has not been demonstrated in mice in vivo. To determine whether basal ASM tone is present in mouse airways we measured respiratory system impedance (Zrs) before and after either atropine or bilateral vagotomy. Zrs was measured using forced oscillations delivered via a wave-tube during slow ( approximately 35s) inflation-deflation maneuvers between transrespiratory pressures (Prs) of 0 and 20 cm H2O. A constant-phase tissue model was applied to the Zrs to calculate airway resistance (R aw), tissue damping (G) and elastance (H). Thoracic gas volume (TGV) was determined plethysmographically at Prs=0 cm H2O and by integration of the inspiratory flow. The relationship between conductance (G aw=1/R aw) and TGV during inflation was also examined. Neither atropine nor vagotomy produced any change in R aw, H, eta (=G/H), TGV or the slope of G aw vs. TGV that was different to that observed in the relevant control groups. These data show that BALB/c mice do not have cholinergic ASM tone in vivo.

Effects of a Program of Hospital-Supervised Chest Physical therapy on Lung Function Tests in Children with Chronic Respiratory Disease: 1-Year Follow-up

To investigate whether a hospital-supervised program of chest physical therapy improves lung function in children with chronic pulmonary diseases, twenty-four children (4 with Kartagener?s syndrome, 12 with common variable immunodeficiency, and 8 with primary ciliary dyskinesia) average age 11.2 +/- 3.2 years, were randomly assigned to a one-month hospital-supervised program of chest physical therapy (13 patients) or to a control group (11 patients) that continued unsupervised chest physical therapy at home. Lung function was assessed before the program, and one and 12 months after. At the one-month assessment, thoracic gas volume was significantly lower in the supervised group than in the controls. At the one-year assessment, forced expiratory volume in one second was significantly higher in the supervised group than in controls. A supervised program of chest physical therapy significantly improved lung function in children with chronic pulmonary diseases.

Commentary on “The role of the large airways on smooth muscle contraction in asthma”

LETTERS TO THE EDITORCommentary on “The role of the large airways on smooth muscle contraction in asthma”Riccardo Pellegrino, and Vito BrusascoRiccardo Pellegrino, and Vito BrusascoPublished Online:01 Oct 2007https://doi.org/10.1152/japplphysiol.00684.2007MoreSectionsPDF (28 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat to the editor: Dr. Permutt (3) hypothesizes that the response to constrictor agents in asthma is the result of large-to-medium airways narrowing, leading to a decrease of vital capacity (VC) and, in turn, of 1-s forced expiratory volume (FEV1). The fall in VC could be due to an increase in residual volume (RV), unless total lung capacity (TLC) also increases, thus compensating for the fall in lung function. The hypothesis opens questions that need to be addressed. If it is known that TLC increases with exacerbations (5), its changes with acute administration of bronchoconstrictor or bronchodilator agents are generally regarded as technical artifacts. Perusal of Dr. Brown and colleagues' data (1) reveals that the decrease in TLC after albuterol could be due either to a too high frequency of panting during measurement of thoracic gas volume or, alternatively, to a decrease in lung elastic recoil (Pel). Unfortunately, neither reason for the TLC increase can be ruled out. Against theoretical predictions on flow dynamics, changes in FEV1 failed to correlate with changes in bronchial diameter. Yet this may not be surprising in view of the dependency of FEV1 on thoracic gas compression, Pel, effects of deep breath, and TLC, all of these being affected by disease and medications. Finally, Dr. Permutt's hypothesis on the site of bronchoconstriction in asthma has to be reconciled with the many imaging, functional, and modeling studies suggesting that it is heterogeneous constriction of the distal airways that is central to the disease (2, 4).REFERENCES1 Brown RH, Pearse DB, Pyrgos G, Liu MC, Togias Alkis, Permutt S. The structural basis of airways hyperresponsiveness in asthma. J Appl Physiol 101: 30–39, 2006.Link | ISI | Google Scholar2 Downie SR, Salome CM, Verbanck S, Thompson BR, Berend N, King GG. Ventilation heterogeneity is a major determinant of airway hyperresponsiveness in asthma, independent of airway inflammation. Thorax 2007 [Epub ahead of print].Google Scholar3 Permutt S. The role of the large airways on smooth muscle contraction in asthma. J Appl Physiol; doi:10.1152/japplphysiol.00568.2007.Google Scholar4 Tgavalekos NT, Tawhai M, Harris RS, Musch G, Vidal-Melo M, Venegas JG, Lutchen KR. Identifying airways responsible for heterogeneous ventilation and mechanical dysfunction in asthma: an image functional modeling approach. J Appl Physiol 99: 2388–2397, 2005.Link | ISI | Google Scholar5 Woolcock AJ, Read J. Lung volumes in exacerbations of asthma. Am J Med 41: 259–273, 1966.Crossref | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: V. Brusasco, Dept. of Internal Medicine, Univ. of Genoa, Respiratory Pathophysiology Unit, Padiglione Maragliano, Ospedale San Martino, Largo R. Benzi, 10, 16132 Genova, Italy (e-mail: [email protected]) Download PDF Previous Back to Top Next FiguresReferencesRelatedInformationCited ByLast Word on Viewpoint “The role of the large airways on smooth muscle contraction in asthma”Solbert Permutt1 October 2007 | Journal of Applied Physiology, Vol. 103, No. 4 More from this issue > Volume 103Issue 4October 2007Pages 1460-1460 Copyright & PermissionsCopyright © 2007 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00684.2007PubMed17916684History Published online 1 October 2007 Published in print 1 October 2007 Metrics

Breath condensate nitrite correlates with hyperinflation in chronic obstructive pulmonary disease

Estimating the degree of pulmonary hyperinflation in chronic obstructive pulmonary disease (COPD) is not always straight forward. Standard pulmonary function tests provide only a crude estimate of this important aspect of COPD. In addition, good patient cooperation cannot always be achieved and therefore adds to the uncertainties with regard to the extent of hyperinflation of the lung. The aim of this investigation was to characterize exhaled breath condensate nitrite in volunteers, healthy smokers, and stable COPD (GOLD-stages 0-4) and to compare this parameter with inflammatory markers in exhaled breath condensate and with lung function in order to test the hypothesis that elevated exhaled breath condensate nitrite reflects hyperinflation in COPD. We found a logarithmic correlation of exhaled breath condensate nitrite to residual volume (r=0.75, p<0.0001), total lung capacity (r=0.51, p<0.0001), and thoracic gas volume (r=0.71, p<0.0001) but no correlation of exhaled breath condensate nitrite concentrations with levels of inflammatory cytokines in exhaled breath condensate (interleukin (IL)-8, IL-1beta, IL-6, IL-10, IL-12, and tumor necrosis factor-alpha). Analysis of COPD subgroups revealed a logarithmic correlation of EBC nitrite to residual volume, total lung capacity, and intrathoracic gas volume exclusively for patients characterized by GOLD classes 2, and higher. Our results confirm a relation of exhaled breath condensate nitrite levels and hyperinflation measured by conventional pulmonary function tests. Investigations using isolated lung models and cells stretched in culture also provide insight into this relation. Exhaled breath condensate nitrite may be a biochemical indicator of pulmonary overdistension.

Long-Term Benefits of Inhaled Tobramycin in Children with Cystic Fibrosis: First Clinical Observations from Poland

Background: Respiratory disease is the major cause of mortality in cystic fibrosis (CF) patients and inhaled antibiotic therapy may contribute to the stabilization of lung function. Objectives: This is a small, open, uncontrolled, observational study of clinical experience obtained with 2 years of maintenance treatment with inhaled tobramycin in 12 children and adolescents with CF. Methods: Twelve subjects aged 6–18 years infected by Pseudomonas aeruginosa were qualified for treatment with inhaled tobramycin. Pulmonary function, weight and height, clinical status, and chest X-ray were continually monitored. After an active 2-year treatment period, results of all measured parameters in our patients were compared with their previous results (2-year period before treatment with tobramycin). Results: During 2 years before treatment with tobramycin solution for inhalation (TOBI), pulmonary function decline was observed, the median value of FEV₁ change was –7.6% (lower quartile –13.1, upper quartile –5.9). After 2 years of treatment, FEV₁ percent predicted value declined by 1.5% (lower quartile –11.1, upper quartile 3.7) from baseline; 2 years of TOBI therapy significantly reduced lung function decline (p = 0.049). There were no significant changes in thoracic gas volume and specific airway resistance before and after treatment. Two years of TOBI therapy significantly improved body mass index (p = 0.02). TOBI treatment significantly delayed progression of pulmonary X-ray changes assessed by Brasfield score (p = 0.02). Conclusions: We found that patients with CF can gain substantial benefits from long-term TOBI treatment, including reduced pulmonary function decline, delayed progression of pulmonary X-ray changes and improved weight gain in growing children and adolescents.

Changes in thoracic gas volume with air-displacement plethysmography after a weight loss program in overweight and obese women

This study was designed to compare measured and predicted thoracic gas volume (V (TG)) after weight loss and to analyze the effect of body composition confounders such as waist circumference (WC) on measured V (TG) changes. Prospective intervention study. Outpatient University Laboratory, Lisbon, Portugal. Eighty-five overweight and obese women (body mass index = 30.0+/-3.5 kg/m(2); age = 39.0+/-5.7 years) participating in a 16-month university-based weight control program designed to increase physical activity and improve diet. Body weight (Wb), body volume (Vb), body density (Db), fat mass (FM), percent fat mass (%FM) and fat-free mass (FFM) were assessed by air-displacement plethysmography (ADP) at baseline and at post-intervention (16 months). The ADP assessment included a protocol to measure V (TG) and a software-based predicted V (TG). Dual-energy X-ray absorptiometry (DXA) (Hologic QDR 1500) was also used to estimate FM, %FM and FFM. Maximal oxygen uptake (VO(2) max) was assessed with a modified Balke cardiopulmonary exercise testing protocol with a breath-by-breath gas analysis. Significant differences between the baseline and post-weight loss intervention were observed for body weight and composition (Vb, Db, %FM, FM and FFM), and measures of V (TG) (measured: Delta=0.2 l, P<0.001; predicted: Delta=0.01 l, P<0.010) variables. Measured V (TG) change was negatively associated with the change in the WC (P=0.008), controlling for VO(2) max and age (P=0.007, P=0.511 and P=0.331). Linear regression analysis results indicated that %FM and FM using the measured and predicted V (TG) explained 72 and 76%, and 86 and 90% respectively, of the variance in %FM and FM changes using dual-energy x-ray absorptiometry. After weight loss, measured V (TG) increased significantly, which was partially attributed to changes is an indicator of body fat distribution such as WC. Consequently, measured and predicted V (TG) should not be used interchangeably when tracking changes in body composition. The mechanisms relating the reduction of an upper body fat distribution with an increase measured V (TG) are worthy of future investigation.

The response to recruitment worsens with progression of lung injury and fibrin accumulation in a mouse model of acid aspiration

Reopening the injured lung with deep inflation (DI) and positive end-expiratory pressure (PEEP) likely depends on the duration and severity of acute lung injury (ALI), key features of which include increased alveolar permeability and fibrin accumulation. We hypothesized that the response to DI and PEEP would worsen as ALI evolves and that this would correspond with increasing accumulation of alveolar fibrin. C57BL/6 mice were anesthetized and aspirated 75 microl of HCl (pH 1.8) or buffered normal saline. Subgroups were reanesthetized 4, 14, 24, and 48 h later. Following DI, tissue damping (G) and elastance (H) were measured periodically at PEEP of 1, 3, and 6 cmH(2)O, and air within the lung (thoracic gas volume) was quantified by microcomputed tomography. Following DI, G and H increased with time during progressive lung derecruitment, the latter confirmed by microcomputed tomography. The rise in H was greater in acid-injured mice than in controls (P < 0.05) and also increased from 4 to 48 h after acid aspiration, reflecting progressively worsening injury. The rise in H was reduced by PEEP, but this effect was significantly blunted by 48 h (P < 0.05), also confirmed by thoracic gas volume. Lung permeability and alveolar fibrin also increased over the 48-h study period, accompanied by increasing levels and transcription of the fibrinolysis inhibitor plasminogen activator inhibitor-1. Lung injury worsens progressively in mice during the 48 h following acid aspiration. This injury manifests as progressively increasing alveolar instability, likely due to surfactant dysfunction caused by increasing levels of alveolar protein and fibrin.

Validity of thoracic gas volume equations in children of varying body mass index classifications

The aim of the study was to evaluate air-displacement plethysmography (ADP) thoracic gas volume (TGV) prediction equations in children representing a wide range of body mass index (BMI). 254 children (5 to 17 years) were recruited from two centres (England and the United States). Subjects were stratified into three BMI categories according to the International Obesity TaskForce (IOTF) criteria: lean (48 male, 42 female), overweight (15 male, 29 female), and obese (52 male, 68 female). As part of the normal ADP procedure, TGV was measured (TGV(Meas)), predicted using child specific equations developed by Fields (TGV(Fields)) and adult derived equations by Crapo (TGV(Crapo)) with percentage body fat (PF) estimates subsequently calculated (PF(Meas), PF(Fields), PF(Crapo)). Compared with the mean TGV(Meas), the TGV(Fields) estimates were within+/-0.2 L in all groups, except obese males (+0.5 L), while the mean TGV(Crapo) estimates were greater than+/-0.3 L in all groups except lean males (+0.1 L). When converted to PF, the mean PF(Fields) estimates were within+/-1% of the measured value in all groups, except obese males (+1.1%), while the mean PF(Crapo) estimates were greater than+/-1% in all groups, except lean males (+0.5%). Using either prediction equation, Bland-Altman analysis revealed that the greatest PF+/-95% limits of agreement were in the lean and overweight groups and lowest in the obese groups. The Fields child-specific TGV prediction equations provide accurate mean PF estimates and appear better than using the Crapo equations if a measured TGV cannot be achieved in children of a wide range of BMI. However, individual predictions may result in large PF errors especially in lean children.

Lessons from structure-function studies in asthma: myths and truths about what we teach

Asthma is a syndrome that is distinguished and diagnosed on the basis of abnormalities of pulmonary function ([7][1]). Patients with asthma should exhibit airflow obstruction characterized by periodic falls in forced expiratory volume in 1 s (FEV1), airflow obstruction that responds or normalizes to

Validity of new child-specific thoracic gas volume prediction equations for air-displacement plethysmography.

BackgroundTo determine the validity of the recently developed child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography (ADP) in diverse pediatric populations.MethodsThree distinct populations were studied: European American and African American children living in Birmingham, Alabama and European children living in Lisbon, Portugal. Each child completed a standard ADP testing protocol, including a measured TGV according to the manufactures software criteria. Measured TGV was compared to the predicted TGV from current adult-based ADP proprietary equations and to the recently developed child-specific TGV equations of Fields et al. Similarly, percent body fat, derived using the TGV prediction equations, was compared to percent body fat derived using measured TGV.ResultsPredicted TGV from adult-based equations was significantly different from measured TGV in girls from each of the three ethnic groups (P < 0.05), however child-specific TGV estimates did not significantly differ from measured TGV in any of the ethnic or gender groups. Percent body fat estimates using adult-derived and child-specific TGV estimates did not differ significantly from percent body fat measures using measured TGV in any of the groups.ConclusionThe child-specific TGV equations developed by Fields et al. provided a modest improvement over the adult-based TGV equations in an ethnically diverse group of children.

Measured Versus Predicted Thoracic Gas Volume and the Impact on Body Composition Measures in Children

Measured Versus Predicted Thoracic Gas Volume and the Impact on Body Composition Measures in Children

Plethysmographic estimation of thoracic gas volume in apneic mice

Electrical stimulation of intercostal muscles was employed to measure thoracic gas volume (TGV) during airway occlusion in the absence of respiratory effort at different levels of lung inflation. In 15 tracheostomized and mechanically ventilated CBA/Ca mice, the value of TGV obtained from the spontaneous breathing effort available in the early phase of the experiments (TGVsp) was compared with those resulting from muscle stimulation (TGVst) at transrespiratory pressures of 0, 10, and 20 cmH2O. A very strong correlation (r2= 0.97) was found, although with a systematically (approximately 16%) higher estimation of TGVst relative to TGVsp, attributable to the different durations of the stimulated (approximately 50 ms) and spontaneous (approximately 200 ms) contractions. Measurements of TGVst before and after injections of 0.2, 0.4, and 0.6 ml of nitrogen into the lungs in six mice resulted in good agreement between the change in TGVst and the injected volume (r2= 0.98). In four mice, TGVsp and TGVst were compared at end expiration with air or a helium-oxygen mixture to confirm the validity of isothermal compression in the alveolar gas. The TGVst values measured at zero transrespiratory pressure in all CBA/Ca mice [0.29 +/- 0.05 (SD) ml] and in C57BL/6 (N = 6; 0.34 +/- 0.08 ml) and BALB/c (N = 6; 0.28 +/- 0.06 ml) mice were in agreement with functional residual capacity values from previous studies in which different techniques were used. This method is particularly useful when TGV is to be determined in the absence of breathing activity, when it must be known at any level of lung inflation or under non-steady-state conditions, such as during pharmaceutical interventions.

Alveolar nitric oxideversusmeasures of peripheral airway dysfunction in severe asthma

Alveolar nitric oxide (NO) is a measure of peripheral airway inflammation in asthma, potentially associated with disease severity. The relationship between alveolar NO and physiological tests of peripheral airway (dys)function has not been investigated. The present authors hypothesised that peripheral airway inflammation and dysfunction are inter-related and associated with asthma severity. Alveolar NO was compared between 17 patients with mild-to-moderate asthma and 14 patients with severe asthma and related to total lung capacity (TLC), residual volume (RV)/TLC, thoracic gas volume (FRC), slope of the single breath nitrogen washout curve (dN2), closing capacity (CC)/TLC and fall in forced vital capacity at the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second. In patients with severe asthma, strong correlations were found between alveolar NO and RV/TLC % pred, FRC % pred, dN2, and CC/TLC. Patients with oral steroid-dependent asthma had higher alveolar NO levels (2.7 ppb) compared with the other patients with severe (0.6 ppb) and mild-to-moderate asthma (0.3 ppb). The present authors conclude that alveolar nitric oxide is closely related to parameters of peripheral airway dysfunction in patients with severe asthma, and that oral steroid-dependent asthmatics have more peripheral airway disease than nonsteroid-dependent asthmatics. This suggests that patients on chronic oral steroid treatment have more extensive disease and require additional anti-inflammatory treatment to better target the peripheral airways.

A Comparison of Hydrostatic Weighing and Air Displacement Plethysmography in Adults With Spinal Cord Injury

Clasey JL, Gater DR Jr. A comparison of hydrostatic weighing and air displacement plethysmography in adults with spinal cord injury. Objectives To compare (1) total body volume (V b) and density (D b) measurements obtained by hydrostatic weighing (HW) and air displacement plethysmography (ADP) in adults with spinal cord injury (SCI); (2) measured and predicted thoracic gas volume (V TG); and (3) differences in percentage of fat measurements using ADP-obtained D b and HW-obtained D b measures that were interchanged in a 4-compartment body composition model (4-comp %fat). Design Twenty adults with SCI underwent ADP and V TG, and HW testing. In a subgroup (n=13) of subjects, 4-comp %fat procedures were computed. Setting Research laboratories in a university setting. Participants Twenty adults with SCI below the T3 vertebrae and motor complete paraplegia. Interventions Not applicable. Main Outcome Measures Statistical analyses, including determination of group mean differences, shared variance, total error, and 95% confidence intervals. Results The 2 methods yielded small yet significantly different V b and D b. The groups’ mean V TG did not differ significantly, but the large relative differences indicated an unacceptable amount of individual error. When the 4-comp %fat measurements were compared, there was a trend toward significant differences ( P=.08). Conclusions ADP is a valid alternative method of determining the V b and D b in adults with SCI; however, the predicted V TG should be used with caution.

Video-Assisted Sympathectomy for Essential Hyperhidrosis

Essential hyperhidrosis is characterized by overactivity of the sympathetic fibers passing through the upper-dorsal ganglia (second and third thoracic ganglia [D2-D3]), and the treatment of choice is video-assisted thoracoscopy sympathectomy. Alterations in cardiopulmonary function after treatment have been reported.To evaluate cardiopulmonary function impairment after sympathectomy in patients with essential hyperhidrosis.Prospective controlled trial at a pulmonary function unit of a university hospital.Twenty patients (2 men and 18 women) with essential hyperhidrosis.Pulmonary function tests, including spirometry and thoracic gas volume, bronchial challenge with methacholine, and maximal exercise, were performed before and 3 months after D2-D3 sympathectomy. Video-assisted sympathectomy was performed using a one-stage bilateral procedure with electrocoagulation of D2-D3 ganglia. Pulmonary function values (spirometrics and volumes) were not statistically different in the two groups. The maximal midexpiratory flow was the only variable that showed significant changes, from 101% (SD, 26%) to 92% (SD, 27%) [p < 0.05]. Ten patients had positive bronchial challenge test results that remained positive 3 months after surgery, and 2 patients whose challenge test results were negative before surgery became positive after sympathectomy. Significant reductions in maximal heart rate (HR) and oxygen and carbon dioxide uptakes were observed during the maximal exercise test.Video-assisted thoracoscopy is a safe treatment, and the observed modifications in cardiopulmonary function only suggest a minimal small airway alterations in the presence of positive bronchial hyperresponsiveness and mild sympathetic blockade in HR. The clinical importance of these findings is not significant.

Effects of montelukast treatment on clinical and inflammatory variables in patients with cystic fibrosis

In cystic fibrosis (CF), the inflammatory process contributes to progressive lung tissue damage. Cysteinyl leukotrienes have been found in the sputum of patients with CF at high concentrations sufficient to cause potent biological effects. To evaluate the effect of anti-inflammatory treatment with montelukast sodium in patients with CF. Twenty-six patients aged 6 to 18 years were recruited to this 20-week, randomized, double-blind, placebo-controlled, crossover trial. Patients received montelukast or placebo for 8 weeks in addition to their regular CF treatment. Before and after treatment, findings from spirometry, whole-body plethysmography, and the clinical wheezing and cough scales were evaluated. At the same time, serum and sputum samples were obtained for the measurement of eosinophil cationic protein, interleukin 10 (IL-10), IL-8, and myeloperoxidase levels. Twenty-three patients completed the study. Compared with placebo use, montelukast treatment significantly improved forced expiratory volume in I second, peak expiratory flow, and forced expiratory flow between 25% and 75% and significantly decreased cough and wheezing scale scores (P < .001 for all). There were no significant changes in vital capacity, thoracic gas volume, airway resistance, and residual volume after treatment. Compared with placebo use, montelukast treatment decreased serum and sputum levels of eosinophil cationic protein and IL-8, decreased sputum levels of myeloperoxidase, and increased serum and sputum levels of IL-10 (P < .001 for all). Montelukast may have measurable anti-inflammatory properties in patients with CF.