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Background and Objectives: Pulmonary Mycobacterium avium complex (pMAC) disease manifests as various types of lesions, such as infiltrates, nodules, cavities, and bronchiectasis. However, the important determinants for clinical parameters in lung involvement are poorly understood. The objective of this study was to obtain quantitative parameters by 3-dimensional CT, and investigate the relationship between these parameters and the pulmonary function tests (PFTs) and health-related quality of life., Material and Methods: Quantitative analysis using CT was performed in 67 pMAC patients. The relationship between new quantitative parameters for evaluating lung involvement using 3-dimensional CT and PFTs or St George's Respiratory Questionnaire (SGRQ) was evaluated., Results: The ratio of infiltration to total lung volume showed significant correlation with the PFT results, especially the percent-predicted forced vital capacity (%FVC; ρ = -0.52), residual volume (ρ = -0.51), and total lung capacity (ρ = -0.59). The cavity volume was strongly correlated with the %FVC (ρ = -0.78) in the cavity group, while the ratio of infiltration to total lung volume was strongly correlated with the %FVC (ρ = -0.53) in the non-cavity group. The ratio of infiltration to total lung volume was significantly correlated with all SGRQ parameters (ρ = 0.41-0.52) in the non-cavity group., Conclusions: Infiltration was an important parameter for the PFTs and SGRQ in pMAC patients according to the 3-dimensional CT analysis. Moreover, cavity volume was an important parameter of the PFTs in the cavity group. Therefore, infiltration and cavity volume are key features for the management of pMAC disease., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Although FEV1/FVC ratio has been shown to be negatively associated with longer duration of asthma; an association between RV/TLC ratio and longer duration of asthma has not been explored., Material and Methods: Patients with established asthma for more than a year and met inclusion and exclusion criteria were recruited. Data obtained by questionnaire after informed consent was obtained, Pulmonary function tests and laboratory results were collected through chart review. Correlation and multiple linear regressions were used to analyze the data., Results: Among the 93 subjects, 61 were women. The mean age of patients was 58 ± 15 years, and the mean duration of asthma was 21 ± 18 years. The ethnic composition included: Caucasians 64%, Hispanics 28% and other groups 8%. The FEV1/FVC ratio was not significantly associated with duration of asthma (R2 = 0.15, p = 0.05). However, the RV/TLC ratio was significantly associated with duration of asthma (R2 = 0.46, p < 0.001)., Conclusion: RV/TLC ratio may be a better indicator than FEV1/FVC ratio to detect airway obstruction related to longer duration of asthma. Lung volume measurements should be done in addition to spirometry to detect changes related to airway obstruction in patients with longer duration of asthma., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Lung volume reduction (LVR) techniques improve lung function in selected patients with emphysema, but the impact of LVR procedures on the asynchronous movement of different chest wall compartments, which is a feature of emphysema, is not known., Methods: We used optoelectronic plethysmography to assess the effect of surgical and bronchoscopic LVR on chest wall asynchrony. Twenty-six patients were assessed before and 3 months after LVR (surgical [n = 9] or bronchoscopic [n = 7]) or a sham/unsuccessful bronchoscopic treatment (control subjects, n = 10). Chest wall volumes were divided into six compartments (left and right of each of pulmonary ribcage [Vrc,p], abdominal ribcage [Vrc,a], and abdomen [Vab]) and phase shift angles (θ) calculated for the asynchrony between Vrc,p and Vrc,a (θRC), and between Vrc,a and Vab (θDIA)., Results: Participants had an FEV₁ of 34.6 ± 18% predicted and a residual volume of 217.8 ± 46.0% predicted with significant chest wall asynchrony during quiet breathing at baseline (θRC, 31.3° ± 38.4°; and θDIA, -38.7° ± 36.3°). Between-group difference in the change in θRC and θDIA during quiet breathing following treatment was 44.3° (95% CI, -78 to -10.6; P = .003) and 34.5° (95% CI, 1.4 to 67.5; P = .007) toward 0° (representing perfect synchrony), respectively, favoring the LVR group. Changes in θRC and θDIA were statistically significant on the treated but not the untreated sides., Conclusions: Successful LVR significantly reduces chest wall asynchrony in patients with emphysema.

Objective: The aim of this work was to investigate if regional differences of specific gas volume (SVg) in the different regions (lobes and bronchopulmonary segments) in healthy volunteers and patients with severe emphysema can be used as a tool for planning lung volume reduction (LVR) in emphysema., Methods: CT scans of 10 healthy subjects and 10 subjects with severe COPD were obtained at end-inspiration (total lung capacity [TLC]) and end-expiration (residual volume [RV]). For each subject, ΔSVg (ΔSVg = SVg,TLC - SVg,RV, where SVg,TLC and SVg,RV are specific gas volume at TLC and RV, respectively) vs ΔV (ΔV = V,TLC-V,RV, where V,TLC and V,RV are lung volume at TLC and RV, respectively) was plotted for the entire lung, each lobe, and all bronchopulmonary segments. For each subject, a heterogeneity index (HI) was defined to quantify the range of variability of ΔSVg/ΔV in all bronchopulmonary regions., Results: In patients with COPD, SVg,TLC and SVg,RV were significantly higher and ΔSVg variations lower than in healthy subjects (P < .001). In COPD, ΔSVg/ΔV slopes were lower in upper lobes than in lower lobes. In healthy subjects, the entire lung, lobes, and bronchopulmonary segments all showed similar ΔSVg/ΔV slopes, whereas in COPD a high variance was found. As a consequence, HI was significantly higher in subjects with COPD than in healthy subjects (0.80 ± 0.34 vs 0.15 ± 0.10, respectively; P < .001)., Conclusions: SVg variations within the lung are highly homogeneous in healthy subjects. Regions with low ΔSVg/ΔV (ie, more pronounced gas trapping) should be considered as target areas for LVR. Regions with negative values of ΔSVg/ΔV identify where collateral ventilation is present. HI is helpful to assess the patient in the different stages of disease and the effect of different LVR treatments.

Background: Hyperinflation refers to a nonspecific increase in absolute lung volumes and has a poor prognosis in COPD. The relative contribution of increased airways resistance and increased parenchymal compliance to hyperinflation of each absolute lung volume is poorly understood. We hypothesized that increased residual volume (RV) and RV/total lung capacity (TLC) would be associated with reduced airway lumen dimensions, whereas increased functional residual capacity (FRC), TLC, and reduced inspiratory capacity (IC)/TLC would be associated with emphysema on CT scan. We examined whether clinical characteristics differed accordingly., Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited smokers aged 50 to 79 years who were free of clinical cardiovascular disease. Gas trapping was defined as RV or RV/TLC greater than the upper limit of normal and hyperexpansion as FRC or TLC greater than the upper limit of normal or IC/TLC less than the lower limit of normal. Airway lumen diameters and percent emphysema &lt; -950 Hounsfield units were quantified on CT images. Analyses were adjusted for age, sex, body size, race/ethnicity, education, and smoking., Results: Among 116 participants completing plethysmography, 15% had gas trapping, 18% has hyperexpansion, and 22% had both. Gas trapping was associated with smaller airway lumen diameters (P = .001), greater dyspnea (P = .01), and chronic bronchitis (P = .03). Hyperexpansion was associated with percent emphysema (P &lt; .001), lower BMI (P = .04), and higher hemoglobin concentration (P = .001)., Conclusions: Gas trapping and hyperexpansion on plethysmography were associated with distinct differences in lung structure and clinical characteristics. Absolute lung volumes should not be considered equivalent in their estimation of hyperinflation and provide insight into the extent of airway and parenchymal abnormalities in COPD.

The characteristics of dyspnoea in idiopathic pulmonary fibrosis (IPF) during a 6-min walk test are not clear. This study was designed to evaluate dyspnoea and desaturation during the 6-min walk test in IPF in comparison with that in chronic obstructive pulmonary disease (COPD), which is one of the most studied chronic lung diseases. The 41 consecutive patients with IPF included in this study were assessed by a 6-min walk test and concurrent measures of disease severity. Forty-one age-matched and resting PaO(2) value-matched COPD patients who had undertaken the test during the same period were selected as the control. Only O(2) saturation at the end of the test was an independent predictor of dyspnoea in IPF (r(2)=0.27, P=0.0005), whereas forced expiratory volume in 1s (FEV(1)) was the only predictor in COPD (r(2)=0.16, P=0.0096). Desaturation was significantly more severe in IPF (83.6+/-9.1% in IPF versus 88.0+/-5.9% in COPD, P<0.001). In contrast, dyspnoea assessed with the Borg scale was significantly more severe in COPD (3.6+/-2.1 in IPF versus 4.6+/-1.9 in COPD, P<0.05). O(2) saturation is an independent predictor of dyspnoea at the end of a 6-min walk test in IPF. In comparison with COPD, desaturation is more severe, although dyspnoea is milder.

Study Objective: To detect dynamic hyperinflation (DH) by evaluating reduction in inspiratory capacity (IC) during metronome-paced hyperventilation (MPH) in patients with moderate-to-severe COPD, studied before and after treatment with tiotropium., Methods: IC and FEV(1) were measured before and immediately after MPH at two times resting the respiratory rate for 20 s in 60 COPD patients (28 men; mean age, 66 +/- 10 years [+/- SD]) before and after 30 days of treatment with tiotropium bromide, 18 mug. Patients were encouraged to maintain a constant tidal volume during MPH., Results: At baseline, mean FEV(1) was 1.5 +/- 0.1 L (+/- SE) [57 +/- 1.6% of predicted], mean FVC was 2.6 +/- 0.1L (77 +/- 1.8% of predicted), and mean FEV(1)/FVC was 56 +/- 1%. After 180 mug of aerosolized albuterol sulfate, mean FEV(1) was 1.7 +/- 0.1 L (63 +/- 1.5% of predicted) [p < 0.001] and mean FEV(1)/FVC was 58 +/- 1%. Compared to baseline, after 30 days and 1.5 h after tiotropium there was an increase in IC of 0.18 +/- 0.04L (p < 0.0001); FEV(1) of 0.13 +/- 0.03 L (5.6 +/- 0.8% of predicted; p = 0.0002); FVC of 0.22 +/- 0.05 L (6.5 +/- 1.3% of predicted; p < 0.001); and decrease in end-expiratory lung volume (EELV)/total lung capacity (TLC) of - 3.1 +/- 0.6% (p = 0.0001); a decrease in end-inspiratory lung volume (EILV)/TLC of - 2.9 +/- 1.3% (p = 0.03); and no change in TLC (- 0.06 +/- 0.05 L). Results following MPH-induced DH at baseline and after 30 days of tiotropium were similar, with decreases in IC (- 0.35 +/- 0.03 L; p < 0.001); FEV(1) (- 0.05 +/- 0.04 L; p = 0.2); and FVC (- 0.22 +/- 0.03 L; p < 0.0001); no change in TLC; and increases in EELV/TLC (11.8 +/- 1.0% of predicted; p < 0.0001) and EILV/TLC (4.0 +/- 1.3% of predicted, p < 0.003)., Conclusion: In patients with moderate-to-severe COPD, tiotropium did not reduce MPH-induced DH and reduction in IC, compared to baseline. However, because tiotropium induced bronchodilation and increased baseline IC, lower operational lung volumes may blunt the effect of MPH-induced DH. The noninvasive simplicity of MPH-induced DH provides a clinically useful screening surrogate to monitor changes in IC following treatment with tiotropium.

Background: Patients with asthma have intermittent or persistent airflow obstruction, most often manifested spirometrically by reduced forced expiratory volume in 1s (FEV(1)) and FEV(1)/vital capacity (VC) ratio. In some patients, the VC may be reduced by air trapping, with an increase in functional residual capacity (FRC) and residual volume (RV) (pseudorestriction). We have reported 12 asthmatic patients with reduced VC and no increase in RV, i.e., a true restrictive impairment [Gill et al. True restrictive impairment in bronchial asthma. Am J Respir Crit Care Med 1999:159:A652]., Objectives: To confirm previous observations of true restrictive impairment (not attributable to air trapping) in patients with asthma, and to estimate its frequency in an asthmatic population., Methods: Review of pulmonary function tests and clinical records of all post-pubertal patients diagnosed as asthma between January 2000 and September 2003 in a 184 bed inner city teaching hospital in Jamaica, Queens, New York. The clinical diagnosis of asthma was accepted when one or more of the following pulmonary function criteria were met: Positive bronchodilator response (BD), positive methacholine, repeated variability in spirometric values. Restriction was defined as decrease in total lung capacity (TLC) or decrease in VC with no increase in functional residual capacity (FRC) plus normal or high FEV(1)/FVC ratio. Patients with any clinical finding consistent with restriction, including a decreased diffusing capacity (DL) or obesity (BMI >30) were excluded., Results: A total of 100 of 413 (24%) patients with asthma had restriction; 21 of these met all exclusions (including DL and BMI) and 11 (of 46) patients with an increased BMI and normal DL normalized their FVC on BD therapy, demonstrating that their pre-BD restrictive impairment could not be attributed to obesity. Plethysmographic FRC was measured in 81 of the 100 patients with restriction and was increased in only seven., Conclusion: True restrictive impairment was noted in at least 32 of 413 asthmatics (8%), consistent with previous observations in asthma and reactive airways dysfunction syndrome. This finding is not widely recognized and should not preclude the diagnosis of asthma, BD testing or appropriate therapy for asthma.

Background: Upper airway (UA) patency during inspiration is determined by the balance between dilating forces generated by UA dilator muscle activity and collapsing forces related to the decreased intraluminal pressure that accompanies flow generated by inspiratory muscle activity. It is possible that the relative strengths of UA dilator and inspiratory pump muscles could be an important determinant of the susceptibility to UA collapse during sleep (ie, obstructive sleep apnea [OSA])., Methods: Measurements of tongue protrusion (TP) force and maximum inspiratory pressure (Pimax) were obtained in 94 patients admitted for overnight polysomnography for suspected OSA, quantified by apnea-hypopnea index (AHI)., Results: There was a direct linear relationship between TP force and Pimax (r(2) = 0.37, p < 0.001). A high ratio of TP force to Pimax (greater than group 90th percentile, 0.027 kg/cm H(2)O) appeared to protect against OSA, as moderate-to-severe OSA (AHI > 20/h) was not observed in any individual with a ratio above this threshold. AHI was not linearly related to TP force, Pimax, or the ratio of TP force to Pimax., Conclusions: UA muscle strength is linearly related to inspiratory pump muscle strength. The ratio of UA muscle strength (TP force) and inspiratory pump muscle strength (Pimax) was not different between individuals with and without OSA; however, a high wakeful ratio of TP force to Pimax appears to be associated with a reduced propensity to moderate-to-severe OSA.

Introduction: To take in charge of an asthmatic child it is necessary to evaluate the lung function., Methods: In this study, the Negative Expiratory Pressure (NEP) has been used for the first time in children with asthma. After lung spirometry by plethysmography, we have used the NEP to assess the prevalence of expiratory flow limitation (FL) during resting breath in 27 asthmatic children (mean age: 11 +/- 2,5 years) 3-4 days after a crisis in both sitting and supine positions., Results: All the children presented an obstructive defect (FEV 1: 63 +/- 13% med) and a dynamic hyperinflation (FRC: 128 +/- 25% med). According to the NEP, 11 children presented an expiratory flow limitation (FL). Asthma was more severe in the FL than in non-FL children (GINA 2002 classification). Among the 11 FL children, 5 were FL in both sitting and supine position and 6 only in supine. Nine of the 27 children were FL with the conventional method. NEP seems a more accurate method to assess the clinical gravity of asthma than FEV 1. The reduction of FRC in the supine position probably explains the greater incidence of FL in supine position., Conclusion: Because of its easy execution, NEP seems to be well adapted for children. Links between FL detected by NEP and clinical signs of asthma has to be assessed by furthers studies including more patients.

Background: The risk of death for patients with end-stage cystic fibrosis awaiting lung transplantation remains high and most patients succumb to respiratory failure. This study was conducted to evaluate the usefulness of ventilation-perfusion scintillation scans, obtained during the pre-transplant period, to identify patterns that predict prognosis while on the waiting list. These patterns were compared with other pulmonary physiologic markers of ventilation and perfusion obtained from pulmonary function and cardiopulmonary exercise tests., Methods: From November 1990 to January 1999, 46 patients with cystic fibrosis were listed for bilateral lung transplantation. Fourteen (30.4%) died while waiting for a transplant (Group 1), whereas 32 were transplanted successfully or remain alive and waiting (Group 2). Mean arterial blood gas values, Brasfield radiograph scores, cardiopulmonary exercise data and the degree of scintillation scan abnormalities between lungs were compared for each group., Results: Mean survival for Group 1 was 10.2 +/- 1.7 months, and for Group 2 was 23.5 +/- 3.0 months (p < 0.001). The right upper lung zone was the most severely affected segment. The Cox proportional hazards model revealed an increased perfusion disparity and resting hypercapnia as the main predictors of death while on the transplant list. The Kaplan-Meier analysis indicated greater survival for the groups with <30% disparity between lungs on the pre-transplant scintillation scans., Conclusions: The results suggest that severe, unilateral perfusion abnormalities seen on scintillation scans in patients with cystic fibrosis are associated with an increased risk of dying while on the lung transplant waiting list and may be helpful in identifying patients who should be considered for early or living-donor transplantation.

Duchenne's muscular dystrophy (DMD), characterized by gradually developing muscular weakness, leads to respiratory symptoms and reduced lung function. We aimed to assess lung function in 25 patients with DMD in relationship to age and muscular function. The 25 boys, mean age 13 years, comprized patients in southern Norway with DMD, taking part in an epidemiological follow-up study. None had chronic respiratory disease. Lung function was measured by maximum expiratory flow-volume loops and whole body plethysmography, and repeated after 1 year (n= 14). Lung function was reduced compared to predicted values for healthy children. Forced expiratory volume in 1 sec (FEV1)% predicted and forced vital capacity (FVC)% predicted correlated (significantly) inversely to age. FEV1 and FVC decreased annually 5.61 and 4.2% of predicted, respectively. Absolute values of FVC (litres) and FEV1 (1 sec(-1)) increased until mean age 14 years, decreasing thereafter. Values in % predicted decreased steadily throughout the age range (6-19 years). Lung function correlated closely to upper limb muscle function.

The product of walking distance and body weight (D x W) mimics the work of walking. We hypothesized the superiority of D x W to walking distance (D) alone in any correlation with lung function, anaerobic threshold (AT) and maximal oxygen uptake (VO2max). We further hypothesized that the D x W product for a 6-min walk test (6 MWT) would correlate with the AT and VO2max because all three are markers of exercise ability. Thirty-three male chronic obstructive pulmonary disease (COPD) patients with mean forced expiratory volume in 1 sec (FEV1) of 1.2+/-0.4 l (range 0.58-1.86 l) were enrolled. Six patients were excluded due to inability to achieve a maximal test. Lung function and self-assessed every-day activities using a oxygen-cost diagram were evaluated before entry of the study. A maximal effort ramp-pattern cardiopulmonary exercise test (CPET) and a 6 MWT were conducted in random order. Borg score, heart rate, and O2 saturation with pulse oximetry (SpO2) were measured during both exercise tests. VO2 AT and minute ventilation were also measured during the CPET. Correlations were sought between the distance covered in the 6 MWT, and the D x W product with AT, VO2max and other variables. The average D and D x W were 456 m and 27.5 kg km(-1), respectively. D x W was superior to D alone when correlated with the VO2max and AT determined from the CPET, while modestly correlated with the change (delta) in Borg score and delta SpO2 in the 6 MWT and self-assessed every-day activities. Distance x weight product was correlated with the AT and VO2max. In addition, D x W was better correlated with diffusing capacity for carbon monoxide and vital capacity than D alone. We conclude that D x W mimics the work of walking better than D and is suggested as a parameter for evaluation of patients' fitness if gas exchange measurements are not available.

Seventy-seven patients with morbid obesity, body mass index (BMI) 40-69.9 kg m(-2), who were candidates for gastroplasty, were studied in our laboratory as part of a pre-operative survey. They had no complaints other than obesity and were not cyanotic. A group of 28 lean subjects (BMI 20-29.8 kg m(-2)) who were candidates for abdominal surgery, without any respiratory complaint, were included as controls. For each patient a pulmonary function test was performed, measuring slow vital capacity with expiratory residual volume (ERV), forced vital capacity (flow/volume) and maximal voluntary ventilation (MVV). In obese patients the MVV is reduced as BMI increases. This results in the reduction of expiratory flows and volumes. Forced expiratory volume in 1 sec (FEV1) is reduced in proportion to the FVC reduction and is related to MVV. It is suggested that the main consequence of the burden of the chest wall by increased adipose mass is a reduction in its compliance, making inspiration increasingly difficult, and resulting in lower static volumes and flows.

Study Objectives: To clarify the pathophysiologic features of the relation between asthma and obesity, we measured the effects of weight reduction on peak expiratory flow (PEF) variability and airways obstruction, compared to simultaneous changes in lung volumes and ventilatory mechanics in obese patients with stable asthma., Methods: Fourteen obese asthma patients (11 women and 3 men; aged 25 to 62 years) were studied before and after a very-low-calorie-diet period of 8 weeks. PEF variability was determined as diurnal and day-to-day variations. FEV(1) and maximal expiratory flow values were measured with a flow-volume spirometer. Lung volumes, airways resistance (Raw), and specific airways conductance were measured using a constant-volume body plethysmograph. Minute ventilation was monitored in patients in supine and standing positions., Results: As patients decreased their body mass index (SD) from 37.2 (3.7) to 32.1(4.2) kg/m(2) (p < 0. 001), diurnal PEF variation declined from 5.5% (2.4) to 4.5% (1.5) (p = 0.01), and day-to-day variation declined from 5.3% (2.6) to 3. 1% (1.3) (p < 0.005). The mean morning PEF, FEV(1), and FVC increased after weight loss (p = 0.001, p < 0.005, and p < 0.05, respectively). Flow rate at the middle part of FVC (FEF(25-75)) increased even when related to lung volumes (FEF(25-75)/FVC; p < 0. 05). Functional residual capacity and expiratory reserve volume were significantly higher after weight loss (p < 0.05 and p < 0.005, respectively). A significant reduction in Raw was found (p < 0.01). Resting minute ventilation decreased after weight loss (p = 0.01)., Conclusion: Weight loss reduces airways obstruction as well as PEF variability in obese patients with asthma. The results suggest that obese patients benefit from weight loss by improved pulmonary mechanics and a better control of airways obstruction.

Study Objective: To determine how the volume and severity of emphysema measured by CT morphometry (CTM) before and after lung volume reduction surgery (LVRS) relates to the functional status of patients after LVRS., Design: A histologically validated CT algorithm was used to quantify the volume and severity of emphysema in 35 patients before and after LVRS: total lung volume (TLV), normal lung volume (< 6.0 mL gas per gram of tissue), volume of mild/moderate emphysema (ME; 6.0 to 10.2 mL gas per gram of tissue), volume of severe emphysema (> 10.2 mL gas per gram of tissue), surface area/volume (SA/V; meters squared per milliliter), and surface area (SA; meters squared). Outcome parameters included maximal cardiopulmonary exercise (CPX) performance in 21 patients and routine pulmonary function in all patients. We hypothesized that baseline CTM parameters predict response to LVRS and that the change in these parameters may offer insight into mechanisms of improvement., Patients and Intervention: Thirty-five patients with severe emphysema who had successful LVRS., Results: The significant decrease in TLV following LVRS was entirely accounted for by a decrease in severe emphysema. The SA/V and the SA both increased significantly following LVRS. The change in maximal CPX in watts following surgery correlated significantly with baseline values of severe emphysema (r = 0.60), which was collinear with TLV, and SA/V. The change in diffusing capacity of the lung for carbon monoxide revealed a significant positive linear relationship with preoperative severe emphysema (r = 0.37) and a negative relationship with ME (r = -0.37). Change in watts revealed a strong relationship with changes in severe emphysema (r = -0.75) and weaker but significant relationships with change in TLV, ME, SA/V, and SA. Other measures of pulmonary function revealed significant albeit less dominant relationships with baseline CTM and change in these indexes., Conclusion: Using CTM, we have identified a close relationship between baseline severe emphysema, or change in severe emphysema, and the improvement in CPX after LVRS. These observations support a potential role of CTM in future clinical trials for predicting responders to LVRS and identifying mechanisms of improvement.

Study Objectives: We sought to investigate the effect of lung volume reduction surgery (LVRS) on regional lung ventilation., Design: Retrospective analysis of routinely acquired data before and after LVRS., Setting: Large, urban, university medical center., Patients: Twenty-nine patients with severe emphysema., Intervention: Bilateral LVRS., Measurements and Results: (133)Xe washout curves during lung scintigraphy exhibit a biphasic pattern (the first component of the washout curve [m(r)] corresponds to an initial rapid phase in washout that reflects larger airways emptying, and the second component [m(s)] reflects a slower phase of washout that is attributed to gas elimination via smaller airways). We analyzed six standardized regions of the lung (upper, mid, and lower zones of the right and left lung), and calculated m(r) and m(s) for each lung region. The mean (+/- SE) baseline FEV(1) was 0.69+/-0.04 L, total lung capacity (TLC) was 139 +/-4% predicted, and the residual volume (RV)/TLC ratio was 65+/-2%. The mean improvement in FEV(1) 3 months post-LVRS was 38%. Post-LVRS, m(r) and m(s) increased in 79 and 74 lung regions, respectively, and there was no relationship with respect to lung regions that had or had not been operated on. The increase in m(s), however, significantly correlated with the increase in FEV(1) (r = 0.66; p<0.0001) and the decrease in RV/TLC (r = -0.67; p<0.0001). An increase in m(s) also correlated with a decrease in PaCO(2) (r = -0.39; p = 0.03), but m(r) showed no relationship with any parameter., Conclusions: Small airways ventilation in lung regions that had and had not been operated on is associated with a greater improvement in lung mechanics following LVRS.

We examined the degree of ventilatory constraint in patients with a history of chronic heart failure (CHF; n = 11; mean +/- SE age, 62 +/- 4 years; cardiac index [CI], 2.0 +/- 0.1; and ejection fraction [EF], 24 +/- 2%) and in control subjects (CTLS; n = 8; age, 61 +/- 5 years; CI, 2.6 +/- 0.3) by plotting the tidal flow-volume responses to graded exercise in relationship to the maximal flow-volume envelope (MFVL). Inspiratory capacity (IC) maneuvers were performed to follow changes in end-expiratory lung volume (EELV) during exercise, and the degree of expiratory flow limitation was assessed as the percent of the tidal volume (VT) that met or exceeded the expiratory boundary of the MFVL. CHF patients had significantly (p < 0.05) reduced baseline pulmonary function (FVC, 76 +/- 4%; FEV(1), 78 +/- 4% predicted) relative to CTLS (FVC, 99 +/- 4%; FEV(1), 102 +/- 4% predicted). At peak exercise, oxygen consumption (VO(2)) and minute ventilation (V(E)) were lower in CHF patients than in CTLS (VO(2), 17 +/- 2 vs 32 +/- 2 mL/kg/min; VE, 56 +/- 4 vs 82 +/- 6 L/min, respectively), whereas VE/carbon dioxide output was higher (42 +/- 4 vs 29 +/- 5). In CTLS, EELV initially decreased with light exercise, but increased as VE and expiratory flow limitation increased. In contrast, the EELV in patients with CHF remained near residual volume (RV) throughout exercise, despite increasing flow limitation. At peak exercise, IC averaged 91 +/- 3% and 79 +/- 4% (p < 0.05) of the FVC in CHF patients and CTLS, respectively, and flow limitation was present over > 45% of the VT in CHF patients vs < 25% in CTLS (despite the higher VE in CTLS). The least fit and most symptomatic CHF patients demonstrated the lowest EELV, the greatest degree of flow limitation, and a limited response to increased inspired carbon dioxide during exercise, all consistent with VE constraint. We conclude that patients with CHF commonly breathe near RV during exertion and experience expiratory flow limitation. This results in VE constraint and may contribute to exertional intolerance.

Setting an appropriate positive end-expiratory pressure (PEEP) value is determined by respiratory mechanics, gas exchange and oxygen transport. As these variables may be optimal at different PEEP values, a unique PEEP value may not exist which satisfies both the demands of minimizing mechanical stress and optimizing oxygen transport. In 15 surfactant-deficient piglets, PEEP was increased progressively. Arterial oxygenation and functional residual capacity (FRC) increased, while specific compliance of the respiratory system decreased. Static compliance increased up to a threshold value of PEEP of 8 cm H2O, after which it decreased. This threshold PEEP did not coincide with the lower inflection point of the inspiratory limb of the pressure-volume (PV) loop. Oxygen transport did not correlate with respiratory mechanics or FRC. In the lavage model, the lower inflection point of the PV curve may reflect opening pressure rather than the pressure required to keep the recruited lung open. Recruitment takes place together with a change in the elastic properties of the already open parts of the lung. No single PEEP level is optimal for both oxygen transport and reduction of mechanical stress.

Study Objectives: To determine the correlates of static lung volumes in patients with airways obstruction, and to determine if static lung volumes differ between asthma and COPD., Patients and Methods: We examined the data from all of the adult patients (mean age of 69) who were referred to a pulmonary function laboratory from January 1990 through July 1994 with an FEV1/FVC ratio of < 0.70 and tested using a body plethysmograph. Correlates were determined using regression analysis., Measurements and Results: Of the 4,774 patients observed with evidence of airways obstruction, 61% were men. Self-reported diagnoses included asthma, 19%; emphysema or COPD, 23%; chronic bronchitis, 1.5%; and alpha1-antiprotease deficiency, 0.6%. Fifty-six percent of the patients did not report a respiratory disease. The degree of hyperinflation, as determined by the residual volume (RV)/total lung capacity (TLC) ratio, or the RV % predicted (but not the TLC % predicted), was strongly associated with the degree of airways obstruction (the FEV1 % predicted). Patients with moderate to severe airways obstruction and high RV and TLC levels were more likely to have COPD than asthma. Of the 1,872 patients with a reduced vital capacity determined by spirometry testing, 87% had hyperinflation as defined by the RV/TLC, and 9.5% had a low TLC (with less severe airways obstruction)., Conclusion: In patients found to have airways obstruction by spirometry, the additional measurement of static lung volumes added little to the clinical interpretation.

Study Objectives: To characterize acute changes in the dynamic, passive mechanical properties of the lungs and chest wall, elastance (E) and resistance (R), caused by lung volume reduction surgery (LVRS)., Design: Prospective data collection., Patients: Nine anesthetized/paralyzed patients with severe emphysema., Interventions: Bilateral LVRS., Measurements and Results: From measurements of airway and esophageal pressures and flow during mechanical ventilation throughout the physiologic range of breathing frequency (f) and tidal volume (VT), E and R of the total respiratory system (Ers and Rrs), lungs (EL and RL), and chest wall (Ecw and Rcw) immediately before and after LVRS were calculated. After surgery, Ers, EL, Rrs, and RL were all greatly increased at each combination off and VT (p<0.05). Ecw and Rcw showed no consistent changes (p>0.05). The increases in EL were greatest in those patients with the lowest residual volumes, highest FEV1 values, and highest maximum voluntary ventilations measured 3 months preoperatively (p<0.05); the increases in RL were greatest in those patients with the lowest preoperative residual volumes (p<0.05). The largest increases in RL were in those patients with the largest decreases in residual volume and total lung capacity, measured 3 months postoperatively, caused by LVRS (p<0.05)., Conclusion: Acute effects of LVRS are large increases in lung elastic tension and resistance; these increases need to be considered in immediate postoperative care, and can be predicted roughly from results of preoperative pulmonary function tests.

Background: Lung volume reduction surgery either via sternotomy or by thoracoscopy has been demonstrated to be effective for selected emphysema patients in North America and Europe. The present study summarizes short-term results of bilateral lung volume reduction performed via median sternotomy for the first consecutive 39 patients with severe diffuse emphysema in Okayama, Japan, from July 1995 to February 1997., Methods: There were 35 men and 4 women, and the age range was 54 to 74 years with a mean age of 65 years. All were former heavy smokers and none of them had alpha1-antitrypsin deficiency. Only 9 patients (23%) showed a bilateral upper lobe pattern of emphysema. The operation was done through a median sternotomy, and the most emphysematous portions were excised bilaterally with a linear stapling device fitted with strips of bovine pericardium to prevent air leakage., Results: No operative death was encountered. The first 33 patients completed 3-month follow-up assessment, and their mean forced expiratory volume in 1 second had improved by 41% from 735 mL to 1,037 mL. Other parameters of pulmonary function tests, arterial blood gas analysis, 6-minute walking distance, and dyspnea scale also had improved significantly. These improvements lasted for at least a year., Conclusions: Bilateral lung volume reduction surgery via median sternotomy is a safe and effective procedure for selected severe emphysema patients. Although the pattern of emphysema might be different between countries, the results in Japanese patients were similar to those previously reported in North American and European patients.

Study Objectives: To verify whether hypoxemia affects respiratory muscle strength in the absence of malnutrition and whether such effect, if present, is reversible with an acute oxygen supplementation., Design: Case series analysis, before-after trial., Setting: Outpatient pneumology departments of two university hospitals., Patients: One hundred twenty patients affected by COPD in stable conditions having actual to ideal body weight ratio of > or =90%., Measurements and Results: Maximal inspiratory pressure (MIP) was measured at functional residual capacity level in the whole sample of subjects and during oxygen supplementation in 58 patients having a PaO2< or =60 mm Hg when breathing in room air. Predictors of MIP were assessed by a multivariate analysis. MIP values before and after oxygen supplementation were compared by a paired t test. MIP was independently correlated with FVC (p<0.001), PaO2 (p<0.01), and age (p<0.01). In the subgroup of hypoxemic patients, MIP values did not change significantly after oxygen supplementation (3.08+/-1.74 vs 3.03+/-1.91 kPa, t=0.43, not significant)., Conclusions: Hypoxemia is an important negative correlate of MIP even in well-nourished COPD patients. Its effect is not reversible with an acute oxygen supplementation.

Background and Objectives: Lung volume reduction surgery (LVRS) improves ventilatory function in selected patients with severe COPD. The reasons for the observed benefits include the following: increased elastic recoil, improved airflow, and lesser dynamic hyperinflation and decreased lung volumes. We reasoned that these changes could also alter respiratory drive., Methods: Respiratory central drive was prospectively assessed using the mouth occlusion pressure (P0.1), and the P0.1 response to increasing CO2 (P0.1/PETCO2 [end-tidal CO2 pressure]), in eight sequential patients before and 3 to 5 months after LVRS. Results were compared with those from 13 control subjects., Results: LVRS decreased total lung capacity from 7.44+/-1.8 L to 5.92+/-1.3 L (p<0.05) and residual volume from 4.97+/-1.5 L to 3.56+/-1.1 L (p<0.05). It also significantly improved FEV1 from 0.85+/-0.26 L to 0.99+/-0.26 L (p<0.05). Baseline P0.1 (3.4+/-1.8 vs 1.4+/-0.4 cm H2O, p<0.01) and P0.1/PETCO2 (0.24+/-0.07 vs 0.11+/-0.04 cm H2O/mm Hg, p<0.05) were higher in patients than in control subjects. After LVRS, P0.1 decreased from 3.4+/-1.8 to 1.3+/-0.75 cm H2O (p<0.01) and P0.1/PETCO2 from 0.24+/-0.07 to 0.16+/-0.06 cm H2O/mm Hg (p<0.05). These postoperative values were similar to those of control subjects. There were no correlations between changes in the factors known to influence central drive (PaO2, PaCO2, age, weight, height, FVC, and FEV1) and changes in P0.1., Conclusions: We conclude that decreased ventilatory drive should be added to the list of benefits of LVRS, and may help explain the symptomatic improvement reported by many patients after this surgery.

Purpose: Lung volume reduction surgery (LVRS) has shown promise for treating patients with severe emphysema in recent clinical trials. However, response following surgery is difficult to assess due to frequent discrepancies between subjective and objective outcomes. We evaluated the relationship between improvement in dyspnea and pulmonary function response in 145 consecutive patients with inhomogeneous emphysema enrolled in a bilateral thoracoscopic lung volume reduction protocol in order to assess predictors of improved dyspnea outcome and correlation of subjective and objective improvement measures., Materials and Methods: Baseline complete pulmonary function testing, spirometry, gas exchange, plethysmography, gas dilution lung volumes, along with resting dyspnea index determinations were performed preoperatively, and repeated short term (mean, 33 days; n=129) and long term (>6 months; mean, 276 days; n=84) following surgery., Results: Improvement in FEV1 percent predicted was significantly associated with improvement in dyspnea scores, though considerable variability exists (r=0.04, p<0.01, short term; r=0.4, p=0.1, long term). In this preselected patient group, those with the extreme degrees of hyperinflation may have less improvement in dyspnea following LVRS than those with milder preoperative hyperinflation. Greater improvement in dyspnea short term and long term was seen in patients with lower presenting residual volume/total lung capacity ratios (r=0.4, p=0.02, short term; r=0.4, p<0.05, long term)., Conclusions: Bilateral thoracoscopic staple LVRS results in significant objective and subjective improvement in patients with severe emphysema and hyperinflation. There was considerable variability between improvement in dyspnea and improvement in spirometry, and preoperative predictors of response may differ between these outcome variables. Further studies are needed to define the long-term implications of these findings.

Study Objective: To evaluate the long-term stability of improvements in exercise capacity and quality of life (QOL) after lung volume reduction surgery (LVRS)., Design: Case-series analysis., Setting: University hospital., Patients: Twenty-six patients with severe airflow obstruction (mean FEV1 of 0.67+/-0.18 L) and moderate to severe hyperinflation (mean total lung capacity of 7.30+/-1.90 L)., Intervention and Measurements: All patients underwent bilateral LVRS via median sternotomy. Serial measurement of lung function, symptom-limited cardiopulmonary exercise tests, 6-min walk distances (6MWD), and sickness impact profile (SIP) scores were done before, and at 3, 6, 12, and 18 months after surgery., Results: FEV1 (0.93+/-0.29 vs 0.68+/-0.19 L, p<0.001) increased while residual volume (3.47+/-1.2 vs 4.77+/-1.5 L, p<0.001) decreased significantly at 3 months post-LVRS compared to baseline, and these changes were maintained at 12 to 18 months follow-up. Similarly, the increase in 6MWD at 3 months post-LVRS (340+/-84 vs 251+/-114 m, p<0.001) was sustained at all follow-up times. On cardiopulmonary exercise testing, total exercise time (9.0+/-1.8 vs 6.1+/-1.9 min, p<0.001), oxygen uptake at peak exercise (VO2 peak) (14.9+/-4 vs 11.9+/-3 mL/kg/min, p<0.001), maximum oxygen pulse (7.43+/-2.37 vs 5.85+/-1.96 mL/beat, p<0.005), and maximum minute ventilation (VEmax) (30.3+/-10 vs 23.5+/-7.1 L/min, p<0.001) increased significantly at 3 months post-LVRS. On serial study following LVRS, total exercise time remained significantly greater at 6 (8.5+/-1.38 min) and 12 months (8.71+/-2.0 min) post-LVRS compared to baseline (5.81+/-1.9 min, p<0.05). VO2 peak tended to be higher at all follow-up periods (3 months, 16.1+/-4.3; 6 months, 14.5+/-2.6; 12 months, 14.1+/-3.5 mL/kg) compared to baseline (12.6+/-3.9 mL/kg, p=0.08). Similarly, maximum O2 pulse tended to be higher in all follow-up studies (3 months, 8.45+/-2.7; 6 months, 7.6+/-1.7; 12 months, 7.42+/-2.1 mL/beat) compared to baseline (6.39+/-2.5 mL/beat, p=0.06). Higher VEmax continued to be observed at 6 (30+/-10 L/min) and 12 months (28+/-10 L/min) post-LVRS, compared to baseline (23+/-7 L/min, p=0.02). VEmax post-LVRS was significantly higher at 3 and 6 months compared to baseline on post-hoc analysis (p<0.05). Overall SIP scores were lower at 3 months (7 vs 18, p<0.0002) post-LVRS and were sustained in long-term follow-up., Conclusion: We conclude that bilateral LVRS via median sternotomy in selected patients with severe, diffuse emphysema improves exercise performance and QOL at 3 months following LVRS and these improvements are maintained for at least 12 to 18 months in follow-up.

Study Objective: The development of right ventricular (RV) hypertrophy in emphysema is accompanied by involvement of the left ventricle (LV) and its systolic function. Our objective was to study the relation between RV hypertrophy and LV ejection fraction in emphysema by means of MRI., Patients: Ten emphysematous patients (FEV1, 0.99+/-0.32 L; FEV1/vital capacity (VC), 0.32+/-0.11 [mean+/-SD]) and 10 age-matched control subjects were included. Exclusion criteria were any history of systemic hypertension, ischemic or valvular heart disease, or episodes of right- and/or left-sided cardiac failure., Measurements and Results: Rapid scout imaging was used to measure RV and LV wall mass, wall thickness, and end-diastolic volume. Stroke volume was derived from the main pulmonary artery flow. RV wall volume, RV wall thickness, and the ratio of RV to LV wall thickness were significantly larger in the patient group than in the control group (p<0.01). Furthermore, patients had significantly lower values of LV ejection fraction (p<0.01) than the control subjects. A flattening or leftward displacement of the ventricular septum during systole was observed. In addition, our study showed an increase of LV ejection fraction proportional with the RV wall thickness (r=0.78, p<0.01) in severely emphysematous patients., Conclusion: These data are in support of the hypothesis that flattening of the interventricular septum explains the relatively normal LV ejection fraction in emphysematous patients with severe RV hypertrophy.

In 283 patients referred for testing in an outpatient pulmonary function laboratory, we studied the single-breath diffusing capacity of the lungs for carbon monoxide (Dco) using the Ogilvie (Og), Jones-Meade (JM), Epidemiological Standardization Project (ESP), and three-phase iterative methods (3PIT, similar to the three equation method). The Dco maneuvers were performed using automated equipment and American Thoracic Society (ATS) recommended procedures. There were small but significant differences in mean Dco, the ESP method yielding the largest, followed in order by JM, 3PIT, and Og methods. The 3PIT and JM Dcos were in close agreement in all degrees and patterns of pulmonary function abnormality. The Og Dco method was 6 percent less than JM in patients with normal pulmonary function, although the difference was less in patients with expiratory flow limitation, restriction, or reduced Dco. There were no differences in the reproducibility of Dco measurements among the methods. Based on these results and a review of the literature, we conclude the following: (1) when measuring single-breath Dco using automated equipment that follows ATS recommended procedures for collecting a single expired gas sample of 500-ml volume, calculated Dco is largest using ESP method, following by JM, 3PIT, and Og methods; (2) in patients with reduced Dco associated with obstructive or restrictive abnormalities, the Og, 3PIT, and JM timing methods are nearly equivalent; and (3) reproducibility of Dco is the same by all methods.

To examine whether respiratory muscle weakness is associated with cardiac function and/or exercise capacity in chronic heart failure (CHF), 23 patients with CHF were evaluated with respiratory muscle strength, pulmonary function tests, cardiac catheterization, and exercise test. The subjects were divided into three groups on their New York Heart Association (NYHA) functional class. Group A consisted of 13 patients with NYHA functional classification class 3 or 4, group B consisted of 10 patients with NYHA classification class 2, and group C consisted of 15 age-matched normal controls. Respiratory muscle strength was assessed with maximal static inspiratory mouth pressure at residual volume level and expiratory mouth pressure at total lung capacity level (PImax, PEmax, respectively). Pulmonary functions in patients with CHF showed almost normal. PImax in group A was significantly less than that in group B or C, although PImax in group B was not significantly different from that in group C. In the patients with CHF, PImax correlated positively with cardiac index and maximal oxygen consumption (r = 0.460 and r = 0.503, p < 0.05, respectively). These findings suggest that inspiratory muscle strength, which was impaired in patients with severe CHF, may be dependent on cardiac function and may be one of the limiting factors on impaired exercise capacity in the patients with CHF.

We studied whether inspiratory muscle training (IMT) changed respiratory sensation during exercise in 12 healthy women; IMT was performed twice daily, for 15 minutes, using a pressure threshold device and continued for 4 weeks. The inspiratory threshold was set to 30 percent of each individual's maximal inspiratory pressure (Pimax). Breathing effort was evaluated during a progressive exercise test using Borg scale. After IMT, both Pimax and maximal transdiaphragmatic pressure increased by 30 percent in the training group (p < 0.05) but did not change in the control group. Prior to IMT, the Borg score increased in proportion to exercise grade. The difference in the sensory score-exercise stage curves before and after IMT in the training group was not significant. No significant difference was noted in the relationship of the Borg score to minute ventilation before and after 4 weeks in either group. We concluded that IMT may not affect respiratory sensation during exercise in normal subjects, although IMT increases diaphragmatic strength.

Seventeen cases of hypersensitivity pneumonitis (HP) at a symptomatic phase were categorized into two groups based on computed tomographic (CT) findings and histologic features of transbronchial lung biopsy specimens, HP accompanied by lung fibrosis (fibrosis group), and HP unaccompanied by lung fibrosis (nonfibrosis group). The fibrosis group comprised bird fancier's lung and HP of unknown etiology, whereas the nonfibrosis group mainly comprised summer-type HP. Comparison of results of pulmonary function tests between these two groups confirmed a restrictive impairment in the fibrosis group. Analyses of cellular components of bronchoalveolar lavage (BAL) fluids revealed lymphocytes, especially CD8+ T lymphocytes, were significantly increased in the nonfibrosis group in comparison with the fibrosis group, whereas CD4+ T cells were increased to the same level in the both groups. Analyses of the onset of disease showed that acute onset was observed mainly in nonfibrosis group and strongly correlated with increased CD8+ T lymphocytes in BAL fluids, while insidious onset was related to lung fibrosis and relatively increased CD4+ T lymphocytes in BAL fluids. These findings raise the possibility that highly elevated CD8+ T cells might have a protective effect on pulmonary fibrosis or that relatively increased CD4+ T cells might play an important role in the pathogenesis of pulmonary fibrosis of HP at the chronic phase.

Magnetic resonance imaging was performed in four male asbestos workers in whom the chest radiograph revealed pleural but not pulmonary or pericardial disease. Patients underwent thoracic multislice spin echo imaging, with measurement of left and right ventricular volumes at end-diastole and end-systole, and a study of the flow in the superior vena cava as an indirect measure to the filling of the right ventricle. Patients also underwent respiratory function tests and high-resolution computed tomography (HRCT). Magnetic resonance, but not HRCT, showed pericardial thickening in two patients. Magnetic resonance demonstrated reduced diastolic flow in the superior vena cava in one patient, reflecting impaired right ventricular filling. All other magnetic resonance measurements of cardiac function were normal. HRCT demonstrated mild asbestosis in three patients in which neither the chest radiograph nor magnetic resonance showed signs of parenchymal disease, and pericardiac calcification without thickening in one patient. It is concluded that magnetic resonance is superior to HRCT in identifying pericardial thickening, but that HRCT is superior to magnetic resonance in identifying asbestos-related pleural and pulmonary disease.

We have examined the effect of the fractional concentration of nitrogen (FIN2) on the decrease in lung volumes which occurs during restricted breathing with oxygen-nitrogen mixtures. Conscious human subjects breathed one of five gas mixtures of oxygen and nitrogen for 15 min on each of five occasions. For the final 5 min of each 15-min period, functional residual capacity (FRC) was reduced by one tidal volume, by external pressurization. After return to normal breathing, the subjects showed a statistically significant decrease in FRC and residual volume (RV), which became larger as FIO2 increased from 30% to 100%. This reduction in lung volumes was resistant to early reexpansion. The maximum decrease in both FRC and RV was found with 100% oxygen, and was 10% of the control lung volumes. The use of a mixture of 75% nitrogen and 25% oxygen prevented this decrease in lung volumes. Nitrogen 50% reduced the decrease in FRC, but did not affect the decrease in RV. The difference in effect on lung volumes between FIO2 25% and 30% was statistically significant, indicating a watershed area for FIN2 between 70% and 75%.

We describe the clinical, radiologic, functional, and pulmonary hemodynamic characteristics of a group of 30 nonsmoking patients with a lung disease that may be related to intense, long-standing indoor wood-smoke exposure. The endoscopic and some of the pathologic findings are also presented. Intense and prolonged wood-smoke inhalation may produce a chronic pulmonary disease that is similar in many aspects to other forms of inorganic dust-exposure interstitial lung disease. It affects mostly country women in their 60s, and severe dyspnea and cough are the outstanding complaints. The chest roentgenograms show a diffuse, bilateral, reticulonodular pattern, combined with normalized or hyperinflated lungs, as well as indirect signs of pulmonary arterial hypertension (PAH). On the pulmonary function test the patients show a mixed restrictive-obstructive pattern with severe hypoxemia and variable degrees of hypercapnia. Endoscopic findings are those of acute and chronic bronchitis and intense anthracotic staining of the airways appears to be quite characteristic. Fibrous and inflammatory focal thickening of the alveolar septa as well as diffuse parenchymal anthracotic deposits are the most prominent pathologic findings, although inflammatory changes of the bronchial epithelium are also present. The patients had severe PAH in which, as in other chronic lung diseases, chronic alveolar hypoxia may play the main pathogenetic role. However, PAH in wood-smoke inhalation-associated lung disease (WSIALD) appears to be more severe than in other forms of interstitial lung disease and tobacco-related COPD. The patients we studied are a selected group and they may represent one end of the spectrum of the WSIALD.

Respiratory problems are a major cause of death in the acute and chronic phases of cervical spinal cord injury (CSCI); CSCI paralyzes the intercostal and abdominal muscles, reducing ability to cough and clear secretions. Impaired cough due to neuromuscular disorders can be assessed with the maximum expiratory pressure (MEP). This study consists of two experiments with CSCI patients. In the first, MEP measurements were recorded with the following maneuvers performed: (1) spontaneous cough attempts, (2) manually assisted cough, and (3) cough attempts with functional electrical stimulation (FES) applied to the abdominal wall. In the second, spontaneous cough attempts and cough attempts with a portable FES unit were recorded. These CSCI patients were found to have a greatly reduced MEP when they coughed spontaneously. Either FES-assisted or manually assisted coughing increased the MEP in all patients studied. By increasing the MEP, abdominal muscle FES could enhance cough in quadriplegics.

Although weaning parameters can accurately predict weaning outcome, variability of the measurements of these parameters has not been closely examined. In the current study, we examined the reproducibility of these parameters using a standardized technique. Before the weaning trial, maximal inspiratory pressure (PImax), minute ventilation (VE), respiratory frequency (f), tidal volume (VT), rapid shallow breathing index (f/VT), and vital capacity (VC) were obtained on three trials over a period of 15 min. The results of these parameters over three measurements were compared. There were no statistical differences in the values of PImax, VE, f, VT, and f/VT over three trials (p = 0.45, p = 0.37, p = 0.69, p = 0.64, p = 0.1, respectively). The VC was the only parameter that showed statistical differences among three trials (p < 0.05). For the group, respiratory frequency had the lowest coefficient of variation (COV = SD/mean x 100 percent) at 6.7 percent while the VC had the highest COV at 19.6 percent. We concluded that most weaning parameters of breathing pattern can be measured reliably with bedside instruments using a standard technique.

Respiratory impedance measurements by means of the technique of forced oscillations together with spirometry and measurements of maximal mouth pressures were performed in 27 patients with a variety of neuromuscular disorders to assess the value of adding respiratory impedance measurements in the evaluation of lung function in neuromuscular disease. Using the technique of forced oscillations, impedance measurements are easily performed in physically disabled persons, since they require little active cooperation and no forced respiratory maneuvers. Normal respiratory impedance characteristics were found, although resistance values were somewhat higher than those found in normal subjects, signifying the absence of airflow limitation. Spirometric values were markedly reduced, as were maximal mouth pressures. No significant correlations were found between the forced expiratory volumes in 1 s (FEV1) and the impedance data. A strong curvilinear relationship was observed between Pemax and the RV/TLC ratio and a strong correlation existed between FEV1 and Premax. It is concluded from our study that forced oscillometry is a useful tool for the assessment or exclusion of airflow obstruction in patients with neuromuscular disorders when plethysmography is difficult to perform and forced expiratory flow-volume data reflect muscle weakness rather than airflow limitation.

We studied eight men with chronic obstructive pulmonary disease (COPD) (age, 60.57 +/- 7.59 years; height, 162 +/- 10.43 cm; weight, 65 +/- 9.7 kg). Functional values of the sample were as follows: FEV1, 46 percent; FVC, 67 percent; PO2, 72.4 mm Hg; and pH, 7.41. We used a modification of the Nickerson and Keens method. Patients were required to perform 65 percent of maximal inspiratory pressure (MIP). We counted the time from the start of the test to exhaustion of the patient (TLIM). We measured basal MIP and maximal expiratory pressure (MEP) (TLC) at the TLIM and 10, 20, and 30 minutes and MIP was different from the basal value (MIP basal, 85.7 cm H2O; MIP 10 minutes, 79.1 cm H2O; MIP 20 minutes, 78.6 cm H2O; MIP 30 minutes, 79.6 cm H2O. The MEP was not different from the basal value. We concluded that in patients with COPD, MIP decreases significantly after inspiration through umbral inspiratory weight equal to 65 percent MIP and does not return to basal value for 30 minutes. The MEP does not change with respect to basal determination.