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PubMed1998

Fixed maximal stroke index in patients after pneumonectomy.

Patients who have undergone pneumonectomy (PNX) show limited exercise capacity, partly attributable to an impaired stroke index (SI). To determine whether this limitation is due to deconditioning, we assessed exercise performance and cardiopulmonary function in seven patients after PNX (age: 59 +/- 2 yr, mean +/- SEM) and eight normal, healthy nonsmokers (52 +/- 3 yr) before and after an ergometer exercise training program for 30 min per day, 5 d per week, for 8 wk at 65% of measured maximal O2 uptake. Lung volume, diffusing capacity of carbon dioxide (DL(CO)) and cardiac index (CI) were determined during steady-state exercise by a rebreathing method. Exercise endurance was measured at 80% of maximal power. As compared with normal subjects, patients who had had PNX showed diminished maximal oxygen uptake (VO2max), as well as diminished lung volumes, ventilatory capacities, and maximal cardiac and stroke indexes. After training, VO2max, endurance, and peripheral O2 extraction improved in both groups. However, maximal cardiac and stroke indexes increased only in normal subjects and not in patients. We conclude that an irreversibly fixed maximal SI is a major source of exercise limitation after PNX, probably because of pulmonary arterial hypertension and/or mechanical distortion of the cardiac fossa. Ventilatory impairment after PNX did not prevent a training-induced increase in VO2max. Exercise training confers significant functional benefit on postpneumonectomy patients by enhancing peripheral O2 extraction.

Adult↗
PubMed1986

High-dose intravenous methylprednisolone pulse therapy as initial treatment in cryptogenic fibrosing alveolitis. A pilot study.

Ten patients with fibrosing alveolitis were treated in a simple random design initially with either a high dose of methylprednisolone (5 patients) or a conventional dose of prednisolone (5 patients) followed by a maintenance dose of 30 mg prednisolone daily. The patients were followed for 6 weeks. No significant (p greater than 0.05) differences were observed between patients with high and low initial dose of glucocorticosteroids, as regards forced vital capacity, transfer factor for carbon monoxide or symptom scores after 3 and 6 weeks of treatment. After 6 weeks the dyspnoea score and the 67Ga uptake decreased, on average, by 74 and 85%, respectively, while forced vital capacity and transfer factor increased by 15 and 29%.

Adult↗
PubMed1994

Mechanisms of increased epithelial lung clearance of DTPA in diffuse fibrosing alveolitis.

The aim of this study was to elucidate possible mechanisms of increased epithelial lung clearance in diffuse fibrosing alveolitis (DFA). We investigated the relationships between epithelial lung clearance as assessed by the clearance of aerosolized 99mTc-diethylene-triamine-penta-acetic acid (RC-DTPA), luminal alveolitis as assessed by bronchoalveolar lavage, and pulmonary function, in 30 nonsmokers with DFA. In 14 of these patients, RC-DTPA and lung function were determined before and during therapy with prednisolone (0.5 mg.kg-1 daily). RC-DTPA was higher in patients with DFA (4.45 +/- 2.50%.min-1) than in normal subjects (1.18 +/- 0.31%.min-1). RC-DTPA did not correlate with the number of alveolar neutrophils, but correlated positively with the number of alveolar lymphocytes, and negatively with vital capacity (VC). RC-DTPA decreased from 6.1 +/- 2.8 to 3.8 +/- 1.9%.min-1 with prednisolone. RC-DTPA before prednisolone correlated positively with the prednisolone-associated improvement in VC. We conclude that in patient with DFA, RC-DTPA is increased, and decreases but does not return to normal with corticosteroid therapy. Our data suggest that in DFA the increase in RC-DTPA could be related to the recoil-induced stretch of the respiratory epithelium and to alveolar lymphocytic inflammation.

Aerosols↗
PubMed1983

Effects of obesity on respiratory function.

Obesity, because it alters the relationship between the lungs, chest wall, and diaphragm, has been expected to alter respiratory function. We studied 43 massively obese but otherwise normal, nonsmoking, young adults with spirometry, lung volume measurement by nitrogen washout, and single-breath diffusing capacity for carbon monoxide (DLCO). Changes in respiratory function were of two types, those that changed in proportion to degree of obesity--expiratory reserve volume (ERV) and DLCO--and those that changed only with extreme obesity--vital capacity, total lung capacity, and maximal voluntary ventilation. When compared with commonly used predicting equations, we found that mean values of subjects grouped by degree of obesity were very close to predicted values, except in those with extreme obesity in whom weight (kg)/height (cm) exceeded 1.0. In 29 subjects who lost a mean of 56 kg, significant increases in vital capacity, ERV, and maximal voluntary ventilation were found, along with a significant decrease in DLCO. Because most subjects fell within the generally accepted 95% confidence limits for the predicted values, we concluded that obesity does not usually preclude use of usual predictors. An abnormal pulmonary function test value should be considered as caused by intrinsic lung disease and not by obesity, except in those with extreme obesity.

Adult↗
PubMed1992

Ventilatory capacity and exercise-induced arterial desaturation of highly trained endurance athletes.

Recent evidence suggested that exercise-induced arterial O2 desaturation may occur in highly trained endurance athletes. So, Dempsey brought the hypothesis that the pulmonary capacity for oxygen transport cannot meet superior demands imposed by cardiovascular system in highly trained endurance athletes, and endurance training primarily causes adaptation in the skeletal muscles and in the systemic cardiovascular system, with little change in the pulmonary system. In the present study, we determined the propriety of the hypothesis due to measure the ventilatory capacity of endurance athletes. Sixteen highly trained endurance athletes (ET) and thirteen untrained subjects (UT) volunteered to participate in these experiments. All subjects performed the four experiments, 1) the highest oxygen uptake (peak VO2) during incremental cycle exercise and ventilation (VE), ventilatory equivalent for O2 (VE/VO2) and arterial O2 saturation (SaO2) at which peak VO2 was observed, 2) the maximal voluntary ventilation for 30 sec at rest (MVV), 3) the pulmonary diffusing capacity for CO (DLCO) and expressed per unit of alveolar lung volume (KCO) at rest by the single breath method, and 4) the ventilatory response to hypercapnia (S) at rest by rebreathing method, were measured. The peak VO2 of ET (66.7 ml.min-1.kg-1) was significantly (30.8%) higher than UT (52.4 ml.min-1.kg-1), and VE/VO2 and SaO2 of ET (29.3 and 93.7%, respectively) were significantly lower than UT (34.6 and 95.8%). There were no differences in VE, MVV, DLCO, and S between two groups.

Adult↗
PubMed2000

Evaluation of diffusing capacity in patients with a restrictive lung disease.

BACKGROUND: In healthy volunteers, the single-breath diffusing capacity of the lung for carbon monoxide (DLCO) decreases and DLCO normalized per liter alveolar volume (VA; DLCO/VA) increases if VA is decreased. We hypothesized that comparison of DLCO/VA with its predicted value at predicted total lung capacity (TLC) will result in an underestimation of the diffusion disorder in patients with a restrictive lung disease, if a similar relationship exists between DLCO/VA and lung volume as found in healthy volunteers. OBJECTIVE: To test this hypothesis, we studied total gas transfer DLCO and DLCO/VA as functions of VA in patients who developed a restrictive lung disease and a diffusion disorder in a short period of time. DESIGN: An observational survey. SETTING: Pulmonary function department. PATIENTS: Thirteen patients without any initial pulmonary pathology who developed the mentioned pulmonary pathology due to bleomycin treatment. INTERVENTIONS: Bleomycin treatment. MEASUREMENTS AND RESULTS: We performed the single-breath test at various VA levels before, during, and after bleomycin treatment. In the majority of the patients, the DLCO vs VA relationship remained parabolic, but shifted downwards during therapy. Therefore, the linear DLCO/VA vs VA relationship shifted downwards, while the negative slope was not changed, indicating the development of a decreased gas transfer. Six patients also developed a volume restriction. CONCLUSIONS: The agreement of the data with the hypothesis increased its probability. Consequently, to evaluate a diffusion disorder, DLCO/VA at a lower actual TLC of patients with a lung restriction should be compared to a reference DLCO/VA at a lung volume equal to the actual TLC.

Adult↗
PubMed1984

Physiologic correlates of airway collapse in chronic airflow obstruction.

Forty percent of 89 patients with chronic airflow obstruction (CAO) demonstrated maximum expiration flow-volume (MEFV) patterns consistent with sudden collapse or marked narrowing of large central airways. In contrast, 43 percent of the CAO patients demonstrated a curvilinear (C) pattern; the remainder (17 percent) were intermediate. Volume displacement plethysmography indicated that the airway collapse (AC) pattern was influenced by, but was not solely, a gas compression artifact. Airway collapse patients had more obstruction and hyperinflation than C patients and also had decreased diffusing capacity, absence of density dependence, reduced lung recoil, and no effort dependence of airflow. Bronchodilator administration in AC patients typically produced large reduction of residual volume and increase of vital capacity, with a smaller increase of airflow. These data suggest that AC patients have significant, partially reversible peripheral airways obstruction plus emphysema. Possible determinants of AC include reduced central airway support, increased peripheral resistance, loss of lung recoil, and increased pleural pressures during forced expiration. The MEFV contour appears to evolve from normal to curvilinear to the AC pattern as the severity of airflow obstruction worsens.

Aged↗
PubMed1997

Effects of a single saturation dive on lung function and exercise performance.

We studied the effects of an experimental saturation dive to 360 and 450 m in a simulation chamber on spirometric lung function, diffusing capacity, pulmonary compliance, and exercise performance in eight professional divers (age 22-40 years). To assess intraindividual variability, all parameters were measured on 2 days before and on 2 consecutive days immediately after the dive. For the group as a whole there was a significant increase in vital capacity and alveolar volume, and a decrease in Krogh factor and specific compliance (P < 0.01). These changes were reduced on the 2nd day after the dive. All subjects showed lowered exercise performance after the dive. Arterial pressure of oxygen and ventilation during exercise increased (P < 0.01), whereas arterial pressure of carbon dioxide, oxygen uptake, and anaerobic threshold decreased (P < 0.01). Exercise parameters showed only a slight trend towards pre-dive values on the 2nd day after a dive. The individual analysis revealed that after the dive two subjects showed a marked decrease in diffusing capacity and a more than average decrease in Krogh factor (TLCO/VA). One of them had signs of mild decompression sickness and the other, signs of pre-existing obstructive airways disease. Our data are compatible with the hypothesis that the effects of a single deep saturation dive on pulmonary function and exercise performance are the results of counteracting mechanisms. We suggest that lung volumes increase due to the enhanced work of breathing during a deep saturation dive and that these changes could mask an impairment in gas exchange. Furthermore, a saturation dive can induce an apparent deterioration of pulmonary function.

Adult↗
PubMed1993

Bronchoalveolar lavage cell analysis and lung function impairment in patients with systemic lupus erythematosus (SLE).

We examined the relationship between peripheral blood and bronchoalveolar lavage (BAL) lymphocyte phenotypes and lung function in 19 patients with SLE, and evaluated their association with disease activity. Lung function assessment showed a mildly restrictive pattern with frequent impairment of transfer factor for carbon monoxide (T1,co) and diffusing capacity of the alveolocapillary membrane (Dm), of late-expiratory airflow rates and with a high prevalence of increased airway resistance. T1,co, Kco and Dm correlated inversely with the numbers of CD8+ cells and CD56+/CD16+/CD3- (NK) cells in BAL. Oxygen radical production, both by stimulated and unstimulated BAL cells and blood polymorphonuclear leucocytes (PMN) was significantly increased in SLE. In comparison with healthy controls, patients with SLE had a lower percentage of CD19+ B cells in the BAL versus an increased percentage of these cells in peripheral blood. HLA-DR expression on CD4+ and CD8+ lung lymphocytes was markedly increased in SLE. Current SLE disease activity was not associated with changes in BAL or peripheral blood lymphocyte phenotypes. Our data suggest that an ongoing cell-mediated immune response is present in the lungs in SLE, particularly involving activated CD8+ T cells and CD56+/CD16+/CD3- NK cells. It is associated with up-regulated local production of oxygen radicals and with impaired pulmonary diffusing capacity. This inflammatory process seems to be independent of general SLE disease activity.

Adult↗
PubMed1989

Comparison of single breath carbon monoxide diffusing capacity and pressure-volume curves in detecting emphysema.

To evaluate the sensitivity of diffusing capacity (DLCO) and pressure-volume (P-V) curves in the detection of emphysema, these tests were compared with pathologic assessment of emphysema in patients undergoing lung resection for a localized tumor, and with the overall extent of emphysema as assessed by computed tomography (CT). The resected lung specimens were fixed in the inflated state and cut at 1-cm intervals in the horizontal plane. The pathologic extent of emphysema was quantitated by comparison with a standard reference panel of emphysema grading. The overall extent of emphysema on CT was assessed by a visual scoring system in a total of 55 patients, 19 undergoing lung resection and 36 not undergoing lung resection. Analysis of 37 patients by pathology scores revealed 18 with no or trivial emphysema (emphysema grades less than or equal to 5; mean grade, 2.2 +/- SD 2.6) and 19 with emphysema (grades greater than or equal to 10; mean grade, 33.2 +/- SD 24.2). Diffusing capacity, the ratio of DLCO to alveolar volume (DLCO/VA), maximal lung elastic recoil (PLmax), and lung elastic recoil at 90% of total lung capacity (PL90) were significantly different between the two groups, whereas K (the exponential constant describing the shape of the P-V curve) was not. The pathology grade of emphysema showed a significant correlation with (DLCO) (r = -0.53) and DLCO/VA (r = -0.55), which was greater than the correlation with PLmax (r = -0.42) and PL90 (r = -0.43).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Pulmonary function in patients presenting with Raynaud's phenomenon without an underlying connective tissue disease. A prospective, longitudinal study.

Forty-two patients presenting with Raynaud's phenomenon (RP) were prospectively evaluated for pulmonary function changes over a 6-year followup period. Fifteen patients had secondary RP at presentation, 27 patients had nonsecondary RP. In the latter group, decreased pulmonary diffusing capacity (Tlco) was observed in only 2 patients (7%) whereas 9 patients with secondary RP (60%) had decreased Tlco. In the group of patients with nonsecondary RP exhibiting one or more autoantibodies, Tlco values were lower than in the group without autoantibodies (p less than 0.01). In patients with nonsecondary RP the duration of disease was correlated with the level of Tlco (r = 0.55), probably explained by a higher prevalence of truly primary RP in patients with longstanding nonsecondary RP. During followup no significant changes in pulmonary function were observed in the group with nonsecondary RP. We conclude that pulmonary function testing in patients presenting with nonsecondary RP without autoantibodies does not appear of clinical value.

Adult↗
PubMed2004

Nailfold capillary microscopy can suggest pulmonary disease activity in systemic sclerosis.

OBJECTIVE: To evaluate the association of capillaroscopic alterations with pulmonary disease activity in systemic sclerosis (SSc). METHODS: Ninety-one patients with SSc were studied by means of interview, physical examination, nailfold capillary microscopy (NCM), serology, pulmonary function tests, esophageal transit scintigraphy, Doppler echocardiography, and pulmonary high resolution computed tomography (HRCT). Pulmonary disease activity was diagnosed by the observation of ground-glass opacities on pulmonary HRCT. Capillary loss on NCM was evaluated using the avascular score: patients with mean score > or = 1 or mean number of megacapillaries per finger > or = 1 were considered to have severe capillaroscopic alterations. RESULTS: Patients with higher skin scores, longer disease duration, signs of peripheral ischemia, esophageal dysfunction, antitopoisomerase I antibodies, and ground-glass opacities had higher mean avascular scores (p < or = 0.05 in all tests). The association between ground-glass opacities and higher avascular scores was particularly strong in patients with disease duration < or = 5 years. Among these patients, ground-glass opacities were present in 14 of 19 patients with severe NCM alterations, but were absent in all patients (n = 8) with mild or no NCM alterations (p < 0.001). ROC curves confirmed the ability of NCM to discriminate between patients with and without ground-glass opacities among those with disease duration < or = 5 years. However, NCM could not predict the presence of reduced pulmonary diffusing capacity. CONCLUSION: The severity of NCM abnormalities is associated with lung disease activity in SSc, particularly when the disease duration is relatively short.

Adult↗
PubMed2004

[Pulmonary function testing before ablative methods].

Laser-induced thermotherapy (LITT) and radiofrequency thermoablation (RFTA) are increasingly used for pulmonary interventions. Primarily patients with severe functional limitations precluding a surgical approach are selected for these procedures. In this patient group a valid preinterventional risk assessment is of paramount importance. The occurrence of a pneumothorax is one of the most important complications associated with these procedures. Therefore, the functional capacity and pulmonary reserve of these patients should allow for at least short periods of lung collapse. The periinterventional risk of these patients can be estimated from basic lung function studies when certain comorbidities are excluded.

Carbon Dioxide↗
PubMed1989

Oxygen transport during exercise in large mammals. II. Oxygen uptake by the pulmonary gas exchanger.

Because the maximal rate of O2 consumption (VO2max) of the horse is 2.6 times larger than that of steers of equal size, we wondered whether their pulmonary gas exchanger is proportionately larger. Three Standardbred racehorses [body mass (Mb) = 447 kg] and three domestic steers (Mb = 474 kg) whose cardiovascular function at VO2max had been thoroughly studied (Jones et al. J. Appl. Physiol. 67: 862-870, 1989) were used to study their lungs by morphometry. The basic morphometric parameters were similar in both species. The nearly 2 times larger lung volumes of the horses caused the gas exchange surfaces and capillary blood volume to be 1.6 to 1.8 times larger. Morphometric pulmonary diffusing capacity was 2 times larger in the horse than in the steer; the 2.6-fold greater rate of O2 uptake thus required the alveolar-capillary PO2 difference to be 1.3 times larger in the horse than in the steer. Combining physiological and morphometric data, we calculated capillary transit time at VO2max to be 0.4-0.5 s. Bohr integration showed capillary blood to be equilibrated with alveolar air after 75 and 58% of transit time in horses and steers, respectively; horses maintain a smaller degree of redundancy in their pulmonary gas exchanger.

Animals↗
PubMed1990

Clinical features of amiodarone-induced pulmonary toxicity.

The incidence and clinical predictors of amiodarone pulmonary toxicity were examined in 573 patients treated with amiodarone for recurrent ventricular (456 patients) or supraventricular (117 patients) tachyarrhythmias. Amiodarone pulmonary toxicity was diagnosed in 33 of the 573 patients (5.8%), based on symptoms and new chest radiographic abnormalities (32 of 33 patients) and supported by abnormal pulmonary biopsy (13 of 14 patients), low pulmonary diffusion capacity (DLCO) (nine of 13 patients), and/or abnormal gallium lung scan (11 of 16 patients). Toxicity occurred between 6 days and 60 months of treatment for a cumulative risk of 9.1%, with the highest incidence occurring during the first 12 months (18 of 33 patients). Older patients developed it more frequently (62.7 +/- 1.7 versus 57.4 +/- 0.5 years, p = 0.018), with no cases diagnosed in patients who started therapy at less than 40 years of age. Gender, underlying heart disease, arrhythmia, and pretreatment chest radiographic, spirometric, or lung volume abnormalities did not predict development of amiodarone pulmonary toxicity, whereas pretreatment DLCO was lower in the group developing it (76.0 +/- 5.5% versus 90.4 +/- 1.4%, p = 0.01). There was a higher mean daily amiodarone maintenance dose in the pulmonary toxicity group (517 +/- 25 versus 409 +/- 6 mg, p less than 0.001) but no difference in loading dose. No patient receiving a mean daily maintenance dose less than 305 mg developed pulmonary toxicity. Patients who developed toxicity had higher plasma desethylamiodarone (2.34 +/- 0.18 versus 1.92 +/- 0.04 micrograms/ml, p = 0.009) but not amiodarone concentrations during maintenance therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiodarone↗
PubMed2002

Three-dimensional, unsteady simulation of alveolar respiration.

A novel macroscopic gas transport model, derived from fundamental engineering principles, is used to simulate the three-dimensional, unsteady respiration process within the alveolar region of the lungs. The simulations, mimicking the single-breath technique for measuring the lung diffusing capacity for carbon-monoxide (CO), allow the prediction of the red blood cell (RBC) distribution effects on the lung diffusing capacity. Results, obtained through numerical simulations, unveil a strong relationship between the type of distribution and the lung diffusing capacity. Several RBC distributions are considered, namely: normal (random), uniform, center-cluster, and corner-cluster red cell distributions. A nondimensional correlation is obtained in terms of a geometric parameter characterizing the RBC distribution, and presented as a useful tool for predicting the RBC distribution effect on the lung diffusing capacity. The effect of red cell movement is not considered in the present study because CO does not equilibrate with capillary blood within the time spent by blood in the capillary. Hence, blood flow effect on CO diffusion is expected to be only marginal.

Carbon Dioxide↗
PubMed2007

Comparison of total-breath and single-breath diffusing capacity in healthy volunteers and COPD patients.

BACKGROUND: The measurement of single-breath diffusing capacity (Dlco(SB)) assumes that diffusing capacity per liter of alveolar volume (Dlco/VA) determined in a 750-mL gas sample represents the diffusing capacity (Dlco) of the entire lung. Fast-responding gas analyzers provide the opportunity to verify this assumption because of the possibility to measure CO and CH(4) fractions continuously throughout the entire expiration. Continuous gas sampling provides more information per measurement, but this information cannot be expressed in the traditional parameters. Our goals were to find new parameters to express the extra information of the continuous gas sampling, and to compare these new parameters with the traditional parameters. METHODS: We compared a new method to determine Dlco with the traditional method in 62 healthy volunteers and 26 COPD patients. Traditionally, Dlco(SB) is determined by multiplying Dlco/VA with alveolar volume, both calculated from gas concentrations in a 750-mL gas sample. The new method calculates total-breath Dlco (Dlco(TB)) by integration of Dlco/VA against exhaled volume. RESULTS: In healthy volunteers, Dlco/VA shows a slight upward slope during exhalation, while in COPD patients Dlco/VA shows a horizontal line. Total-breath total lung capacity (TLC) is larger than single-breath TLC both in healthy volunteers and in COPD patients, leading to a Dlco(TB) that is significantly larger than Dlco(SB) in both groups (p < 0.001). CONCLUSION: The assumption that a 750-mL gas sample represents the entire lung seems to be correct for Dlco/VA but not for the CH(4) fraction in case of ventilation inhomogeneity.

Adult↗