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PubMed1980

Determinants of maximal expiratory flow and density dependence in normal humans.

There is a large variability in maximal expiratory flow (V) and density dependence (DD) in normal humans. Lung mechanics and flow-volume curves were obtained in 40 normal males while they breathed air or helium-oxygen (80%-20%). Static lung recoil (Pst) at 50% vital capacity, total lung capacity, and pulmonary resistance each correlated (P < 0.05) with airflow at 50% vital capacity. The relationship of V and Pst was described by Pst = 1/2 p V2/A2 + RV, where p is gas density, A is the critical area at the flow-limiting site, and R is peripheral resistance. At constant Pst and R, this simplified equation predicts an inverse relation between DD and airflow, which was found at recoil pressures of 8 and 7 cmH2O (P < 0.05). If peripheral losses are small, subjects with smaller flow-limiting airways would have lower airflows but higher DD than subjects with larger airways. Our findings are consistent with concept of dysanaptic growth and suggest that the central airways play a significant role in determining V and DD in normal humans.

Adult↗

PubMedDate not supplied

[Differential diagnosis of chronic obstructive lung disease, A statistical analysis of the discriminating power of various lung function tests (author's transl)].

Among 65 patients admitted to the hospital for chronic obstructive lung disease, the following pulmonary tests were systematically performed : spirometric vital capacity and total lung capacity, FEV1, functional residual capacity and total lung capacity measured by body plethysmography, airway resistance and specific conductance, CO diffusion capacity measured by single-breath test, N2 clearance by single breath oxygen dilution, and blood gases. The patients were divided into bronchitics, emphysematous and broncho-emphysematous, according to the clinical and radiological Nash's score, and to another personal score derived from the former. The simple and multiple correlations between the clinico-radiological score and the functional results are low. The clustering analysis groups the 65 patients into four clouds of points, around two principal axes : the volume axis and the overinflation axis. This study indicates that the most suggestive results for emphysema diagnosis are increased FRC and TLC and low Tlco/V'a. The clinical score is not dominant for the clustering of the patients into the dynamic clouds. Beneath the bronchitic, the broncho-emphysematous and the emphysematous groups, the clustering analysis individualizes a fourth group of cases characterized by chronic asthma, and which were not isolated by Nash's score.

Airway Resistance↗

PubMed1988

Pulmonary function in young and older athletes and untrained men.

This study compared the lung volumes and pulmonary functions of older endurance-trained athletes with those of healthy sedentary age-matched controls, young athletes, and young untrained men to determine whether training affects the age-associated changes in these variables. Despite large differences in maximal 02 consumption (VO2max), the older athletes and their sedentary peers had similar values for all pulmonary variables when expressed as absolute values. However, because the older athletes were shorter than the older sedentary men, their vital capacity, total lung capacity (TLC), and forced expiratory volume in 1 s were significantly larger than those of the older sedentary men when normalized for age and height; the average values for maximal voluntary ventilation and residual volume (RV) were also larger in the older athletes when normalized for age and height, but the differences were not significant. The young trained and untrained men did not differ in any of these measures. TLC was the only pulmonary variable that was the same in the young and older men; RV and the RV-to-TLC ratio were larger, whereas all other pulmonary function and volume measures were lower in the older men compared with the younger men. The older athletes were the only group whose lung volumes and pulmonary function measures were all, except for RV, substantially greater than expected based on their age and height. Thus prolonged strenuous endurance training in these older highly trained endurance athletes appears to have altered the decline in pulmonary function and volumes associated with aging.

Adult↗

PubMed1987

Pulmonary function in patients with sarcoidosis. A three year follow-up.

During a 3 year period, 101 patients were consecutively diagnosed as having sarcoidosis. During the 3 year follow-up 9 patients died, 6 of them directly or indirectly due to their sarcoidosis. In 78 patients bronchoscopy and spirometry were performed at the primary investigation, and after 3 years a new spirometry was performed. A positive bronchial mucosal biopsy, bronchial sarcoidosis, was found in 31 (40%) of the 78 patients. Mean values of vital capacity, total lung capacity and forced expiratory volume in one second were normal in both patients with bronchial sarcoidosis and those without. Abnormal spirometry was found in 16 (21%) patients at the initial examination and in 11 (14%) at the follow-up. There were 10 (32%) patients with and 6 (13%) without bronchial sarcoidosis who had an abnormal spirometry. At follow-up a normalized lung function was found in 8 (50%) of the 16 patients with abnormal spirometry. Only 3 (4.8%) patients with initially normal lung function had abnormal lung function at follow-up. Our findings indicate a very little risk of developing abnormal lung function if there are normal findings at the primary investigation. Corticosteroids seem to have some effect, especially in patients with endobronchial sarcoidosis.

Adult↗

PubMed1976

An analysis of potential physiological predictors of respiratory adequacy following cardiac surgery.

More than 50 potential physiological and clinical predictors of postoperative respiratory adequacy were examined in an attempt to identify those few variables which, singly or in combination, best predicted the outcome of the first trial of spontaneous respiration following cardiac surgery. This trial was initiated when patients seemed hemodynamically stable and relatively alert following surgery. Analysis of data from 124 patients identified the following useful predictors: forced vital capacity, total lung capacity, and maximal mid-expiratory flow rate from preoperative pulmonary function tests; resting cardiac index from preoperative cardiac catheterization; postoperative compliance and resistance measured by a computer-based monitoring system; postoperative vital capacity per kilogram, and maximum inspiratory force, measured at the bedside prior to the weaning trial. Stepwise linear discriminant analysis indicated that vital capacity per kilogram and maximum inspiratory force were the most useful predictors, the dividing line between successes and failures being represented by a vital capacity per kilogram of 15 ml. and a maximum inspiratory force of 28 cm. H2O. Mean values of successes were 18.3 +/- 7 ml. per kilogram and 30.7 +/- 9 cm. H2O and, for failures, 11.9 +/- 4 ml. per kilogram and 24.3 +/- 8.4 cm H2O. These physiological variables assess patient effort acting upon an abnormal pulmonary system. Measurements of passive pulmonary mechanics, cardiac function, and the measurement of arterial blood gases were suprisingly poor predictors.

Airway Resistance↗

PubMed1987

Longitudinal changes in lung function and respiratory symptoms in progressive systemic sclerosis. Prospective study.

Most patients with progressive systemic sclerosis (PSS) exhibit lung involvement. However, the natural history of lung disease in PSS remains poorly defined. To evaluate lung function over time in PSS, a battery of lung function tests were prospectively performed serially between 1973 and 1982 in 61 patients with PSS. Functional indexes of restriction (vital capacity and total lung capacity) and diffusion impairment (diffusing capacity) showed greater-than-expected annual rates of change. Male subjects showed a trend toward faster declines in forced vital capacity, forced expired volume in one second, total lung capacity, and functional residual capacity and a more rapid increase in static recoil pressure at 90 percent of total lung capacity than did female subjects. Nonsmokers had greater rates of decline in total lung capacity and static lung compliance (but not in forced vital capacity or diffusing capacity) and a greater rate of increase in static recoil pressure than did current and former smokers. Level of lung function at initial study visit, age, race, and chlorambucil therapy had no significant effect on the annual rates of change in lung function, whereas longer duration of disease prior to study entry was associated with a slower annual decrease in lung volumes. Between the first and last visits (mean interval 3.1 years, maximum nine years), the frequency of abnormality in pulmonary function test results showed significant change only in the diffusing capacity (60 percent increasing to 82 percent) and static lung compliance (40 percent increasing to 54 percent), whereas the frequency of respiratory symptoms showed little change. These findings indicate an overall indolent progression of PSS-related lung disease, with substantial individual variability.

Adult↗

PubMed1975

Factors influencing the measurement of closing volume.

The various factors influencing closing volume were studied by performing the single-breath N2 test on 9 healthy nonsmokers. Time of day, day of the week, and preceding volume history had no effect on either closing volume or alveolar plateau. Slow inspiratory flow resulted in larger ratio of closing volume to vital capacity, ratio of closing capacity to total lung capacity, and change in N2 concentration than fast inspiratory flow. Voluntary regulation of the expiratory flow resulted in smaller ratios of closing volume to vital capacity and closing capacity to total lung capacity than when flow was regulated by a resistance. Prolonged breath holding of the inspired O2 led to larger ratio of closing volume to vital capacity and ratio of closing capacity to total lung capacity. To obtain uniform, comparable closing volumes, it is suggested that the subject inspire slowly, control expiratory flow (preferably voluntarily), and not pause between inspiration and expiration.

Adult↗

PubMed1983

Respiratory muscle and pulmonary function in polymyositis and other proximal myopathies.

We studied 53 patients with proximal myopathy to determine at what level of muscle weakness hypercapnic respiratory failure is likely, and which tests of pulmonary function or respiratory muscle strength would best suggest this development. Respiratory muscle strength was determined from maximal static efforts and in half the patients, both inspiratory and expiratory muscle strengths were less than 50% of normal. In the 37 patients without lung disease respiratory muscle weakness was accompanied by significant decreases in vital capacity, total lung capacity, and maximum voluntary ventilation; by significant increases in residual volume and arterial carbon dioxide tension (PaCO2); and greater likelihood of dependence on ventilators, atelectasis, and pneumonia. Hypercapnia was particularly likely when respiratory muscle strength was less than 30% of normal in uncomplicated myopathy, and when vital capacity was less than 55% of the predicted value in any patient.

Adult↗

PubMed1989

Transmission to the chest of sound introduced at the mouth.

We examined the transmission to the chest wall of white noise and 25-Hz square-wave-generated noise introduced at the mouth of five healthy subjects. The output audio signals were recorded over the left and right upper and lower lung zones, posteriorly. Sound measurements were made during apnea at functional residual capacity, total lung capacity, and residual volume both after breathing air and an 80% He-20% O2 (heliox) gas mixture. We calculated the peak-to-peak amplitude, the peak frequency, and the midpower frequency of the output sound. We found no consistent variations in the values of these indexes due to lung volume or resident gas density. In all cases, the transmitted sound was most intense at the right upper zone. This could not be explained on the basis of technical factors but was probably the result of normal asymmetry of the mediastinal anatomy. These data suggest that sound introduced through the mouth of healthy individuals excites intrathoracic structures but is transmitted through the parenchyma in such a manner that it is not markedly affected by familiar physiological variables. This must be taken into account if objective acoustical tests of lung physiology are to be developed.

Adult↗

PubMed1989

Occupational lung function impairment in never-smoking Danish welders.

In order to study the effect of welding fumes on lung function, 74 high-exposed welders and 31 age-matched electricians were examined in 1982. None had ever smoked tobacco or been exposed to known or potentially noxious agents to the lungs. A significant difference was found between the welders and the control group in vital capacity, total lung capacity, forced expiratory volume in one second, peak expiratory flow rate, maximal expiratory flow rate at 75% of vital capacity, diffusion capacity and slope of the alveolar plateau. The lungs of the welders were physiologically 10-15 years older than those of the control group. Thirty percent of the welders had a well defined respiratory disease. Their lung function impairment was predominantly obstructive (16 persons), but restrictive patterns were also seen (6 persons).

Adult↗

PubMed1978

Interpretation of lung function tests in the sickle-cell haemoglobinopathies.

Prediction equations have been evolved for the assessment of vital capacity, total lung capacity, and the single breath carbon monoxide transfer factor in haemoglobin SS and haemoglobin SC disease. These relationships take account of the growth disorder and anaemia in the sickle-cell states. The results suggest that, in the clinically stable state, any effects of alveolar capillary sickling and haemoconcentration and any altered reactivity of haemoglobins S and C with the test gas are of no significance for clinical respiratory physiology. Sex differences in lung function appear independent of haemoglobin type.

Adult↗

PubMed1979

Morphologic-physiologic correlates of the severity of fibrosis and degree of cellularity in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of lung parenchyma characterized by a chronic inflammatory cellular infiltration and varying degrees of interstitial fibrosis. Current data indicate that the severity of fibrosis and the degree of cellularity determine, in part, the prognosis of IPF and the response to therapy. Whereas lung biopsy gives the best assessement of fibrosis and cellularity, physiologic studies are used to stage and monitor the disease process. To determine which physiologic studies correlate best with severity of fibrosis and degree of cellularity, these parameters were graded in lung biopsies of 23 patients with IPF and compared with a variety of physiologic studies. Although vital capacity, total lung capacity, and diffusing capacity are commonly used as objective monitors of the disease process, none of these parameters correlated with either the severity of fibrosis or the degree of cellularity in biopsy specimens. In contrast, almost all parameters of lung distensibility correlated with the morphologic assessment of degree of fibrosis; compliance had the best correlation. Parameters of distensibility, however, correlated poorly with the degree of cellularity. In comparison, gas exchange during exercise correlated with both morphologic parameters; the exercise-induced changes in arterial oxygen pressure per liter of oxygen consumed had a high correlation with the degree of fibrosis (r = 0.89; P less than 0.001) and correlated to a lesser extent with the degree of cellularity (r = 0.56; P = 0.009). In contrast, neither the resting arterial oxygen tension nor the arterial oxygen tension at maximal exercise correlated with the morphologic assessment of degree of fibrosis or the degree of cellularity. These morphologic-physiologic comparisons suggest that (a) lung volumes and diffusing capacity are poor monitors of both the degree of fibrosis and the degree of cellularity; (b) the fibrotic process contributes, at least in part, to parameters of lung distensibility, and both fibrosis and cellularity contribute to gas exchange alterations during exercise; and (c) parameters of lung distensibility and exercise-induced gas exchange alterations may be useful in staging the severity of disease in IPF.

Adult↗

PubMed1989

Lung function in essential mixed cryoglobulinemia: a short-term follow-up.

Lung involvement in essential mixed cryoglobulinemia (EMC) has been recently described. In order to assess whether patients with EMC experience an accelerated deterioration of lung function, nineteen patients (17 females, 2 males; 49.6 +/- 6.6 years) underwent a short-term follow-up of lung function, chest X-ray and serologic investigations. Reduction of forced expiratory flows and presence of roentgenologic signs of interstitial involvement were confirmed in the baseline evaluation. In addition, a decrease of diffusing capacity was shown. After a mean interval of 15 months, no significant change in lung function was found, with the exception of decrease in maximal expiratory flow at 50% of forced vital capacity, total lung capacity, functional residual capacity, coefficient of transfer of CO. A slight decrease of hemolitic complement (CH50) and of complement fraction (C3) was also observed. This study suggests that patients with EMC tend to have an involvement of pulmonary interstitial space, possibly related to immune complex deposition, but they do not show a severe decline of lung function. Periodical assessment of lung function and chest X-ray is, however, worthwhile.

Adult↗

PubMed2005

Pulmonary function impairment in children following hematopoietic stem cell transplantation.

BACKGROUND: Deterioration of pulmonary function after hematopoietic stem cell transplantation (SCT) is a well-known late effect of this treatment, but the course of pulmonary function over time is less clear. The aim of our study was to establish both the prevalence and course of pulmonary function abnormalities in children following SCT. METHODS: Thirty-nine of 106 patients, who visited a post-SCT late effects clinic and who underwent a pulmonary function test (PFT) both before and at least twice after SCT were included in this study. Forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and total lung diffusion capacity (TLCO) were determined and recorded as percentage predicted for age, sex, and length matched controls. Values of less than 80% of predicted were considered abnormal. Change in PFT parameters over time was determined by comparing the mean PFT parameter in our group at three different time points: pre-SCT, < or =1 year post-SCT (SCTpost1) and >1 year post-SCT (SCTpost2). RESULTS: After SCT restrictive and/or diffusion abnormalities are most prevalent (45% and 76% at SCTpost1, respectively). A significant decrease of TLC (-9.7%) and TLCO (-20.3%) was observed during the first year after SCT, with improvement over time, but no normalization. Obstructive lung disease was less common (6% at SCTpost1). Clinical signs of lung function impairment were rare. CONCLUSIONS: Restrictive and diffusion lung function disorders are common after SCT. They improve over time but do not normalize. As only a few patients with pulmonary function abnormalities had clinical signs of lung function impairment, the clinical relevance of performing long-term follow-up of PFT is questionable.

Adolescent↗

PubMedDate not supplied

Ventilatory function in cervical and high thoracic spinal cord injury. Relationship to level of injury and tone.

Weakness and spasticity of chest wall muscles are known to adversely affect pulmonary function in spinal cord-injured patients. To test the assertion that impaired strength and increased tone contribute to ventilation deficits, 52 patients with recent acute traumatic cervical and high thoracic spinal cord injury underwent complete pulmonary function testing. Regression analyses were performed to determine relationships between spinal cord injury level and pulmonary function test results and between Ashworth scale tone ratings and pulmonary function test results. Level of injury was found to be significantly correlated with expiratory reserve volume (and percent predicted expiratory reserve volume), residual volume/total lung capacity ratio, and negative inspiratory pressure but not with vital capacity, forced expiratory volume in one second, forced expiratory volume in one second/vital capacity ratio, inspiratory capacity, total lung capacity, functional residual capacity, residual volume, or positive expiratory pressure. There were significant correlations between Ashworth Scale tone ratings and negative inspiratory pressure but not between tone ratings and any of the other pulmonary function test results. It appears that muscle strength may be a more important factor than muscle tone in determining pulmonary function in spinal cord-injured patients and that both strength and tone are closely related to negative inspiratory pressure.

Adolescent↗

PubMed1992

Morbidity, mortality, and early results of single versus bilateral lung transplantation for emphysema.

Both single lung transplantation and bilateral lung transplantation have been successful in patients with chronic obstructive pulmonary disease. Limited availability of donor lungs dictates wider use of single lung transplantation as long as this procedure provides a comparable functional result at less risk. Early morbidity, mortality rates, and functional results were compared in 32 consecutive patients undergoing either single or bilateral lung transplantation for end-stage chronic obstructive pulmonary disease. When pretransplantation and posttransplantation values of forced expiratory volume in 1 second, single breath diffusing capacity, total lung capacity, arterial oxygen tension, and 6-minute walking distance were compared, statistically significant improvement (p less than 0.01) was seen in both groups. However, significantly higher values (p less than 0.01) were attained for forced expiratory volume in 1 second, single breath diffusing capacity, and arterial oxygen tension in the bilateral transplantation group than in the single lung transplantation group. Patients receiving bilateral lung transplants were at greater risk for postoperative complications, especially cardiac arrhythmias and bronchial anastomotic defects. Actuarial survival for the single lung transplantation group was 93% at 1 year, versus 87% at 6 months and 71% at 1 year for the bilateral lung transplantation group. The optimal transplantation procedure for patients with chronic obstructive pulmonary disease has not been determined. Longer follow-up periods are needed to define better the roles of bilateral and single lung transplantation in this group of patients.

Age Factors↗

PubMed2005

Comparison of lung function after myeloablative and 2 Gy of total body irradiation-based regimens for hematopoietic stem cell transplantation.

Lung function decline is a well-recognized occurrence after myeloablative hematopoietic stem cell transplantation (HCT) that has not been studied after nonmyeloablative conditioning regimens. We examined the lung function of patients before and after 2-Gy total body irradiation-based nonmyeloablative and myeloablative preparative regimens. Before HCT, at day 100, and 1 year after HCT, nonmyeloablative patients had lower 1-second forced expiratory volume (FEV1), forced vital capacity, total lung capacity, residual volume, and carbon monoxide diffusion capacity. However, after transplantation, the risk for experiencing a >20% per year decrease of FEV 1 was significantly lower for nonmyeloablative than myeloablative patients >50 years of age (odds ratio, 0.3; 95% confidence interval, 0.1-0.8; P = .01). Lower pretransplantation FEV 1 was associated with a higher mortality rate for both groups, with the highest mortality risk among patients with a pretransplantation FEV 1 <60% (nonmyeloablative: hazard ratio, 3.9; 95% confidence interval, 1.9-8.0; myeloablative: hazard ratio, 7.2; 95% confidence interval, 2.5-21.2). These results suggest that despite having worse lung function, patients who receive the 2-Gy total body irradiation-based nonmyeloablative regimen will likely experience less pulmonary toxicity than patients who receive a myeloablative regimen, and this may have important clinical implications when deciding on a conditioning regimen for patients >50 years of age with compromised pretransplantation lung function.

Adult↗

PubMed1986

Number of patients required in lung function studies.

Tables are presented showing estimates of the number of subjects which is required to give an 80% or 90% chance of detecting various differences in forced expiratory volume in one second, forced vital capacity, total lung capacity, transfer factor, and residual volume between the mean of two groups by means of Student's t test.

Humans↗