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PubMed1975

Sensitivity of volume of isoflow in the detection of mild airway obstruction.

The relative sensitivity of volume of isoflow test for detecting obstruction was compared to that of other tests, including flow at 60 per cent of total lung capacity, closing volumes, and frequency dependence of dynamic lung compliance. The volume of isoflow was measured in a waterless spirometer after 3 vital capacity inspirations of a mixture of 80 per cent oxygen. We studied 22 asymptomatic, healthy smokers (18 men and 4 women, 32.5 +/- 7.2 years of age, who smoked 5 to 20 pack-years). Thirteen smokers had an abnormal volume of isoflow, yet only 4 had an abnormal flow at 60 per cent of total lung capacity and 2 had an abnormal closing volume. Abnormal frequency dependence of dynamic lung compliance was demonstrated in 3 of 7 smokers tested with an abnormal volume of isoflow; none was detected in 7 smokers tested with normal volume of isoflow. Static pressure-volume curves and diffusing capacity were normal in all smokers with an abnormal volume of isoflow, and after bronchodilator inhalation, volume of isoflow improved in one half of the subjects. These results suggest reversible, intrinsic airway obstruction in the presence of normal flow at 60 per cent of total lung capacity and closing volume. Furthermore, volume of isoflow was a more sensitive test that flow at 60 per cent total lung capacity, closing volume, or frequency dependence of dynamic lung compliance.

Adult↗
PubMed2002

Pulmonary extravascular fluid accumulation in recreational climbers: a prospective study.

BACKGROUND: High altitude pulmonary oedema (HAPE) that is severe enough to require urgent medical care is infrequent. We hypothesised that subclinical HAPE is far more frequent than suspected during even modest climbs of average effort. METHODS: We assessed 262 consecutive climbers of Monte Rosa (4559 m), before ascent and about 24 h later on the summit 1 h after arriving, by clinical examination, electrocardiography, oximetry, spirometry, carbon monoxide transfer, and closing volume. A chest radiograph was taken at altitude. FINDINGS: Only one climber was evacuated for HAPE, but 40 (15%) of 262 climbers had chest rales or interstitial oedema on radiograph after ascent. Of 37 of these climbers, 34 (92%) showed increased closing volume. Of the 197 climbers without oedema, 146 (74%) had an increase in closing volume at altitude. With no change in vital capacity, forced expiratory volume in 1 s and forced expiratory flow at 25-75% of forced vital capacity increased slightly at altitude, without evidence of oedema. If we assume that an increased closing volume at altitude indicates increased pulmonary extravascular fluid, our data suggest that three of every four healthy, recreational climbers have mild subclinical HAPE shortly after a modest climb. INTERPRETATION: The risk of HAPE might not be confined to a small group of genetically susceptible people, but likely exists for most climbers if the rate of ascent and degree of physical effort are great enough, especially if lung size is normal or low.

Adult↗
PubMed1979

Effect of posture on lung volume: airway closure and gas exchange in hemidiaphragmatic paralysis.

The effects of posture on lung volume, airway closure, and gas exchange were studied in eight patients with hemidiaphragmatic paralysis. The mean vital capacity in the sitting position was 81% of predicted normal, and in the supine posture fell by a further 19% in right-sided but only 10% in left-sided paralysis. The mean arterial oxygen tension was less than predicted in the sitting posture and fell significantly on lying. Single breath gas transfer factor was normal in all cases whereas the diffusion coefficient was greater than predicted in the sitting posture and rose even further on lying. Closing volume showed no positional change but closing volume as a percentage of vital capacity was higher in the supine position. Regional airways closure was expressed as the relationship expiratory reserve volume minus closing volume. Negative values were found in only two of the subjects in the sitting position but seven had negative values supine, indicating significant airway closure during tidal breathing in this position.

Adult↗
PubMed1975

The early detection of airway obstruction.

To assess the sensitivity of tests for early, small airway obstruction, we selected 52 cigarette smokers with a ratio of 1-sec forced expiratory volume to forced vital capacity greater than 70 per cent from a smoking cessation clinic. From these subjects, 29 of the 46 tested demonstrated frequency dependence of dynamic compliance, a finding arbitrarily defined as indicative of small airway obstruction in this group. Dynamic compliance was correlated with the British Medical Research Council questionnaire, routine pulmonary function tests, closing volume as a per cent of vital capacity, maximal expiratory flow-volume curves, and flow dependence of distribution of inhaled boluses of xenon-133 (finite difference Xe). Symptoms of respiratory disease, and abnormal flow-volume curves, specific conductances, and ratios of residual volume to total lung capacity were also present in some subjects, but they correlated very poorly with frequency dependence of dynamic compliance. On the other hand, finite difference Xe was abnormal in 85 per cent of cases with frequency dependence of compliance and closing volume was abnormal in 70 per cent. In 8 of 12 subjects restudied 2 months after they stopped smoking, dynamic compliance was less frequency dependent than before smoking cessation. Similar improvements were noted in finite difference Xe, but closing volume was unchanged. Although closing volume and dynamic compliance tended to be abnormal in the same subject, concordance was not excellent, and the effects of smoking cessation suggested that the 2 tests had different determinants.

Adult↗
PubMed2004

The efficacy of low prime volume completely closed cardiopulmonary bypass in coronary artery revascularization.

PURPOSE: This study was conducted to evaluate and demonstrate the efficacy of low prime volume completely closed cardiopulmonary bypass (LPVP) in arrested coronary artery bypass grafting (CABG). We improved the percutaneous cardiopulmonary support (PCPS) circuit to reduce the deleterious effects of cardiopulmonary bypass (CPB). METHODS: Between April 1999 and May 2003, among 228 isolated CABG procedures, 47 procedures using LPVP (group L) and 86 procedures using standard prime volume open CPB (group S) were compared. The LPVP priming volume was 590 mL; the circuit was completely closed with a soft reservoir. Cardiac arrest was obtained by warm blood cardioplegia. RESULTS: The following average values were obtained: packed red blood cell transfusions, 0.88 +/- 1.4 U (group L) vs. 2.1 +/- 2.5 U (group S); intraoperative lowest hematocrit value, 28.7 +/- 4.6% (group L) vs. 22.4 +/- 3.3% (group S); blood loss over first 24 hours, 439 +/- 242 mL (group L) vs. 599 +/- 409 mL (group S); ventilation time, 5.1 +/- 3.1 hours (group L) vs. 10.4 +/- 14.9 hours (group S). CONCLUSION: Compared to standard prime volume open CPB, LPVP resulted in fewer deleterious operative effects. Less blood loss, fewer blood transfusions, and earlier patient recovery was noted with LPVP. Thus, LPVP is a very efficient form of CPB.

Aged↗
PubMed1979

Distribution of ventilation in normal children.

Measurements of closing volume and the distribution fo ventilation by both single-breath (SBN2) and multiple-breath nitrogen washout methods were obtained in 376 healthy boys and girls, ages 6 to 18 years. A closing volume could be demonstrated in 39 percent of the subjects, and closing volume expressed as percentage of vital capacity did not change with height. Closing capacity expressed as percentage of total lung capacity showed a slight decrease with height. The slope of phase III of the SBN2 curve decreased with height. Single compartment N2 washout curves were observed in 72 percent of the subjects, and the incidence of single compartment curves increased with age. In those subjects with two compartment N2 washout curves, the relative compartmental ventilation became more even with increasing height. Our observations suggest that parallel units among peripheral airways grow at different rates.

Adolescent↗
PubMed1979

Alpha1-antitrypsin deficiency: genetic, clinical and functional correlations in a three generation family.

alpha1-antitrypsin (alpha1-AT) deficiency is a hereditary condition transmitted as an autosomal codominant trait. Fully deficient homozygotes develop chronic obstructive pulmonary disease at an early age. It remains controversial whether heterozygotes develop some degree of airway disease at an early age which results in severe obstructive disease later in life. We studied 12 alpha1-AT-deficient members of a family spanning three generations by extensive pulmonary function tests, clinical history and genetic determinations. 3 of the subjects were homozygotes and showed important clinical and lung function abnormalities by the age of 30. Two out of 9 heterozygotes, a female and a male, had decreased dynamic compliance, elevated closing volume and low PaO2. 3 showed clinical and physiological abnormalities (elevation in functional residual capacity and residual volume, low FEV1/FVC and elevated closing volume); however, these alterations could be attributed to their smoking habits or concomitant medical condition. The remaining 4 subjects were normal. None of the heterozygotes showed alterations in the static elastic recoil of the lung or static compliance.

Adolescent↗
PubMed1977

Evaluation of the risk of postoperative pulmonary complications.

Ten of 40 patients who underwent major thoracic or abdominal operations developed postoperative pulmonary complications, consisting of six massive atelectasis, three pneumonias and one edema. They were mostly thoracotomy cases and cigarette smokers. Many of these complications would have been prevented, if reliable pulmonary function tests are available to predict preoperatively such occurrence. Flow-volume curve tracing and closing volume measurement were evaluated in this respect. Both flow at the point of functional residual capacity on flow-volume curve, and the closing capacity subtracted from functional residual capacity were found to be well correlated with the occurrence of postoperative complications and can be used to evaluate the risk of pulmonary complications developing in postoperative period.

Abdomen↗
PubMed1978

A factor analytic approach to an effective lung function screening protocol.

Interrelationships among simple indices of pulmonary function derived from flow-volume curves and single-breath nitrogen tests were investigated by performing a factor analysis on data obtained from a generally healthy office working population (n = 388). Smoking was regarded as the major contribution to pulmonary dysfunction. Delta nitrogen was largely independent of all other measures, while flow-volume measures, including flow rates at high and low lung volumes, were highly intercorrelated but largely independent of closing volume and closing capacity. Delta nitrogen was most affected by smoking in both sexes. Scores derived from flow-volume measurements and from closing-volume measurements were significantly different, on the average, between male smokers and male nonsmokers. The methods and results presented prove to be useful in the design of protocols for effective pulmonary testing of large populations.

Adult↗
PubMed1978

Distribution of bronchodilatation in normal subjects: beta agonist versus atropine.

Bronchodilatation was produced in normal subjects by the inhalation of a parasympatholytic agent (atropine) and the response was compared to that occurring after the inhalation of a beta-adrenergic agent (isoetharine). Doses were chosen that resulted in equivalent increases in specific airway conductance (78 +/- 9% for atropine; 88 +/- 21% for isoetharine). Anatomic dead space and volume at the onset of the terminal nitrogen rise (closing volume) were measured before and after each agent. Although there was no difference in the degree of overall bronchodilatation after the two drugs, anatomical dead space increased significantly more after atropine than isoetharine (+17% vs. +6%, P less than 0.01), and closing volume increased significantly after isoetharine (P less than 0.005) but did not change with atropine. We interpret these differences to indicate a greater effect of cholinergic antagonists on the more central airways and a greater effect of beta-adrenergic stimulants on peripheral airways.

Adult↗
PubMed1975

Responses to cotton dust.

Twelve cotton textile workers were studied: (1) to compare standard measures of volume and expiratory flow, maximal expiratory flow volume (MEFV) curves, closing volume (CV), and closing capacity (CC) in detection of airway narrowing with cotton dust exposure; (2) to evaluate the response of arterial blood gases to exposure; (3) to measure changes in leukocytes in peripheral blood and airway secretions; and (4) to assess the temporal relationships and correlations between measures. Change in expiratory flow (FEV) most consistently and significantly discriminated between the control and cotton dust exposures. Vmax50%FVC was a more sensitive indicator, but variance was increased proportionately. CV and CC changed inconsistently with relatively large variances. The PaO-2 decreased overall and two subjects had large decrements. Peripheral blood and polymorphonuclear cell counts increased with exposure to cotton dust and polymorphonuclear leukocytes were recruited to the nasal mucosa. Chest tightness and decreased flow were temporally correlated with leukocyte recruitment that may be important in respiratory disease among cotton textile workers and therefore deserves further investigation.

Adult↗
PubMedDate not supplied

Reference values for lung function tests in females. Regression equations with smoking variables.

Prediction formulas for static and dynamic spirometry, gas distribution, static lung mechanics and transfer test were derived from measurements in healthy females. The measurements included total lung capacity, residual volume, airway resistance, static elastic recoil pressure of the lung, static compliance, closing volume, slope of the alveolar plateau (phase III), flow-volume variables (including mean transit time) during breathing of air or a helium/oxygen mixture, and conventional spirometric indices. The results from 86 smokers and 100 never-smokers were evaluated separately and combined. For all lung function tests, a single regression equation including time-related smoking variables, valid for both smokers and never-smokers, was obtained. For many lung function tests, a nonlinear age coefficient resulted in a significant reduction in variance compared with simple linear models. Heavy tobacco smoking influenced most lung function tests less than ageing from 20 to 70 years, but for airway resistance, volumic airway conductance, closing volume, phase III, FEV1/VC, volume of isoflow and mean transit time the opposite was found.

Adult↗
PubMed1980

[Mechanical effects of obesity on lung function (author's transl)].

Spirometry, blood gases, steady state diffusing lung capacity for carbon monoxyde, ductance for carbon monoxyde were determined in 27 obeses. In 13 of them we also measured closing volume. In 80 per cent of these patients we observed a decrease in expiratory reserve volume certainly due to a shift on the right of the chest wall volume-pressure curve. In 50% of the obeses we found an arterial hypoxia, usually observed when the expiratory level was lower than closing volume. Finally in 20% of the subjects we observed a decrease in diffusing lung capacity and/or ductances probably due to an important fall in and expiratory level at the closing volume level with impairment of the distribution of ventilation.

Adolescent↗
PubMed1977

[Respiratory physiology during water immersion (author's transl)].

In this review, the author recalls the essential modifications induced by water immersion up to the neck. The ventilatory mechanics show an important decrease of end expiratory level being able to bring a ventilation in closing volume. We notice an increase of cardiac output, of pulmonary artery pressure and central blood volume. After the age of 25, we notice an hypoxia likely due to ventilation at closing volume level.

Airway Resistance↗
PubMed1999

[Modifications of respiratory function during pregnancy].

During pregnancy, changes in the thoracic configuration subsequent to progressive increase in the abdominal volume have a moderate effect on respiratory function. The cephalic displacement of the diaphragm reduces the expiratory reserve volume and the residual volume. The main consequence is an increase in the closing volume of the airways due to the fact that the lower residual functional capacity occurs during the tidal volume. The increase in the closing volume decreases the ventilation of the adjacent alveolar areas which could explain an increased heterogenicity of the ventilation-perfusion ratios. Increased tidal volume is almost always observed during pregnancy and is the cause of hyperventilation and a major increase in alveolar ventilation which can reach 70% of the post partum value. This hyperventilation is probably due to increased chemosensitivity of the CO2 respiratory centers induced by the hyperprogesteronism observed during pregnancy.

Estrogens↗
PubMed1984

Small airways changes in workers exposed to asbestos.

Although restriction is considered the classic pulmonary function profile of asbestosis, studies suggest that obstruction of the peripheral airways not revealed by standard spirometry is equally frequent and indicative of peribronchiolar fibrosis. We recorded flows and volumes from maximal expiratory flow volume (MEFV) curves, closing volume data and the phase III slope of the alveolar plateau for 610 litigants, 575 men and 35 women, exposed to asbestos for varying periods in a single workplace in northern New Jersey. Smokers (260) included current smokers and subjects who had stopped within the previous 10 years; nonsmokers (350) had either never smoked or had given up for more than 10 years. Analyses were made for both groups according to years worked. Compared to predicted, smokers and nonsmokers had significantly higher closing capacities (p less than 0.01) and delta N2% (p less than 0.001) means, and lower forced vital capacity (FVC), forced expiratory volume for the first second (FEV1.0, maximal expiratory flow rate (MEFR) and peak expiratory flow rate (PEFR) functions (p less than 0.05); the flow rate after 75% of the FVC had been exhaled (FEF75%) values were significantly reduced (p less than 0.01) only for workers exposed for more than 30 years. The change from predicted was significantly more rapid for smokers, compared with nonsmokers, for FVC, FEV1.0, PEFR, MEFR and FEF75% means, while the increase in closing capacity (CC) was twice as rapid for nonsmokers and the two groups did not differ in their mean rates of rise for delta N2%. CC and the slope of the alveolar plateau appeared to be the measures best able to discriminate between the data for both smoking and nonsmoking asbestos workers and their lung function prediction means.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Small airways in progressive systemic sclerosis (PSS).

Obstructive disease involving peripheral airways has been noted in diffuse interstitial pulmonary disease, including sarcoidosis and cryptogenic fibrosing alveolitis. The possibility of obstruction of small airways in progressive systemic sclerosis (PSS) has been suggested by widespread bronchiolectasis and peribronchial fibrosis noted at necropsy. We performed pulmonary function studies in 39 subjects (22 nonsmokers and 17 smokers) with PSS, most of whom had functional evidence of interstitial pulmonary involvement (increased static recoil pressure and reduced diffusing capacity). The 1 second forced expiratory volume to forced vital capacity ratio (FEV1:FVC) was normal in all subjects. Although the severity of the restrictive process was greater in nonsmokers compared with that in smokers, the maximal mid-expiratory flow rate, closing volume, closing capacity, volume of isoflow, change in maximal expiratory flow at 50 per cent of vital capacity during 80 per cent helium--20 per cent oxygen breathing compared with air breathing (delta Vmax50), ratio of dynamic to static lung compliance at different breathing frequencies and upstream airway conductance at static recoil pressures of 5 and 10 cm H2O were nearly always normal in the nonsmokers but were frequently abnormal in the smokers with PSS. These findings suggest that diffuse interstitial pulmonary disease due to PSS generally does not lead to functional evidence of obstruction in peripheral airways and that when the latter is found it can likely be attributed to the effects of concomitant cigarette smoking.

Adult↗
PubMed1989

Short-term effects of smoking cessation: benefit or penalty?

Eight of ten cigarette smokers successful in a smoking cessation group therapy program were examined, initially, and at six and 12 months postcessation. Examination included completion of a respiratory questionnaire and selective pulmonary function testing that included maximum expiratory flow volume curves, slope of phase 3 alveolar plateau, and closing volume. Two symptomatic subjects became symptom-free within six months postcessation. Results indicate a mean weight gain of 4.1 kg within 12 months (P less than 0.01), deterioration in mean forced expiratory volume in one second as percent of forced vital capacity (P less than 0.05), and deterioration in mean forced expiratory volume in three seconds as percent of forced vital capacity postcessation (P less than 0.05). Other tests derived from the maximum expiratory flow-volume curve, slope of phase 3, or closing volume showed no change. These results may be explained by a number of factors and may have implications for future studies.

Adult↗