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Serial lung function tests were performed on 17 patients with asbestosis. A marked fall in the transfer factor often preceded any significant decline in the vital capacity. Changes in vital capacity and transfer factor did not appear to give any indication of the prognosis in these patients. Death was more commonly due to carcinoma of the lung than to the effects of the lung fibrosis.
A comparison of physical capacity, (measured by vital capacity, muscular strength and physical work capacity) in twin boys and controls failed to indicate significant differences. Intrapair correlations showed the MZ twins to be much more similar than the DZ twins in all the capacity measures. The correlations were lower, however, for both MZ and DZ twins for physical work capacity than for the other two capacity variables. When amount of physical exercise during leisure time is kept under control, the DZ twins tend to be more similar for physical work capacity or muscular strength, and the correlations tend to be of the same magnitude for MZ twins. Physical work capacity therefore appears, in this study, to be a more environmentally influenced variable than either vital capacity or muscular strength.
Ventilatory capacity (forced vital capacity, forced expiratory volume and maximal voluntary ventilation) among Highland Bods (3514 m altitude) was higher than in an ethnically similar population residing at a lower altitude in Kulu Valley (1500--2200 m). Increased ventilatory capacity appears to have developed among native highlanders as a consequence of a biological response to high altitude. Numerous factors such as low oxygen pressure, increased work-load and minimal air pollution may explain these findings.
This study evaluated maximum expiratory flow rates with respect to lung volume and maximum recoil pressure in selected patients with diffuse interstitial lung disease who had normal large airway function by standard technique. Coefficient of retraction was normal or greater than normal in all. Peak flow varied directly with lung volume as in normals. At 50% vital capacity (VC) and 25% VC, the absolute flow rates varied from higher to lower than normal. However, when flow was adjusted to volume, the flow/volume ratio was normal or high in all. Flow/volume ratio at mid-lung volume appeared to increase with increase in coefficient of retraction. Patients with frequency dependence of compliance had lower flow/volume ratios at 25% VC than those without, although still within normal range. Thus, despite recognized wide variations in normals, the flow/volume ratio is pertinent to the evaluation of reduced air flow rates in in interstitial lung disease to distinguish abnormal upstream airway resistance from volume-dependent reduction of flow rate. An effort-independent flow rate that yields a supernormal flow/volume ratio suggests increased recoil properties of the respiratory system.
The purpose of this study was to obtain more information about the effect on lung function of stopping smoking or of modifying the smoking habit and to determine the time course of change. We followed a group of 75 cigarette smokers who attended a smoking cessation clinic in May 1973, using a respiratory symptom questionnaire, spirometry, closing volumes, and the slope of the alveolar plateau of the single-breath nitrogen test. Subjects were tested before stopping smoking and at 1, 3, 6, and 12 months after the initial testing. We found a significant (P less than 0.05) improvement in closing volume as a percentage of vital capacity and closing capacity as a percentage of total lung capacity at 6 and 12 months and in the slope of the alveolar plateau at 1, 6, and 12 months in those who stopped smoking. There was also a dramatic decrease in respiratory symptoms in those who stopped smoking, a moderate decrease in those who reduced their consumption by at least 25 per cent, and very little change in those who did not appreciably modify their smoking consumption.
Flows measured from maximal expiratory flow-volume (MEFV) curves were used to evaluate the efficacy of postural drainage in improving ventilatory function acutely. Maximal expiratory flow-volume curves were obtained for 9 cystic fibrosis subjects and 10 subjects with chronic bronchitis before and 5, 15, and 45 min after a 30-min session of postural drainage with percussion, vibration, and coughing. Forced vital capacity (FVC) was significantly increased 45 min after drainage for the combining group. Flows at high lung volumes were different for the 2 subgroups. Subjects with cystic fibrosis demonstrated a significant increase in peak expiratory flow rates 45 min after drainage and an increase in forced expiratory volume in one sec at all time intervals. The subjects with chronic bronchitis had a decreased peak expiratory flow rate 5 min after drainage, but by 45 min, it had returned to baseline. There was no significant change in one-sec forced expiratory volume at any time interval for the chronic bronchitis subgroup. Changes in flows at low lung volumes were similar for the 2 subgroups. Forty-five min after drainage there was an increase in flow rates near 50 per cent of FVC. Flows near 25 per cent of FVC were increased 15 and 45 min after drainage. This study demonstrated that postural drainage with coughing resulted in significant improvement in flows at low lung volumes. Changes in flows at high lung volumes were less consistent.
We performed a double-blind study on the effect of oral administration of 10 mg of delta9-tetrahydrocannabinol on specific airway conductance (Gaw/VL) and the maximal expiratory flow at 50% of vital capacity (Vmax 50%) in six control and six asthmatic subjects. In control subjects, there was a slight but statistically significant increase in Gaw/VL after oral administration of delta9-tetrahydrocannabinol; however, there was no significant increase in Vmax 50%. One of the asthmatic patients developed severe bronchoconstriction following administration of delta9-tetrahydrocannabinol; among the remaining five patients, there were variable changes in Gaw/VL and Vmax 50% after oral administration of delta9-tetrahydrocannabinol, but mean changes were not significant. Mild effects on the central nervous system (CNS) were observed in three subjects; six subjects, three of whom had unpleasant mood changes, had more prominent CNS effects. We concluded that oral administration of delta9-tetrahydrocannabinol is unlikely to be of therepeutic value in asthma, since its bronchodilator action was mild and inconstant and was associated with significant CNS effects. Moreover, one asthmatic patient developed severe bronchoconstriction following oral administration of delta 9-tetrahydrocannabinol.
The effect of smoking three cigarettes in rapid succession on maximal and partial expiratory flow rates was studied in ten healthy smokers. The mean decrease in maximal midexpiratory flow and partial midexpiratory and end-expiratory flow was statistically significant. The response was maximal after the first cigarette. These results suggest that the instantaneous midexpiratory flow after 50% of the forced vital capacity has been exhaled is a useful indicator of irritation of the airways. Reduction of partial expiratory flow rates was three times greater than reduction of maximal expiratory flow rates. We suggest the use of partial expiratory flow curves as a screening test for irritants of the airways.
63 spinners exposed to cotton dust and 75 spinners exposed to asbestos dust were examined. In the women working in asbestos spinning room chronic nonspecific respiratory tract diseases prevalence was found to amount to 30% and in the cotton exposed group it was 15%. Mean values of lungs' vital capacity remained within the due values, although they were statistically significantly lower in asbestos exposed spinners (p less than 0,001). On the other hand, the percentage ratio of the forced expiratory capacity of 1 second was statistically significantly lower (0,001 less than p less than 0,01) in those exposed to cotton dust. The authors point to the occurrence of functional disturbances of the respiratory tract prior to radiological symptoms of lung asbestosis and their correlation with clinical symptoms.
Forced expiratory spirograms and peak expiratory flow were measured in 102 resident male medical students (60 nonsmokers and 42 smokers). Forced vital capacity; forced expiratory volume in 1 sec; forced expiratory volume in 1 sec expressed as a percentage of forced vital capacity; forced expiratory flows between 80 and 70 per cent, between 55 and 45 per cent, between 30 and 20 per cent, and between 15 and 5 per cent of the forced vital capacity; forced expiratory time for the last 0.5 liter of the forced vital capacity; and maximal mid-expiratory flow were determined from the forced expiratory spirogram. Peak expiratory flow, all forced expiratory flows (except the forced expiratory volume in 1 sec), and the ratio of forced expiratory volume in 1 sec to forced vital capacity were significantly lower, and forced expiratory time for the last 0.5 liter of the forced vital capacity was significantly higher in the heavy smokers (those who had smoked a lifetime total of more than 10,000 cigarettes) than the nonsmokers. The light smokers (those who smoked a lifetime total of fewer than 10,000 cigarettes) had values between those of nonsmokers and the heavy smokers. Thus, a definite dose-related response to smoking was seen. Flows at lower lung volumes showed greater percentage changes than flows at higher lung volumes. The forced expiratory flow between 30 and 20 per cent of the forced vital capacity was the most sensitive test for detecting abnormality in smokers. Among heavy smokers, 58 per cent had abnormally low forced expiratory flow between 30 and 20 per cent of the forced vital capacity, whereas only 47 per cent had abnormally low ratio of forced expiratory volume in 1 sec to forced vital capacity, and 32 percent had abnormally low maximal mid-expiratory flow. The results show that even subjects with short smoking histories may have changes in pulmonary function that probably reflect narrowing of small airways. Moreover, these changes can easily be detected by simple tests, such as evaluation of a forced expiratory spirogram.
The aims were to examine the gas exchange and arterial blood gas abnormalities among patients with scoliosis, and the correlation of these abnormalities with age and severity of deformity. Means among 51 patients were as follows: age 25.4 +/- 17.5 yr, angle of scoliosis 80.2 +/- 29.9 (SD), vital capacity 1.94 +/- 0.91 (SD) (i.e. 60.6 +/- 19.2% of predicted), PaO2 85.8 +/- 12.0 (SD), PaCO2 42.4 +/- 8.0, physiological dead space to tidal volume ratio 0.438 +/- 0.074 (SD), and alveolar-arterial oxygen difference breathing air 14.9 +/- 8.9 (SD). Statistically significant correlations were as follows: the PaCO2 and physiological dead space to tidal volume ratio increased with age, and the PaO2 and alveolar ventilation decreased with age. The PaO2, alveolar ventilation, and tidal volume were inversely related to the angle of scoliosis and directly related to the vital capacity, precent predicted vital capacity, and the compliance of the respiratory system. The physiological dead space to tidal volume ratio and the alveolar-arterial oxygen difference were inversely related to the vital capacity, percent predicted vital capacity, and the compliance of the respiratory system. PaCO2 was directly related to the elastance of the respiratory system. We conclude that ventilation-blood flow maldistribution as a result of deformity of the rib cage was the primary abnormality in gas exchange, and that with age there was progressive deterioration in gas exchange. The age-dependent increase in PaCO2 and decrease in alveolar ventilation were due to the increasing physiological dead space to tidal volume ratio and failure of a compensatory increase in ventilation.
Spirometry should be more widely used in routine examinations. Equipment should meet the individual physician's or hospital's needs and include either a dependable water-sealed spirometer or an easily calibrated and accurate electronic spirometer. Justifiable concern over the reliability of electronic spirometers has resulted in requests to determine performance standards for these medical devices. Predicted normal standards must apply to the particular spirometer. Recommended tests are those of vital capacity (VC), forced vital capacity (FVC), one-second forced expiratory volume (FEV(1)), the ratio of one-second forced expiratory flow (FEF200-1200) and forced midexpiratory flow (FEF25-75 percent). The maximum voluntary ventilation (MVV) test may be useful for evaluation of work disability and detection of extrathoracic obstruction. Additional consideration may be given to measurements of total lung capacity (TLC) to discriminate between restrictive and obstructive impairment and the forced end-expiratory flow (FEF75-85 percent) to detect mild small airway obstruction. At this time, flow-volume curves measurement cannot be justified for routine clinical use.
To determine the best procedure for reading maximal expiratory flow-volume curves 2 sets of 5 curves were obtained one hour apart in 89 subjects and processed digitally according to 8 different methods. Four indices were considered: the forced expiratory flows at 25, 50, and 75 per cent of the forced vital capacity, and the maximal mid-expiratory flow. When selecting the curve yielding the largest forced vital capacity or the largest sum of forced vital capacity and forced expiratory volume in 1 sec, flow values were significantly lower (P less than 0.001) and were often less reproducible than those obtained with most of the other methods. Computing the mean of the indices among the curves with the 2 largest forced vital capacities also provided comparatively low values, but with with better reproducibility. In contrast, maximal flows were probably overestimated by using the highest values among the curves having forced vital capacity or a surface area within 5 per cent of the largest, or when reading the indices on a composite curve obtained by superimposing individual breaths at residual volume. More reproducible and, probably, unbiased data may be drawn from the composite curves obtained by superimposing the breaths either at total lung capacity or on the descending limb.
Pulmonary functions of patients with allergic bronchopulmonary aspergillosis were studied during an acute episode (n = 6); during a mean follow-up period of 44 months (range four months--14.8 years) (n = 16); and for any correlation between duration of ABPA and asthma with the total lung capacity (helium dilution), 1 second forced expiratory volume (FEV1), vital capacity, 1 second forced expiratory volume-forced vital capacity ratio (FEV1:FVC per cent) and diffusing capacity of carbon monoxide (DL:CO) (single breath) for the entire group (n = 22). All patients were treated with corticosteroids (intermittent or continuous) and bronchodilators. For the 16 patients, slopes using linear regression analysis were determined from the function as per cent predicted versus time in months from diagnosis and then analyzed for significance. Significant functional loss was shown in three of 16 patients for FEV1, two of 16 patients for vital capacity, one of 16 patients for FEV1:FVC per cent, none of 10 patients for DL:CO and one of 10 patients for total lung cital capacity, FEV1:FVC per cent and the duration of asthma or allergic bronchopulmonary aspergillosis was found by multiple regression analysis correcting for age and smoking (mean 4.24 years; range 0.3 to 14.8 years). Roentgenographic criteria and blood eosinophilia were used to define a "flare" of allergic bronchopulmonary aspergillosis. The six patients during a flare showed a significant reduction in total lung capacity (P less than 0.001), vital capacity (P less than 0.05), FEV1 (P less than 0.01) and DL:CO (P less than 0.001) which uniformly returned to baseline values during steroid therapy. The FEV1:FVC per cent remained unaltered. These findings, contrary to suggestions in the literature, indicate that in the majority of our patients there was no significant progressive functional deterioration after diagnosis. However, during acute episodes of allergic bronchopulmonary aspergillosis, transient reduction of volumes and DL:CO were uniformly present.
Improved airway resistance following bronchodilator inhalation is not always accompanied by improvement in forced expiratory flow. We studied 241 patients with airways obstruction to learn whether changes in static lung volumes (vital capacity and function residual capacity measured by body plethysmography [FRCB]) would reveal bronchodilation not demonstrated by expiratory flow rates (the ratio of forced vital capacity at one second to the total forced vital capacity [FEV1/FVC]), and the forced expiratory flow for the midportion of the forced vital capacity (FEF25--75%). A significant fall in Raw occurred in 129 patients, 46 of whom had a significant increase in vital capacity (mean of + 465 ml +/- 43, P less than 0.001) and a fall in FRCB (mean of -763 ml +/- 78 P less than 0.001) with no change in FEV1/FVC% of FEF25--75%. We interpret these data to indicate that improvement in static lung volumes can reflect bronchodilation in the absence of improved expiratory flow.
To study the effects of upper mantle radiation therapy on pulmonary function, forced expiratory volume in one second (FEV1), vital capacity (VC), inspiratory capacity (IC), diffusing capacity for CO (DLCO) and diffusion per unit of alveolar volume (DL/VA were determined in 28 patients with Hodgkin's disease, stages 1--3, before therapy and at regular intervals thereafter. Within the first year of follow-up there were significant declines in DLCO, VC, and IC, whereas there were no significant changes in FEV1 or DL/VA. DLCO showed the greatest decline in the largest number of subjects (22/28). Eleven of the 22 had 20 to 60 percent decline of DLCO from baseline. The maximum mean decline in DLCO was -12.7 +/- 3 percent at the 87th +/- 3 days from initiation of therapy postradiation sustained through the 150th day and improving to pretreatment value (+/- 5 percent) by the 8th to 12th month. The changes in DLCO seemed to be independent of the radiation dose ranges evaluated, clinically apparent intrathoracic lymphoma, postradiation radiographic abnormalities and respiratory symptoms. We concluded that impairment in diffusing capacity and loss of vital capacity will develop in most patients receiving upper mantle radiation therapy, indicating that pulmonary reaction occurs despite lung shielding. The functional losses were prolonged and occasionally severe, but were transient and subclinical in most but not all cases. A case of fatal radiation pneumonitis affecting the lung beyond the field of irradiation is reported.
A composite statistical analysis was made of the results from four trials comprising patients undergoing upper abdominal operations. It revealed a marked correlation between the neuroticism score as measured by a personality inventory before operation and the percentage vital capacity impairment found after operation. Neuroticism correlated also with pain as measured by a visual analogue scale. The vital capacity impairment and subjective pain readings were interrelated and both neuroticism and vital capacity impairment were related to the chest complication rate. Personality assessment before operation can identify one group of patients who will have marked pain and limitation of vital capacity after operation.
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.