Selection of reproducible forced expirograms: percentage or fixed-volume criterion.

The aim of this study was to evaluate whether the intrasession reproducibility of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) depends on height and lung volume. FVC tracings of 740 subjects (350 males) from a general population sample living in North Italy were analyzed. Subjects filled out a standardized questionnaire and performed three acceptable FVC maneuvers following the American Thoracic Society recommendations. The differences between the largest and the second largest FVC and FEV1 were computed as absolute (DeltaFVC, DeltaFEV1) and as percentage values (DeltaFVC%, DeltaFEV1%). The higher the tertiles of the largest FVC and FEV1 were, the higher were DeltaFVC and DeltaFEV1. Regarding FVC, borderline differences in both sexes for DeltaFVC and in males significant differences for DeltaFVC% were found among the tertiles. Regarding FEV1, in both sexes DeltaFEV1 significantly differed among the tertiles. DeltaFVC and DeltaFEV1 correlated with height and lung volume in both sexes, except for DeltaFVC versus the largest FVC in females. When DeltaFVC and DeltaFEV1 were analyzed with respect to respiratory symptoms/diseases and smoking habit, no significant differences were observed in both sexes, except for DeltaFEV1 between ever- and never-smoking males. It may be concluded that the intrasession within-subject variability of FVC and FEV1 is proportional to lung volume and height, regardless of the sex, presence of symptoms and smoking habit. Thus, our results confirm the usefulness of a reproducibility criterion based on a percentage rather than on a fixed volume.

Residual volume in a general population. Effects of body size, age, cigarette smoking, and respiratory symptoms.

Residual volume (RV) was obtained by subtracting vital capacity from total lung capacity determined by the single breath helium dilution (TLCsb) to measure CO diffusing capacity in 2,680 subjects (8 to 64 years old) of a general population sample. There were 712 normal subjects (243 male and 469 female subjects) selected to evaluate the pattern of RV by age and to derive reference values for internal comparisons. From 8 to 20 years old, RV showed an increase because of the cross-sectional body size effect; after 20 to 30 years, RV was still increasing, however, at a lower level. Age and height coefficients were significantly related to RV in younger and older ages, both in male and female subjects. The RV percent predicted and RV/TLC percent were higher in smokers when compared to nonsmokers and exsmokers (the difference was significant in male subjects). A dose-response effect was observed between RV percent predicted, RV/TLC percent, and pack-years. The RV percent predicted and RV/TLC percent were significantly higher in smokers and nonsmokers with FEV1 percent predicted below the normal limit (the difference was significant in male subjects). Moreover, higher values of RV percent predicted and RV/TLC percent were observed in subjects with wheezy symptoms in male smokers and nonsmokers. A negative significant correlation was observed between RV/TLC percent and the diffusing capacity adjusted for lung volume (DL/VA) in smokers, exsmokers and nonsmokers of both sexes, confirming the hypothesis that the decrease in DL/VA may be ascribed to the enlargement of terminal air spaces. In conclusion, determination of RV by the single breath helium dilution method is suitable in epidemiology, and it allows additional important information for understanding the physiopathologic mechanisms related to the pathogenesis of chronic obstructive lung disease.

Prevalence rates of respiratory symptoms in Italian general population samples exposed to different levels of air pollution.

We surveyed two general population samples aged 8 to 64 living in the unpolluted, rural area of the Po Delta (northern Italy) (n = 3289) and in the urban area of Pisa (central Italy) (n = 2917). Each subject filled out a standardized interviewer-administered questionnaire. The Pisa sample was divided into three groups according to their residence in the urban-suburban areas and to outdoor air pollution exposure (automobile exhaust only or industrial fumes as well). Significantly higher prevalence rates of all the respiratory symptoms and diseases were found in Pisa compared with the Po Delta. In particular, rhinitis and wheezing symptoms were higher in all the three urban zones; chronic cough and phlegm were higher in the zone with the automobile exhaust and the additional industrial exposure. Current smoking was more frequent in the rural area, but the urban smokers had a higher lifetime cigarette consumption. Childhood respiratory trouble and recurrent respiratory illnesses were evenly distributed. Exposure to parental smoking in childhood and lower educational level were more frequent in Po Delta, whereas familial history of respiratory/allergic disorders and work and indoor exposures were more often reported in the city. Multiple logistic regression models estimating independently the role of the various risk factors showed significant odds ratios associated with residence in Pisa for all the symptoms but chronic phlegm. For example, those living in the urban-industrial zone had an odds ratio of 4.0 (4.3-3.7) for rhinitis and 2.8 (3.0-2.6) for wheeze with respect to those living in the Po Delta.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional results of bronchial sleeve lobectomy.

The primary purpose of this study was to evaluate whether preservation of lung function parallels preservation of anatomy following elective bronchial sleeve-lobectomy (BSL). Between January 1984 and July 1988, 21 male patients (median age 51 years) with non-small cell lung cancer (n = 18), atypical carcinoid (n = 2) and inflammatory stenosis (n = 1) entered the study. Pulmonary function tests were performed pre- and postoperatively (at 3 and 12 months) and included spirometry, a quantitative perfusion lung scan and arterial blood gas analysis. The majority of operations were performed on the right lung (n = 15, 71%), with no operative deaths or major complications. Three months after surgery, the values of PaO2, PaCO2 and overall perfusion improved significantly (P less than 0.05), while there was a non significant improvement of the forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). The only parameter correlating (r = 0.46) and significantly (p = 0.032) predicting outcome after resection was overall perfusion. The preserved, reimplanted lobe rather than contralateral lobe(s) significantly (p = 0.014) contributed to remaining overall function. In 16 patients examined 12 months post-operatively a further improvement in pulmonary function occurred. The data presented demonstrate that preservation of pulmonary function parallels preservation of anatomy following BSL and that the functional contribution of reimplanted, ipsilateral lobe(s) is of paramount importance.

Single breath nitrogen test in an epidemiologic survey in North Italy. Reliability, reference values and relationships with symptoms.

The usefulness of single breath nitrogen test (SBN2) was evaluated in a cross-sectional epidemiologic survey on a general population sample (n = 3,289) of North Italy. Each subject was submitted to CNR standardized questionnaire and to lung function testing using automated equipment (Hewlett-Packard 47804S). Acceptable closing volume (CV) and slope of alveolar plateau (DN2%/L) tracings were performed by only 1,370 and 1,982 subjects respectively, in comparison with the 2,638 diffusing capacity and the 3,079 forced vital capacity acceptable maneuvers. Prediction equations were computed on normal subjects for CV indices, with the exception of DN2%/L: they were similar to those found in other studies. Significant differences among smoking categories were found for all the SBN2 parameters in males, but only for DN2%/L in females. The latter was also able to distinguish either subjects with airway obstruction from those without it or symptomatic from asymptomatic individuals, but DN2%/L did not give more information than Vmax75, a sensitive index of flow volume curve. Our results suggest that the place of SBN2 in large scale epidemiologic testing has not been justified.

Prevalence of respiratory symptoms in an unpolluted area of northern Italy.

Using a multistage stratified geographic cluster sample of households living in an unpolluted area of Northern Italy (near Venice), we enrolled 3289 inhabitants (aged 8-64 yr) for a longitudinal respiratory study. During the first cross-sectional survey, before the start of operation of a large oil-burning thermoelectric power plant, they completed a standardized administered questionnaire and performed several lung function tests. In the whole sample, dyspnoea grade 1 (11%), chronic cough and chronic phlegm (9%) were the most frequent respiratory symptoms; all the symptoms except dyspnoea were more prevalent in males than in females. Smokers (S) showed higher prevalence rates than ex-smokers (ES) and nonsmokers (NS), especially in males. In both sexes, the frequency of respiratory symptoms increased with increasing smoking as assessed by pack-years. An inverse relationship between prevalence of symptoms and socio-economic status was also observed. All tests of lung function were significantly impaired in S compared with NS in males; single-breath CO diffusing capacity and slope of alveolar plateau but not spirometric indices were significantly impaired in female S compared to female ES and NS. Finally, our prevalence rates were lower than in other epidemiological surveys: this result may be ascribed to the low levels of air pollution measured in the area.

[Cross-over epidemiologic study of symptoms and respiratory function in workers at a furniture factory]. / Indagine epidemiologica trasversale sui sintomi e la funzione respiratoria nei lavoratori di un mobilificio.

An epidemiological survey on symptoms and diseases (collected with CNR standardized questionnaire) and on lung function (forced vital capacity and derived indexes; CO diffusing capacity) has been carried on in workers of a furniture plant in Arezzo. Significantly higher prevalence rates of cough in smokers than in non smokers, and of cough, phlegm, wheeze in non smoker workers than in the control group from a general population sample were present. A not significant relationship of symptoms and working years was also found. Lung function indices were in the normal range; smokers had significantly lower values than non smokers. A lower FEV1%, after adjusting for age and smoking, was shown by subjects with more working years. Thus, in a modern furniture plant the risk of adverse health effect seems to be slight: this conclusion may be confirmed by the ongoing longitudinal survey.

[Respiratory function in chemical workers]. / Funzione respiratoria in lavoratori chimici.

The authors have evaluated the trend of the forced expiratory flows at low lung volumes and of the diffusing capacity for CO in a group of chemical workers of a dye factory, exposed to mineral dusts, organic pigments and solvents. Prevalences of chronic bronchitis and dyspnea, as evaluated by CNR questionnaire, were 15 and 32%. FEF25-75, MEF50 and MEF75 showed statistically significant differences with reference values. The reduction of KCO% was almost completely accounted for by smoking habit. During exercise, DLCOSS2 did not reach the expected values. 71% of the subjects with a diagnosis of COLD had worked more than 15 years in the dye factory. These results suggest a negative effect of the working environment, together with cigarette smoking, on lung function of subjects with a medium-long-term exposure.