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Biomedical subjects

R Prediletto

Publications and source records attributed to R Prediletto.

30 records · Page 2Linked to original sources
PubMed1991

Respiratory effects of occupational exposure in a general population sample in north Italy.

We assessed the effects of occupational exposure in a general population sample living in an unpolluted rural area of North Italy. In the age range of 18 to 64 yr, there were 417 participants who reported any exposure to dusts, chemicals, or gases and 1,218 who reported no exposure. Each subject completed a standardized interviewer-administered questionnaire (CNR-questionnaire). A variable proportion of participants succeeded in performing flow-volume curves, diffusing capacity of carbon monoxide, and slope of alveolar plateau of nitrogen. There was no significant difference for symptom prevalence rates between exposed and nonexposed in men and women who smoke. In nonsmoking women, those exposed showed significantly higher prevalence rates for exertional dyspnea and asthma. Regarding lung function, in exposed male smokers there was a significantly higher slope of the alveolar plateau. In exposed female nonsmokers, FEV1 and forced expiratory flows were significantly lower. Multiple logistic models in the overall group, accounting for age, smoking, and pack-years, showed that work exposure was associated significantly with higher risks for all symptoms in men (e.g., odds ratio: 2.76 for dyspnea, 2.31 for asthma, 1.69 for cough, and 1.64 for phlegm); in females, the association was significant for dyspnea (OR = 3.74) and asthma (OR = 3.29). Exposed men also had a significantly higher risk for %FEV1 or FEV1/FVC% below 70 (OR = 1.45). Our findings confirm those of the other few epidemiologic surveys in general population samples and contribute to the suggestion of a causal association between occupational exposure and chronic obstructive pulmonary disease.

Adult↗
PubMed1990

Carbon monoxide diffusing capacity, other indices of lung function, and respiratory symptoms in a general population sample.

To assess the relationships among single-breath diffusing capacity for CO (DLCOsb) (13), respiratory symptoms, and cigarette smoking in a general population sample, the data of 718 men and 894 women 20 yr of age or older were analyzed, and comparisons were performed with flow-volume curve (MEFV) variables and the slope of the alveolar plateau (DN2%/L) as well. Percent predicted DLCOsb and its correction for alveolar volume (DL/VA) were significantly lower in smokers than in nonsmokers. The relationship of presence/absence of respiratory symptoms and cigarette smoking with DLCOsb and DL/VA was significant. DLCO indices were almost always selected as discriminant variables in multivariate analysis between asymptomatic and symptomatic subjects. Poor concordance among lung function tests was evident: in men, 30% with abnormal (i.e., lower than 97.5% percentile) and 21% with normal DLCO indices also had abnormal MEFV parameters and/or DN2%/L. In women, the corresponding figures were 24 and 10%, respectively. In men, when considering only DLCO indices, the percentage of symptomatic subjects with abnormal lung function tests ranged from 33% in those with at least one symptom to 45% in those complaining of dyspnea. When the proportion of symptomatic subjects with DN2%/L and MEFV abnormalities were added, it increased to 56 and 66%, respectively. However, in women the proportion of symptomatic subjects with abnormal lung function indices was very small. These results indicate the usefulness of including CO diffusing capacity in epidemiologic surveys in the detection of abnormalities.

Adolescent↗
PubMed1990

Natural course of treated pulmonary embolism. Evaluation by perfusion lung scintigraphy, gas exchange, and chest roentgenogram.

Perfusion lung scintigrams, pulmonary gas exchange data, and chest roentgenograms were obtained in 33 patients during acute embolism and over the following six months in order to assess their clinical usefulness in monitoring the effect of therapy. To this purpose, the measurement of pulmonary gas exchange and the presence of chest x-ray findings were compared with perfusion lung scintigraphic abnormalities both at diagnosis and after 7, 30, and 180 days during treatment. More than 50 percent of the pulmonary arterial tree was obstructed at diagnosis, and a large part of perfusion recovery was complete within the first month. All of the gas exchange parameters were abnormal at diagnosis, and the rate of their improvement was related to that of perfusion recovery. Interestingly, PaO2st (ie, PaO2 corrected for hyperventilation) and VE tended to return to normal during the first month as a consequence of the progressive recovery of perfusion, whereas oxygen and carbon dioxide gradients and physiologic dead space showed the persistence of some abnormalities six months after diagnosis. Significant correlations were observed between the number of ULSs evaluated on the perfusion lung scintigram (and considered an index of the severity of pulmonary embolization) and all of the gas exchange parameters at diagnosis (correlation coefficients averaged from 0.41 to 0.73) and after 7 and 30 days. The enlargement of the right descending pulmonary artery and particularly the "sausage" sign and the Westermark sign were significantly associated with a higher degree of gas exchange impairment and with a more severe embolization. In conclusion, this study demonstrates that perfusion lung scintigraphy has a primary role in monitoring the recovery of patients with pulmonary embolism under treatment. Moreover, the chest roentgenogram may help in this purpose. A second major result is that the simple measurement of some gas exchange parameters may allow the assessment of functional recovery of these patients, thus giving additional information about the effect of therapy.

Carbon Dioxide↗
PubMed1989

Effects of childhood and adolescence-adulthood respiratory infections in a general population.

The role of childhood respiratory infections before 12 yrs of age (CRI) and during adolescence-adulthood (ARI) was studied in a general population sample (n = 3,289), living in an unpolluted area of Northern Italy. The presence of respiratory symptoms and diseases, as well as risk factors for obstructive airways disease (OAD), was assessed by a standardized questionnaire. Forced vital capacity and derived expiratory flows, and single-breath diffusing capacity were measured using computerized instrumentation. There were 1,185 (36.2%) subjects who reported pertussis (PT), 374 (11.4%) recurrent chest colds, pneumonia and croup, singly or in combination, with or without pertussis (CRI), and 1,718 (52.4%) reported no respiratory infections in childhood (NOCRI). Prevalence rates of respiratory symptoms and diseases were significantly higher in subjects of the CRI group in all ages, and in older smokers. Wheeze and attacks of shortness of breath with wheeze were significantly higher in younger nonsmoking subjects with a history of CRI. Respiratory symptoms and diseases were not more prevalent in subjects of the PT group. Prevalence rates of respiratory symptoms and diseases were significantly higher in subjects with a history of ARI, both in smokers and nonsmokers. Lung function parameters adjusted for sex, age and smoking were significantly lower in CRI subjects; PT subjects showed lower values than NOCRI subjects. A significantly higher prevalence rate of ARI was present in subjects who reported CRI, both in smokers and nonsmokers. Subjects with both CRI and ARI showed the highest prevalence of respiratory symptoms and diseases. In addition, they had the lowest lung function values regardless of smoking habit.

Adolescent↗
PubMed1988

Ventilation-perfusion heterogeneity and gas exchange variables in acute pulmonary embolism evaluated by two different computerized techniques.

The mechanisms by which the disturbances of gas exchange develop in human pulmonary embolism are unknown. We investigated whether the inequality of ventilation-perfusion ratio is associated with the abnormalities of pulmonary gas exchange as evaluated by two different computerized techniques. We measured the alveolar to arterial gradients of oxygen and carbon dioxide by means of a computer based system with a mass spectrometer and the ventilation-perfusion distributions by the multiple inert gas technique in 5 patients with acute pulmonary embolism. In these subjects there was a marked ventilation-perfusion inhomogeneity, as detected from inert gases and this finding was in agreement with the impairment of the alveolar to arterial gradients and of their derived indexes. Consideration on the responsible mechanisms for the disturbances of gas exchange are also reported. In conclusion these two computerized techniques provide a useful assessment of the ventilation-perfusion relationships in order to explain the disturbances of gas exchange in critically ill patients.

Acute Disease↗
PubMed1988

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.

Adolescent↗
PubMed1988

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.

Age Factors↗
PubMed1986

The assessment of gas exchange by automated analysis of O2 and CO2 alveolar to arterial differences.

A computer program to measure breath by breath alveolar pressure (PA) and alveolar to arterial difference (AaD) for O2 and CO2, by a mass-spectrometer has been implemented. The program allows the determination of alveolar gas by different methods: 1. Bohr's equation (BE); 2. ideal alveolar air equation for O2 (IDO2); 3. end-tidal (ET); 4. by the Rahn's definition of 'mean alveolar gas', i.e., alveolar pressures are defined when instantaneous respiratory exchange ratio (IRQ) equals mean respiratory exchange ratio (MRQ). This automated technique has been used in 16 patients with chronic obstructive lung disease (COLD) and 15 patients with pulmonary embolism (APE). In both groups of patients it was always possible to find in each breath the point where IRQ = MRQ and therefore to measure AaD by RD. IDO2 was significantly lower than PAO2 by the other methods. Also ET values of O2 and CO2 were significantly different from RD and BE in both groups of patients, however the difference was consistently higher in COLD patients. The different shape of the expirograms (steeper expirograms in COLD) is responsible for this different result. RD and BE AaD characterize gas exchange more precisely than ET, because the contribution of high VA/Q units is also evaluated. This is particularly important in COLD patients. Consideration on dead space measurements are also reported both for COLD and APE patients. In conclusion this automated technique provides the assessment of gas exchange for the use in clinical respiratory physiology and for the monitoring of gas-exchange in critically ill patients.

Aged↗
PubMedDate not supplied

[Changes in pulmonary gas exchange in chronic obstructive bronchopneumopathies and their modifications induced by therapy].

In order to assess the mechanisms of gas exchange disturbances (i.e. to what extent shunting and diffusion impairment contribute to hypoxemia) in chronic obstructive pulmonary disease (COPD) and respiratory failure, ventilation-perfusion relationships (V/Q) by the multiple inert gas elimination technique were obtained in 16 patients with respiratory failure breakthrough. In 6 instances the study was repeated after long-term treatment with the aim to analyze V/Q changes after therapy. Initially, patients showed severe hypoxemia and hypercapnia and they presented signs of marked bronchoconstriction. A great dispersion of V and Q distribution was present as indicated by the marked increase of the second moment of V and Q distributions. Interestingly, few patients presented a unimodal distribution of both V and Q, whereas most-patients had bimodal distributions where the ventilation was distributed in a mode such that high V/Q areas were present between 10 and 100 of V/Q ratio and blood flow was displaced leftward or toward lower V/Q values. No correlations were found between V and Q distribution and clinical types A or B of COPD. Significant relationships were found between measured and calculated arterial PO2 (r = 0.90, p less than 0.001) and between measured PO2 and the sum of the fractional perfusion to regions with V/Q ratio less than 0.1, suggesting that V/Q inequality and shunting, instead of the impairment of diffusion equilibration, can account for all the hypoxemia. Finally, the reduced inhomogeneity of ventilation after treatment, especially in the fraction located in high V/Q regions is mostly related to some functional and reversible damages in COPD.

Aged↗
PubMedDate not supplied

SPECT perfusion imaging with 123I-HIPDM in a patient with pulmonary embolism.

The use of 123I-N,N,N'trimethyl-N'-2-hydroxy-3-methyl-5-iodobenzyl-1,3-propanediami ne (123I-HIPDM) as a lung perfusion tracer in a patient with pulmonary embolism is shown. 123I-HIPDM is compared with 99mTc-labeled human albumin microspheres (HAM) using both planar and tomographic (SPECT) imaging. Pulmonary segmental defects are shown by 123I-HIPDM as well as by HAM, with a slightly better definition of perfused areas. Tomograms better show segmental shape of perfusion defects. 123I-HIPDM may be proposed as lung perfusion tracer for both clinical and experimental purposes.

Humans↗
PubMedDate not supplied

Reference values for vital capacity and flow-volume curves from a general population study.

A longitudinal epidemiological respiratory study has been started in the North of Italy to investigate the natural history of obstructive airways disease and the long-term effect of SO2 exposure. The first cross-sectional study was completed in this unpolluted area before the activation of a thermoelectric power plant (500 tons of SO2 produced daily). Follow-up surveys are planned after pollution emission starts for a period of ten years. A sample (n = 3289) representative of the general population was drawn from the villages of the area according to the different risks of pollution exposure. Subjects completed questionnaires and performed lung function tests, including forced expiratory (FVC) manoeuvres. For 801 'normal' subjects, prediction equations have been derived in age/sex groups for slow vital capacity (VC) and variables from the FVC manoeuvre. Comparisons with predictions of other studies are reported. Differences among FVC predictions were found, indicating that the use of different criteria for determination of the FVC manoeuvre end-point can affect results. In 'normals' VC was higher than FVC in older subjects. The difference between VC and FVC may be hypothesized as an epidemiological indication of the ageing effect on the mechanical properties of the ventilatory system.

Adolescent↗