Three techniques for studying nasal mucociliary clearance have been compared in 20 normal subjects, aged 19 to 26. Three different tracers used were deposited on the septum or the nasal floor. The transport rate of a 250 micron anion resin particle tagged with 99mTc was measured over a distance of 3.5 cm. This method was used as reference. The transport time of saccharin was measured when the subjects tasted its sweetness on swallowing. The transport time of 600 micron aluminium discs was measured by observing their arrival at the pharynx. For each method, duplicate measurements were carried out over a 24 hour period. Despite the large variations in the results from one day to the next, a significant negative correlation (r = -0.59, p less than 0.001) was observed between the transport rate of the radioactive particles and the transport time of the saccharin. The daily variations in nasal clearance for these two methods were also significantly correlated (r = -0.53, p less than 0.02). These results validate the suitability of the saccharin method as a simple screening test for detecting abnormally low values of nasal mucociliary clearance. In our group of 20 subjects, 5 were characterized by a low nasal mucociliary clearance, whichever method was used.

Adult↗

PubMedDate not supplied

Improved respiratory CO2-He analysis for peripheral airways impairment detection. Utilization possibilities of a new computerized system in preventive medicine studies.

The authors illustrate the application possibilities in occupational and preventive medicine of a recently computerized system for the evaluation of peripheral ventilatory non-homogeneities with or without alveolar air trapping. The method consists of an improved individual multiple breath by breath test utilizing the analysis of the respiratory gases CO2 and He. It is based on the results of previous experimental measurements performed simultaneously in different pulmonary sectors an depends on the technical possibility of signalizing out-of-phase expired CO2-He mixtures at the end of the inert gas clearance when in subjects with peripheral respiratory disorders the two gases CO2 and He arrive at the mouth at different times, during the same expiration and cause different, opposite signals. The applied physiological reliability of the measurements was experimentally verified, their technical specificity was recently established. The use of a new computerized system allows actually automatic, on-line measurements under the control of the operator, following a standardized method. The resolution power of the signals is very high. The calculation of the results is performed by the software. The system is easy to transport and can be used in the field for screening on large groups of persons in preventive medicine inquiries and during occupational medicine checks. Quite recently it has been usefully employed during an investigation on 200 subjects, occupationally exposed (policemen of the city traffic department of the town of Bologna).

Breath Tests↗

PubMedDate not supplied

[Partial pulmonary CO flow and detection of distribution disorders in epidemiological surveys].

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Adult↗

PubMedDate not supplied

Effects of chronic exposure to diisocyanates.

The pulmonary effects of chronic exposure to isocyanates (mainly MDI) at low levels (less than 0.02 ppm) were studied in a five year longitudinal survey of workers from two factories producing polyurethane foam. A respiratory questionnaire, flow volume curves and a single breath CO diffusion test were done at the beginning of the survey and repeated five years later; 318 workers (214 men, 104 women) of whom 83 (group I) were unexposed, 117 indirectly exposed (group II) and 118 directly exposed to isocyanates (group III) were examined. Five years later, half of the initial cohort only was still active and re-examined. The longitudinal analysis distinguished unexposed workers at both examinations (group A), indirectly at both examinations (group. B), directly exposed at both examinations (group. C) and workers exposed directly at first examination and retired from risk at the second (group. D). The decline of VC and FEV1 was not significantly different between exposed and unexposed. On the contrary, DLCO declined significantly in group C compared to the others. The results indicate that even at 'safe levels', chronic exposure to isocyanates involved a respiratory risk.

Air Pollutants, Occupational↗

PubMedDate not supplied

Comparative value of respiratory input and transfer impedances in field studies.

Total respiratory impedance was obtained from 4 to 30 Hz in 39 healthy males and in 140 iron miners by studying the relationship between transrespiratory pressure and mouth flow when forced oscillations were applied to the respiratory system in two different ways: by varying pressure at the mouth (input impedance, Zin); by varying pressure around the chest (transfer impedance, Ztr). Zin was characterized by the slope (S) and intercept (R0) of the resistance-frequency curve, by the resonant frequency (fn), and by total respiratory inertance (I) and compliance (C) obtained from the reactance. Transfer resistance and reactance curves were respectively analysed with a two-parameter (m1, m3) and a three-parameter (m0, m2, m4) equation. Significant correlations were found between impedance indices, particularly between m1 and both R0 (r = 0.931; p less than 0.001) and m2 (r = 0.739; p less than 0.001), and also between impedance indices and maximal expiratory flows. Nonsmoking miners (n = 40), compared to control nonsmokers (n = 16), had slightly lower maximal flows at high lung volumes (p less than 0.05) and higher values of m1 (p less than 0.001), R0, S, m3 (p less than 0.01) and m2 (p less than 0.05). In contrast, miners who smoked (n = 46) mainly differed from miners who did not smoke by lower flows at middle and low lung volumes (p less than 0.01) and larger m0 (p less than 0.01), m2 and m4 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Respiratory input and transfer impedances in children 9-13 years old.

Reference values for respiratory impedances in children are scarce and limited to the situation where pressure is varied at the mouth. Total respiratory impedance was therefore measured from 4 to 30 Hz in 69 healthy children (9-13 yr) with both a pressure input at the mouth (input impedance, Zin) and a pressure input at the chest (transfer impedance, Ztr). Zin was characterized by the average resistance (R), the low-frequency limit of resistance (R0), the slope of the resistance-frequency curve (S), respiratory elastance (E) and respiratory inertance (I). Similar coefficients (R0', S', E', I'), some of which however have slightly different physiological meanings, were derived from Ztr. R, R0 and R0' were found to be significantly correlated to body height (p less than 0.001) and, independently, to age (p less than 0.05): R (kPa X l-1 X s) = 1.76-5.29 10(-3) height (cm) -4.13 10(-2) age (yr). Elastances were better correlated to height than to age: E (kPa X l-1) = 20.95-0.101 height (cm) and inertances better correlated to age than to height: I (Pa X l-1 X s2) = 4.39-0.128 age (yr). S and S' were not correlated to biometric variables. No difference was found between children living in polluted (n = 36) and nonpolluted (n = 33) areas, except for S which was significantly lower in the first group (p less than 0.01).

Adolescent↗

PubMedDate not supplied

The single-breath nitrogen test does not detect functional impairment in children with passive exposure to tobacco smoke.

Respiratory symptoms and pulmonary function were compared in 46 nonsmoking children aged 10 to 16 years, whose parents were smokers, and an identical number of children (matched for sex, age and height) whose parents were nonsmokers. Passive exposure to parental tobacco smoke resulted in a higher prevalence of respiratory symptoms, more frequent upper airway infections and a significant decrease in forced expiratory flows; these effects were more marked in boys. The single-breath nitrogen washout test, a sensitive test of small airways obstruction in adults, did not detect any effect of involuntary smoking in this limited sample of children.

Adolescent↗