No abstract

A number of numeric measurements have been suggested to describe the pattern of deposition of inhaled aerosols, but there is little information about the relationship between the different measurements. We compared four different methods for analysis of aerosol deposition pattern with respect to their ability to separate patients with chronic bronchitis (CB) from healthy subjects, and with respect to their relationship to a simple index of airflow obstruction. Twelve healthy subjects and 22 patients with CB were studied. All the subjects inhaled a radiolabelled aerosol produced with an air-jet nebulizer. The aerosol contained albumin millimicrospheres labelled with 99Tcm. The ratio of peripheral to central deposition--the penetration index, the coefficient of variation, the coefficient of skewness and the quotient between maximum and mean value deposition were calculated using a gamma camera. The differences between the patients and the healthy subjects were statistically significant for all variables (p < 0.001). The sensitivity of measurements of aerosol deposition for detection of CB was similar to that of forced expiratory volume in one second (FEV1). We found strong correlations between the indices of aerosol deposition and FEV1 between all indices. In clinical routine practice, studies of aerosol deposition offer little advantage in the evaluation of patients with CB. Any of the indices may be suitable for evaluation of aerosol deposition in e.g. studies of inhaled pharmaceuticals.

No abstract

We measured mucociliary clearance at rest and during exercise in 11 healthy non-smoking men. The subjects inhaled an aerosol containing [99Tcm]albumin millimicrospheres with deep inhalations. Four sets of scintigraphic images were obtained with 15-min intervals. Lung retention of radioactivity was quantified using a gamma camera and the clearance of particles from the lungs calculated for each 15-min period. The first image was obtained directly after inhalation, the second after a period of 15-min rest, the third after a period of exercise on a bicycle ergometer (workload approximately 80% of predicted maximum capacity) and the final fourth image after another period of rest. We found small differences in clearance rate at rest and during exercise indicating that there is no substantial change in the clearance rate during exercise in normal subjects.

A recent experimental study has shown that ethanol concentrations below 1% increase ciliary beat frequency in preparations of sheep trachea. This study was designed to investigate whether low ethanol concentrations also increase mucociliary clearance in man. Mucociliary clearance was measured using inhaled, radiolabelled particles. Clearance was measured in normal men for 30 min under baseline conditions. The subjects then ingested 28 g of ethanol, and clearance was measured for a further 40 min. The subjects reached a mean plasma concentration of 0.04% 30 min after ethanol intake. The mean half-life of the radioactive particles in the lung was 160 min under basal conditions and 257 min after ethanol ingestion. The difference was not statistically significant. We conclude that low ethanol concentrations do not increase mucociliary clearance in man.