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A Van Muylem

Publications and source records attributed to A Van Muylem.

22 records · Page 2Linked to original sources
PubMed1992

Inert gas single-breath washout and structural alteration of respiratory bronchioles.

With the perspective of establishing a link between a respiratory function test and alterations of membranous bronchioles, respiratory bronchioles, and alveolar ducts, we performed forced expirations and four kinds of single-breath washout maneuvers on 27 men due to undergo a lobectomy for peripheral bronchial carcinoma. For the single-breath washouts, the inhaled gas mixture consisted of 90% O2, 5% He, 5% SF6. The four maneuvers were the standard vital capacity test and three successive inhalations of 0.5, 1, and 1.5 L from functional residual capacity. The slopes of N2, He, and SF6 for each maneuver were computed, as well as a new index (I2) describing the relative decrease of the difference between the SF6 and the He slopes induced by a larger inspiratory volume. The histologic analysis focused on pigmentation, inflammation, and fibrosis of membranous bronchioles, respiratory bronchioles, and alveolar ducts. There was a linear relationship with a highly significant correlation coefficient between the new index I2 and the degree of inflammatory (r = 0.73) and fibrotic (r = 0.63) changes of the respiratory bronchioles; this correlation persisted in patients with a normal FEV1/VC ratio. These preliminary data open the way to finding a test for early peripheral (intraacinar) airway dysfunction.

Adult↗
PubMed1983

Variability in lung elasticity measurements in normal humans.

The variability of quasistatic lung inspiratory and expiratory pressure-volume (P-V) curves has been investigated in 8 young healthy volunteers studied on 4 occasions. The reproducibility of the total lung capacity (TLC) measured by body plethysmography was good, with a mean coefficient of variation of 1.8 +/- 0.9% (SD). The following variables were calculated from the P-V curves: the recoil pressures measured at TLC and 90, 80, 70, 60, and 50% TLC, as well as the compliance at functional residual capacity. For all the variables considered the intraseries variance was similar to the interseries variance so that all the individual results were pooled together. For each variable a coefficient of variation was calculated for each subject, as well as an F ratio to compare the interindividual differences to the intraindividual differences. For the variables obtained from the expiratory P-V curve, the lowest coefficient of variation was found for elastic lung recoil pressure, 90% TLC (6.6 +/- 2.6%, mean +/- SD). The reproducibility of the inspiratory P-V curve was found to be somewhat better than that of the expiratory one, with a coefficient of variation of 3.4 +/- 0.8% at 90% TLC. In absolute terms at that same level, the mean standard error of measurements was 1.2 cm H2O for the expiratory curves and 0.8 cm H2O for the inspiratory ones. It is concluded that in terms of reproducibility the best index of lung elasticity is the recoil pressure measured at 90% TLC and that the inspiratory curve is even better than the expiratory one.

Adult↗
PubMedDate not supplied

Inspiratory and expiratory lung pressure-volume curve in healthy males and females.

Quasistatic lung inspiratory and expiratory pressure-volume curves were obtained in 58 healthy nonsmoking males (mean age +/- SD: 42.8 +/- 15.1 years; range 22.70) and 56 healthy nonsmoking females (mean age +/- SD: 41.4 +/- 15.6 years; range: 21-76). Inspiratory and expiratory lung recoil pressures were measured at fixed percentages of TLC (100, 95, 90, 80, 70, 60 and 50%). In both sexes, inspiratory as well as expiratory lung recoil pressures were found to decrease linearly with aging (p less than 0.01 for all r values). There was no significant difference between males and females. At and above the 70% TLC level, the slopes of the age-related decreases in lung recoil were similar for the inspiratory and expiratory curves. At the 60% TLC level, the decrease in expiratory lung recoil was significantly (p less than 0.01) faster than the decrease in inspiratory lung recoil, presumably reflecting the influence of airway opening on the inspiratory pressure in older subjects. The shape of the expiratory PV curve described by the K index of the exponential model was similar in both sexes and changed with aging, K increasing significantly (p less than 0.01). By contrast, the shape of the inspiratory limb of the PV curve did not vary with aging. Consequently, the shape of the inspiratory PV curve cannot be predicted from the expiratory one and has to be measured directly.

Adult↗