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Biomedical subjects

A Zapletal

Publications and source records attributed to A Zapletal.

At least 73 records · Page 4Linked to original sources

Maximum expiratory flow rates in induced bronchoconstriction in man.

We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rates on MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment.

Acetylcholine↗

Lung function in children and adolescents with idiopathic interstitial pulmonary fibrosis.

Lung function of 65 patients who had idiopathic interstitial pulmonary fibrosis (IIPF) that had been treated with prednisone was evaluated by tests of ventilatory function, lung mechanics, and gas exchange at rest and during exercise. Ages on initial investigation ranged from 5 to 20 years. In 35 of 65 patients the studies were repeated an average of four times over a period of 1 to 9 years. Results of the first testing were as follows: vital capacity (VC)-significantly reduced in all patients; inspiratory capacity (IC)-significantly reduced in all patients; total lung capacity (TLC)-reduced in 91%; functional residual capacity (FRC)-reduced in 31%; residual volume (RV)-reduced in 6%; elastic recoil of the lungs (Pstl)-significantly increased in 97% at 100% TLC, significantly increased in 52% at 90% TLC, reduced in 68% at 60% TLC; 7) static compliance (Cst)-reduced in 83%; 8) dynamic compliance (Cdyn)-reduced in 88%; 9) specific airway conductance at FRC level (Gaw/TGVex)-significantly increased in 50%; 10) maximum expiratory flow rates at 60% TLC (Vmax 60% TLC, in TLC/s)-significantly reduced in 33%; 11) upstream airway conductance (Gus 60% TLC, in TLC/s/cm H2O)-reduced in 32%; 12) diffusing capacity of the lungs for carbon monoxide (DLco) related to body-surface area-abnormal in 58% (when corrected for lung size, i.e., DLco/TLC, abnormal in only 8%); 13) PaO2 at rest and after 6 minutes submaximal exercise-reduced in 25% and 63%, respectively. Changes in lung function that occurred with growth were assessed in terms of percentages of predicted values. Results showed that the VC and IC remained significantly reduced. An actual reduction of TLC, FRC, RV, breathing frequency, DLCO, and Pstl at 100% and 90% TLC was observed. Increases were seen in Pstl at 60% TLC, Gaw/TGVex, Vmax, and Cst. Indices of lung elasticity suggested that regions of fibrosis and emphysema had become present. Smaller patients were also noted to have stiffer lungs.

Adolescent↗

Lung function in VSD patients after corrective heart surgery.

Static lung volumes, lung elasticity, and airway patency indices were measured in 47 children operated on for ventricular septal defect (VSD). Open-heart surgery was performed at the age of 0.6-12.0 years (median 4.1 years). In the first group (34 subjects), after primary repair of the VSD, there was an increase in lung recoil pressure at 100% of total lung capacity (TLC) (128% of the predicted value) and a reduction in specific airway conductance (sGaw) (75% of the predicted value). In the second group (13 patients), who had had previous pulmonary artery banding at 0.2-4.0 years (median 0.7 year) there was an increased functional residual capacity/TLC ratio (111% of predicted value), reduced sGaw (69% of predicted value), and reduced maximum expiratory flow at 25% of vital capacity (79% of predicted value). Lung volumes were insignificantly reduced in both groups. The frequency of lung function disturbances was similar in the two groups (71% of patients in the former group and 77% of patients in the latter group). A linear positive correlation between specific airway conductance and the mean pulmonary artery pressure (mPAP) (r = 0.793, p < 0.006) was observed in children with an mPAP <30 mmHg prior to open-heart surgery. A positive correlation between static recoil pressure at full inflation and mPAP (r = 0.545, p < 0.03) was found in children with an mPAP > 30 mmHg. The severity of congenital heart disease prior to surgery and the influence of the timing of the surgical procedures may cause the differences in lung function tests between the groups.

Airway Obstruction↗