Respiration; international review of thoracic diseases
-
In order to assess the effect of breathing pattern on measurements of dead space ventilation (VD/VT) during exercise, we studied 6 patients with the complaint of exertional dyspnea. They had essentially normal resting pulmonary function studies and the only abnormality noted during an initial exercise study was an elevated VD/VT associated with a rapid respiratory rate. ⋯ During the exercise study with coaching, the VD/VT response was normal. We conclude that breathing pattern during exercise influences VD/VT and that an increase in total minute ventilation which is accomplished by a preferential increase in respiratory rate may result in an abnormally high VD/VT.
-
Although restriction is considered the classic pulmonary function profile of asbestosis, studies suggest that obstruction of the peripheral airways not revealed by standard spirometry is equally frequent and indicative of peribronchiolar fibrosis. We recorded flows and volumes from maximal expiratory flow volume (MEFV) curves, closing volume data and the phase III slope of the alveolar plateau for 610 litigants, 575 men and 35 women, exposed to asbestos for varying periods in a single workplace in northern New Jersey. Smokers (260) included current smokers and subjects who had stopped within the previous 10 years; nonsmokers (350) had either never smoked or had given up for more than 10 years. ⋯ Compared to predicted, smokers and nonsmokers had significantly higher closing capacities (p less than 0.01) and delta N2% (p less than 0.001) means, and lower forced vital capacity (FVC), forced expiratory volume for the first second (FEV1.0, maximal expiratory flow rate (MEFR) and peak expiratory flow rate (PEFR) functions (p less than 0.05); the flow rate after 75% of the FVC had been exhaled (FEF75%) values were significantly reduced (p less than 0.01) only for workers exposed for more than 30 years. The change from predicted was significantly more rapid for smokers, compared with nonsmokers, for FVC, FEV1.0, PEFR, MEFR and FEF75% means, while the increase in closing capacity (CC) was twice as rapid for nonsmokers and the two groups did not differ in their mean rates of rise for delta N2%. CC and the slope of the alveolar plateau appeared to be the measures best able to discriminate between the data for both smoking and nonsmoking asbestos workers and their lung function prediction means.(ABSTRACT TRUNCATED AT 250 WORDS)
-
The applicability of nasal challenge for etiologic diagnosis of extrinsic asthma was evaluated by assessing easiness of performance, precision, and cost of a standardized test by metered nebulizer in 20 asthmatics with and without concurrent rhinitis submitted also to skin prick tests and RAST. Although less sensitive than in the group with rhinitis (where precision was 90.4%), the nasal provocation test proved to be an easy, inexpensive, and specific (82.3%) means for contributing to the identification of allergic sensitization in patients affected by asthma alone.
-
The cough reflex in anaesthetized rabbits was elicited by irritation of the larynx with ammonia, inhalation of ammonia into the lungs, and mechanical stimulation of the tracheobronchial tree with a catheter. After block of lung stretch receptors with sulphur dioxide and virtual abolition of the Breuer-Hering inflation reflex, the cough response to all three stimuli was far less frequent and, when it occurred, was weaker especially with respect to the expiratory efforts. It is concluded that the Breuer-Hering reflex enhances the cough reflex, although modification of the sensitivity of tracheobronchial cough and irritant receptors by sulphur dioxide may also influence the cough.
-
Case Reports
Uncontrollable life-threatening status asthmaticus--an indicator for termination of pregnancy by cesarean section.
Two pregnant women with severe status asthmaticus unresponsive to intensive medical treatment are reported. Termination of pregnancies by cesarean section was followed by a dramatic improvement within 24 h. Termination of pregnancy is indicated in life-threatening status asthmaticus.