Airway constriction

Forced expiration is commonly used to assess pulmonary function in both healthy and impaired individuals. Static measures of lung volumes (TLC, Vj, FRC) fail to detect dynamic changes in pulmonary function that are attributable to disease (e.g., asthmatic airway constriction). Obtaining maximum expiratory flow-volume (MEFV) curves (Fig. 5.21) permits derivation of key parameters in detecting changes in lung function. 

The term anaphylactic shock describes a severe generalized type I allergic reaction associated with cardiovascular shock, airway constriction and heart arrhythmias, which, if left untreated, may cause death. 

Kriesman, FI., Mitchell, C. and Bouhuys, A. (1977). Inhibition of histamine-induced airway constriction negative results with oxtriphylline and ascorbic acid. Lung 154, 223-229. 

Treatment of severe acute asthma includes the use of oxygen for the rapid reversal of hypoxemia, a short-acting P2-agonist to reverse airway constriction, and a systemic corticosteroid to attenuate the inflammatory response.1 Close monitoring of objective measures such as FEVi or PEF is important to quantify the response to therapy. Because recovery from exacerbations is often gradual, intensified therapy should be continued for several days. 

Small airway constriction and recruitment of leukocytes on pulmonary surfaces are prominent, documented responses to the inhalation of cotton dust. Currently, one or both of these effects are generally ascribed to endotoxin (8-10), to antigen-antibody reactions (11), to lacinilene C-7 methyl ether (1, 13), to a low molecular weight ( 1000 daltons), neutral, highly water soluble substance that is stable in boiling water and found in cotton bracts (14), to chemotaxins present in cotton mill dust extracts (15, 16) or to histamine releasing substances (17). 

Cotton Bract and Acute Airway Constriction in Humans... 

Because the respiratory tract is an initial target of any air pollutant challenge, it usually receives primary attention in tests to determine irritant effects of exposure. Other aspects of interest include hematology, blood enzyme biochemistry, eye irritation, and p chomotor performance. Constriction of the large airways, maldistribution of ventilation due to narrowing in some small airways, constriction of peripheral lung units, and mechanical or gas diffusion impairment due to edema are possible effects of insult by pollutants. A variety of pulmonary tests is required to examine the possibilities. 

Anticholinergics, like atropine and its derivative ipratropium bromide block cholinergic pathways that cause airway constriction. They may provide added bronchodi-lator effect in patients who are receiving beta -adrenergic agents for asthma. 

Short-term relief is thus most effectively achieved by agents that relax airway smooth muscle, of which B-adrenoceptor stimulants (see Chapter 9) are the most effective and most widely used. Theophylline, a methylxanthine drug, and antimuscarinic agents (see Chapter 8) are also used for reversal of airway constriction. 

Wheezing Breathing with a rasp or whistling sound a sign of airway constriction or obstruction... 

Gundel, RH., Letts, L.G. and Gleich, G.J. (1991). Human eosinophil major basic protein induces airway constriction and airway hyperresponsiveness in primates. J. Clin. Invest. 87, 1470-1473. 

Weiss, J.W., Drazen, J.M., McFadden, E.R, Jr., Weller, P., Corey, E.J., Lewis, RA. and Austen, K.F. (1983). Airway constriction in normal humans produced by inhalation of leukotriene D potency, time course and efiect of acetyl salicylic acid. J. Am. Med. Assoc. 249, 2814—2817. 

Murai, M., Morimoto, H., Maeda, Y. and Fujii, T. (1992). Effects of the tripeptide substance P antagonist, FRl 13680, on airway constriction and airway edema induced by neurokinins in guinea pigs. Eur. J. Pharmacol. 217, 23-29. 

Albuterol D-isomer may provoke airway constriction L-isomer avoids side effects... 

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