Asthmatic attacks, incidence

Exposure to the gas is extremely dangerous, causing irritation of the eyes, chest pain, cough, fever, and severe asthmatic attacks. A chemist briefly exposed to an unknown concentration in a laboratory developed a violent cough and shortness of breath, leading to severe pulmonary edema symptoms completely subsided within 2 weeks. In a fatal incident, another chemist exposed to an unknown concentration of diazomethane, as well as other irritant gases, experienced immediate respira-... 

Epidural/Intrathecal administration Limit epidural or intrathecal administration of preservative-free morphine and sufentanil to the lumbar area. Intrathecal use has been associated with a higher incidence of respiratory depression than epidural use. Asthma and other respiratory conditions The use of bisulfites is contraindicated in asthmatic patients. Bisulfites and morphine may potentiate each other, preventing use by causing severe adverse reactions. Use with extreme caution in patients having an acute asthmatic attack, bronchial asthma, chronic obstructive pulmonary disease or cor pulmonale, a substantially decreased respiratory reserve, and preexisting respiratory depression, hypoxia, or hypercapnia. Even usual therapeutic doses of narcotics may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea. Reserve use for those whose conditions require endotracheal intubation and respiratory support or control of ventilation. In these patients, consider alternative nonopioid analgesics, and employ only under careful medical supervision at the lowest effective dose. 

Cromones such as cromolyn sodium (Intal, Nasal-crom) and nedocromil sodium (Tilade) can help prevent bronchospasm in people with asthma. These drugs are not bronchodilators and will not reverse bronchoconstriction during an asthmatic attack. Hence, these agents must be taken prior to the onset of bronchoconstriction, and they must typically be administered prophylactically to prevent asthma attacks that are initiated by specific, well-defined activities (e.g., exercise, exposure to a friend s pet, pollen).107 Likewise, the regular use of these drugs several times each day for several months may decrease airway hyperresponsiveness so that the incidence of asthmatic attacks decreases.102,113... 

Fig. 2 Incidence of asthmatic attacks in about 1600 patients during a 24 hr cycle. (From Ref. l)...

In some early cases an increased incidence of asthmatic attacks was reported by asthmatic patients (35). 

Drugs in this group are also known as mast-cell stabilizers and they probably work by blocking the release of mediators such as histamine and serotonin in the lung, although their exact mode of action is unknown. They can be used prophylactically to reduce the incidence of asthmatic attacks and to allow reduction in the doses of other drugs. They are not used in chronic bronchitis. 

Clinical experience relating ascorbic acid to asthma is conflicting. Studies by several investigators have failed to illustrate any response of asthmatics to ascorbic acid treatment (Malo et al., 1983 Kreisman et al., 1977). Some investigators were also unable to show any improvement of histamine-induced bronchoconstriction by ascorbic acid (Kreisman et al., 1977). However, other investigators were able to illustrate the beneficial effect of a daily intake of ascorbic acid on the incidence of asthmatic attacks (Anah et al., 1980). It was also shown that ascorbic acid tends to ameliorate the airway constriction induced by histamine and metacholine in normal subjects (Mohsenin et al., 1983 Anah et al., 1980 Zuskin et al, 1973). 

Sensitizer A chemical that causes vulnerable, exposed individuals to develop a respiratory allergic reaction following repeated exposure. Methylene bisphenyl isocyanate, TDI, and trimelhtic anhydride are examples of respiratory sensitizers. It should be noted that sensitizing chemicals that are inhaled have the propensity to also induce dermal sensitization and that skin exposure to sensitizers (e.g., ammonium thioglyco-late) can induce respiratory sensitization. It has been reported that people with asthma have a higher incidence of food allergies and has been hypothesized that allergic reactions to food may lead to asthmatic attacks [7]. Such cross-sensitization will be discussed later and in Chapter 27. 

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