الفهرس | Only 14 pages are availabe for public view |
Abstract Reactive airway disease is usually applied to patients with dyspnea, wheezing, cough, and production of sputum. Almost invariably there is a history of inhaled bronchodilator use. The mention of such airway hyperactivity immediately focuses on asthmatic patients with intermittent bouts of severe airflow obstruction. It also occurs in patients with chronic bronchitis and emphysema as well as allergic rhinitis and upper and lower respiratory tract infections. Anaesthetizing patients with reactive airway disease is a challenge to the anesthetist; he has to be selective in the choice of technique and the use of drugs on such patients to avoid the provocation of bronchospasm. Careful preoperative identification of patients at risk for perioperative bronchospasm is important in planning a rational approach for anesthetic care. Respiratory symptoms such as nocturnal dyspnea , chest tightness on awakening , an associated breathlessness and wheezing in response to various respiratory irritants such as cold air appear highly predictive of increased bronchial reactivity. Regional anesthesia constitutes an ideal choice in the patient with reactive airway disease because it eliminates the need for airway instrumentation and the possibility of eliciting airway reflexes. However, if high levels of sensory and motor block are required they may produce severe anxiety and actually incite bronchospasm. When general anesthesia is required, the primary goal is the prevention of reflex airway constriction. This is best accomplished by avoiding mechanical stimulation of the airway in the presence of inadequate anesthesia. If wheezing occurs, it is important to identify the potential causes to limit the extent of the bronchospasm and render it more readily reversible with therapy. In patients with airway obstruction and bronchial reactivity, preoperative treatment with β2-adrenergic agonists and corticosteroids should be considered. β2 adrenergic agonists have been shown to attenuate the reflex bronchoconstriction following endotracheal intubation. Even with this intervention, significant bronchoconstriction and wheezing occurs following intubation. Combined treatment with corticosteroids and a β2 adrenergic agonist can improve preoperative lung function and decrease the incidence of wheezing following endotracheal intubation. During the intra- and postoperative period there are a lot of risks associated with anesthesia in the patient with reactive airway diseases. Severe intraoperative complications in patients with asthma include hypoxia and cardiac arrest. Bronchospasm and mucus secretions may compromise oxygen delivery with consequent tissue hypoxia. Cardiac arrest may occur as a result of hypoxemia, as a side effect of the drugs used to treat severe bronchospasm, secondary to underlying electrolyte abnormalities, or as a result of dynamic hyperinflation. |