Rare side effects (liver damage) Methylxanthines.May be as effective as inhaled steroids.Atrovent dose: 250-500mcg/dose up to q 20min, usually q2-4hrs.Complications include drying of the airways and rarely, increased wheezing.Bronchodilate and decrease mucus production.M 3 receptor cause bronchoconstriction Physical Exam.M 2 receptor inhibits acetylcholine release, leading to bronchodilation.Beta – 3 subtypes – b 2 is common in airway smooth muscle – Activation leads to increase in cAMP.– Vasoactive intestinal polypeptide, Substance P, NO Receptors Non-adrenergic non-cholinergic (NANC) – Role in humans not determined.Sympathetic – Plays little role in humans since only pulmonary vasculature, not airway smooth muscle, is innervated.Parasympathetic – Stimulation via the vagus leads to airway constriction.

Numerous soluble products of the cells exacerbate asthma: – Interleukins – Bradykinins – Histamine Neurologic.

Numerous cells involved: – Mast cells – Eosinophils – Lymphocytes (TH-2 cells) – Neutrophils – Epithelial cells Cytokines.

Numerous things can trigger asthma attacks: – Allergens – Exercise – Stress – Viruses – Medicines – Noxious stimuli Cellular component.

Muscles of expiration are not designed for active expiration and quickly become fatigued, leading to respiratory failure and death.

In addition, active expiration may be required to return the lung volume to FRC.

Air-trapping may lead to air-leak, which can be fatal.

Air-trapping and over-expansion of alveoli is a hallmark of asthma.

Asthma is an obstructive pulmonary disease.

Asthma has several components: – Cellular – Cytokines – Neurologic Pathophysiology.

Asthma is characterized by bronchospasm, airway edema, and mucus production.Asthma is a chronic inflammatory disease of the airways.Prior asthma episode requiring mechanical ventilation is strong predictor of subsequent asthma death.15-24 year-olds are at higher risk of dying from asthma than are 0-4 year olds.Incidence, hospitalization rate, and death rate is increasing each year.5,000 people (mostly adults) die each year.

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