bronkdilatation

Bronkdilatation, also known as bronchodilation, is the widening of the airways in the lungs, resulting from relaxation of bronchial smooth muscle and a resulting decrease in airway resistance. It increases the diameter of bronchi and bronchioles, facilitating airflow and improving ventilation to the alveoli. Bronchodilation can occur naturally as part of normal respiratory regulation or be induced pharmacologically.

Physiologically, bronchodilation is driven by autonomic pathways and mediators that relax airway smooth muscle. Sympathetic stimulation acting on beta-2 adrenergic receptors promotes relaxation, while cholinergic activity tends to constrict airways. Various inflammatory and reflex processes in conditions such as asthma and chronic obstructive pulmonary disease can modify bronchial tone and responsiveness, sometimes leading to exaggerated dilation or constriction depending on the context.

Clinically, bronchodilator responsiveness is assessed with spirometry. A significant bronchodilator response is typically defined as an increase in forced expiratory volume in one second (FEV1) or forced vital capacity (FVC) after inhaled bronchodilator by at least 12% and 200 milliliters. This responsiveness helps differentiate reversible airway obstruction from fixed obstruction and guides diagnosis and treatment planning.

Therapeutically, bronchodilation is achieved with inhaled medications. Short-acting beta-2 agonists (e.g., albuterol) provide rapid relief, while long-acting beta-2 agonists (e.g., formoterol, salmeterol) are used for maintenance. Anticholinergic agents (tiotropium, ipratropium) and, less commonly, methylxanthines (theophylline) also promote bronchodilation. Combination inhalers pair bronchodilators with anti-inflammatory agents or other bronchodilators. Bronchodilators are central to management strategies for asthma and COPD, alongside anti-inflammatory therapies and non-pharmacologic approaches. Potential adverse effects include tachycardia and tremor with beta-agonists, and dry mouth with anticholinergics.