Which sign indicates a severe asthma attack?

A severe asthma attack is characterized by significant respiratory distress, and the use of accessory muscles is a key indicator of this severity. When an individual experiences a severe exacerbation of asthma, the typical muscles involved in breathing (the diaphragm and intercostal muscles) may not be sufficient to get enough air into the lungs. As a result, the body recruits additional muscles, such as those in the neck (sternocleidomastoid) and shoulders (trapezius), to assist with inhalation. This is a clear sign that the patient is struggling to breathe and requires immediate medical attention.

While prolonged expiratory phase, stridor, and chest tightness can also be associated with respiratory issues, they do not specifically indicate the level of respiratory distress seen in a severe asthma attack quite as clearly as the use of accessory muscles. Prolonged expiratory phase may occur in asthma but might not be present in all cases, and it primarily reflects obstruction rather than the immediate muscle engagement. Stridor typically suggests upper airway obstruction, which is not characteristic of asthma. Chest tightness is a common symptom in asthma but is more indicative of the condition rather than an immediate sign of an attack's severity. The use of accessory muscles, however, is a direct