What causes increased airway resistance and obstruction in the pathogenesis of status asthmaticus?

Updated: Jun 17, 2020
  • Author: Constantine K Saadeh, MD; Chief Editor: John J Oppenheimer, MD  more...
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Answer

Bronchospasm, mucus plugging, and edema in the peripheral airways result in increased airway resistance and obstruction. Air trapping results in lung hyperinflation, ventilation/perfusion (V/Q) mismatch, and increased dead space ventilation. The lung becomes inflated near the end-inspiratory end of the pulmonary compliance curve, with decreased compliance and increased work of breathing.

The increased pleural and intra-alveolar pressures that result from obstruction and hyperinflation, together with the mechanical forces of the distended alveoli, eventually lead to a decrease in alveolar perfusion. The combination of atelectasis and decreased perfusion leads to V/Q mismatch within lung units. The V/Q mismatch and resultant hypoxemia trigger an increase in minute ventilation.


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