Abstract

We report a case of severe status asthmaticus in a 3-year-old boy who required mechanical ventilatory support. He initially presented with rapidly progressing respiratory distress and spontaneous air leaks. Although he was intubated and received mechanical ventilation, dynamic hyperinflation and air leaks were aggravated. We applied the volume control mode, providing sufficient tidal volume (10 ml/kg), a reduced respiratory rate (25/minute), and a prolonged expiratory time (1.8 seconds) to overcome dynamic hyperinflation. After allowing full expiration of trapped air, his over-expanded lung volumes were decreased and the air leaks resolved. He made a complete recovery without sequelae. Dynamic hyperinflation in asthmatic patients occurs from incomplete exhalation throughout narrowed airways. Controlled hypoventilation or permissive hypercapnia is an important lung-protective ventilator strategy and is beneficial in reducing dynamic hyperinflation. We suggest a controlled hypoventilation strategy with a prolonged expiratory time for patients in severe status asthmaticus with dynamic hyperinflation.

• Keywords: air leak;controlled hypoventilation;intrinsic positive-pressure respiration;permissive hypercapnia;status asthmaticus;