Table. 2—

Risk factors and diagnostic criteria of severe asthma exacerbation

Patients at risk for respiratory failure who could benefit from NPPV trial
Diagnostic criteria of severe asthma (at least one of the following)
    Use of accessory muscles
    Paradoxical pulse >25 mmHg
    fC >110 beats·min−1
    Respiratory rate >25–30 breaths·min−1
    Limited ability to speak
    PEF or FEV1 <50% pred
    Arterial oxygen saturation <91–92% with oxygen flow of ≤10 L·min−1
Risk factors for severe asthma exacerbation
    Recent hospitalisation
    Prior ICU admission with mechanical ventilation
    Poor adherence to therapy
    High allergen exposure
  • NPPV: noninvasive positive pressure ventilation; fC: cardiac frequency; PEF: peak expiratory flow; FEV1: forced expiratory volume in 1 s; % pred: % predicted; ICU: intensive care unit.