You Have Intubated an Asthmatic... Now What?: Initial Ventilator Settings in Severe Asthma Exacerbation
In the setting of a severe asthma exacerbation that is refractory to medical mangagment and noninvasive ventilation, mechanical ventilation can be life-saving. However, the ventilator can quickly kill your patient if careful thought is not taken to address the unique respiratory needs and pulmonary physiology inherent to severe asthma. This post aims to provide an introduction to the initial ventilator settings your patient with severe asthma should have in the immediate post-intubation period. Severe asthma exacerabtion is not a clinical entity where your "run of the mill" ventilator settings will be safe for you patient. Keep in mind that patients with severe asthma have an obstructive respiratory pattern with a prolonged expiratory phase.
Initial Ventilator Settings:
Respiratory Rate: 10 breaths/minute although your patient might require <10 breaths/minute to allow full expiration.
Tidal Volume: 6 cc/kg based on Ideal Body Weight. Limiting tidal volume will reduce the risk of dynamic hyperinflation.
FIO2: 100% initially then titrate down to SpO2 >90% or PaO2 >60 mmHg.
PEEP: 0 mm/Hg if intrinsic PEEP is <10 cm H2O or <80% of intrinsic PEEP.
I:E Time: 1:4. Can go up to 1:5.
Inspiratory Flow Rate: 90 L/minute initially although your patient may need >100 L/minute.