Use large ET tube (at least 8.0 if possible): minimizes airway resistance, facilitates aggressive pulmonary toilet and bronchoscopy if needed
Consider using ketamine as induction agent as it has bronchodilator properties and can maintain blood pressure
Appropriate choices for initial sedation includes propofol, fentanyl, and ketamine
Vent management strategies
No overall outcome differences between volume vs pressure control modes. Volume control has been recommended as initial mode due to familiarity and ensures your set tidal volume will be delivered.
Goal is to minimize autoPEEP, which occurs from incomplete exhalation prior to initiation of next inhaled breath. This can be achieved by adjusting a few vent settings: decreasing RR, decreasing I:E ratio, decreasing inspiratory time, or increasing inspiratory flow rate. Allow for permissive hypercapnia, pH >7.2 has been advocated though precise target is unknown.
If patient becomes hemodynamically unstable, consider first disconnecting the ventilator from the ET tube and manually decompress the chest to facilitate exhalation.
Peak inspiratory pressures are expected to be high in the acute severe asthmatic. More important is to keep plateau pressures <30 cm H2O to prevent lung injury.
Don't forget to continue asthma-directed therapy. Administer albuterol via in-line nebulization unit of the vent.
Laher AE, Buchanan SK. Mechanically Ventilating the Severe Asthmatic. Journal of Intensive Care Medicine. 2018;33(9):491-501.