Written by Clay Smith
This is a spoon-feed version on how to manage the worst asthmatic patients. Here are the pearls to manage these life-threatening cases.
Why does this matter?
In the U.S. 25,000 to 50,000 asthma exacerbations need ICU care. How can we spot these people and best treat them once we identify them?
How to be a bad-as…thma
This is a “how-to” piece from Chest, with pearls on diagnosing and managing the most severe asthma cases.
Triage: An initial assessment of tripoding, silent chest (no breath sounds), and paradoxical abdominal breathing indicates a severe, life-threatening presentation. Peak flow <50-60% predicted is also a bad sign. The author recommends using an objective scoring system.
Pharmacologic Treatment: This is a no-brainer: albuterol, ipratropium, and steroids are key. Corticosteroids should be given as soon as possible after arrival and are usually best IV when severe. IV beta-agonists may be used if inhaled therapy is not feasible. The author recommends magnesium sulphate in severe cases. I think this is iffy. Use conservative oxygen to keep SpO2 92-97% and avoid hyperoxia. High-flow nasal cannula is not favored by this author in place of non-invasive ventilation. In patients who progress despite these agents, IV epinephrine is an option. Avoid IV aminophylline. Heliox is an option if FiO2 requirement is <30%. The author will try it for 15 minutes and give up if not improved. No biologics, like benralizumab, are currently approved for severe asthma.
Non-invasive ventilation: The author recommends BPAP 10/5 cm H2O to start. My comment: I use BPAP when I fear the patient is tiring and may progress to need intubation. I would rather not intubate if at all possible. Also, only use BPAP if a patient has good mental status. Vomiting in a tightly sealed mask…yeah, that’s bad, worse if the patient is altered.
Mechanical Ventilation: Assume it will be a difficult airway. Use a larger, 8-0 tube in adults to reduce resistance if you can. Strongly consider delayed sequence intubation. Ketamine is the ideal induction agent in asthma. Go with a low initial respiratory rate, 8-10/min, and reduce the inspiratory time (1:3 or 1:4) to allow a longer expiratory phase. Use 6-8 mL/kg tidal volume. Keep plateau pressures <30cm H2O. Sometimes you have to disconnect the ventilator and press on the chest to assist in exhalation. Allow permissive hypercarbia. Dexmedetomidine for long-term sedation does not suppress respiratory drive. Learn to Manage the Vent Like a Pro.
Other: Patients with refractory acidosis should be given early consideration as potential candidates for ECMO. Bronchoscopy can help if mucus plugging becomes a problem.
Management of Life-Threatening Asthma: Severe Asthma Series. Chest. 2022 Feb 23;S0012-3692(22)00395-6. doi: 10.1016/j.chest.2022.02.029. Online ahead of print.