Inflammatory and microbiological associations with near-fatal asthma requiring extracorporeal membrane oxygenation

Patel, Sunil; Shah, Neeraj M.; Malhotra, Akanksha M.; Lockie, Christopher; Camporota, Luigi; Barrett, Nicholas; Kent, Brian D.; Jackson, David J.

A limitation of this study is its retrospective design, which introduces the possibility of information bias. Additionally, some important clinical background characteristics, including prior exacerbation frequency and information regarding adherence to maintenance inhaled therapies, were not available. However, we were able to partially acquire data relating to prehospital corticosteroid use (table 1) . From these data, we found that a greater percentage of patients without any formal treatment for their asthma required ECMO (17% versus 4%). Interestingly, a lower percentage of patients receiving moderate and high-dose inhaled corticosteroids (ICS) and/or long-acting β-agonists required ECMO compared to those requiring mechanical ventilation only (moderate: 17% versus 27%; high: 6% versus 12%). Furthermore, no patient in either treatment group required long-term oral corticosteroids or biologic agents. In those requiring ECMO, we found that in the year preceding acute admission, only 31% (seven out of 22) received regular ICS, 36% had documentation of regular short-acting β-agonist use and 31% had received at least one 7-day course of oral corticosteroids (data not shown). Similar data in the mechanical ventilation-only group were not collected and therefore, in this cohort, we cannot comment on whether levels of treatment are associated with need for ECMO. Of note, no patient had an indication other than asthma for corticosteroid use or other immunosuppression of any form; thus, the microbiological isolates are unlikely to have been influenced by secondary factors.