Characteristics, Management, and Outcomes of Acute Life-Threatening Asthma in Adult Intensive Care

TL;DR

This study examines the characteristics, treatment, and outcomes of adults with severe asthma requiring ICU care, finding that certain blood markers predict the need for invasive ventilation.

Contribution

The study identifies pH, PaCO2, and white cell count as prognostic markers for severity in acute life-threatening asthma.

Findings

30% of patients required invasive mechanical ventilation (IMV).

pH and PaCO2 were the best predictors of IMV requirement.

28-day mortality was low at 1%.

Abstract

Background: There is limited evidence regarding the management of acute life-threatening asthma in intensive care units (ICUs), and few guidelines have details on this. We aimed to describe the characteristics, management, and outcomes of adults with life-threatening asthma requiring ICU admission. Methods: In this single-centre retrospective observational study, we included consecutive adults with acute asthma requiring ICU admission between 1 January 2016 and 31 December 2023. Our primary outcome was requirement for invasive mechanical ventilation (IMV). Results: We included 100 patients (median age 42.5 years, 67% female). The median pH, PaCO2, and white cell count (WCC) on ICU admission were 7.37, 39 mmHg, and 13.6 × 109/L. There were 30 patients (30%) who required IMV, and the best predictors of IMV requirement were pH (AUC 0.772) and PaCO2 (AUC 0.809). In univariate analysis, IMV requirement was associated with both increasing WCC (OR 1.14) and proven bacterial infection (OR 8.50). A variety of respiratory support strategies were utilised, with 38 patients (38%) receiving only non-invasive respiratory support. Conclusions: Our data highlight key characteristics which may be risk factors for acute asthma requiring ICU admission and suggest that pH, PaCO2, and WCC are prognostic markers for disease severity. Our overall outcomes were good, with an IMV requirement of 30% and a 28-day mortality of 1%.

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