Early Prediction of Intensive Care Admission in Emergency Department Patients With Asthma

Abstract

Background: Emergency physicians must choose whether patients with asthma are admitted to a hospital ward or a higher level of care, such as an intermediate care unit (IMC) or intensive care unit (ICU).

Objective: This study aimed to determine which variables, available early during emergency department (ED) visits, are associated with IMC/ICU admission.

Methods: In this retrospective chart review (records from 2015-2018), two trained abstractors, blinded to study hypothesis, abstracted data on predictor variables and disposition (ward vs. IMC/ICU). Predictor variables were defined explicitly and abstracted from the periods of ED arrival and after treatment with 7.5 mg nebulized albuterol. Distress was defined as tripod positioning or speaking in broken sentences. "Arrival" and "after treatment" scoring systems were derived based on adjusted odds ratios (aOR) for predictor variables. We performed analyses using SAS^Ⓡ, version 9.4 (SAS Institute).

Results: Among 273 patients, 105 required admission to an IMC/ICU. At presentation, distress (aOR 2.1, 95% confidence interval [CI] 1.1-3.9), room air SpO₂ ≥95% (aOR 0.29, 95% CI 0.14-0.62), respiratory rate > 20 breaths/min (aOR 1.9, 95% CI 1.0-3.3), and retractions (aOR 1.9, 95% CI 1.1-3.3) were associated with IMC/ICU admission. After initial bronchodilator therapy, heart rate > 120 beats/min (aOR 7.1, 95% CI 2.0-25), room air SpO₂ ≥ 95% (aOR 0.15, 95% CI 0.07-0.34), and noninvasive ventilation (aOR 6.5, 95% CI 2.5-17) were associated with IMC/ICU admission. Both scoring systems stratified risk of IMC/ICU admission into low-risk (9-10%) and high-risk (70-100%) groups.

Conclusions: Combinations of predictor variables, available early in a patient's stay, stratify risk of admission to an IMC/ICU bed.

Keywords: asthma; crowding; emergency service; hospital; intensive care units; risk assessment.