O0437 Oct.5: 3:31pm - Helium-Oxygen Mixture (Heliox) for Refractory Status Asthmaticus in the Intensive Care Unit: An Epidemiologic and Exploratory Comparative Analysis

Background /

Purpose:
Status asthmaticus (SA) is a disease of immune dysregulation with severe bronchospasm, airway obstruction, and respiratory acidosis. Heliox as adjunctive therapy for SA may improve laminar flow in obstructed airways and potentially increase deposition of aerosolized medications. Using a large national registry, we seek to describe Heliox prescribing patterns among pediatric centers over a 10-year period and determine if rates of mechanical ventilation (MV) or length of stay (LOS) vary with exposure to Heliox.

Methods:
We performed a multicenter, retrospective cohort study using the Pediatric Health Information System® registry for children 5-17 years of age admitted to the pediatric intensive care unit (PICU) for SA from 2010 through 2019. We excluded children with congenital heart disease, acute chest syndrome, neuromuscular disease, tracheostomy dependence, primary oncologic disease, or transplantation / immunosuppression. The primary outcome was Heliox prescribing patterns chronologically and by hospital center. A subgroup analysis was performed among centers that prescribed Heliox in a minimum of 1% of children and among subjects who received at least one adjunctive asthma therapy in addition to continuous albuterol (i.e. terbutaline, aminophylline, ketamine, Heliox, or bilevel positive pressure ventilation). The primary outcomes for the subgroup analysis included LOS and MV rate. Statistics were descriptive (proportions, frequencies, and means ± standard deviations) and comparative (χ2, Wilcoxon rank-sum, and student's t tests).

Results:
19,780 children admitted to the PICU for SA were studied among 42 centers. In general, the mean age was 9.7 ± 3.4 years, 71.3% had moderate to severe NHLBI Asthma Severity Classification, and mean LOS was 3.3 ± 2.3 days. The MV rate was 12.8% and Heliox was prescribed in 13%. We observed (Figure 1) a decline in Heliox use by 1.2% annually from 21.2% in 2010 to 9.3% in 2019 that varied substantially by center (10.3 ± 20.2%, Figure 2). In the subgroup analysis (n=6,874 from 28 centers), we observed an overall MV rate of 20.4% with a reduced rate in those given Heliox (15.8% versus 22.9%, p<0.001). Adjusting for mechanical ventilation, we noted a reduced mean LOS in the Heliox cohort (3.1 ± 1.5 days versus 3.8 ± 1.9 days, p<0.001).

Conclusions:
In the past decade, Heliox use for children with SA has reduced by 1.2% annually and rates vary by center. We can only speculate as to the etiology of this observation, but assume it is from the lack of adequately powered, prospective data. When accounting for asthma severity, MV rates and LOS appear lower in children given Heliox. Prospective, controlled analyses are needed to define the role of Heliox for SA.