441 - Impact of nitrogen washout using high concentration of oxygen on radiographic resolution of neonatal symptomatic non-tension pneumothorax

Poster Number: 441
Publication Number: 441.227

Jessie E. Magnani, University of Michigan Medical School, Medford, OR, United States; Rebecca J. Vartanian, University of Michigan Medical School, Ann Arbor, MI, United States; Mohammad A. Attar, University of Michigan Medical School, Ann Arbor, MI, United States; Subrata Sarkar, University of Michigan Medical School, Ann Arbor, MI, United States

Background: There is a paucity of literature on the efficacy of higher concentrations of oxygen (O2) for nitrogen (N2) washout to treat infants with symptomatic non-tension pneumothorax (PTX). Two recent retrospective studies by Clark et al. and Shaireen et al. comparing N2 washout and targeted O2 therapy found no difference in the time to resolution of clinical symptoms, but neither study evaluated the time to resolution of PTX on x-ray. We hypothesized higher O2 concentrations for N2 washout would be associated with faster radiographic resolution of PTX compared to other conservative management practices.

Objective: To establish the time to radiographic resolution of symptomatic non-tension PTX for neonates treated with either N2 washout or management with targeted O2 therapy.

Design/Methods: A retrospective chart review of 147 infants born ≥34 0/7 weeks with radiographically confirmed PTX who had follow-up chest x-rays every 4-12 hours to look for progression of PTX. Data collection included time taken for resolution of PTX and resolution of clinical symptoms. Infants were analyzed in 2 groups 1) High-concentration O2 (1.0 FiO2) therapy with either oxygen hood or with nasal cannula; 2) Targeted O2 therapy (O2 supplementation to maintain targeted SpO2) with or without using non-invasive respiratory support.

Results: Sixty-five of the 147 infants had symptomatic non-tension PTX shortly after birth (figure 1). Thirty-three infants were managed with N2 washout and 32 infants received targeted O2 therapy at the discretion of the Attending neonatologist. The median time to radiographic resolution [42.5 hours, IQR 25-87] and improvement [17.5 hours, IQR 12-37] of PTX was significantly less in infants treated with N2 washout compared to infants who received targeted O2 therapy [resolution: 77.1 hours, IQR 39-139, p=0.044; improvement: 40.4 hours, IQR 16-78, p=0.030]. However, time to resolution of clinical symptoms, number of follow up x-rays, and length of hospital stay were similar between the two groups (table 1). Twelve infants (36%) in the N2 washout and 3 infants (9%) in the targeted O2 therapy group remained symptomatic even after radiographic resolution of PTX (p=0.017).Conclusion(s): Nitrogen washout was associated with faster radiographic resolution of non-tension PTX when compared with targeted O2 therapy in our population of term and late preterm newborns. However, length of stay was similar between the two groups probably because more infants in the N2 washout group remained symptomatic, likely due to underlying lung disease, even after their PTX resolved.
Figure 1. Patient Flow Chart
Table 1. Comparison of demographics, monitoring characteristics, and outcome between infants managed with high-concentration oxygen (N2 Washout) and infants who received symptomatic management with targeted oxygen therapy.