Empowering Respiratory Therapists to Restrict Nebulized 3% Saline and N-Acetylcysteine During Mechanical Ventilation

Background: We previously implemented a policy that enabled respiratory therapists to reject orders for nebulized 3% hypertonic saline and/or N-acetylcysteine (HTS/NAC) that did not conform to the American Association for Respiratory Care (AARC) Clinical Practice Guideline. Outcomes of adhering to this more conservative approach are not well studied. We sought to determine if an approach conforming to guidelines is noninferior to a previously practiced more liberal approach. Methods: We performed a retrospective analysis of 2,272 subjects receiving mechanical ventilation ≥48 h within 5 adult ICUs between June 2020 and August 2023. The primary outcome was ventilator-free days at day 28 (VFD28). Secondary outcomes included ventilator days, ICU days, hospital stay, re-intubation rates, and mortality. Analysis was stratified by before and after policy implementation (see intervention) and by receiving HTS/NAC or not (ϕHTS/NAC). The latter was examined before and after propensity matching. The Δ for noninferiority was -0.5 days for VFD28 and +0.5 days for other continuous variables. As outcomes were not normally distributed, we analyzed them using Mann-Whitney U statistics. Results: Two thousand two hundred seventy-two subjects were evaluated. The mean age was 58.70 + 16.13 years and 929 (40.9%) subjects were women. HTS/NAC administration was reduced after policy implementation (40.2% before policy and 8.9% after policy; a reduction of 77.9%). The post-policy group and ϕHTS/NAC before and after propensity matching groups were all noninferior to the comparators. Subjects had significantly more VFD28 in the post-policy group, median (IQR), post 21 (0-25), pre: 20 (0-24), P = .02; and in the ϕHTS/NAC group, before matching ϕHTS/NAC: 21 (0-25), HTS/NAC: 18 (0-23), P < .001 and after propensity matching ϕHTS/NAC: 21 (0-25), HTS/NAC; 18 (0-23), P < .001. Conclusions: Restricting practice to conform to the AARC Clinical Practice Guideline was noninferior to more liberal use. The use of HTS/NAC in mechanically ventilated subjects does not appear efficacious and is both costly and time-consuming.