Background: Continuous albuterol manufacturing changes have created supply chain shortages and differences in manufacturing processes for available products. Drug diluents have a significant impact on inhaled respiratory medications that can be interfaced with mechanical ventilators. Two major manufacturers, Nephron and STAQ Pharma, dilute albuterol with sterile water and normal saline solution, respectively. We observed, via the Children’s Hospital Association (CHA) discussion forum, that various children’s hospitals faced issues with increased crystallization in their ventilators during continuous albuterol nebulization. We aim to determine if the albuterol diluent type influences filter weight and build-up that could impact ventilator functionality. Methods: In an IRB-exempt bench study, two models were used: model 1, simulating a 40 kg patient, and model 2, a 10 kg patient. In all models, a Getinge Servo-U ventilator, F&P MR850 heater (set 37°C), Intersurgical LTD filta-guard bacterial filters, and Alaris syringe pump were utilized. A F&P RT280 circuit was used for model 1 and a F&P RT265 for model 2. Model 1 ventilator settings included SIMV/PRVC, VT 240 mL, frequency 20, PEEP 5, i-Time 0.8 s, and PS 10 cm H2O. Model 2 ventilator settings included SIMV/PRVC, VT 60 mL, frequency 30, PEEP 5 cm H2O, i-Time 0.5 s, and PS 10 cm H2O. The Alaris syringe pumps were set with an albuterol dosage of 20mg/h utilizing a syringe filled with 1.67mg/mL albuterol concentration. Per our institution’s policy, two bacterial filters were placed on the expiratory end of the circuit for each trial. The bacterial filters were measured before nebulization initiation and again at 3- and 5-h intervals. The filters were measured again 24 h later. Bench models were completed twice, once with albuterol with sterile water diluent and once with albuterol with normal saline diluent. The filter weights were compared. Results: In both models, at all time intervals, the total weight of the bacterial filters from normal saline diluent was heavier than that of the sterile water diluent filters (Table 1). Conclusions: In our bench model, diluent type utilized with continuous albuterol influences ventilator circuit moisture and filter build-up. In our practice, double filters, changed frequently, prevent negative patient impact with both diluent types. Further studies must be done to assess the effects in a patient care setting on ventilator functionality with varying drug delivery rates.Filter WeightsModel 1New/Dry Weight (g)3-hour weight (g)5-hour weight (g)Dry Weight x 24hr (g)New Filter vs Dry Weight x 24hr (g)Sterile Water Diluent80808180+0Normal Saline Diluent78828281+3Model 2 Sterile Water Diluent78828379+1Normal Saline Diluent77818281+4Table 1 displays the weight of filters in our bench study at varying time intervals compared by model and diluent type.
Panetta et al. (Tue,) studied this question.