The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts


Dave N. Crotwell, Tien Tran, John Salyer; Respiratory Care, Seattle ChildrenÂ’s Hospital, Seattle, WA

Background: Clinical observations led to speculation there is high variability in output of the SPAG-2 during Ribavirin delivery. High nebulizer residual volume has been observed after many hours of use. Methods: We tested 3 different SPAG-2 units, which were all set up according to manufacturers recommendations. Each was < 2 years old and filled with 100 mL sterile H2O. Units were run at regulator pressure = 26 psi, nebulizer flow = 8 L/m and drying air flow = 6 L/m.. At the end of 5 one-hour epochs residual volume was measured using a graduated cylinder and subtracted from the original total volume to determine the amount nebulized each hour. We visually verified nebulizer function by noting that all three units produced approximately one-half inch diameter spray patterns on the wall of the flask. Results: Data are displayed in the table below. Mean output for all epochs and devices was 6.6 mL + 4.8 mL per hour. This yielded a coefficient of variation of 74%.Conclusion/Discussion: According to the manufacturers specifications, SPAG-2 should have an output range of 12.5 to 15.0 mL/hr. Our tests showed high variability in the output within and between units and that none of the units came close to performing according to the manufacturers claims. A limitation of this study is that we did not actually use a solution of Ribavirin dissolved in sterile water, owing the very high cost of the drug (list price $4963 per 6 g vial. However, our findings confirmed many reports from clinicians that the SPAG-2 has large and varying residual volumes at the end of nebulizations periods when using Ribavirin solution. This poor performance could lead to low and or inconsistent drug delivery and may have a negative impact on outcomes of patients who need the drug and certainly could contribute to frequent observations that the drug did not seem to work. Assuming our current customary dosing schedule of a single 6 g dose diluted into 100 mL of sterile H2O, given for 2 hours, TID, and further assuming an actual nebulization rate of 6.6 mL/hr and a cost of $49.63/mL, we may be wasting about 60 mL of the drug per day or about $2978. Further study may be needed to find better methods of delivering this drug. Sponsored Research - None