The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts


Bernhart Hochleitner, Ron Sherman; The Reading Hospital and Medical Center, Reading, PA

OBJECTIVE: Optimal oxygen titration points during continuous positive airway pressure (CPAP) therapy with full face mask (FFM) have not been established. Our goal was to find the optimal oxygen titration point within a CPAP delivery system by analyzing oxygen concentrations. METHOD: An Invacare Polaris EX CPAP machine was used to deliver CPAP+5 via a Hudson RCI non-invasive vent circuit with an exhalation port proximal to the FFM. A hole was drilled in the front of a Respironics Performatrack FFM. A flow diverter was inserted into the hole and sealed with caulk. A micro-fuel cell T-7 was attached to the flow diverter and connected to a TED 191 oxygen monitor. This allowed for oxygen concentrations to be measured directly in the FFM. A respiratory therapist served as a volunteer by wearing the FFM during CPAP delivery and oxygen titration. Oxygen was titrated at three points along the CPAP delivery system; proximal to the Polaris EX, between the mask and exhalation port, and directly into the FFM. Titrated liter flows were 2, 3, 4, 5, & 6 L/min. Each liter flow was maintained for three minutes, respiratory rate was maintained at 12 BPM, and FiO2 was measured at beginning of each inspiration and the average recorded. The study was carried out over the course of one week with the same volunteer participating. RESULTS: The highest FiO2s were recorded with oxygen titrated directly into the FFM. Oxygen titrated proximal to the CPAP (PCPAP) machine had the next highest recorded FiO2s and oxygen titrated between the full face mask and exhalation port (FFMEP) provided the lowest recorded FiO2s. Results are expressed as L/min=FiO2. FFM titration results: 2=27, 3=34, 4=40, 5=48, 6=56. PCPAP titration results: 2=24, 3=27, 4=32, 5=39, 6=43. FFMEP titration results: 2=23, 3=26, 4=28, 5=31, 6=35. CONCLUSION: Our study is the first to confirm the optimal oxygen titration point within the described CPAP delivery system. The highest FiO2 measured was with oxygen titrated directly into a FFM, though actual FiO2 delivery to the lungs was not measured. There was a greater range in FiO2 delivery with FFM titration. It was theorized that this was due to the oxygen reservoir effect of the FFM and lack of exhalation port within the FFM which maintained oxygen concentrations. Variability in FiO2 was observed during the volunteer's respiratory cycle which was theorized to be due to gas mixing and oxygen/CPAP flow variability. Further study of these findings will be conducted. Sponsored Research - None