Objective: The aim of this study was to investigate the effects of different oxygen delivery methods during noninvasive positive-pressure ventilation (NPPV) on transcutaneous oxygen pressure (PtcO2), transcutaneous carbon dioxide pressure (PtcCO2) and fraction of inspired oxygen (FiO2) in order to find more effective oxygen delivery methods.
Methods: A total of 20 healthy volunteers participated in this study, all of whom received NPPV. All volunteers received oxygen through a nasal cannula (NC) located in a mask or through a mask alone (OSTM) (oxygen flow rate was 3L/min and 5L/min), PtcO2 and PtcCO2 were measured, and the effects of the 2 methods of oxygen concentration on PtcO2 and PtcCO2 levels were evaluated during noninvasive ventilation. Then, the additional oxygen concentration was stopped, oxygen was delivered through the ventilator, and the oxygen concentration was adjusted so that the PtcO2 reached the same oxygen concentration level as noted through the NC or OSTM. This concentration of oxygen indirectly reflects FiO2 in different oxygen delivery methods.
Results: When NPPV was used under the same pressure, FiO2 increased from 44.4% to 65.3% when oxygen was delivered through an NC compared with oxygen supplied by OSTM alone. PtcO2 was also significantly increased from 18.9% to 24.9%; the difference was significant (P < .05), while there was no significant change in PtcCO2 (P > .05).
Conclusion: When NPPV is used, an NC can obviously improve FiO2 and PtcO2 without increasing PtcCO2. It can save oxygen and is more suitable for NPPV during an emergency and for home use.