Feasibility and Efficacy of Pulsed-Dose Oxygen Delivery During Noninvasive Ventilation.

Abstract

It is difficult to apply noninvasive ventilation (NIV) simultaneously with pulsed-dose oxygen delivery. We evaluated the feasibility and efficacy of pulsed-dose oxygen delivery during NIV. A bench study was conducted using a simulated lung during NIV, with a breathing frequency of 10 or 20 breaths/min and 3 oxygen injection sites (site A on face mask, site B proximal to face mask, and site C at the ventilator outlet) with continuous flow oxygen delivery of 1, 3, or 5 L/min) or pulsed-dose oxygen delivery (numerical settings of 1, 3, or 5 representing the oxygen pulse characteristics). [Formula: see text] under different experimental conditions and the influence of mode of oxygen delivery on NIV (compared to baseline and continuous flow oxygen delivery vs pulsed-dose oxygen delivery) were compared. In the clinical study, we enrolled 10 subjects with COPD exacerbation who received NIV with either continuous flow oxygen delivery or pulsed-dose oxygen delivery. Under the same targeted pulse oxygen saturation (88-92%), the numerical settings of different modes of oxygen delivery were titrated, and the clinical parameters during the different modes of oxygen delivery were compared. In the bench study, the ratio of the [Formula: see text] with pulsed-dose oxygen delivery to the [Formula: see text] with continuous flow oxygen delivery at the same numerical setting was 0.94 ± 0.15. The oxygen injection site had a significant influence on [Formula: see text] in pulsed-dose oxygen delivery or continuous flow oxygen delivery mode (P < .05). Pulsed-dose oxygen delivery worked effectively with the ventilator, as demonstrated by the fine synchronization in the breathing cycle of the ventilator, the simulated lung, and the pulsed-dose oxygen delivery. When compared with each other or compared to the baseline individually, pulsed-dose oxygen delivery and continuous flow oxygen delivery showed no clinically important effects on NIV (all P > .05 or changes < 10%). In the clinical study, the mean numerical settings for pulsed-dose oxygen delivery and continuous flow oxygen delivery modes after titration were 2.68 ± 0.32 and 2.31 ± 0.56 L/min, respectively. There was no significant difference between continuous flow oxygen delivery and pulsed-dose oxygen delivery (P > .05). Integration of pulsed-dose oxygen delivery into NIV could achieve efficacy similar to that achieved with continuous flow oxygen delivery.