Effect of Different Interfaces on F_IO2and CO₂Rebreathing During Noninvasive Ventilation

Abstract

BACKGROUND: Improving F IO 2 and reducing CO 2 rebreathing (V ICO 2) are the key means to improve the therapeutic efficacy of noninvasive ventilation (NIV). This study aimed to investigate the impact of interface design on F IO 2 and V ICO 2 during NIV. METHODS: A simulated lung model was established to analyze 17 different interfaces. CO 2 was injected into the outlet of the simulated lung, and the noninvasive ventilator was connected to the simulated lung to simulate the application of NIV in patients with COPD with hypercapnia. F IO 2 and V ICO 2 were calculated by mathematical integration of synchronously collected data pertaining to real-time pressure, flow, oxygen concentration, and CO 2 concentration in the breathing circuit. Comparisons were performed between different types (nasal vs oronasal) and models of interfaces as well as between interfaces with different leak positions. Correlation of F IO 2 and V ICO 2 with inner volume and leakage, respectively, and the correlation between F IO 2 and V ICO 2 were analyzed. RESULTS: F IO 2 levels were significantly different with a nasal or an oronasal mask (0.45 6 0.05% vs 0.41 6 0.08%, respectively; P < .001). F IO 2 levels associated with different models of interfaces varied significantly (all P < .001); V ICO 2 did not differ significantly among the different interfaces (P 5 .19). Leak position significantly affected F IO 2 and V ICO 2 (all P < .001). Both inner volume and leakage significantly correlated with F IO 2 (r 5 20.23, P < .001; r 5 20.08, P 5 .02). There was a significant correlation between F IO 2 and V ICO 2 (r 5 0.43, P < .01); the general linear equation was y 5 0.17 + 0.02x (r 5 0.43, R 2 5 0.19). CONCLUSIONS: The design of the interface had a significant impact on F IO 2 and V ICO 2 during NIV. F IO 2 and V ICO 2 showed a significant positive correlation, although the effect size of correlation was moderate.

Potential rebreathing of carbon dioxide during noninvasive ventilation provided by critical care ventilator

“…Masks were fit on volunteers as recommended without overtightening, and volunteers did not perceive a leak nor did it impact ventilator synchrony. Others have reported that interface’s dead space and amount of leakage impacts volume of inspired carbon dioxide ( V ICO2 ) [ 13 ]. In our study, the differences in dead space may have affect CO 2 rebreathing clearance as observed in Figure 3 , since median F ICO2 was higher for the full-face masks.…”

Technische Aspekte und Neuerungen in der nicht-invasiven und invasiven Beatmung

“…Erhöht man zusätzlich den Grundflow ("Bias-Flow"), dann verstärkt sich dieser Effekt [18]. Ferner beeinflussen die Bauart der Maske (nasal vs. Full-Face), der Maskentyp, der Totraum der Maske und die Position des Ausatemöffnung sowohl die F i O 2 als auch die F i CO 2 [19].…”

Effects of jet nebulization on ventilator performance with different invasive ventilation modes: A bench study

“…Users can set the corresponding compliance, resistance, and inspiratory negative pressure generated by an inspiratory muscle according to different models of lung disease. The parameters used in this study to simulate a COPD patient were adapted from previous publications (14)(15)(16), as follows: compliance 60 mL/cmH 2 O, inspiratory resistance 10 cmH 2 O/L/s, expiratory resistance 15 cmH 2 O/L/s, and maximum drop in inspiratory pressure −5 cmH 2 O. To simulate the negative pressure produced by the respiratory muscles, 5% of the respiratory cycle time was set to active inspiration, 3% was set to end-inspiratory hold, and 15% was set to return pressure to the baseline.…”