Noninvasive CPAP with face mask: comparison among new air-entrainment masks and the Boussignac valve.
BACKGROUND
The performances of 2 noninvasive CPAP systems (high flow and low flow air-entrainment masks) were compared to the Boussignac valve in 3 different scenarios.


METHODS
Scenario 1: pneumatic lung simulator with a tachypnea pattern (tidal volume 800 mL at 40 breaths/min). Scenario 2: Ten healthy subjects studied during tidal breaths and tachypnea. Scenario 3: Twenty ICU subjects enrolled for a noninvasive CPAP session. Differences between set and effective CPAP level and F(IO(2)), as well as the lowest airway pressure and the pressure swing around the imposed CPAP level, were analyzed. The lowest airway pressure and swing were correlated to the pressure-time product (area of the airway pressure curve below the CPAP level) measured with the simulator. P(aO(2)) was a subject's further performance index.


RESULTS
Lung simulator: Boussignac F(IO(2)) was 0.54, even if supplied with pure oxygen. The air-entrainment masks had higher swing than the Boussignac (P = .007). Pressure-time product correlated better with pressure swing (Spearman correlation coefficient [ρ] = 0.97) than with lowest airway pressure (ρ = 0.92). In healthy subjects, the high-flow air-entrainment mask showed lower difference between set and effective F(IO(2)) (P < .001), and lowest airway pressure (P < .001), compared to the Boussignac valve. In all measurements the Boussignac valve showed higher than imposed CPAP level (P < .001). In ICU subjects the high-flow mask had lower swing than the Boussignac valve (P = .03) with similar P(aO(2)) increase.


CONCLUSIONS
High-flow air-entrainment mask showed the best performance in human subjects. During high flow demand, the Boussignac valve delivered lower than expected F(IO(2)) and showed higher dynamic hyper-pressurization than the air-entrainment masks.
Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Polo Universitario San Paolo, Milan, Italy. giovanni.mistraletti@unimi.it
Giovanni
G
Mistraletti
Matteo
M
Giacomini
Giovanni
G
Sabbatini
Riccardo
R
Pinciroli
Elena S
ES
Mantovani
Michele
M
Umbrello
Debora
D
Palmisano
Paolo
P
Formenti
Anne L L
AL
Destrebecq
Gaetano
G
Iapichino
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D045422:Continuous Positive Airway Pressure / Q000295:instrumentation*; D005260:Female; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D008397:Masks; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011312:Pressure; D056152:Respiratory Rate; D013990:Tidal Volume; D015300:Ventilator Weaning; D055815:Young Adult
D010100:Oxygen