1327 Expiratory Resistance of Cpap Devices for Preterm Infants

Abstract

Introduction: CPAP systems for preterm infantswork with conventional ventilators or use a jetventilation system. It is assumed that the mostimportant advantage of jet-CPAP systems is a lowerexpiratory resistance. We investigated the expiratoryresistance of seven different CPAP systems. Methods: We studied two primary-care CPAPsystems, 3 jet-CPAP generators and 2 conventionalCPAP devices. All devices were adjusted at 6mbar and connected with a test lung simulating astandardized expiration volume. Maximum pressureincrease during expiration was measured andmaximum expiratory resistance was calculated. Results: In primary-care CPAP devices themaximum expiratory resistance of the Benvenistevalve was 9.7mbar/l/s (SD 1.2) while that of theNeopuff was 102.8mbar/l/s (SD 7.9) (p< 0.01). Injet-CPAP devices the expiratory resistance of theInfant Flow was 6.8mbar/l/s (SD 1.7), the one ofthe Medijet REF 1000 was 43.5mbar/l/s (SD 1.5)and that of the Medijet REF 1010 was 36.7mbar/l/s(SD 0.3) (p< 0.01). In conventional CPAP systemsthe expiratory resistance of the Baby-Flow was29.7mbar/l/s (SD 1.1) and that of the Bubble-CPAPwas 37.1mbar/l/s (SD 4.3) (p< 0.01). Conclusion: All CPAP devices created an expiratoryresistance. Jet-CPAP devices did not produce lowerexpiratory resistance than conventional CPAPdevices.