Return of neonatal CPAP resistance - the Medijet device family examined using in vitro flow simulations.

AIM: Medijet nasal continuous positive airway pressure (CPAP) generators are a family of devices developed from the Benveniste valve. Previous studies have shown that the in vitro performance of the Medijet disposable generator was similar to the Neopuff resistor system. We hypothesised that resistance would be the main mechanism of CPAP generation in the Medijet disposable generator.

METHODS: The in vitro performance of the Medijet reusable and disposable systems, the Neopuff resistor system and the Benveniste and Infant Flow nonresistor systems were investigated using static and dynamic bench tests.

RESULTS: Large differences in performance were found between the different systems. The disposable Medijet demonstrated high resistance, low pressure stability and high imposed work of breathing. The results also showed that encapsulating the Benveniste valve changed it into a resistor system.

CONCLUSION: The main mechanism of CPAP generation for the disposable Medijet generator was resistance. The Medijet device family showed increasing resistance with each design generation. The high resistance of the Medijet disposable generator could be of great value when examining the clinical importance of pressure stability. Our results suggest that this device should be used cautiously in patients where pressure-stable CPAP is believed to be clinically important.