Hello everybody, I have a question for you respiratory gurus. Where I work we have a new ventilator that can provide both CPAP and NIPPV (AKA BiPAP). Both modes can provide non-invasive therapy to spontaneously breathing patients. My question comes down to the following; is there any significant physiological difference between CPAP + PS and NIPPV? With CPAP + PS I have a pressure low, the underlying CPAP and a pressure high, the PS which is above the CPAP. With NIPPV I have a pressure low, the EPAP and a pressure high, the IPAP. As far as I can tell, these methods provide the same physiological action because you in fact have a pressure high and a pressure low with both modes.