Ok here is the article

Randomized Trial of Bilevel versus Continuous Positive Airway Pressure for Acute Pulmonary Edema.

Small study but  helps reassure us that unlike past non RCT studies that showed trend towards worse outcomes with BiPAP and cardiogenic pulmonary oedema, there was reduced ICU admission rate and better oxygenation, but no difference in mortality.

So certainly can initiate with CPAP and if not responding increase to BiPAP, as prelude to RSI, but maybe the BiPAP will obviate need for RSI and ICU admission