California Subscriber
Answer: Code 94660 is used to bill for the initiation of CPAP or BiPAP. But if there are any other E/M services on the same day, including critical care, you may bill for the ventilation initiation or the E/M service, not both.
Bill the service that takes precedence during the day. Critical care would take precedence over CPAP or BiPAP. CPAP or BiPAP might or might not take precedence over an E/M service.