Wiki billing 94770 documentation requirements

[Dialmam]

I have a new intensivist that cares for critically ill patients in ICU setting. For those that are intubated, it is standard to record those values including an EtCO2 value. The new physician wants to bill separately for EtCO2 CPT 94770 "Carbon dioxide, expired gas determination by infrared analyzer".

Are there any documentation requirements for this aside from just review of the values? CPT assistant was not very helpful and I can't find any other credible resources.

Thanks