I have a client who is marking the following on the reports:

Stroke Volume Variation(SVV)
Cardiac Output (CO).

He explained it as follows: "This is monitoring of the cardiovascular function of patient on bigger and sicker patients, and it is done and calculate by having both Arterial line and Central line placement. A new monitor that we have."

Are these items separately billable and if so, what CPT codes apply? I think they are part of the overall procedure and monitoring but want to double check.