Question: Does the end time need to be documented for 36620? Or does the anesthesia provider just need to note the start time? Mississippi Subscriber Answer: Line placements common to anesthesia such as 36620 (Arterial catheterization or cannulation for sampling, monitoring or transfusion [separate procedure]; percutaneous) are flat-fee services rather than timed procedures (which is different from codes listed in the anesthesia section of CPT®. Do be sure that the documentation states which provider placed the line (such as an anesthesiologist, CRNA, SRNA, or surgeon). If a provider who is not part of your anesthesia staff places the line, it is not a billable service for anesthesia.