When reviewing the code descriptors, it appears that the physician is not the one performing the actual diagnostic procedure as seen with 99144 and 99145, So I was looking more towards 99149/99150. I also include the time guidelines of the mid-way point for coding add on code and additional units.
99149 Moderate sedation services (other than those services described by codes 00100-01999), provided by a physician or other qualified health care professional other than the health care professional performing the diagnostic or therapeutic service that the sedation supports; age 5 years or older, first 30 minutes intra-service time
99150 Moderate sedation services (other than those services described by codes 00100-01999), provided by a physician or other qualified health care professional other than the health care professional performing the diagnostic or therapeutic service that the sedation supports; each additional 15 minutes intra-service time (List separately in addition to code for primary service)
99144 Moderate sedation services (other than those services described by codes 00100-01999) provided by the same physician or other qualified health care professional performing the diagnostic or therapeutic service that the sedation supports, requiring the presence of an independent trained observer to assist in the monitoring of the patient's level of consciousness and physiological status; age 5 years or older, first 30 minutes intra-service time
99145 Moderate sedation services (other than those services described by codes 00100-01999) provided by the same physician or other qualified health care professional performing the diagnostic or therapeutic service that the sedation supports, requiring the presence of an independent trained observer to assist in the monitoring of the patient's level of consciousness and physiological status; each additional 15 minutes intra-service time (List separately in addition to code for primary service)
" the new Time guidelines in the Introduction to CPT 2011 overrides the instructions published in the February 2006 CPT Assistant issue. Based upon current CPT guidelines, the appropriate reporting of moderate sedation performed by an independent observer on an adult that lasts 35 minutes would be reported with only code 99144. The rationale for reporting is that when codes are ranked in sequential typical times and the acutal time is between two typical times, the code with the typical time closest to the actual time is used. The ?35 minutes? is closer to the stated time in code 99144 (first 30 minutes intra-service time). A unit of time is attained when the mid-point is passed. Therefore, in order to report an additional 15 minutes of intra-service time (as represented by code 99145 and 99150), the mid-point of 7.5 minutes must be passed."