CPT codes for Hospital observation billing

Hi Everyone,

I am so confused. Please help.

In Our hospital we have seperate Obsevation unit next to Emergency department.

Patient was seen by Dr.X. EKG and some medications were ordered and services rendered in Emergency room then transfered to Observation Unit to monitor his/her condition.

Question :

1) Do I code ED E/M level with EKG, injections along with Observation codes for OBS Doctor? (2 Phsycicians involved?) OR

2) Because of Patient care was transfered to Observation Doctor. It should be one Doctor only?

If that is a case how do we bill for ED service (EKG and injections?)

Thank you.

CPT codes for Hospital observation billing