Do you have a Coder's Desk Reference? If you read the description it states: A pulmonary stress test is performed to test how much air moves in and out of the lungs during exercies and to determine where breathing problems are occurring, since it may be in the lungs, heart, or circulation. It then goes on to state how the test is done...Involving a stationary bike, or treadmill and measuring heart rate, breathing and blood pressure. A spirometry is also done as mentioned before.
So you should compare that to your documentation. If they just walked the patient down the hall or something and just did a pulse ox, you could code for the pulse ox and an E/M, again if the documentation supports this, if not just the pulse ox. Also, 94761 is for multiple measurements, so was this done multiple times or just once. One measurement would be 94760. Not all payors will pay for a pulse ox with an E/M...Medicare/Medicaid for example. So you may only be able to charge for an E/M, if there is documentation for this.