Unfortunately, there is no standard nor easy way to measure oxygen tension. I also am not aware of many studies that have shown that improvement in oxygen tension leading to improvement in the erections.
An ultrasound to image the penis and blood flow can be considered. Use of other ED medications like Levitra or Cialis can also be considered. I would also check metabolic diseases like diabetes or thyroid dysfunction.
If the symptoms continue, these questions can be addressed with your personal urologist.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_