Low oxygen blood levels

I took the Fen Phen diet pills and now have Aortic and Mitral Valve regurgitation.  While on a pulse oximeter, my levels will go from 92 to 81 without any change in activity.  Sitting or standing the meter bounced around continuously.   Lung xrays are clear.  Being on portable oxygen at 3 liters, does not seem to make a difference.  Could this also be because of the Fen Phen?

[National Jewish Health]

I am sorry to hear of your misfortune.  In addition to causing valvular heart disease, including tricuspid valve disease, Fen Phen has also been shown to cause pulmonary hypertension.  What you describe suggests that you are having what is called right to left shunting of blood through an atrial septal defect, which is a hole between the upper chambers of your heart.  This could be due to pulmonary hypertension, tricuspid insufficiency or a combination of the two.  That your arterial oxygen saturation remains unchanged with the use of supplemental oxygen, would be consistent with shunting of blood from the right side of your heart to the left side of your heart.

In this circumstance, surgical closure of the atrial septal defect has been associated with a reduction of pulmonary hypertension in some instances and unchanged or worsened in others, putting additional strain on the right ventricle side of your heart.

If you prove to have a shunt, any consideration of surgery, on your part, should only be addressed with specialists in pulmonary hypertension of which there are now many in pulmonary hypertension clinics at almost every academic medical center in the US, and by surgeons with vast experience in the surgical management of Fen Phen induced cardiac valvular disease with pulmonary hypertension.

Good luck.