I'm surprised, (not arguing), but I have one lung. Lost the other to chemo and hospital pneumonia. The other has COPD. All that happened before the pump was put in. I had to be infection free for 12 months before I could have the pump surgery. They check my oxygen saturation like they check everyone's but they don't watch my lung function. My pump guy is a neurosurgeon and a researcher. Extremely brilliant guy. I"ll ask him next time I go for an oil change. Good luck with your stimulator.