Is Pulse Flow of Oxygen Enough?

Dear Dr. Mahler: My pulmonary rehab coordinator encouraged me to write to you. I use oxygen from a small tank with activities at 3 that has pulse flow. Whenever I do anything, my oxygen saturation falls quickly to the low 80s and then comes back to the low 90s after I stop and rest. I have severe COPD and am on “triple therapy” according to my pulmonary doctor. I have a stationary oxygen concentrator at home also set at 3, but I don’t seem to have the same drops in my saturation level when doing things at home. I know that I could breathe better if I could keep my oxygen level above 90% with daily activities. Any suggestions? Crystal from  Brooklyn, NY  Dear Crystal: Your problem is not unusual. Here are the basics. The concentrator in your home delivers oxygen at a continuous flow. You said that your portable oxygen tank is set at pulse  flow. This means that the oxygen is flowing only when you first start to breathe in and then stops flowing when you stop inhaling. This is also called oxygen on demand. This pulse flow system allows you to use the tank longer before it runs out of oxygen. In some individuals the pulse flow does not provide enough oxygen for the demands of your daily activities. I suspect that you will require a portable oxygen system that delivers continuous flow rather than pulse flow.
Woman using portable oxygen concentrator with continuous flow of oxygen

Woman using portable oxygen concentrator with continuous flow of oxygen

I suggest that you ask your pulmonary doctor to have your oxygen saturation measured in the office or pulmonary function laboratory doing the same activity such as walking with both continuous and pulse flow of oxygen. This will indicate whether you will require continuous flow of oxygen when you are active. If so, this means that the tank will not last as long as it currently does when you are using it. You may need to carry an additional tank if you are away from home for a long time. Or, you might consider asking for a portable oxygen concentrator that provides both continuous and pulse flow. Best wishes, Donald A. Mahler, M.D.  

Donald A. Mahler, M.D. is Emeritus Professor of Medicine at Geisel School of Medicine at Dartmouth in Hanover, New Hampshire. He works as a pulmonary physician at Valley Regional Hospital in Claremont, NH, where he is Director of Respiratory Services.