Reading oxygen flowmeters

[Kitiger, RN]

When you read an oxygen flowmeter, do you read at the top of the bubble, the middle of the bubble, or the bottom of the bubble?

I was taught to read the middle of the bubble. And that is what I'm finding on the internet. But the worker who delivered an oxygen concentrator to my client's home said I should read the bubble at the bottom.

Is the flowmeter on a concentrator different from the flowmeter that attaches to an E tank? What is being taught these days?

https://jim.bmj.com/content/53/1/S314.5

https://www.bing.com/search?q=How do you read an oxygen flowmeter&qs=n&form=QBRE&sp=-1&pq=how do you read an oxygen flowmeter&sc=0-35&sk=&cvid=5506A0ED74C4452392F21DFE0A946DE1

[Kitiger, RN]

I decided that the reason the worker insisted on reading the bottom of the bubble is because he read it while standing up and looking down. I always read it with my face in the same plane, not looking down.

[Wlaurie, RN]

Yes, you are correct. The middle of the bubble tells you the o2 that is flowing.

[Kitiger, RN]

I have one client (taller than I) who reads the middle of the bubble while looking down at the flowmeter. Since I read it with my face in the same plane, I consistently read 0.25 LPM lower. 

This is with an O2 concentrator, the BIG, heavy kind that uses an air compressor.