Nasal Mask Flow Rate Waveform Examples

[Jay Aitchsee]

This image contains examples of the various kinds of breathing that can be done while wearing a Nasal Mask. Flow Rate waveforms generated while wearing a nasal mask can be confusing. Flow Rate is just that, the machine is measuring the Rate of Flow past the sensor which is located in the machine remotely from the patient. With a nasal mask, the only Flow the machine can measure directly is that which flows through the hose into or out of the nose. Flow that enters or leaves the lungs by way of the mouth can not be measured directly because the hose is not attached to the mouth. So with a Nasal Mask, Flow Rate means Nasal Flow Rate, we are looking at the Nasal Flow (which BTW, includes leaks through the nose and out the mouth, or around the edges of the mask).
Below we see how the inability to directly sense mouth flow affects the shape of the Flow Rate Waveform. The sample is about 8 minutes long, done when I was awake and runs through a series of nasal/oral breathing combinations. The zoomed portions are about 1 minute in length and run consecutively starting at about 16:15 to about 16:20.

• From the top, in order:
  • Flow Rate : The Sample Segment
    Flow Rate 1: Nose In, Nose Out; Normal Breathing;
    Flow Rate 2: Nose In, Mouth Out; Commonly seen
    Flow Rate 3: Mouth In, Mouth Out; Flat line. The machine is unable to sense approximately 12 breaths and scores a 47 second apnea. Occasionally seen as a break in therapy.
    Flow Rate 4: Mouth in, Nose out; seen often as a flat line between two exhales, an inhale by mouth.

• From the top, in order:
  • Flow Rate : The Sample Segment
    Flow Rate 1: Nose In, Nose Out; Normal Breathing;
    Flow Rate 2: Nose In, Mouth Out; Commonly seen
    Flow Rate 3: Mouth In, Mouth Out; Flat line. The machine is unable to sense approximately 12 breaths and scores a 47 second apnea. Occasionally seen as a break in therapy.
    Flow Rate 4: Mouth in, Nose out; seen often as a flat line between two exhales, an inhale by mouth.

[palerider]

niiiice. well done, Sir.

[Jay Aitchsee]

niiiice. well done, Sir.

Thanks, you deserve the credit. You remember when I asked you about the funky waveform I had observed from a friend and you turned up the posting by Pugsy? Well, that got me looking for another reference and I couldn't find one, so I had to make it myself.

[palerider]

niiiice. well done, Sir.

Thanks, you deserve the credit. You remember when I asked you about the funky waveform I had observed from a friend and you turned up the posting by Pugsy? Well, that got me looking for another reference and I couldn't find one, so I had to make it myself.

maybe a bit of inspiration, but I think the credit is all to you.

nice use of the clone feature to show multiple flow lines, too.