Nasal Air Flow Sensor During PSG

For sleep techs or those of you who recently had a PSG or who WELL REMEMBER their PSG:

What type of nasal air flow sensor did they place at your nose to monitor breaths or, if a sleep tech, do you use in your sleep lab or clinic?

I swear that I remember all past PSGs used a small "button" type of nasal air flow sensor placed just at the opening of one nostril.

I don't ever remember a red circular "wire" that laid partially on your lip below your nose bent "in half" so that the other laid against the division between nostrils. It is "form" of the sensor that struck me as DEFINITELY different.

This current "form" of nasal air flow sensor was not as "convenient". We never had trouble w/this particular reporting item staying in position in previous PSGs but this PSG the tech had to come in several times to better position it to get a reading. It just didn't maintain proper "contact". This BEFORE I went to sleep.

I can see where this type of sensor might give better readings (if it stayed in place) that the "button" type since it supposedly would "read" breaths from BOTH nostrils whereas the "button" type would only be reading breath from one nostril and if the patient had some impaired breathing thru one nostril or the other the "reading" wouldn't be as accurate.

But what good is it if it doesn't stay in place as well?

If a sleep tech what type of nasal air flow sensor do you find most stable and giving the better information? What types or styles of nasal air flow sensors are available?

Slinky, was it like the red one on this Dymedix web site?

http://www.dymedix.com/products.shtml
RealFlo™ Reusable

Your past PSG's probably were using a thermistor instead of a transducer.

I think I've read that the new accreditation requirements by the AASM (American Academy of Sleep Medicine) make labs use an airflow pressure transducer instead of (or perhaps with) the older method of using a thermistor.

If it was a pressure transducer, that's a good thing. Of course, it would a better thing if it stays in place.

Maybe your fuming was melting the little thingie.

They used both on me...thermistor and transducer...at my study. I think the transducer they used for me was white, not red. Don't really remember the color.

SAG can tell you all about the benefits of transducer vs thermistor.

As best I understand it, the thermistor simply measures temperature. Exhaled breath being warmer. A pressure transducer measures the actual air flow as you breathe in and out. Thermistor isn't as informative as transducer, I think.

Nope, that isn't the one, RG. If you looked at it from the side the red wire circle or oval would be shaped in a wide V. From the front it looked like a circle or oval. Again, looking at it from the side, one top end of the V would rest against the division between nostrils, the other top end of the V would fit against your upper lip. Color is immaterial, it is the FORM.

Interesting illustration of the snore sensor at that URL! Never had to have one of those taped ON my nose!! Golly goshes, such interesting devices they come up w/for PSGs. If I were younger I'd get sleep tech training just to satisfy my curiosity!!! It would be less frustrating and easier to satisfy my curiosity!! Curiosities??

I think you are probably right, the others were thermistors and this was some sort of transducer. And it makes more sense to me even if all it did was monitor air flow thru both nostrils instead of just one.

Using both, as you had, what do you think the advantage is?

RestedGal wrote:Maybe your fuming was melting the little thingie. ... As best I understand it, the thermistor simply measures temperature. Exhaled breath being warmer. A pressure transducer measures the actual air flow as you breathe in and out. Thermistor isn't as informative as transducer, I think.

Now THAT is interesting if you are correct! I was thinking more in terms of say someone w/a deviated septum, regardless how slight, having stronger air flow thru one nostril than the other. I never thought of the difference in temperature between exhale and inhaled air. It would seem to me that air flow thru BOTH nostrils would be the better indicator than air temperature thru ONE nostril.

Thanks, RG! Maybe I should get a face lift and fake birth certificate and get some sleep tech training. I understand there is a "school" in Flint, MI which is "only" an hour's drive from me.

Hi Slinky,
There are many types of thermistors and pressure tranducers. The thermistors are used to measure temperature changes and the pressure tranducers measure pressure changes. It is now recommended to use both during PSG. Our thermistor has 2 metal prongs that "float" below each nostril and a metal prong that "floats in front of the mouth. It picks up air flow-cool as you breathe in and warm as you breathe out. The pressure tranducer we use has a nasal cannula similar to that used for dispensing oxygen. If you google either, you may be able to find pics and descriptions of both to help you understand better.
Lisa

Thank you, Lisa. That sounds a little more like the one used this PSG, except the one used had nothing like a nasal cannula for 02. This one used was just NOT at all a very stable or secure one. And I SURE can't imagine using it WITH a CPAP mask. That wire would have then dug into the upper lip pretty bad w/the CPAP mask also sitting on the lip had we used one.

FOUND IT!!! The picture of the nasal air flow sensor used during this recent PSG is pictured about half way down this page:

http://www.braebon.com/faqs.html#airflow

As near as I can tell it is only a transistor, measuring air flow temperature?? But that wouldn't meet both pressure and temperature guidelines.

Yes, this is works with temperature. Cool as you breathe in and warm as you breathe out-- Wave form. We can see apneas and hypopneas with this, howver hypopneas are better seen with nasal pressure tranducer. The new recommendations are to be implemented by July 2008. The nasal pressure tranducer would have sat on top of the thermistor. We use both, a bit more uncomfortable. We do not use a thermistor with cpap unless the cpap flow to the computer is not working. I have not been exposed to any other labs. I know there is a lot of different equipment out there. This is just how we use the sensors here.
Lisa

Thank you, lmmo. I suppose it isn't at all necessary for a patient to know stuff like this but .... this particular transistor was such a PITA compared to the type I had experienced before ... I sure hope they don't use it for me again!

Its good to know that at least at your lab they don't use a thermistor when titrating w/CPAP as I'm sure that I'll be brought back for a titration again. There's hope for me then that we won't have to play around with that Braebon for that!

A sleep lab tech told me in Chat just yesterday that air flow creates noise and that the transducer turns noise into electrical signals that the 'puter can read during the evaluation or titration. Again, immaterial to the patient but that "I" found interesting and sure did appreciate the explanation.

I don't have the scored report yet, too much snow yesterday to drive in and pick it up, but since w/COPD I often experience quite a few hypopneas according to my Resmed's nightly data it will be kind of interesting to see how the PSG's hypopneas compare to the Resmed's the night before and the night after. Not that the Resmed data will be of any "official" importance, but ..... ahhh the little things that can "amuse" a patient!

I sooo appreciate you techs, RPSGTs and RTs that take the time to drop in and reply to or comment on our posts!!!! Thank you yet again.