Question about SNIP (nasal inspiratory pressure)

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Danijela

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PALS
Diagnosis
11/2008
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UK
State
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Bolton
SNIP - Sniff Nasal Inspiratory Pressure

Does anyone have this test done at their clinic alongside FVC?

I am interested in the correct procedure, as my partner's results seem to vary very much, from unrealistic 140cm H2o (deep sea divers!) to 59cm H20 (death within 6 months!)

Sometimes they close his free nostril (the one free of the nasal plug), sometimes they don't. My partner feels that the test is not performed correctly.

Also, does anyone knows what the correlation between FVC values and SNIP values is? His FVC is normal.

Thanks. D
 
Dani,

I don't remember having this done (?) (could have, memory is good, but short LOL) However, I do have another pulmo appt coming up soon. Will see if I can learn anything about it then.

IMHO, it does not follow that Laurence's FVC would be fine, and yet the other test showing such a dramatic change...
 
Here in the US we have a device called a NIF (negative inspiratory pressure) which is measured with a mouthpiece and it measures how much negative force you can generate. you have to be able to make a tight seal around the mouthpiece though. It is a way of measuring lung strength.
Barb
 
My Respirologist would just have me sniff, cough etc while examining me and looking at the FVC results. Never used machines for sniffing.

AL.
 
Thanks all for your responses. It is a relatively new 'device' her in the UK and they have just started using it with ALS patients at our clinic.

It is meant to be provide more accurate reading about respiratory health than that indicated by FVC alone. I have read an article suggesting that using SNIP testing more readily would probably result in recognition of need for NIV about 6 months earlier than when using just FVC measurements. We don't even get NIV here in the UK as a matter of course. Many PALS die having never been offered NIV. It makes me angry. And there are more cuts to come in good old NHS.

rose - it would be great if you could find something more about it when meeting your pulmo, it would be much appreaciated. I am primarily interested in the correct procedure for accurate reading, but have also read that people with bulbar symptoms may benefit from using the device as no lip seal is required (basically, they place a kind of plug in one of the nostrils).

Dani
 
Hi Dani, my hubby has been offered N.I.V. when he needs it. He hasn't had the snip sniff test and we've no idea what his F.V.C. is at the moment but he finds it hard to cough or sniff. I've mentioned (several times) the 'T' word tracheostomy and have been told he won't be refused. Hope they keep to that.....
Keep us posted.
Best wishes, Cherry.
 
Cherry, glad to hear that. As you know it can be a postcode lottery in the uk. I know of several pals fighting for NIV to no avail.
 
Back to this SNIP issue. Laurence had his FVC done yesterday and it was 95%, SNIP is 45 cmH20, with one reading being as low as 30. SNIP of 30 cmH20 is an indicator of death within 3 months. I am finding it hard to believe that the two results do not correlate. He has no difficulty breathing, even when flat on the bed. I am hoping that the procedure was not performed correctly, and L also felt that the nasal plug used did not fit very well and that there was a leak. Still, this worries me. Unfortunately, we had the breathing tests done AFTER seing the neuro (?) so could not get any feedback from him. Will be contacting him, but any thoughts would be welcome.

D
 
Dani, this is just a thought, but could he have simply been fatigued when that low score of 30 occurred? Doctor visits are very tiring for me. Since my voice varies widely according to fatigue or strength, I'd think the SNIP may, also.
Ann
 
Ann, the test was performed at the end of a very long day. We took our son for a trial run at the nursery (for the first time!) in the morning, then spent hours at the clinic in the afternoon. I always find it draining, and I am the healthy one.

The consultant whom Laurence usually sees has responded to our query, and will arrange a repeat test. He mentioned that it is not uncommon to get such discrepancy in results (FVC and SNIP) due to many factors, one of which would be a poor technique on behalf of the patient. While he values such tests ,he mentioned that there is a lot to be said about "good old fashioned neurological examination" and doctor's experience. I agree, but at the same time it is not unheard of that a PAL passes away in their sleep, suddenly, even with relatively high values of FVC. So, I am glad we are repeating the test, as this will either trigger some action or put our minds to rest.

Dani
 
You are right, Dani... I've also seen where high FVC pals die. I'm glad the test will be repeated, and hope it happens that Laurence gets good scores. When we go to sleep it's also at the end of a tiring day, so the test at that end of fatigue is probably most fitting, anyway.
 
Dani, I think ALL of those test values can change to a degree depending not only on how they are performed (the technician as well as patient) and how tired the person is for the testing. My FVC has swung from as low as 70% to as high as 100%. Last time it was tested it was 80%. My mep and mip are not tested as often, and have not climbed up after coming down. They are pretty low at about 20% & 40%, and I have no intentions at all of dying within the next few months! Unlike your Laurence, laying flat (or even on my sides) does have a tremendous detrimental effect for me though. I've not had the SNIP test.

How I feel about how I feel (how's that for a sentence) but in other words, just my impression, not with medical knowledge to back it up. I think, because my MEP is so bad and I am actually aware of it, in that it does impact my everyday life, I think if I were to get another chest infection with a bad cough, or any real need to cough, that this would be significant to how well I could bounce back. But, I do have the cough assist machine, and use it somewhat regularly. Not like I'm supposed to, but I make the attempt.
 
Thanks for you input. We are back at the clinic for the repeat of the test, plus some earlobe blood gas testing (never had this done!). Will keep you updated.

"how I feel about how I feel" is absolutely brilliant, will have to use it now myself ;0

D
 
Last edited:
Update:

Laurence went back to the clinic today, following our concern about an extremely low SNIP reading, pointing that he has 3 months left to live.

This time (thanks to our insistance on correctly following the test procedure, and a member of this forum sending me a manual for the machine) his SNIP reading is over 100 cmH20, which is very good! So I am relieved and pleased, and grateful. However, I wish I did not have to carry the burden of fear due to people's incompetence.

Here are a few things we have learned regarding breathing tests (FVC/SNIP) and the outcomes:

- empty stomach (better result) vs full stomach

- degree of tiredness

- number of times one is asked to repeat the test (with SNIP the results tend to get better with repetition/practice, with FVC worse/tiredness)

- differring results when standing up, sittting down and lying down (important especially if you have difficulty breathing when lying down)

- the importance of good seal (especially for bulbar patiens) be it for FVC or nasal plug seal in SNIP testing

- incorrect measurement of your weight and hight can result in an incorrect predicted result, hence skewed reading (we have seen many PALS not being weighed properly, especially if they have difficulty moving/transferring)

Dani
 
Very good news, Dani! And thank you for the information, which is very helpful.
Ann
 
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