Okay, the first article is a bit to weed through so here is the pertinent portion.

The Single-Breath-Count Test
In light of the need and the urgency to identify ventilatory
muscular deterioration quickly, a tool must be adopted that
has the following attributes: (1) improves triage, not impede
it; (2) has the necessary sensitivity and specificity to assess
ventilatory muscular strength; (3) be inexpensive; (4) be easily
reproducible; (5) be easily taught; (6) be easily learned;
and (7) be easily administered.
Such a tool has been available and meets the requirements
necessary to be an effective triage instrument in the
assessment and disposition of suspected botulism poisoning.
The tool is the Single-Breath-Count Test (SBCT). It
has been used to evaluate the ventilatory status of patients
with suspected or extant neuromuscular compromise (e.g.,
myasthenia gravis, Guillain-Barre syndrome, and botulism).
1315 The test is performed by having the patient
count out loud after taking one deep breath. Most adults
with normal ventilatory function are able to count to 50 in
a single breath.13 A single breath count of

The second link doesn't work so here is the tidbit:




Myasthenia Gravis and Neuromuscular Respiratory Failure







General Issues Regarding Neuromuscular Respiratory Failure



Neuromuscular disorders may cause:

weakness of the diaphragm (resulting in hypoventilation)

weakness of the oropharyngeal and upper airway muscles (leading to aspiration or obstruction).

Patients may present with respiratory failure:

due to progression of a chronic progressive neuromuscular condition such as ALS or muscular dystrophy.

as an early or presenting manifestation of an acquired disorder as is the case with GBS, botulism, and myasthenia gravis.

Signs and Symptoms:

Nocturnal or sleep associated hypoventilation (headaches upon awakening, daytime fatigue, daytime sleepiness, etc.) weakness of the diaphragm

Slurry/nasal speech weakness of the palate

Dysphonia (raspy voice) weakness of the larynx

Weak cough weakness of the epiglottis

Accessory muscle usage

Tachycardia

Physical Exam:

Ask pt to cough or sniff

Observe for paradoxical abdominal wall movement

o Normally, with inspiration as the diaphragm contracts, the abdomen is forced down leading to protrusion of the belly. In severe diaphragm weakness, inspiration may be more dependent on the intercostal and accessory muscles, in which case the weak diaphragm muscle may be drawn up into the chest with inspiration, leading to a sunken or scaphoid appearance to the abdomen.

The Counting Test

o take a huge breath and count aloud. Determine how high the patient can count in one breath. If the patient can count to "10" on one breath they likely have a forced vital capacity of about 1000 ml, if they can count to "25" then the vital capacity can be estimated at about 2000 ml.

Spirometry:

Forced vital capacity:

Respiratory failure is likely when FVC falls below 15-20 ml/kg. In an average size adult 15-20 ml/kg equals about 1000 ml.

In the acute setting the vital capacity should be monitored at least q4 hrs.

Peak inspiratory force:

< 25 cm/H20 is typically associated with impending respiratory failure.

ABG & O2 sat:

insensitive measure in the acute setting

When To Intubate:

1) In the patient with acute or subacute progressive weakness, when the FVC < 15 ml/kg (about 1000 ml in the average size adult)

2) Poorly protected airway (oropharyngeal weakness)

patient cannot handle oral secretion (choking)

intermittent aspiration

upper airway obstruction

3) Significant hypoxemia

4) If the patient just "looks bad" or appears to be struggling to breath

thanks Cathi for finding this...

There are other links, but in practical use for us, not triage situations, we need to know where we are at our best and how much compromise we have right now.

When they are doing studies, they use a metronome at 2 second intervals for each number outloud. We are not likely to count too fast, especially if we are having trouble, so just take a deep breath and if you can't count to twenty before you have to take another that is 911 territory, 10 is impending respiratory failure. Since we tend to get in trouble fast, any falling single breath count is worrisome, especially as you get under thirty (that is breath counts, not age).

As Cathi reports, 50 is normal. At my best right now, I can't get there. when I can, maybe I can hike to Beauty Spot, at least I will have some reserve! b.

Thanks Cathi and B.-
This helps so much. I always took a big breath and counted a fast as I possible could (like a child showing how fast he could count) so as long as I got to 30, I wasn't worried. Now I see by counting more slowly, maybe I should worry a bit.
1 second intervals seem like a long space, tried that. 2 second intervals are forever!
I did double my count the day after Plex:).
Looked in the piano bench for the metronome but couldn't find it. That means I have to climb the stairs to look in son's room---that will have to happen after I use spoons for the grocery store. I'll be packing it in my suitcase for Colorado!
-sherry

Well, I didn't pay very close attention. That first article I posted cut off in a very important spot didn't it? I'm not at the top of my game to say the least. I will try that one again.

I'm still a little confused. So we should count one number every 2 seconds?

Last year I could count to 50. This week I'm having problems and I am hitting somewhere in the mid 20-30 range. My kids both had their wisdom teeth out yesterday and I have been playing nurse. Too much stress.

This too shall pass.

Here we go:

Most adults with normal ventilatory function are able to count to 50 in
a single breath.13 A single breath count of

What the heck?! For some reason it just won't post the end of that sentence, lol. Ok, fine, I'll type it in manually.

"A single breath count of

I give up. I'm going home.

is this similar to the pulmonary function test? I'm scheduled for one in a couple of weeks. I know i'm gonna fail big time.

After trying to post that silly sentence I'm almost afraid to try to answer you Terri.

In a word, no. The pulmonary function test should include a lot of things. I had one prior to my thymectomy. It was done by the respiratory therapist and included all the vital capacity and forced inspiratory max measurements along with an arterial blood gas among other measurements that I have forgotten in the last two years.

I had just completed 5 rounds of PLEX and did okay but had to be allowed to rest in order to pass the test at the end. Thankfully the respiratory therapist was understanding and did let me rest.

I have used the single breath test and even had several neruo exams when the doctor did the test. I personally like using my peak flow meter to keep track of how I am doing. Peak flow meters are normally used by asthmatics which I have, including COPD.

Peak flow meters give you a very similar results as the single breath test but much easier to do. I do three tests and use my best results to record. I would recommend mentioning this to your doctor. Your doctor should also be able to tell you at what measurement levels that you should either call their office or go to the ER.

Peak flow meters are very inexpensive. I have one in my house and keep one in my car. I believe you can find them at drug stores or online. My asthma doctor and Mayo Hospital give me one free.

http://www.lung.org/lung-disease/asthma/living-with-asthma/take-control-of-your-asthma/measuring-your-peak-flow-rate.html

Bruce

Cathi,
Thanks for posting this topic, because it is one I needed. I just tried it and only got to 19. Not good I know. I will try again tomorrow to see how I do.
Cathy

thank you!

I did this test for the first time yesterday. Yesterday I began struggling by the time I reached 32, yay me, I think.

Thank you for the peak flow meter suggestion Bruce. I have a volumetric spirometer but have not used it since my diagnosis. I wonder if it would help strengthen the lungs as it is intended to do or in fact diminish function.