Compare our outputs from Pulse Oximeters

[tylerz]

Not sure how many people out there have access to pulse oximeters and also have the ability to acquire the complete log of the oximeter during their static. However, if there are some people out there maybe we can share output results.

Here is one from the other night where I did a slow breath-up for the first time in half a year. I over venitlated due to a pee-break part way through. So actually I did 7:30 breath-up then took my break and came back to do 4:30 breath-up.

http://quietdeep.com/misc/2004-04-16-static.txt

Hope to see other results.

Cheers,

Tyler

[glennv]

Tyler,

Great idea.
Maybe it's easier to read if you drop it into Excell and create a simple graph of it. Makes it easier to compare etc.
Here is my 7 min static
http://cgi.tachyon-consulting.nl/fre...tic_O2_BPM.php

prep:
about 5 minutes slow breathing followed by a ~1 min deep faster breathing to hyperventilation. Then 1 minute very slow breathing to bring back down the HR , 2 big final breaths + little packing and go.


Also check out Sebastian Naslund's recent 7'04'' at:
http://www.webvideo.nu/freediving/features/7min.html
and the great and extensive "samba" experiments with a pulseoxymeter : http://www.webvideo.nu/freediving/features/samba.html

[tylerz]

Wonderful Glen! Here is my data in graph form:

http://quietdeep.com/images/misc/2004-04-16-static.gif

Cheers,

Tyler

[Ulf]

Could you tell when the contractions started on these statics?
Another thing that would be interesting to see is a max static without breathup and compare that to the other. My gues is that the O2 will start to drop erlier...

Ulf

[ADR]

I've been meaning to post my data since I stuffed up an bought the exact one Eric told me to avoid! ....speaking of which, does anyone know how to hook a laptop up to the 25pin serial plug on the back of a Ohmeda 3700 pulse oximeter. I've been thinking of trying to write a VB app and find a relevant comms port control object but it's been about 5 years since I cut any code so was hoping someone might have already solved this and would be willing to share some code???

Andy

[efattah]

To connect your pulse oximeter to your computer, just get the appropriate serial cable (DB9 to DB9 or DB25 to DB9), plug it into your PC, and then run an application like hyperterminal, and set the serial port options to what your oximeter uses (i.e. 9600 baud, 1 stop bit, etc..)

No programming required. Tyler is also using the 3700 Ohmeda (he's borrowing mine!)


Eric Fattah
BC, Canada

[tylerz]

Ulf,

My contractions began at 4:27. I will eventually get the output of a no breath-up static and put it up, but I as well would expect the O2 to be lower at the beginning, but towards the end I expect the O2 to be relatively the same. In general the more hyperventilating one does, I think the sharper the curve drop-off of O2 saturation. That is the O2 saturation is dropping faster at the end of the static, even though it was higher for longer at the beginning when compared to a no breath-up static.


Regarding oximeter output:

I couldn't find any online documentation on the Ohmeda 3700, but through trial an error, I found it works with 1200 baud, 8 bits, parity none, 1 stop bit, flow control hardware. Find a serial cable with one end being a female 25-pin connector and the other end begin the opposite of whatever connector is on your computer, generally a 9-ping male connector would be required on the other end.

Cheers,

Tyler

[ADR]

Thanks Eric and Tyler I can't wait to get home and try it.

I feel better about my purchase already...if Eric's old Ohmeda 3700 is good enough for Tyler then it is easily good enough for my novice needs :-)

Andy

[tylerz]

Well, "beggers can't be choosers", so I make the most of what I can. Even though it may be inaccurate to some degree, the most beneficial aspects may be the comparisons over successive outputs and the overall trend of the output curve, as opposed to the accuracy of any given instantaneous sample. It definately gives accurate heart-rate readings for me, unless I am having heavy contractions as you can see at the end of my output.

It also is brilliant at noticing metabolic changes in my body which is useful to see what helps or hinders your body's consumption of oxygen. The other day I took Niacin (B3) and later on my resting O2 saturation had plummeted as I expected.

[DeepThought]

Why should B3 have such a result?
I take vitamin supplemnts (centrum) after my daily morning statics, so I don't exepct it to interfere with the statics the day after.
In anyway I didn't expect general supplements to make any effect at all. What quantity of B3 did you take? how long before the static?

[tylerz]

I have been taking 500mg tablets, not multi-vitamins.
See the article here:
http://www.oralchelation.com/technical/niacin.htm

To summarize these cause the small capillaries to expand, thereby allowing more blood flow to the whole of the body near the skin surface. One is subjected to a "flush", where some (me at this dose) can see your whole body go red and you get itchy to some degree from released histamine. Nourishment of cells at these locations is increased and more oxygen I expect would be consumed. The effect probably only occurs with a dosage over 100mg, but depends on the person.

[Ulf]

Thanks Tyler
it seems that the contractions start about the same time as the O2 starts to drop and the pulse start to drop at the same time...
Another interesting thing is that the O2 drop seems to accelerate. I thought the body would try to save O2 as it gets lower...shouldn't the lowered puls save O2...?

Ulf

[efattah]

During a static your pO2 decreases somewhat constantly, but it is the SaO2 which 'appears' to decrease faster, because of the sigmoidal shape of the SaO2-pO2 curve (Hb-O2 affinity curve).

My experiments lead me to believe that the lowest rate of O2 consumption occurs while you resist contractions, and during the first, weak contractions. When contractions go into body-buckling mode, the muscular effort increases O2 consumption somewhat (at least in me).


Eric Fattah
BC, Canada

[DeepThought]

10x for the link and info Tyler. I'll check it out.

SaO2 is in your blood and PO2 is in your lungs?
I'm really in the dark as to the difference between the 2.
I always assumed that Sao2 is amount of O2 saturated in your blood - linked to hemoglobin. Was I wrong?
What's PO2?

(I'll start learning chemistry only in October/November I think, sorry.)

[tylerz]

Correct about the SaO2, but the PO2 is the partial pressure of oxygen gas and this pressure exists wherever the oxygen exists, meaning in the blood, the tissues, and as well the lungs.

More discussions on DB regarding these are at:

http://forums.deeperblue.net/showthr...threadid=38817