Correlating Zeo data with other monitoring...

published by Hypnagog on Wed, 05/18/2011 - 08:32
English

Previously I've compared Zeo data with pulse oximetry and saw a good correlation.   

The ZEO detects REM really well in a family member who has a known REM related hypoventilation issue, the oxygen desaturations, increase in heart rate and peaks of CO2 on the graph below correspond well to periods of REM detected by ZEO… (In the graph, the CO2 is high to begin with as I was titrating the BiPAP to bring it down, but once it was down, the oxygen desaturations were still there, although nowhere near as bad as before. In subsequent titrations they were eliminated, but this graph shows the REM correlation quite well).

http://blog.myzeo.com/forum/as.....ion/#p1170   After titrating BiPAP to virtually eliminate oxygen desaturations due to hypopneas, the transcutaneous CO2 trend shows another good correlation with Zeo's reporting of both REM and wake.  

At first I doubted the awakenings reported by Zeo, but they tie in really well with drops in CO2 in the second half of the night, which suggests more efficient breathing during the periods of wake – despite the fact that the awakenings were not remembered. (The first half should be discounted due to other variations in the ventilator settings and sleep position).

Forums:

Niko

Fri, 07/01/2011 - 04:33

How do you measure CO2? With the BiPAP?

I've had that Contec pulse oximeter for a while now, but haven't done any measuring during sleep yet.

Hypnagog

Fri, 07/01/2011 - 08:47

Niko said:

How do you measure CO2? With the BiPAP?

I've had that Contec pulse oximeter for a while now, but haven't done any measuring during sleep yet.

 

Hi Niko,

 

There are a couple of ways to measure CO2. I've tried the following:

 

EtCO2 using a capnograph with trending capabilities. This  is useful for spot-checking and trending for someone not on BiPAP as it uses small nasal cannulae to sample the expired CO2.

This is the model that I own: http://www.medical-supplies-an.....d=00002156

…or if the person is on ventilation (and so their nose can't be accessed easily)…

 

Transcutaneous CO2, which is a bit more involved as the unit required two gas canisters to calibrate it, plus fairly expensive membranes and other consumables. This type of monitor heats a probe up to 44.5 – 45 degrees C and this then is placed on the skin to monitor the CO2 in the bloodstream. On my monitor (a fairly old one), the probe site needs to be changed every 4 hours or so as it can cause superficial burns. I think that there are newer ones that use infra-red probes with a longer site time now.

This is the model that I own: http://www.charter-kontron.com.....lesAid.pdf

 

Both types of monitor can be picked up relatively cheaply on ebay every now and then.

Niko

Sun, 07/03/2011 - 11:48

Good info, thanks. The first one is definitely interesting. I wonder if we can expect a cheaper device to arrive on the market within the not too distant future.