DIY NRB Capnography Device for the Paramedic

In today's times, money is tight. Agencies cannot always afford to buy the nasal cannula EtCO2 device. Because of this, it is important that you have an understanding on how make your own EtCO2 device.

For this particular post, I am going to focus on the use of a non-rebreather with the EtCO2 device.

Capnography is a critical tool in patient treatments. Capnography can used in various situations, to help guide the diagnosis, how well the treatments are working, and overall how the patient is doing. For example, if you run on a difficulty in breathing patient, Capnography can be used to determine the patients real-time respiratory rate, their exhaled CO2 level (EtCO2), and even provides a waveform, to help determine the respiratory status of the patient.

This particular post is not going to go into detail on the entire usage of capnography, indications, etc., but this post is geared to show you how to make your own capnography device using four simple tools. If you would like to read more about EtCO2, visit paramedicstudentcentral.webs.com for the PDF PowerPoint presentation.

To start, you will need a non-rebreather (NRB), EtCO2 capnography device (the device used for ET Tubes), oxygen, and a capnography capable monitor.

I have personally tried a few different ways, on how to set up the capnography device for the best reading and waveform outcome. The method that I prefer to use is where you stick the capnography tube into the NRB.

Place the patient on a NRB, with high-flow oxygen. Never withhold oxygen, in order to do this. To do this, take the capnography device, and cut off the end where the attachment is to attach it to the ET Tube. Now, you will have the attachment that goes into the monitor, and just a long tube. Attach the attachment device to the monitor. Now, take the other end of the capnography tube and slide it into one of the small holes on the NRB (where the rubber valve is). It should come out to looking like this:

(click photo to enlarge)

You want to try to get the capnography tube to be as close to the pt's lips are possible. Personally, I set it up so that the end of the capnography tube sits just inside the lip. After you have your placement, if needed, you can place a piece of tape on the tube and tape it to the NRB.

The capnometry and respiratory rate may no be as accurate as it would be with a real commercial device, but the waveform itself will be easily identifiable. Here is an example waveform of the DIY NRB Capnography with oxygen at 15-lpm:

(click photo to enlarge it)

A second way that you can do this, is by following the same steps and equipment as above, but instead of cutting off the EtCO2 ET Tube attachment, you cut a hole into the NRB (preferably cut out one of the valves), and slip the capnography device into the NRB. It should look like this:

(click picture to enlarge it)

The main issue that I have with this method, besides the capnometry number may not be accurate, is that the waveform doesn't seem to be as clear as compared to the first method.

Notice how the waveform is choppy, when you compare it to the first method:

(click picture to enlarge it)

I am not sure if the waveform is so choppy because of the oxygen back flowing into the capnography tubing, or if I just am not placing the device deep enough into the NRB. I will be running more trial runs (on my less critical patients, since I like the first method the most), to see if I can come up with a good way to run the second method.

I have tried different methods to DIY NRB capnography, but to me, the first method seems to work the best. As always, follow your companies and medical control authorities protocols.

NEVER WITHHOLD OXYGEN FROM A PATIENT WHO NEEDS OXYGEN,  JUST TO DO THIS DIY SETUP.

*NOTE: My posts are usually always sourced. However, this entire post is a "my opinion" post. Their are videos on youtube to show you how to do this DIY, but I have yet to see actually research performed. Again, this post is my opinion, based on my experience. ALWAYS follow your company policies and procedures, as well as your medical control authorities protocols.