Capnography for Paramedics: April 2007 Log

Faking a Seizure

I had a patient faking a seizure, who I wrote about in Wine Coolers. Bottom line, while he was thrashing about but his capnography showed regular respirations with an ETCO2 of 35. You can't be having a gran mal seizure and be breathing.

CHF-cardiac asthma

Did a call today for a man with dsypnea, wheezing and increasing edema over three weeks. His wife said the doctor increased his Lasix yesterday from 20 to 40 and gave him an inhaler. She said the inhaler wasn't working. The man had pitting edema up to his thighs, and could not breathe when he lay flat. I could hear some crackles. When we moved him from his wheelchair to the stretcher, the wheezing suddenly became very audible. I put him on the capnography.

Nice upright expiration wave form. I withheld a treatment and went with some nitro, which made him feel much better.

CPAP's Affect on Capnography

We just got CPAP so I ran a little experiment on myself, hooking myself up to capnography and then progressive forces of CPAP. For the most part CPAP had little affect on the reading, although the first time I did it, my ETCO2 dropped markedly because I wasn't holding a tight seal. Once I held a seal, the most I can say is CPAP made my ETCO2 go down slightly. When I factored in a slightly increased respiratory rate, I'd call it a wash.

Capnographs

I recieved the following from Eric at EMS Haiku, who is very knowledgeable in capnography.

Capnograph 1 is from an 11-month old child we were transporting to an out-of-town facility.

She had been diagnosed with bi-basilar pneumonia. As you can see, the wave forms are rounded on both sides. We were using a nasal cannula sampler.
Capnograph 2 is from the same child, after the prongs were readjusted to fit correctly.

You can see that the wave forms are much more normal, and that the EtCO2 value is 27, down from 34. I remember you talking about positioning of the sampler unit and degredation of the wave forms/values. I think this is a graphic example.

Capnograph 3 is from an adult.

We were called to a rural clinic to transport her to the local hospital. She had been diagnosed with bronchial pneumonia 10 days ago & given Cipro. She had worsening respiratory distress this morning and came into the clinic. Staff there had given her 2 Xopenex treatments w/o change. We arrived & put her on the EtCO2 and got this result. My partner (his first day practicing as a Paramedic) maintained the breathing treatment, and actually started a 3rd treatment (with Atrovent) during transport. There was absolutely no change in her presentation, clinical status, or EtCO2 by the time we got her to the hospital. We had talked about the fact that her EtCO2 was normal, and I did ask him later why he did the 3rd treatment. He basically said that it might have helped and he pretty much didn't know what else to do.
Anyway, some interesting stuff (at least to me, and possibly to you) to share. What it means to me is that 1) make sure the sampling prongs are inserted appropriately, and to trouble-shoot unusual wave forms, and 2) that EtCO2 really does indicate as well as rule out the need for breathing treatments.

Thanks, Eric.

Seizure

I had a seizure patient today who was just coming out of his postictal phase. I was taping down the IV when he started seizing again. While I went for the lock box to get the ativan, I tossed a capnofilter to my partner and asked him to put it on. It took about thirty seconds for him to do it, just as the seizure was subsiding. I could see right away the patient was breathing. His ETCO2 was 50. It soon went down to 33 as he recovered. I am going to try to put a capnofilter on all seizure patients now as soon as I get them so I will be able to capture a full seizureif they have another one.

Later today bored I tried to replicate the strips below. I was able to replicate the slow inspiration, but could not make myself breath in any way to create the pneumothorax strip. I'll be curious if I get another pneumo patient if the strip will look anything like that one.

Two Interesting Strips

80-year-old man from nursing home with a fever of 103. Aphasic from old CVA, history of aspiration pneumonia, vomiting this morning, the staff thinks he has aspirated. I hear rhonchi throughout. RR is 40. Sat 94% on 02. HR is 100. I'm thinking aspiration pneumonia. The wave form is a little odd. With that notch in the middle of the expiratory plateau. Same wave form throughout trip.

Turns out, he has a pneumonthorax.

2.

This is a man with a broken arm who got 12 mg of MS. While he is maintaining an ETCO2 of 34 with a RR of 12, and is alert, but subdued. His pain has gone from a 10 to hardly noticable. He has a long slow inspiration.

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