I continue to use capnography regularly on non-intubated patients. I have had two interesting calls lately.
CPAP -- The ETCO2 worked quite well through the CPAP mask on a patient in pulmonary edema. He was very tired when we got there with an ETCO2 of 50 that quickly came down to the 30's once we had the ETCO2 on. Unfortunately, I didn't get very good quality strips in the heat of the call.
Seizure -- We had a patient with a high blood sugar exhibiting stroke like symptoms who had a sudden seizure that I wrote about in Richter Scale. I had the ETCO2 cannula on initially and got a reading of 35, which made me think he wasn't in DKA. There was no Kussmal breathing or fruity acetone to his breath. He kept pulling the cannuala off, so we switched it to a regular 02 cannula, thinking the CO2 mouth flap was bothering him, then he started seizing. One of my crew managed to get the ETCO2 back on and it showed a sudden steady rise throughout the seizure from the 30's up to 69. After we broke the seizure with Ativan, his ETCO2 came back down to the 30's. Again, unfortunately, I wasn't able to get very good strips, but I did get part of the trend summary that showed the episode of hypoventilation during the seizure
insert trend Summary
His CO2 at the hospital was 22, which didn't square with what we were getting. Their diagnosis was DKA, although a review of the lab values and further study and suggestions from others have convinced me what he really had was Hyperosmolar Hyperglycemic Nonketotic Coma (HHNK).