As the patient was being transferred from the house to the medic unit, one of the providers ran ahead to prepare the CPAP set-up. During the transfer to the medic unit, the patient appeared to become slightly less agitated - which could be a good thing but is often a very bad thing (i.e. was the patient's becoming so hypercarbic and hypoxic that her mental status was declining?). Once loaded in the medic unit the crew was faced with the decision of continuing current treatments versus being more aggressive and attempting to assist the patient with a BVM.
It was at this point that the crew noted a nice correlation between steadily declining ETCO2 levels, improving SpO2 levels, and a slowing of the patient's respiratory rate (again, slowing of the respiratory rate could have been a very good thing or a very bad thing). Based on a synthesis of this graphic and numerical data and clinical reassessment of the patient, the decision was made to continue nebs, oxygen, and hold off on CPAP or more aggressive measures as it appeared the patient was clinically improving. Her decline in agitation was actually a sign of clinical improvement. As the hypercarbia and hypoxemia both improved, the patient's tachypnea resolved and her respiratory effort became less labored.
The trend summary above was printed off the LP15 at the end of the call.
This case highlights a few very important items:
1. The value of a case review
There are so many things that can be reviewed in this one call: the severe respiratory distress protocol, the physiology and pharmacology of asthma, the appearance of a capnography tracing in obstructive pulmonary disease states, indications and contraindications for epinephrine and CPAP, the differential diagnosis of an elevated or depressed end-tidal CO2 level, and the list goes on. Case reviews should never focus on discipline or fault finding - they should focus on education, discussion of best practice, sharing ideas, personal improvement, and system improvement.
2. Examination of trends
We see this theme throughout our practice of prehospital care. One 12-lead EKG is usually insufficient while caring for and transporting a patient with chest pain. We often need to examine serial EKGs to detect dynamic changes. Similarly, trending this patient's ETCO2 levels and correlating this trend with the other vital data points of respiratory rate and SpO2 was highly reassuring to this crew that their therapies were indeed resulting in clinical improvement. The amount and clarity of the data that can be obtained from the LP15 'Trend Summary' function is awesome. Providers should get in the habit of looking at trend summaries with their DOs and correlating the hemodynamic and physiologic trends they observe with the patient's clinical status and the treatments rendered.
3. $6 well spent
A microstream end-tidal nasal cannula costs about 10-times that of a regular nasal cannula (6 dollars vs. 60 cents). Nasal capnography doesn't need to be placed on every patient's face that requires a nasal cannula. End-tidal CO2 levels (capnometry) and graphic capnography don't need to be monitored for every patient that requires oxygen. But in the subset of patients with moderate to severe respiratory distress - be it from an asthma or CHF exacerbation, opioid overdose, severe pneumonia, angioedema, or respiratory distress of unclear etiology - there is clearly a role for nasal capnography in monitoring a patient's response to therapy and to aid in guidance of treatment priorities.
4. Gratification
The trend summary here is an essence a report card with an A+ in patient care. Every once in a while its nice to know that what we do actually works and makes a difference. In this case, I am confident that the rapid actions of M 56 and EMS 5 prevented this patient from progressing to florid respiratory failure and the need for intubation.
Job well done and thank you for sharing this case with me.
If you have any good or bad experiences or interesting cases with nasal capnography - please share them with me so I can share them with all of our providers as we begin to insert this tool into our arsenal of mobile life saving technology.
