Monitoring sedated patients without airway devices in place is often based on the time machine, the pulse oximeter, showing you what the patient’s oxygen saturation in the lungs were 30 seconds ago. Also, it doesn’t tell you if the patient has stopped breathing before you’ve already started rushing down the Oxyhemo-Coaster. Nasal prongs with a sample tube for CO2 can make all the difference.
We use the set in the picture below. It works similar to a side stream sampler and just plugs into a EtCO2 monitor. It works wonderfully, both on adults and kids. We also use it for one of the more scary procedures I’ve seen before coming to my current hospital and getting accustomed to it: Deeply sedating kids for spontaneous ventilation during MRI. In my former hospital we used to intubate kids for that. And so we needed MRI proof ventilators and infusion pumps and it was a big set-up, including the risks of intubation. But in my current hospital, the kids gets sedated with a high bolus dose of Thiopental, are mask ventilated for a few moments, after which spontaneous ventilation resumes and the scan starts.
During the scan, they’re monitored with EKG, pulse oximetry and nasal prong EtCO2. The nasal prongs actually sample CO2 from the mouth, but gives oxygen supplement through the nose as a normal set of nasal prongs. The capnography lets you monitor:
1) Respiration rate
2) Airway patency from the CO2 waveform
3) End tidal CO2 levels.
So, with this monitoring, the procedure makes perfect sense. We mainly use it for our MRI kids, but I would like to see it extended to any sort of spontaneously breathing procedural sedation.