Senior Forum Member
Joined: Nov 2004
Wed Jan 17, 2007 11:11 PM
Originally posted by: BENDAVIS
The patient's in arrest? I wouldn't worry about it. ETCO2 isn't a good tool for tube confirmation in arrested pt.s. Even with good CPR and no exsanguination, pulmonary perfusion pressures are significantly significantly reduced. You can be extremely acidotic, and if there's no (or minimal) perfusion to the pulmonary vasculature, your CO2 may be negative. A far superior device for this situation is the esophageal detector device (EDD).
[Don't get me wrong, I like using ETCO2 as a prognostic tool; if I'm getting good waveform and good CO2, I'm thinking about possible ROSC, and I've read the study on survival approaching zero with ETCO2 of < 10 mmHg @ 20 mins. It's just not a good tool for initial confirmation in arrested pt.s].
If this is a perfusing pt. with an ETCO2 of zero, it's time to worry. Then you've got to start looking at other options. Are there lung sounds, epigastric sounds, =chest rise, tube condensation. Can the tube be visualised passing through the cords on direct laryngoscopy? is there a tube obstruction? (i.e. can you pass a suction catheter down it), is there a pneumothorax, mucus plug?, etc. Secondary confirmation is just part of the overall clinical picture, and equipment failure is an ever-present part of EMS.
I respect everyone's awareness of tube displacement -- I, also, don't, want to be that guy who brings in the unrecognised esophageal. But there's far more to tube confirmation than ETCO2 or CXR -- direct visualisation of the tube passing the cords and stopping at the marker remains an excellent primary tool.
I'm going to have to disagree on this one Ben. Except for some very rare circumstances you should have a waveform, even if a very small one, in your arrested patient. If you dont either you need to start some CPR or think about how long tha patient has really been down. Unless your talking about colormetric then I will have to disagree that it is not an effective confirmation.
A 2005 study comparing field intubations that used continuous capnography to confirm intubations versus non-use showed zero unrecognized misplaced intubations in the monitoring group versus 23% misplaced tubes in the unmonitored group. -Silverstir, Annals of Emergency Medicine, May 2005
“When exhaled CO2 is detected (positive reading for CO2) in cardiac arrest, it is usually a reliable indicator of tube position in the trachea.” - The American Heart Association 2005 CPR and ECG Guidelines
I agree nothing is ever full proof, but I personally have found etCO2 waveform much better than an EDD for confirmation. I also know of another study that found similar results of esophegeal intubation, I just cant find it off hand right now. Everybody wants to practice evidence based medicine, until the evidence disagrees with you.