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Capnography Uses and Discussion with Peter Canning and Tom Bouthilett
Transcript of main discussion (Part 1)
Jamie: I’m going start off—Peter, I know you’ve been talking about capnography and linking to some things you put together on capnography for a long time in your blog. This is something that right now is really the standard for confirmation of ET tube placement in the field whether they are using a colorimetric device which is a very crude form of measurement of carbon dioxide exhalation or waveform capnography. It is really the standard of care and can tell us a lot of things. How have you seen that developed over the years as you’ve been watching this come into play?
Peter: Well, when I first started as a paramedic back since 1993, we didn’t even always have the colorimetric device. When you try to put a tube in, there were all sorts of different ways to try to confirm it and you were always rechecking to see if your tube was good. It may have put a very stressful during the course of a transport. Eventually we got the waveform capnography. Since we have started doing that it’s been great as far as when you’re doing a cardiac arrest. You know your tube is good and you just look over at the monitors. As long as you see waveform, you know your tube is still in there. One of the other things that I found that it’s been very helpful for is now when I intubate what I do is actually put the capnography filter on the tube before I go in and attach it to the monitor. I go in. I pass the tube. If they’re doing CPR on a patient, I can turn and look at the monitor and I will see a waveform that coincides with the CPR, let’s me know that I’m good. If it’s a breathing patient, I can turn and look and see a waveform there. I know I’m in before I’ve even had the chance to check the lung sounds. I still do check the lung sounds to make certain that I’m not too far in the main stem. I find that’s been extremely helpful for intubations.
Tom: That is an awesome tip.
Jamie: I was just saying I’m like writing that one down. We always talk about using it for post-intubation confirmation but to use it as a device to assist during the intubation, wow, that’s just amazing.
Peter: Yes, it’s really good. What’s interesting with all the talk that they had about the cardio-cerebral resuscitation where you’re using— just putting the non-rebreather on, this actually provide proof that the CPR is ventilating somebody. The first time I went in that way, I looked. The respiratory rate was 100 and I saw these little lines and I said, “What is that?” It actually was the CPR. With each CPR compression the end-tidal was coming out. The patient was actually being passively ventilated with the CPR.
Jamie: Peter, this is why we should have talked to you a lot sooner. I’m going to have to make sure I put you on a calendar or something where I can make sure we bring you back in because that is an amazing tip. It makes sense. I can’t believe I didn’t think of it myself. It’s so simple a thing to do and yet it’s something that we haven’t really thought of. Is that something you work on spreading around your system as a clinical coordinator?
Peter: Right. Yes. Absolutely. Another thing, we don’t do rapid sequence intubation. There are some cases where you might nasally intubate somebody and put the capnography filter on when you’re sliding the tube down and just watch. You can see whether you’re in or not based on whether you’re getting a waveform as you’re sliding the tube down.
Tom: That makes a lot more sense to me than using the whistle.
Peter: Right. Absolutely.
Tom: Because you’re actually getting that feedback of actual CO2 coming out of the tube. That’s fascinating. I think any discussion about pre-hospital intubation and waveform capnography really wouldn’t be complete without mentioning the study that took place in Florida, the Katz and Falk study that showed an astonishing rate of misplaced tracheal tubes. I think it was 25%, Peter, something like [unintelligible]?
Peter: It was pretty horrifying, the rate.
Tom: Another thing that I found even perhaps more interesting is, in various discussions on some of the National Listserves, one of the QI officers for Orange County Fire Rescue which I believe encompasses Orlando, they were quite embarrassed by the study and so they did system-wide remediation of airway and they introduced waveform capnography. Then there was a follow-up study, I don’t know if it was three years or five years later, but what was so interesting about it is that EMS systems that delivered patients to this hospital where the physicians were doing direct laryngoscopy to confirm tube placement, those systems that had not switched waveform capnography repeated the exact same results of 25% of their tubes being misplaced. I think 2/3 of those were in the esophagus. But Orange County Fire Rescue had completely eliminated the problem of unrecognized esophageal intubation. I was so impressed by that. I think, in fact, that maybe what led to the mandate in Florida that all ALS units have to be equipped with waveform capnography.
Peter: Yes. I’m just thinking today’s times when you have this. It should be absolutely required across the board. It was interesting our state-wide medical advisory committee was looking at this equipment for ambulances that has just been updated by a national group. It actually has an American College of Surgeons, American College of Emergency Physicians, National Association of EMS Physicians, they came out with this list of what should be on all the ambulances. I was looking through it I was shocked to find that for capnography, the only thing that they did not require—okay, here it is, it says, “End-tidal CO2 detection capnography colorimetric or quantitative capnometry.” It just seems to me that not requiring the waveform capnography is terrible. The colorimetric just does not work nearly as well. I think that if you have the waveform capnography, you’re not going to have misplaced tubes.
Tom: Right. Well, I think the 2010 AHA guidelines just took care of that problem.
Peter: Right. Yes, they said “Level 1 recommendation.”
Jamie: Yes. We talked about this time when we talked with Dr. Kleinman about the new ECC update. There are still organizations in EMS out there that are still implementing 12-leads. They’re still making that the standard of care. There are places that haven’t reached the 2005 guidelines standards. Do we think that this is something that needs to be mandated? Because right now it’s a recommendation for standard of care but there’s a cost associated with it. For smaller rural organizations, for instance, is it worth spending the money? I think it is because it’s such as powerful tool. Do you see this accelerating acceptance in uptake of these devices?
Tom: I certainly do. Yes, I, 100%, believe that it should be mandated along with 12-lead ECG monitors because left to their own devices, I think some EMS systems will be dragged only kicking and screaming into the 21st century. Especially with the ever-growing body of evidence that EMS in many instances causes harm with our airway management and with unrecognized esophageal intubation. Now, you can argue that our failure to triage a STEMI patient to the correct hospital increases their mortality and hence it harms patients. But that’s an act of omission which I think is a little differently than performing a procedure that harms a patient. That’s critically important that that be addressed. Clearly, this issue went on for a really long time before EMS nationally finally started to wake up and realized that we have a problem.
Jamie: Peter, in your area, you’re an educator, you’re a clinical coordinator in your region, is this the standard of care where you are – do you see agencies around you that are still not bought in to using these types of devices?
Peter: For pre-hospital in our region, everybody uses the waveform capnography and the 12-leads. It’s been a little slow getting everybody to it but they pretty come to it and were mandating it now. The thing that I find, we’ve mentioned before we started recording, is that we’re bringing in people intubated into the hospitals waveform capnography, were showing up in the ER. The ER doctors are removing them from the waveform capnography and fuddling around trying to find their colorimetric device to put on to confirm it. It’s really interesting that this is again another one of the areas where EMS seems to be leading the pack and ER is somewhat is behind. Years ago, anesthesiology used to have the highest malpractice rates of anyone. When they went to capnography, their rates just dropped completely because they no longer had the problems with the misplaced ET tubes. I think it should be mandatory in all ERs and certainly in the field. If you’re going to be dropping ET tubes, you have to have waveform capnography.
Tom: And to the anesthesiology’s credit, they were early adopters of techniques from aviation like CIRS [risk] management. They were the ones that came in and said, “You know what, an unrecognized esophageal intubation is never acceptable and our rate should be zero.” They went forward with that mentality, which is a mentality that any healthcare professional who intubates should believe that to the core of their being. I’m afraid that maybe in EMS we thought that the occasional gut tube was either the cost of doing business or – frankly, with the occasions in my career have been aware where a gut has been placed, I am only aware of one time that the paramedic just said – he threw up their hands and said, “You know what, I did it. I missed it. I was wrong.” All the rest had these magical migrations. I’m not saying that they never occur but I think if the tube falls out of the trachea, it doesn’t then reinsert itself into the esophagus with an inflated cuff.
Peter: Right. It always seems “misplaced on transfer” as the term that people rely on. What I like about the continuous waveform capnography is that should your tube become misplaced during transport or during transfer, you can see it right away. Where without the waveform capnography, it’s going to be a little while before you could recognize it as it becomes misplaced. The ability to have [unintelligible] right way is huge.
Tom: I agree. In fact, I don’t remember—it might have been in JEMS, this is going back a few years—but there was an article, I remember the name of the article, I just don’t remember what magazine it was in. It was called “Whose tube is it anyway?” I think if memory serves, it might have been San Diego where this took place. They mandate there that after they capture the airway with a tracheal tube then they print out this capnogram. Then they do the same thing as they pull into the hospital. They brought the patient and apparently the tube became dislodged somewhere between the gurney and the bed. They had unfortunately had one of these maintenance physicians there that had the temper tantrums and yanked it out and accused them of placing the tube in the esophagus and stormed off and wouldn’t really converse with the paramedics. Well, they had I think a very outstanding QI process. That is, when and if that sort of thing happens, day or night, 24/7, a QI officer takes the unit out of service and comes immediately to the hospital to investigate.
This isn’t something that hangs over the paramedic’s head for three weeks and they’re worried if they’re going to get disciplined and now the people that were involved, time has sort of affected their memory. They were taken out of service immediately. The QI officer came to the hospital, the paramedic said, “Here’s the capnography strip as we pulled into the hospital.” The QI officer went over to the emergency physician and didn’t say, “Read it and weep,” but said, “Hey, look, with respect sir, you’re mistaken. Here’s the capnogram as they pulled in the hospital.” The guy said, “Oh, okay. My bad.”
Peter: We had a similar case here where the trauma surgeon pulled the tube, berated the paramedic, called his medical control, and wanted his license pulled. The medic was able to produce not just the strip when he intubated and when he transferred but a continuous code, the trans-summary showing that he was in clearly the whole time and then he got an apology. We really try to encourage our medics to make that final print before they transfer over.
Tom: In addition to being outstanding patient care, there is also a risk management and reputation component.
Jamie: Actually, I think, for the hospital setting, the fact that it has become the standard of care—well, actually, advanced faster. We’ve seen that similar pronouncement in the EMS side I think. Hospitals will look at that and say, “We need to have some kind of waveform capnography available in the ER for confirmation of tube placement.” I suspect that we’re going to see the uptake and perhaps understanding of the use abilities of this type of tool to not only confirm placement but also that return of circulation. Tom, you’ve seen it. I’m sure, Peter, you’ve seen it. I’ve seen it. It’s amazing to watch that waveform suddenly change in the midst of CPR where nothing else has changed on the outside other than your standard interventions and suddenly you have a clear return of circulation because of the change in the waveform.
Peter: Right. It’s a wonderful thing to see when you get that. I’ve recorded that a number of times. Right along with using that capnography to gauge the return of spontaneous circulation, you can also use it when you lose circulation. What may happen, you intubate the patient. Their end-tidal might be 15 or 20. You’re doing CPR. You’re giving the drugs and suddenly the number goes up to 45, 50. You stop. You’ve got pulses. You got a blood pressure. You congratulate each other. You put the patient on the stretcher and then as you start to leave the house you look over and where it was 50, now it’s back down to 15. You’ve lost pulses. You need to start doing CPR again. As opposed to previously every several minutes you might stop to check to see how the blood pressure was. Here it was going to show right away that you’re losing the pulses.
Tom: That’s an excellent point. I think it also needs to be said placing a tracheal tube in the esophagus is not the only way that we can harm the patient with intubation. If we bag them too frequently once the airway is captured, that’s another way. Left to our own devices, I think this has been studied numerous times that it’s shown all types of healthcare providers, not just EMTs or paramedics, squeeze the bag way too often.
Peter: Yes. Absolutely. I love having the monitor now. Whoever is doing the bagging, I point to the monitor and I say, “Okay, there’s your respiratory rate. You want to have it at ten or whatever depending on the situation.” I can coach him how much to squeeze it. I can look over to see if they are hypoventilating or hyperventilating them.
Tom: I also love to see the change in the histogram when they swap out a tired guy that’s been doing chest compressions.
Jamie: Isn’t that amazing> It really confirms that as much as we’d like to think we’re big he-men, firefighter types, that we can do compressions all day long, it really confirms all of the studies that have said two minutes is about the limit for an individual, they need a break.
Peter: Right. I’ve had – in the town I work in, the police department is the first responders and a number of police officers are body builders. They show up and start doing CPR and I point to the monitor and I say, “Okay, you have number, it’s like 15 now. Do as good a CPR as you can and try to raise that number up.” These guys do such powerful strong CPR that they can really get that number up quite a bit. There are some cases – I agree with switching out every two minutes if you have comparable compressors but you may be on-scene where you have a slight partner and you have one of these body-builders. The slight partner just can’t do good enough CPR and the body-builder can really do excellent CPR. But then again, you do have the situations where we use to have is the police sergeant who would be sweating and be doing CPR for 20 minutes and says, “No, I’m fine. I’m fine.” But you’re not fine because the quality of the CPR goes down. Now with the capnography, we can measure that as it happens. When you first intubate somebody, the number that you get can be very predictive of two things. One, it can be predictive of the chances of resuscitating the person. It can also be instructive as to how somebody collapses. If I’m standing with my twin brother and I’m chewing a sandwich. Suddenly, I choked on that sandwich and dropped down. My twin brother suddenly suffers a Vfib arrest and the paramedics arrive five minutes later. Our end-tidals are going to be different. The person who had the Vfib, the end-tidal is going to be lower because the heart has not been pumping. With somebody who’s had a respiratory arrest, what’s happening is the heart is going to continue to pump for a while but the person is not able to be ventilated. That person, when they get intubated, they’re going to have a very high end-tidal. If you show up, you might be able to think, “Okay, this is a respiratory arrest as opposed to a cardiac cause,” as far as the predictive nature, basically, the higher your initial reading, the greater the likelihood that the person will come back. That applies to like the average people. The one confounder is if you have a patient that’s normally very hypercapneic and then you may get that very high numbers that don’t apply.
Jamie: Tom, can you explain a little bit about why that higher level of CO2 being exhaled is an indicator of better resuscitation rate?
Tom: Well, I think it may. I don’t know for sure, Jamie. But I think it may have something to do with organ perfusion. If your lungs are well-perfused at the capillary level, then you’re going to have more gas exchange taking place. It seems to me the longer the arrest goes on as the organ start to shut down, you have less pulmonary circulation and so you have less CO2 being produced.
Jamie: Peter, would you agree?
Peter: Yes. I would agree with that.
Tom: Just one final thought to what Peter just said, termination out-of-hospital cardiac arrest, if you’ve worked the patient for 20 minutes and you’ve had no return of spontaneous circulation, and your CO2 level is down at 10 or below, then my understanding is that it’s highly correlated to a patient whose prognosis is essentially zero.
Peter: Right. Yes. That’s been borne out in studies.
Jamie: Hopefully, it will continue to move in the direction of confirmation of completing the code and calling the arrest in the field. I know that the American Heart Association, the most recent ECC guidelines, spelled out definitively a need to not be needlessly transporting cardiac arrest patients on an emergency basis just for safety of the providers and the public at-large if there was no clear need to bring that patient in to resuscitate them. Hopefully using these types of tools and the studies that are confirming that these are definitive, we can continue to be able to provide good care in the field but also protect our professionals and the people on the highway. We don’t need another ambulance running down the road at high speed if the patient is non-viable.
Tom: That’s for sure.
Peter: Right. I agree