The following content is sponsored by Masimo
By Greg Bogosian
EMS1 Contributor
We recently had the chance to sit down with Dr. Dan Davis, head of rescusitation for the University of California - San Diego hospital, to discuss his thoughts on the current and future status of the usage of capnography data in managing patient care. Dr. Davis is also the principal investigator for the San Diego Rescusitation Outcomes Consortium, a NIH-funded research effort. Through devices such as Masimo’s new EMMA capnograph, capnography is becoming ever more increasingly the standard of care when it comes to not only resuscitation efforts, but in many other scenarios as well. What follows is an edited version of that discussion.
Q: Dr. Davis, thanks for taking the time out to speak with EMS1.com today. I’d like to start by asking if you could give us a little bit of background on who you are, and what your role currently is in relation to EMS.
A: Well, I’m an ER physician at the Univeristy of California San Diego. We have two facilities, both of which are urban academic institutions, with a total of about 400 beds. One of those is a trauma center, which is also our receiving facility for STEMI and cardiac arrest patients. The inner-city facility mainly sees a more indigent population, whereas our La Jolla campus, which also has our cancer center, tends to see a more affluent population. I am the medical director for 5 air medical bases in southern California, and also the scientific advisor for Air Methods Corporation, which has hundreds of bases around the country. Additionally, I’m also the resuscitation director for the hospital. As to my research interests, I’m the principal investigator for resuscitation for San Diego for the Resuscitation Outcomes Consortium – the main NIH effort to conduct controlled trials. I’m also currently overseeing resuscitation trials with San Diego ground ems and aeromedical EMS.
Q: What are some of the challenges which have been seen in patient care that can be addressed through capnography, measured with capnograph devices such as the EMMA?
A: In terms of a discussion with a bias towards resuscitation during cardiac arrest and trauma, there were a number of issues identified very early on, which the use of capnography, including via the EMMA device, address.
In the cardiac arrest world, the maintenance of optimal blood flow for as long as possible is standard of care, and the best surrogate for an actual measurement of pulmonary blood flow is the patient’s EtCO2 in the arrest scenario. In a normally-perfusing patient, EtCO2 varies with changes in ventilation, but in a low-flow state, it indicates a change in perfusion – a unique parameter. Since cardiac arrest is the ultimate low-flow state, EtCO2 therefore becomes a good indicator of perfusion… it can guide CPR efforts in progress (by telling the provider they need to compress deeper, etc.), and then have them look for changes in the patient’s EtCO2 level to tell you that you’re producing better blood flow.
In terms of the need to define moment of reperfusion, or the return of spontaneous circulation (ROSC), it appears that during chest compressions, a rise in EtCO2 is the best indicator that we have of ROSC — and can be assessed during compressions. To be able to determine the return of a pulse without stopping compressions is hugely beneficial. In Ventura County, Oxnard EMS is now conducting their resuscitations based on EtCO2 levels – and they’re posting amazing results, it keeps them on the chest longer during their efforts.
EtCO2 can also give you some prognostic information, or it appears to – with gradually increasing EtCO2, that tells you that you have signs of improving circulation, and so your resuscitation efforts are not futile. In the opposite scenario, if you know that you have good compressions and are seeing a decreasing EtCO2, then it may be a sign that your efforts are facing increasing futility. We’ve even been able to associate a patient’s EtCO2 prior to a shock with success of shock… we’re still looking at the link, but there may be one in terms of being able to tell how well a shock will perform for an arrest patient.
On another leg, EMMA in a perfusing patient tells you about ventilation – my research and that of others is that it presents the biggest opportunity in all of pre-hospital care, since the task of ventilation is often done wrong, too fast or too deep, and often given to someone without a lot of training (the traditional thinking is that we don’t want to “waste” the capabilities of our ALS skill providers). EMMA puts the seat of those efforts right at the point of contact with patient – the way things are now, that ventilation provider might not be able to even see the monitor before when ventilating. By having it right at the patient, EMMA brings EtCO2 from the realm of only the ALS provider to the basic as well, via communication from ALS where they define parameters, or we might start teaching it to BLS… they might even come to know more about etc02 than the critical care attending in the hospital, in a way.
I’ve helped Masimo by advising them and creating training around a platform of EMMA usage, after having had the device in the hospital for quite some time. We’ve developed training and protocols around the device to ensure best utilization possible based upon that work.
In terms of field utilization, San Diego was one of the first to use EtCO2, back in around 2000, and demonstrate with it that routine ventilation was not very good, and better ventilation had a connection with better training and survival rates. When it came time to pick a defibrillator/montior for the UCSD hospitals, the director at the time and I pushed to include EtCO2 — believe it or not, our existing ones didn’t have it even though the EMS units did did. When we showed the hospital directors the prior EMS results, they were able to adopt EtCO2 in-hospital, and in turn that led to its increasing adoption by ground EMS and air-medical, since we continued to demonstrate good outcomes.
While the traditional usage of EtCO2 was in preventing esophageal intubation, we’ve found that we can save 10 to 100 times more patients per year using it to monitor perfusion parameters, including during arrests and in treating those who are in respiratory distress. In the latter, the usage for non-invasive EtCO2 monitoring, which is coming up on the EMMA platform, will really be the next hot-topic for EMS usage. If you understand how EtCO2 varies in different states, then it can be one of the most accurate indicators of patient status.
Q: So what kind of difference do you see the EMMA system making in terms of applied EMS care?
A: Since the EMMA is less expensive than other platforms, and now brings in waveform capnography, there’s no excuse not to have waveform EtCO2 as gold standard for tube placement. The EMMA uniquely makes that affordable for everyone, really, and task forces on head injury have put in place guidelines for EtCO2 levels as well... there are really a number of EMS scenarios in which it is important information to have.
EMMA also puts the data right there at the hands of the person ventilating, which I think will enhance our ability to achieve the recommended guidelines for reaching EtCO2 levels. It can be brought in anywhere, which becomes important because it’s available anytime you have a defibrillator… it really opens up a lot of opportunity for treatment using those numbers. You can literally wear it around your neck on a lanyard, if you wanted to, it weighs almost nothing.
EMMA also gets something else right, in terms of how the information is displayed to the provider, especially with the waveform placement, which shows you a recent history of their results right there at the provider’s fingertips – it’s really sophisticated physiologic data, and that makes the EMMA a game changer. There are so many parameters out there now, maybe 20 or so, to monitor during a code, that how you present that information to the provider can really influence how they use it to their patient’s best benefit.
