Unconsciously Cool: ROSC, Survival Soar With ARCTIC Program
Therapeutic hypothermia for cardiac arrest patients is increasingly coming to the field, but that doesn't mean all the questions surrounding it have been definitively resolved. Among the most prominent yet unanswered is, when should cooling optimally begin?
Typically, for EMS systems, the answer has been after return of spontaneous circulation. But under a novel program in Virginia, it's happening even earlier--with striking results.
Under the ARCTIC program--a joint effort of the Richmond Ambulance Authority and Virginia Commonwealth University Medical Center--patients are cooled as resuscitation attempts occur, and receive a broad complement of additional therapies and support both pre- and in hospital. The cumulative results: an almost twofold improvement in ROSC, from 25% in 2001 to 46% in 2008, and an increase in survival to discharge from 9.7% in 2003 to 17.9% by the end of 2008.
"Our approach was to do something a bit different," says Joseph Ornato, MD, chair of VCU's Department of Emergency Medicine and medical director of the Richmond Ambulance Authority. "The basis is animal data that pretty consistently suggests that the earlier you initiate cooling, particularly during the resuscitation process, the more likely you are to get a good neurologic outcome."
The most comprehensive program of its kind in the United States, ARCTIC (for Advanced Resuscitation Cooling Therapeutics and Intensive Care) has two goals: to restart the heart as quickly as possible, and to start cooling as early as possible and transport patients to a single specialized postresuscitation facility in hopes of preserving their brains.
Aspects of the program include:
Good quality CPR, with automated chest compressions and interposed ventilations, performed for 2-3 minutes before the rhythm is analyzed and not stopped during defibrillation;
Simplified airway management: Medics make one pass with an ET tube. If they can't see cords easily, or can't quickly confirm they're in the right place, they abort and use a King airway.
Drugs to restart the heart: a regimen of alternating vasopressin and epinephrine. If IV access isn't gained on the first pass, drugs are given IO. Cooling is achieved with 4°C saline.
The last two components have contributed to a reduction of almost six minutes in time to first drug.
The high-level care continues at VCU under the auspices of physicians and nurses trained and experienced in postresuscitation care. They continue cooling by placing a high-tech plastic coil into a large vein and maintaining a patient body temperature of 93ºF for at least 24 hours.
The ARCTIC data should be of interest to EMS systems looking at prehospital cooling, in particular cooling after ROSC. While that may represent the emerging norm, it's not really supported by the literature, Ornato says.
"There have really only been two published studies that looked at whether cooling initiated after return of spontaneous circulation improves survival, and both were negative," he notes. One, from Seattle, had a small number of cases but did not show any overall improvement. The other, from Australia, ended early when cooling after ROSC showed no benefit.
"The trend in EMS to initiate cooling early may ultimately be proven to have benefit, and I certainly hope that's the case," Ornato says. "But I think it's up for grabs as to whether cooling after ROSC will have any benefit."
Feedback May Help ID Tired Rescuers
The quality of our CPR isn't always what it could be. Anything that can help optimize it, then, seems likely to help us help patients more effectively.
A pair of poster presentations at the American Heart Association's 2009 Scientific Sessions last November support that proposition. In the first, "Early Markers of Rescuer's Fatigue," investigators found that using a real-time CPR feedback device--ZOLL's PocketCPR--could accurately measure compression depth and may help identify when rescuers are becoming tired. In the second, "Do We Need to Switch Rescuers Every Two Minutes?" they found that real-time feedback helped hospital providers compress for an average of four minutes, instead of the standard two, before the depth of their compressions degraded. If this translates to the field, it could mean fewer interruptions to switch providers during sustained CPR.
"What we found is that perceived fatigue is not necessarily a correlator with quality of CPR," says the studies' lead author, Charles Pozner, MD, director of the STRATUS Center for Medical Simulation at Brigham & Women's Hospital in Boston. "We used to think as you got tired, your CPR would get worse, but that didn't correlate at all. What correlates is just whether you're doing it well enough. And unless you have feedback that tells you that, somebody holding pulses or some other adjunct, then it can be a crapshoot."
"Early Markers" hypothesized that suboptimal CPR quality results from fatigue, and that identifying early signals of that fatigue may enable better CPR. Researchers used the PocketCPR device to measure the compression rate and depth of hospital nurses over six minutes on a manikin, and monitored their heart rate and pulse oximetry, along with their perceptions of fatigue.
They found that compression depth degraded after one minute unrelated to fatigue, but didn't change thereafter, and rescuers' heart rates peaked at around two minutes, then decreased before stabilizing at around four minutes. Their pulse oximetry bottomed out at around two minutes, then rose. Perceived fatigue increased significantly after the first two minutes, but quality compressions were provided for an average of four minutes.
Their conclusions: Peak heart rate and low SpO2 coincided with the onset of fatigue, but did not predict CPR performance, and the PocketCPR provided good measurement of compression quality, which "could be a more accurate marker" of fatigue.
The second project assessed the physiologic need to change rescuers every two minutes, which could contribute to decreases in cardiocerebral perfusion. Investigators had 25 hospital nurses perform six minutes of compressions on a simulator--the study group with PocketCPR, a control group without--and continuously monitored compression depth and rate. Participants again rated their perceived fatigue.
Among both groups, the proportion of participants providing adequate compression depth decreased over time, but at every minute was lower among the control group than the feedback group. Fatigue again increased after the first two minutes, but did not correlate to compression quality.
Without the feedback, the authors concluded, compression quality was inadequate at every time interval measured. Compressions were better with feedback, but depth declined and fatigue increased at around four minutes.
Coinciding with the new research, ZOLL rolled out its PocketCPR iPhone training app—a CPR training program and practice tool based on the company's Real CPR Help technology. Also available from the Apple iTunes App Store, it was downloaded more than 17,000 times in its first week.
Survey Finds CPR Skills Overestimated
Odds are, at CPR, you're not as good as you think you are. That's not a new finding; a number of studies in recent years have reported that healthcare professionals across the spectrum usually fall short of AHA recommendations for this basic lifesaving skill. But it may be new to you: Recent data from the CPR Improvement Working Group suggests providers vastly overestimate their own abilities when it comes to CPR delivery.
Specifically, while 75% of providers included in the group's recent survey of CPR performance among physicians, nurses and EMS providers in four countries thought they performed it "very well" or "extremely well," barely a quarter actually reported rate, depth and ratio compliant with 2005 AHA/ILCOR guidelines.
"Everybody wants to do a good job, but I think we're finding out that it's very hard to know if you are," says Vinay Nadkarni, MD, chair of critical care medicine at the Children's Hospital of Philadelphia, who is a member of the expert council advising the Working Group's efforts. "The guidelines are based on science, but they're hard to implement, and it's just hard to know when you're doing a good job."
That's where the CPR Improvement Working Group comes in. It was created in 2008 by representatives from major vendors Laerdal, Philips and ZOLL to improve the prevalence of good CPR and raise awareness of the technologies that can help achieve it. Those include CPR assistance and feedback technologies. Multiple studies over the last decade suggest that real-time feedback like audio prompts can help improve CPR quality. That's why members of the expert council--an international panel of top luminaries in the field of resuscitation science--are backing the group's efforts.
"It's the first time I know of where the manufacturers have really come together and said, 'There's a lot we need to know about how things are being done and what's needed,'" says Nadkarni, associate director of the Center for Resuscitation Science at the University of Pennsylvania School of Medicine. "Rather than each individual company trying to promote their own stuff, they pooled their resources and created this resource for everybody. Now individual manufacturers can take that information and figure out how to build their own devices that do what needs to be done."
What needs to be done? Overall, several things. First would be reconsidering how guidelines are taught, trained and practiced, because they don't appear to be getting through: Among U.S. rescuers, only 25% responding to the survey achieved rate, depth and ratio all compliant with guidelines. The ratio was the element most likely to be incorrect. Second is feedback or debriefing: Only 27% of American providers said they always or frequently got it. However, Americans were most likely to get instantaneous feedback, with a rate of 18%.
But, importantly, debriefing and feedback should be part of a comprehensive quality management/improvement program that measures and evaluates all aspects of resuscitation and strives to better them. "That means refreshers before resuscitation; monitoring with feedback during resuscitation; and immediate feedback on how we did after resuscitation," says Nadkarni.