The Municipal Emergency Medical Services of Vienna implemented a standardized post-resuscitation feedback system and performed a two-year evaluation of its impact on performance and patient outcomes. They recently published their results in “Resuscitation.”
Within 48 hours of every out-of-hospital cardiac arrest (OHCA) from August 2013 through July 2015 (n = 2466) providers received comprehensive feedback on their performance related to “compression rate, compression ratio, ventilation rate, chest compression during defibrillator loading phase, total duration of hands-off intervals and measurement of end-tidal carbon dioxide (etCO2).”
The thresholds for “good performance/guideline conformity” vs. “wrong/missing” performance and guideline conformity were based on predetermined American Heart Association (AHA) and European Resuscitation Council (ERC) cutoffs. They are described in Figure 2 in the paper.
The primary outcomes were compared across four 6-month periods and included return of spontaneous circulation for at least 20 minutes (sustained ROSC), survival to hospital discharge, 30-day survival, and good neurological status as measured by a CPC score of 1 or 2 at both discharge and 30-days.
The median chest compression rate and ratio both stayed constant at 107 compressions per minute and 82 percent respectively. The number of cases with a chest compression interruption longer than 30 seconds decreased significantly, by 6.2 percent between periods 1 and 4. The authors suggest this was in part due to an 8.9 percent increase in continuous chest compressions while charging the defibrillator.
There was no change in the rate of sustained ROSC, the percent of patients pronounced in the field or 30-day survival. There were improvements in survival to hospital discharge (6.3 percent) and neurologically intact survival (16.2 percent) between the first and fourth study period.
Memorable quotes on the post-resuscitation feedback system study
Here are three memorable quotes from this article.
“We found that compression ratio less than 75 percent and hands-off episodes more than 30 seconds were significantly and independently associated with poor neurological outcome.”
“A high level of training and education of critical care skills for healthcare professionals represents a key figure in the transmission of up-to-date evidence based guidelines to ALS providers.”
“The increased chest compression ratio seems to ensure a constant and sufficient cerebral perfusion and oxygenation, which mirrors a potential explanation for the observed increasing fraction of favorable neurological outcome, since cerebral damage is more likely to occur in case of prolonged no-flow.”
Key takeaways on the ROSC study
Here are five key takeaways from this study.
1. You can’t manage what you don’t measure
I applaud the Municipal EMS system in Vienna for taking the time-consuming step of starting to measure their cardiac arrest process performance. This is not easy to do and takes a commitment from multiple stakeholders to achieve.
Any agency serious about improving their cardiac arrest survival has to start somewhere, and this is a great option because it includes the providers directly involved in patient care, thus creating more opportunities for buy in and improvements across the entire organization.
2. How data is displayed matters
While this was a research project, it also falls squarely into quality improvement. By comparing only four time periods, the results could be misleading. This study design allowed the authors to compare discrete sections of time as it related to the start of the intervention, it also meant the natural variation over that time was lost.
A more appropriate data display and comparative tool would have been a run chart which allows for an objective comparison of process changes while protecting the natural variation that is present within any system; preventing administration, researchers, authors from prematurely claiming success.
3. The AHA and ERC guidelines are floors, not ceilings
We know chest compressions save lives. Our goal should be no interruptions and a 100 percent chest compression ratio. Achieving such a goal is impossible unless there is only one round of CPR before efforts are ceased. However, coming close isn’t impossible.
With that in mind, here are some recommended targets:
- No resuscitation should have chest compression interruptions longer than about 10 seconds or the time it takes the AED to analyze the rhythm. Ten seconds is also more than enough time for compressors to switch or to deliver a shock. This means the chest compression ratio should be closer to 95 percent than 75 percent.
- There should be no interruptions for advanced airway management. Learn to intubate during chest compressions, or default to an easier airway management tool.
- Don’t set a range for the chest compression rate, pick a number (110 seems reasonable), turn on a metronome and let it do the heavy lifting.
4. Color can connote culture
The decision to use red to represent “failure” is an interesting one. Red may have worked in this system, but it might not be the right choice for every agency, especially one introducing a new model of feedback. Any feedback should also come with the caveat that a small proportion of cases will have extenuating circumstances.
5. Make it about the system of care
Given the high cognitive burden during this type of case, poor performance is likely a symptom of something larger at the system level, not a failure of single provider or group of providers. Remember there is no silver bullet for cardiac arrest care, just silver buckshot. So no single change should have a large impact. Changing a system takes time, patience and perseverance.
