Cardiac & Resuscitation, Patient Care

Research Studies Measure Prehospital Glucagon Use & Global EMT Competency

Issue 1 and Volume 38.

In the hierarchy of research, a case report often serves only as an FYI or a good war story. In the case of the below study, we’re lucky the authors had research on administration of intranasal (IN) glucose published for the first time in a peer-review journal. I recommend you read it more for the review of the literature on IN medication administration than for any earth-shattering news about glucagon.

I did find it interesting, however, that 2 mg of IN glucagon was just as speedy at raising blood sugar as 1 mg of intramuscular (IM) glucagon, according to a 1992 study by Rosenfalck published in Diabetes Research and Clinical Practice, and that few studies have successfully compared IV dextrose to IM glucagon. With a single dose of IN glucagon being around $1.50 vs. $8 for dextrose, I doubt we’ll see IN glucagon replace IV dextrose as a first-line drug. But this write-up gives us some ammunition for medical directors to approve the IN glucagon route as well as intramuscular. I’ve already fired off the e-mail to my medical directors. Will you?

Paramedic Competence
Tavares W, Boet S, Theriault R, et al. Global rating scale for the assessment of paramedic clinical competence.
Prehosp Emerg Care. 2012; Jul 26 [Epub ahead of print.]

We seldom see educational research in EMS, and even less frequently a study dealing with clinical competency. Kudos to this Canadian all-star group for tackling such a difficult subject with such a thorough methodology.

The group videotaped 81 performances of 61 EMS students and 24 active paramedics responding to a simulated scenario. Two trained evaluators reviewed each video using a prototype global rating scale (GRS). The objective was to see if the GRS would correctly identify a competent performance. The candidates were lone paramedics responding to a simulated unstable cardiac patient in the back of a transfer ambulance on the side of the road, which deteriorates into cardiac arrest. The two EMTs were allowed to assist the paramedic being tested, and the scenario lasted nine minutes. A high-fidelity manikin was used.

The rating scale included eight dimensions, or rubrics. These were distilled by a national expert panel using a modified Delphi process from 257 observable paramedic clinical behaviors. The final rubrics were situation awareness, history gathering (i.e., interviewing), patient assessment (i.e., physical exam), decision making (i.e., differential diagnosis), resource use (i.e., leadership and delegation of tasks), communication and procedural skills. Finally, an overall clinical performance score was assigned.

It’s particularly encouraging that these dimensions match the recently released National Registry paramedic psychomotor competency package evaluations. Although the NREMT followed a different methodology, the categories are identical, giving these rubrics more validity.

Interestingly, the individual categories didn’t seem to be as reliable as the overall rating. The authors note that raters had difficulty differentiating between the dimensions, and suggest that a “Gestalt” categorical judgment or “halo effect” may be at work. Still, they noted, the GRS accurately identified who should pass and who should fail. Without a doubt, every EMS educator should read this study and start using these rubrics.

An adjectival rating scale from 1–7 similar to a Likert scale was used, with 1 being unsafe, then unsatisfactory, poor/weak, marginal, competent, highly competent and 7 being exceptional. Although these authors didn’t comment on their 1–7 scale, previous studies have shown poor results using similar rating scales.

From the descriptive statistics in this study it would appear the scale could be simplified without affecting the accuracy of the pass/fail ratings, similar to those recently proposed by the NREMT.

Although it appears we’re getting closer to having defensible tools to measure clinical competency, the reproducibility of these methods would be challenging, such as what would be required for large programs or even state and national exams.

Not everyone has access to high-fidelity manikins, quality video recording, archiving and raters with 22 and 11 years of experience. Both were trained over a 60-minute period and viewed all the videos, presumably gaining quite a bit of experience along the way. 

Adjectival rating scale refers to a numeric appraisal (similar to a pain scale rating) based on descriptions (adjectives) that best fit their assessment.

Watch Box: Rate Matters
Idris A, Guffey D, Pepe P, et al. The ROC investigators. The interaction of chest compression rates with the impedance threshold device and association with survival following out-of-hospital cardiac arrest.

In the December 2011 Research Review column, I reviewed the National Institutes of Health Resuscitation Outcomes Consortium (ROC) study that evaluated the impedance threshold device (ITD) in a large multi-center clinical trial called the PRIMED trial (published in the New England Journal of Medicine in September 2011). It reported no difference between use of an active ITD and a placebo (or sham) ITD. This has always puzzled me because I have used an ITD for years and have seen it work.

In November 2012, Ahamed Idris, MD, presented an abstract at the American Heart Association (AHA) Resuscitation Science Symposium (ReSS), reporting that chest compressions for patients in the ROC database weren’t necessarily performed at the 100 per minute rate recommended in the study protocol or by the AHA; in fact, more than half of the more than 10,000 patients received chest compression rates that were too slow (less than 90 per minute) or too fast (greater than 110 per minute). The data showed that the faster the chest compression rate, the worse the outcomes.

This is reminiscent of the findings of Thomas Aufderheide, MD, that hyperventilation is deadly in cardiac arrest. The ROC study confirmed that for chest compression rates, like ventilation, more is not better, and in fact, more can be harmful. Idris presented additional ROC data that shed new light on my confusion about the ITD’s previously reported efficacy. He reported that there was a significant interaction between chest compression rate and ITD efficacy. Their adjusted model predicted greater survival to discharge when the ITD was used at AHA-recommended compression rates of around 100 per minute, compared with conventional CPR without an active ITD at similar rates. Clearly, CPR needs to be performed correctly in order to fairly assess new technologies like the ITD.

Idris and colleagues are planning to follow up the paper soon. If the paper mirrors the abstract, we will see the first randomized, controlled, double-blinded clinical trial to demonstrate that the ITD improves survival to hospital discharge with favorable neurologic outcome with properly performed chest compressions.

Bottom Line
What we know: Compression rates affect survival rates. The faster the compression rates, the worse the outcomes.
What this study adds: When an ITD is used as intended (at AHA-recommended chest compression rates), observed survival-to-hospital discharge is considerably increased compared to CPR without an ITD.