My dad was an exceptional EMT. He liked the word “technician” in his title because he started his early adult life as a mechanic at a busy, full-service gas station in Scranton, Pa. There he learned to tune engines and assess and fix gas, oil and electrical disturbances. He was proud of the fact the vehicles he handled left the station running smooth and efficiently.
When he joined the Scranton Fire Department and oversaw the ambulance division, he would always defer his major ambulance problems to the city’s “Master Mechanic” to fix. This was the most-experienced mechanic who could find and fix the most difficult of problems, similar to trauma surgeons, ICU staff and other specialists our patients are often transferred to.
He often reflected on how hard it was to tune a car “back then,” with just his ears, a screwdriver and a basic timing light. Today, we link a computer to the car’s circuitry and a printout instantly diagnoses the car’s maladies. Hmm—sounds like our 12-lead system’s advanced ST segment elevated myocardial infarction (STEMI) interpretation in comparison to the limited 3-lead strips we had to interpret in the ’70s and ’80s.
In addition, many of today’s ambulances are equipped with technology that can automatically interpret, telemeter and, in many instances, allow us to fix the problems in our emergency vehicles while they’re still on the road.
My dad used to say that, in many ways, EMTs and paramedics were also skilled mechanics. We’re assigned patients who have fluid, fuel pump or electrical problems and we have to tune them up or do the best we can to keep their vital organs functioning as normal as possible until we pass them on to our “master mechanics” at specialty medical centers.
I have always taken this analogy as a compliment to our profession and I believe the words “technology” and “technician” are especially relevant to EMS today. As you’ll read about in this issue’s Case of the Month, EMS technology is so advanced that mechanical CPR devices now perform compressions so accurately and consistently we have patients speaking to us while in ventricular fibrillation. There aren’t many “old salts” who can say that about manual CPR resuscitations they’ve managed.
This is occurring because these devices now replicate the continuous function of the patient’s pump until specialists (“master mechanics”) can fix the maladies in the patient’s heart, electrical systems or other vital organs.
In reality, as in this issue’s Case, the problems that send many patients into cardiac arrest can often be fixed while the heart is continually being pumped by a mechanical device—similar to what occurs during cardiac bypass surgery.
Despite knowing this, there are countless naysayers who believe the old way we tried to maintain perfusion—manual CPR—is as good as mechanical CPR. If I had a dollar for every medical director, EMS provider or manager who told me their crews and fire first responders perform “perfect,” consistent CPR, I’d be a rich man. They know it can’t possibly be true but refuse to admit it.
In fact, those same experts, who know manual CPR is only 30% as effective as the normal heart’s capability, will never take my challenge to see how consistently (and continuously) their staff can “stay on the chest” and maintain cardiac output while being monitored for 30 minutes by a wireless simulator.
Whether it’s tradition, ego-related or just plain stubbornness, many EMS providers and medical directors refuse to accept the fact that technological advances now allow us to replicate the heart’s cardiac output in the field to keep patients alive.
They also won’t admit that, when tasked with packaging, moving the patient down narrow hallways and stairways out to—and into—the ambulance, their crews are “all over the map” and have a lot of interruptions in compression delivery. They wouldn’t drive their car far with a bad fuel pump or use a piece of fire apparatus with a faulty pump, but they’ll allow a person’s loved one’s heart (and brain) to be starved of precious oxygenated blood.
THE LINC TRIAL
A recent research article in the December 2013 issue of the Journal of the American Medical Association, titled “The LINC randomized trial,” concluded mechanical CPR was no better than manual CPR. It was a multicenter randomized clinical trial of 2,589 patients with out-of-hospital cardiac arrest conducted between January 2008 and February 2013 (five years).
Initiated by Uppsala University in Uppsala, Sweden, the study involved four Swedish, one British and one Dutch ambulance service and their referring hospitals. Duration of patient follow-up was six months post discharge.1
If you just read the study’s conclusion you might be convinced manual CPR is equal to mechanical CPR:
In patients with out-of-hospital cardiac arrest, mechanical chest compressions in combination with defibrillation during ongoing compressions provided no improved 4-hour survival vs. manual CPR according to guidelines. There was a good neurological outcome in the vast majority of survivors in both groups, and neurological outcomes improved over time. Thus, in clinical practice, CPR with this mechanical device using the presented algorithm can be delivered without major complications, but did not result in improved outcomes compared with manual chest compressions.
However, if you read the full report you’ll realize research can’t always replicate reality in the field, where there are interruptions caused by many factors.
The study’s introduction (and footnotes 1–13) point out what we all know:
- One important link is the delivery of high-quality chest compressions to achieve return of spontaneous circulation (ROSC).
- The effectiveness of manual chest compressions depends on the endurance and skills of rescuers; and manual compressions provide only approximately 30% of normal cardiac output.
- Manual CPR is also limited by prolonged hands-off time, and its quality is particularly poor when administered during patient transport. Mechanical chest compression devices have therefore been developed to improve CPR.
- Experimental studies with the mechanical chest compression device used in this study have shown improved organ perfusion pressures, enhanced cerebral blood flow, and higher end-tidal CO2 compared with manual CPR, with the latter also supported by clinical data.
- This [mechanical] device sustains adequate circulation during percutaneous coronary intervention and has been used in cases of hypothermia/drowning.1
So why, then, was it concluded that mechanical CPR wasn’t superior to manual CPR?
I believe the answer lies in the frequent training and very close monitoring of the crews involved in the LINC study to ensure “patients randomized to receive manual CPR were treated in accordance with the 2005 European Resuscitation Council guidelines.”1
To ensure adherence to the study design, and ensure the crews involved in the study were able to compete with the mechanical compression device used during the study, all EMS personnel were extensively trained in both algorithms (manual and mechanical) used in the study and were retrained every six months during the entire study period.1
In an agency that has 640 EMS providers, if you have to retrain them and reevaluate just their CPR skills twice a year for three hours each time to obtain results similar to the LINC trial, that would equate to 5,840 hours of CPR training annually—29,200 hours over five years. (See Table 1.)
Most systems can’t pull crews off the road for 5,840 hours a year to perfect CPR skills. In addition, agencies can’t afford to pay straight or overtime wages to replicate the LINC results.
If you have a 640-person workforce, use a paramedic salary range of $40,000–$100,000, retrain your firefighters via rotation and in-service training, and pay just the 12-hour shift medics overtime to be retrained to match the LINC study performance, it will cost your system $346,154 over the five year period. And that doesn’t include any instructor or on-duty firefighter in-service expenses.
For $300,000, budgeted over the same five year time period, you could place a mechanical CPR device on 20 ambulances, obtain the same (or better) results and save more than $46,000. (See Table 1.)
But it’s not just about saving money; it’s about improving resuscitation rates, particularly in large systems that can’t replicate the LINC training regimen. In the JanuaryJEMS article about the Memphis Fire Department, it was pointed out that after placing a mechanical CPR device on each ambulance, the Memphis ROSC rates rose from 18% to 26.3%. Doesn’t seem to jive with the LINC trial does it?
It’s simple mechanics. Computerized mechanical devices assemble and paint your car, package your food, ventilate you and bypass your blood in the operating room, identify STEMIs in the field and tune up your ambulances.
I believe additional studies and a true look at mitigating prehospital environment factors and the cost of training will show that mechanical compression devices are as effective, if not better and more cost effective, as manual CPR in the long run.
1. Rubertsson S, Lindgren E, Smekal D, et al. Mechanical chest compressions and simultaneous defibrillation vs. conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest—the LINC randomized trial. JAMA . Nov. 17, 2013. [Epub ahead of print.]
Learn more from A.J. Heightman at the EMS Today Conference & Expo, Feb. 5–8 in Washington, D.C., EMSToday.com