Testimony of Maura Duffy at FDA Advisory Committee on Reclassification of External Cardiac Compressors

Testimony by Maura Duffy

September 11, 2013

 

My name is Maura Duffy and I am a Nationally Registered Emergency Medical Technician who worked a Basic Life Support ambulance for 3 years. I currently work as a Research Assistant at the National Research Center for Women & Families.  I am here today to speak on behalf of myself and Dr. Diana Zuckerman, president of the National Research Center, which is a nonprofit think tank that uses research data to evaluate the safety and efficacy of medical treatments. The Center does not accept funding from companies that make medical products so I have no conflicts of interest.

We strongly oppose the proposal to reclassify External Cardiac Compressors Class III devices to Class II (special controls).

ECC devices are used by emergency medical personnel to automate chest compressions during CPR. As an EMT, I have performed manual CPR and I have seen ECCs used, although I myself have not used them. If these devices were as effective as manual CPR, they could save lives when emergency responders get fatigued performing chest compressions.

Only one large, well-powered randomized controlled clinical trial, called the ASPIRE study, has ever compared these devices to manual CPR. That trial was conducted in five sites. It was stopped early by the data and safety monitoring board for ethical reasons, because the patients who received CPR using these devices were significantly more likely to experience brain damage than those given manual CPR

Of the patients receiving CPR from cardiac compressors, only 6% survived long enough to be discharged from the hospital, compared to 10% receiving manual CPR.  That difference is quite dramatic, but only marginally significant at the .06 level.

Although not the perfect study, the ASPIRE trial is the best one that has been done. The other randomized, controlled clinical studies did not include enough surviving patients to determine whether ECC patients were more or less likely to survive compared to manual CPR patients.

In 2011, the Cochrane collaboration conducted a systematic review of ECC compared to manual CPR.   As most of you know, Cochrane reviews are considered the best source of unbiased, scientifically sound reviews.  Only 4 studies, with data from a total of 868 patients, met all the criteria for inclusion in the Cochrane review. The Cochrane review concluded that there was insufficient evidence of either benefit or harm from using ECCs.

Several other studies have compared CPR delivered by ECC device to manual CPR by measuring surrogate markers that were believed to predict survival. However, these studies included very small sample sizes, and of the 35 patients enrolled in two of the studies, none survived to hospital discharge.

In 1980, the FDA determined that ECC devices were life-sustaining devices and therefore clinical trials were needed to provide reasonable assurance of safety and effectiveness. Unfortunately, the FDA never required manufacturers to submit clinical trial data to prove which – if any — of these devices are safe and effective.

The FDA has proposed several special controls, which would be better than nothing.  However, adding special controls to a 510k review, still will not provide 4 essential safeguards that Class III devices receive when they are reviewed under the Pre-market approval process:

1. Proof of safety and efficacy based on short-term clinical trials

2. FDA’s authority to require post-market, long-term clinical trial safety data as a condition of approval

3. FDA’s authority to inspect the manufacturing facility prior to approval

4. FDA authority to rescind approval if the device is later found to be unsafe

Use of ECCs can cause delays in CPR, and this is even more likely if the ECC malfunctions. That’s why clinical trials are so important.

Is better training the answer?  A manikin study of 21 Swedish ambulance crews compared manual CPR to ECC compression, after being trained by an instructor from the manufacturer, plus at least one local training session.  Even so, 9 of the 21 crews failed to apply the mandatory stabilization strap on the device, and this resulted in fewer adequate compressions.

One more issue: will these devices only be used when absolutely needed? I can tell you from experience that EMS crews are often eager to use the new, “sexy” equipment on the ambulance. Since performing CPR is physically and mentally grueling, emergency responders may be over-eager to automate chest compressions if given the choice. For that reason, it is essential that the FDA make sure that each new version of these devices work BEFORE they put them on the market.

We agree with the American Heart Association’s statement that “[t]here is insufficient evidence to support or refute the routine use of mechanical piston devices in the treatment of cardiac arrest.”

The FDA may reclassify a Class III device to Class II if the agency “determines that special controls would provide reasonable assurance of the safety and effectiveness of the device.”  Unfortunately, there is NO SCIENTIFIC EVIDENCE that special controls are sufficient to provide reasonable assurance of safety and effectiveness for these devices, because the best designed randomized controlled clinical trial indicates that ECC devices are associated with worse survival and worse neurological outcomes. For that reason, these devices should only be approved by the FDA on the basis of clinical trials of specific devices, not assumptions about all these ECC devices in general. Since the device will probably malfunction or be used improperly at least some of the time, it is especially important for the FDA to require clear evidence of efficacy when used correctly.

In conclusion, clinical trials are required for these life-sustaining devices, because there is not enough scientific evidence to determine whether using these devices in CPR will improve patient outcomes or instead reduce chances of survival and lead to greater brain damage among survivors.  Please vote against changing the classification to Class II.

Thank you for the opportunity to comment on this important matter.