In the past few months the US Food and Drug Administration has launched a Medical device Innovation Initiative to address the Automated External Defibrillator, or AED in order to “improve these technologies so that we can save more lives” as said by the Director of the FDA’s Center for Devices and Radiological Health (CDRH,) Jeffrey Shuren M.D. What the FDA fails to understand that the defibrillator is a unique medical device that treats a patient that is collapsed and considered expired; the timely presence of an AED facilitates a small percentage chance of survival after collapse, not an assurance of survival. A higher proliferation of AEDs – driven by economics and secondarily accessibility increase the chances that an AED is available in locations that cardiac arrest can occur. With the FDA’s proposed higher regulation of AEDs will increase costs, lower innovation and consequently decrease the numbers of AEDs. This will lower the chances of a timely defibrillation with an AED and as a result increase the numbers of deaths due to sudden cardiac arrest, defeating the increases in survival seen over the last couple decades. The FDA is creating an unintended consequence with this initiative and instead of promoting public health is diminishing public wellbeing. The FDA would be best to foster public health by allowing manufacturers to lower costs with less regulation and higher industry innovation, thus escalating AED proliferation and increasing, statistically, survival of citizens collapsing from cardiac arrest.
Background
In 1775 Peter Christian Abildgaard, a Danish veterinarian and physician, performed experiments on chickens; he showed that he could make chickens lifeless with an electrical impulse passed through the body, and he could restore a heart pulse with a second impulse if it was passed across the chest. Though Abildgaard did not document this as inducing ventricular fibrillation and subsequently defibrillation – it is arguably the first use of an external defibrillator. (Driscol TE, 1975) Centuries later, the essence of defibrillation is the same, an electrical impulse is passed through the chest, and a lifeless body (from cardiac arrest) is revived. This is one of the exceptional characteristics of the defibrillator – the patient being treated is lifeless.
Since Abildgaard’s time the medical community has become much more learned as to the mechanisms that he observed on his fowl. It is thought that by shocking the hens with electricity he caused ventricular fibrillation; consequently by following with a counter shock he defibrillated making the heart contract correctly instead of twitching. Ventricular fibrillation (or VF) is known to be the cause of sudden cardiac arrest and sudden cardiac death. It is a condition of uncoordinated contraction of the ventricular cardiac muscles causing the heart to tremble instead of contracting properly. The underlying cause of VF is not completely understood, and the symptoms of VF and subsequently cardiac arrest and death can occur in what would be considered a healthy heart.
Cardiac arrest is a leading cause of death in the United States and accounts for 300,000 to 400,000 deaths per year. (Shah JS, 2006) (Sachdev M, 2010) Ventricular Fibrillation is the initial rhythm in approximately 30% of cardiac arrests thereby accounting for 100,000 such events yearly in the US. (Sherman LD, 2008) Sudden Cardiac Arrest is not a heart attack by definition. A heart attack is myocardial infarction, which is caused by a blockage in the arteries to the heart muscle causing ischemia, in other words restriction of blood flow and in turn oxygen shortage which causes death or infarction of the of the heart muscle tissue – the myocardium. Sudden Cardiac Arrest can be caused by a heart attack, but the underlying mechanism of the cardiac arrest is the cessation of the cardiac muscles to contract properly, the heart will quiver as an example in cardiac arrest. The defibrillator is the only device to counteract this killer.
Defibrillation and the AED
The advent of defibrillator started in the 1920’s with funding from Consolidated Edison (Con Edison) the power company. Con Edison was concerned with the high number of electrical shocks and accidental deaths occurring to their line men. The first external defibrillations where performed in the 50’s, the AED was an advent in the 80’s when computer analysis of heart Electrocardiogram (ECG) was combined with defibrillation – allowing for a device to analyze the heart rhythm and if the heart signal is one that can be defibrillated, the AED delivers the appropriate electrical impulse.
The American Heart Association recognized the importance of the AED and in 1991 the AHA issued a challenge to manufacturers to develop simple, low-cost automatic defibrillators for use where large numbers of people congregate. Since then, considerable advances have occurred, and several manufacturers have developed small, lightweight, simple semiautomatic external defibrillators (AEDs) for use by the public. (Cobb LA, 1992)
The number of AEDs in use has grown from 15 thousand in 1996 to 1.65 million in 2009. (Shah JS, 2006) Data collected over the time that AEDs have been available show that more than 95 percent of cardiac arrest victims die before reaching the hospital. More importantly, in cities where defibrillation was provided within 5 to 7 minutes, the survival rate from sudden cardiac arrest was as high as 30–45 percent. (AHA, 2011) (Eisenberg MS, 2009) The most important determinant of successful return to circulation is the time interval from onset of ventricular fibrillation to initial intervention. The time from onset of VF to defibrillation is the key element in the acute management of the cardiac arrest victim. The chance of survival decreases 7% to 10% for each minute that defibrillation is delayed as shown in the figure below. (O'Rouke) (Calans, 2004) Defibrillation alone often results in successful resuscitation if delivered four minutes of cardiac arrest. (Calans, 2004)
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Figure 1 Exponential Decline in Rate of Survival after Sudden Cardiac Arrest as Time to Defibrillation Increases |
Public Access Defibrillation
“Public Access Defibrillation (PAD), which places AEDs in the hands of trained laypersons, has the potential to be the single greatest advance in the treatment of ventricular fibrillation cardiac arrest since the development of the CPR.” (AHA, Guidelines 2000 for Cardiopulmonary Resuscitadon and Emergency Cardiovascular Care. Part 4: the automated external defihrillaror: key link ill the chain of survival, 2000)
Walking in Chicago O’hare Airport from ticket counter to the terminal, one will encounter multiple AED’s along the way. This was an intentional installation placing AEDs 60-90 walk/seconds apart from each other. The City of Chicago started this program in 1999, placing highly visible AEDs for public use at O’hare and Midway as part of the Chicago Heart Save Program sparked from the PAD program. (Caffrey, 2002) The airports serve over 100 million passengers per year; in a two year period 21 persons had cardiac arrest – 18 of which had ventricular fibrillation for which an AED can be used. Of those 18 people, 11 where successfully resuscitated – over 61%. In comparison the survival rate across the United States is 5%. (Caffrey, 2002) The study concluded that AEDs placed in readily accessible, well marked public areas are effective in assisting patients with cardiac arrest. (Caffrey, 2002) It is the abundance of AEDs in a populated area that increase public health.
The FDA’s role in AEDs
FDA’s mission is to protect and promote public health, in 1976 under the Federal FD&C Act the regulatory controls for medical devices was established. Under this Act, the FDA established a three tiered risk based classification. The lowest risk level is Class 1 and products in this class are things such as tongue depressors, sterile gloves etc. where the patient risk is low. Class 2 products are things such as contact lenses, patient monitors and manual defibrillators. Class 3 products are those that are of highest risk such as stents and artificial hearts, where the risk to patient is the highest. Due to the innovative quality of the AEDs, they were given a Class 3 designation when they were determined to be substantially equivalent to similar Class 3 devices that were on the market. Market approval to sell devices is based on this classification system.
In general there are two routes to obtain market approval on a medical device. One is what is called the 510(k), designated for the section of the regulation. In this process the manufacturer demonstrates equivalence to products that are already on the market. This pathway is typically reserved for Class I and Class II devices, but which has also been used for some Class III devices that were allowed to be reviewed under the 510(k) regulations until reclassified or determined to require a Pre Market Approval. The second pathway, designed for riskier products is the Pre Market Approval (PMA) process – which to manufacturers generally means clinical trials to establish safety and efficacy, a costly proposition.
AEDs have always been regulated through the 510(k) process. According to a 1990 amendment to the 1976 legislation, the FDA must either down-classify AEDs to Class II or keep AEDs as Class III and require they go through the more PMA process. The FDA is now proceeding with the formal classification of AEDs. During this time since AEDs have come on the market to today, manufacturers have demonstrated the efficacy of the AED, they have shown to ability to meet demands for the product which was driven by effective saving of lives. Why would the FDA counteract this obvious public benefit?
The FDA is concerned with the number of adverse reports concerning AEDs. As stated by the FDA, “during the past five years, the FDA’s CDRH has received more than 28,000 medical device reports associated with the failures of external defibrillators and manufacturers conducted dozens of recalls involving hundreds of thousands of the devices.” In a study by Dr. Jignesh Shah in the Journal of American Medical Association, 2.78 million AED device years where observed from 1996 - 2005. In that time 21.2% of the AEDs distributed were recalled, due to electrical or software problems. The author concluded that “AED advisories occur frequently and affect many devices. Actual AED malfunctions do occur occasionally, although the number of observed malfunctions is small compared with the number of lives saved by these important devices. As the prevalence of AEDs continues to increase, the number of devices affected by advisories can also be expected to increase. Efforts should be directed at developing a reliable system to locate and repair potentially defective devices in a timely fashion.” (Shah JS, 2006) The prevalence of adverse reports has not changed over the last couple decades, and as demonstrated in this study malfunctions can occur, but the rate of occurrence is much smaller than the number of lives saved.
It is fundamental in the AED business to fix problems as they are identified. AED manufacturers are obliged to identify problems, file them with the FDA as Medical Device Reporting (MDR). The FDA compiles this data into a database of Adverse Event Reporting. Adverse reports can also come from the general public, but in the case of AEDs only 2% come from the public 98% of the adverse reports are from the manufacturers themselves. The manufacturers are identifying problems and fixing them as they arise.
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Figure 2 Slide from the FDA AED meetings. Over 98% of Adverse Reports come from manufacturers and a very small number from user facilities such as hospitals. |
Similar to the FDA’s actions in the mid 90’s Laerdal identified a problem with a component, recalled devices without affecting customers and filed a Medical Device Reporting (MDR) with the FDA per the regulation – noted as an adverse event report. The FDA acting with little comprehension issued a safety alert on that AED device. (Cummins RO, 1995) How many cardiac arrests did the FDA adversely affect due to its uninformed choices? How many people will die from cardiac arrest tomorrow because of FDA’s actions today?
The increase of adverse events, as noted by Shah, will also increase with the number of AEDs in circulation. (Shah JS, 2006) Taking the data of AED population and folding over the FDA data of adverse data reports one can identify that the number of adverse reports has the same trend as predicted by Shah.
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Figure 3 AED Population with data derived from FDA and Shah, with FDA adverse events that where available plotted. |
The same trends in as seen in 2004 are seen in 2008 in terms of percentage of adverse reports. This should not be a factor in the FDA’s decision to reclassify the AEDs. Instead The FDA should focus on the benefit to the public with having a large population of AEDs in circulation and what percentage of the public will continue to live because there was an AED at hand. Reclassifying the AED, forcing manufacturers to go through a PMA will drive up AED costs. In the FDA NEWs website the news blurb read – “In a move that could cost device makers millions of dollars, an FDA advisory panel has backed the agency’s proposal to classify automated external defibrillators (AEDs) as Class III devices that must go through the PMA process” (FDA News, 2011) It’s not the device makers that will absorb that cost – that cost will be passed on to the end customer – a customer with a fixed budget to purchase AEDs for their casinos, churches, gyms... Does one need anything more than common sense to determine that the end customer will buy fewer devices if they are more expensive? It is common sense that with fewer AEDs more people will unnecessarily die.
“The FDA managers may need to take a long hard look at the actions of the agency and consider that through the shortsighted actions the FDA itself may be considered a serious danger to, and not a watchdog for our nation’s public health. “ (Cummins RO, 1995) The FDA has myopic vision and does not see the forest for the trees. It is of greater public wellbeing for the FDA to down classify AEDs to the same level as their cousins the defibrillators – it is the numbers of AEDs that save lives.
Works Cited
AHA. (2011, 03 01). Cardiac Arrest. Retrieved 03 01, 2011, from American Heart Association: http://www.americanheart.org/presenter.jhtml?identifier=4481
AHA. (2000). Guidelines 2000 for Cardiopulmonary Resuscitadon and Emergency Cardiovascular Care. Part 4: the automated external defihrillaror: key link ill the chain of survival. Circulation , 160-167.
Caffrey, S. (2002). Feasibility of public access to defibrillation. Curr Opin Crit Care , 8 (3), 195-198.
Calans, D. (2004). Out of Hospital Cardiac Arrest - The Solution is Shocking. New England Journal of Medicine , 632-634.
Cobb LA, E. M. (1992). Report of the American Heart Association Task Force on the Future of Cardiopulmonary Resuscitation. Circulation , 85, 2346-2355.
Cummins RO, W. R. (1995). Ventricular fibrillation, automatic external defibrillators, and the United States Food and Drug Administration: confrontation without comprehension. Ann Emerg Med , 26 (5), 632-631.
Driscol TE, R. O. (1975). The remarkable Dr. Abildgaard and countershock. The bicentennial of his electrical experiments on animals. 83(6).
Eisenberg MS, P. B. (2009). Defining and improving survival rates from cardiac arrest in US communities. JAMA , 301 (8), 860-862.
FDA News. (2011, 02 01). FDA News Bulletin - Panel: AEDs Should Stay Class III and Be Subject to the PMA Path. Retrieved 03 01, 2011, from FDA News: http://www.fdanews.com/newsletter/article?articleId=133873&issueId=14426
O'Rouke, R. (n.d.). Saving Lives in the Sky. Correspondence to Robert A. O'Rourke, MD, Charles Conrad Brown Distinguished Professor in Cardiovascular Disease .
Sachdev M, F. B. (2010). Failure in short-term prediction of ventricular tachycardia and entricular fibrillation from continuous electrocardiogram in intensive care unit patients. J Electrocardiol , 43 (6), 400-7.
Shah JS, M. W. (2006). Recalls and safety alerts affecting automated external defibrillators. JAMA , 296, 655-660.
Sherman LD, R. T. (2008). Logarithm of the absolute correlations of the ECG waveform estimates duration of ventricular fibrillation and predicts successful defibrillation. Resuscitation , 78 (3), 346-354.
Sullivan, R. (2010, 12 15). Adverse Event Reporting-presentation. FDA Public Workshop on External Defibrillators, December 15-16, 2010 . Silver Spring, MD, USA: FDA.
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