The History Of Defibrillators

Here are some interesting facts and historical events that lead to the discovery and development of the modern automatic external defibrillators (AEDs).

Fibrillation

Towards the end of the 18th century the Danish physician, veterinarian and scientist Peter Christian Abildgaard was doing different types of medical research on animals. He observed on hens that by administrating electric shocks, he could actually stop their heartbeat. He also noticed that a pulse re-appeared if other series of shocks were administrated on the chest of the birds. These were the first steps made towards the discovery of fibrillation and defibrillation. Almost 75 years after Abildgaard's discovery, in 1849, the scientists Ludwig and Hoffa put into words what Abildgaard has demonstrated with the help of the hens. Ludwig and Hoffa were the first people to use and clearly define the phrase fibrillation of the ventricles, though some historians claim that the first documents on ventricular fibrillation date back to 1500 BC in Ancient Egypt. Here are some more facts regarding the history of defibrillators:

Still, the most precise definition of ventricular fibrillation, that is valid up until today, was given by John A. Mac William, a former student of Ludwig. The ventricular fibrillation is a cardiac condition that is described as chaotic, uncoordinated contractions of the muscles of the ventricles that result in heart arrest. If the muscles are unevenly contracted, the blood circulation will be stopped and this will result in death.

In 1900, Prevost and Battelli started doing research on dogs, trying to understand and monitor ventricular fibrillation. They have proven that by alternating different electrical shock intensities like AC and DC they could induce ventricular fibrillation. Using a stronger shock, they were able to defibrillate the ventricles.

Wiggers and Wegria continued the work of Prevost and Battelli, discovering the most susceptible stage in the cardiac cycle to provoke ventricular fibrillation. They observed that using the right electrical current strength could re-instate the pulse. They used the term of 'countershocking' for ventricular fibrillation, a term that is no longer used today, but has been replaced by defibrillation.

Recent History Of Defibrillators

After having identified what can be done in order to fix the fibrillation of the ventricles, there was a need to find and manufacture some equipment that could be safely applied on humans, not only on dogs and hens. The improvement of defibrillators was strongly influenced by the financial support of the Consolidated Edison of New York. This happened in the 1920s, and was a reaction to the alarming numbers of deaths caused by electric shock accidents. Another two decades passed until the first successful defibrillation was conducted. The authors were a team of doctors guided by Dr. Beck.

They were the first to use internal cardiac paddles that were specially created for defibrillation. They succeeded in bringing back to life a 14-year old boy by applying 2110-volt and 1.5 amp AC shocks. Nine years later, in 1956, the newspapers announced the following: a team led by Dr. Zoll has improved Dr. Beck's performance by doing the first external defibrillation ever. He used a 15 amp AC current that produced 710 Volts and held it for a very short period of time on the chest of the patient. He managed to re-instate a normal heart rate and the normality in the ventricular muscle contraction just by administrating an AC shock.

Still, years later Alexander, Kleiger and Lown have proven that DC current shocks are safer and more effective than AC shocks while performing a defibrillation. In 1966, the first out-of-hospital defibrillation was accomplished. This happened in Belfast on an ambulance. The very first defibrillation performed by emergency medical technicians without the assistance of any physician took place in Portland , Oregon in 1969.

Automatic External Defibrillators (AEDs)

The Portland area was a fertile land for creating avant-garde equipment used to defibrillate. At the beginning of the 1970s, Dr. Arch Diack, DR. W. Stanley Welborn and Robert Rullman have tested several types of Automatic External Defibrillators. They started promoting their hype equipment throughout an organization called Cardiac Resuscitator Corporation. In Brighton , England , at the beginning of the 1980s there were several experiments carried out before the arrival at the hospital.

The Heart Aid was being utilized; this was a device that weighed 28 pounds (quite heavy compared to the 5 pound AEDs available on the market today!). This device was used to trace ECG and deliver the proper electrical shocks. In 1982, the Food and Drug Administration in the US has given consent for emergency medical technicians (EMT) to perform defibrillation. Nowadays, any person that has received basic training may use an AED in a vital situation. The modern technology has made it possible for the AEDs of today to be easy to use. This may save lives, considering the fact that every minute that passes without intervention decreases the patient's chances of survival by 10%. Due to the fact that over 50% of the sudden heart arrests happen in public places, several AEDs have been made available for public use in airports, important buildings, institutions and schools.

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