Defibrillator, a bit of history

By Cristiano Antonino On Jun 28, 2023

An early prototype defibrillator was built by the American surgeon Claude S. Beck at the University of Cleveland in 1974; it saved the life of a 14-year-old boy who suffered ventricular fibrillation during surgery

It was a heavy and difficult piece of equipment to transport, powered by alternating current and required the use of a transformer to supply voltage up to 1000 volts.

Electrodes were applied directly to the ventricles and from then on its use became indispensable in operating theatres around the world.

In 1952, Dr Zoll and a team of doctors from Boston observed that defibrillation could be effective even without opening the chest; they applied the external electrodes to the chests of two patients in cardiac arrest and succeeded in resuscitating them.

The first died after only 20 minutes while the second survived for 11 months after receiving electrical cardiac stimulation for 52 consecutive hours.

In 1960, the first alternating current devices were replaced by direct current ones.

The latter, causing fewer complications, immediately appeared more effective.

In 1965, Frank Pantridge, a professor from Northern Ireland, invented the first portable defibrillator

It used a device powered by a car battery and was installed in an ambulance and first used in 1966.

Up until the 1970s, the equipment was manual and the operator, using an oscilloscope (an electronic measuring instrument that allows the time-domain trend of electrical signals to be displayed on a two-dimensional graph and direct voltage and period readings to be taken) had to determine the patient’s state and set the shock.

In the following decade, defibrillators were invented with a programme capable of operating autonomously and instructing the operator by means of speech synthesis systems.

The first implantable defibrillator models were subsequently introduced; they weighed an average of about 300 grams and were about the size of a pocket radio and inserted into an abdominal skin pocket.

In the case of necessary fibrillation, it was capable of giving a discharge of up to 34 joules.

Clearly, with technological progress, these devices have also been improved.

But the first device that can be compared to our current AEDs dates back to 1899.

When, thanks to the physiologists Provost and Batelli of the University of Geneva, they discovered through their research into ventricular fibrillation, the possibility of inducing cardiac arrhythmia by administering electrical impulses directly to the cardiac surface in laboratory dogs.

It was a discovery of some significance, but due to the use of very high voltages, the dogs’ hearts could no longer return to the normal activity that would allow them to survive.

Initially, this led to the demonisation of the defibrillator.

Subsequent research in fact ended up focusing on the negative sides and aspects of fibrillation instead of all the positive ones we know today that are true lifesavers.

In addition to manual defibrillators, there are semi-automatic defibrillators that allow non-medical personnel to perform defibrillation.

The chances of saving a person in the event of cardio-respiratory arrest without consequences to the brain drop by 10% every minute.

It is essential to perform cardiac massage with mouth-to-mouth or mouth-to-nose ventilation or breathing through a mask-fitted balloon in order to maintain a constant and sufficient blood supply to the brain.

After 4 minutes of no oxygen to the brain, brain damage occurs, most often irreversibly; from 6 minutes onwards, in addition to irreversible brain damage, there is the risk of motor and speech deficits, or of affecting the person’s state of consciousness, an example being victims in a vegetative state.

Defibrillation should never be performed if one is near abundant water or if the victim is wet

A wet body causes electrical discharges to dissipate, adversely affecting the effect they should have on the heart.

In such cases the victim should be transported, clearly if not exposing him or her to further danger, to dry places; if necessary the victim should be stripped and dried as best as possible.

The maximum energy required is about 360 joules, in adults; usually the higher the energy, the more effective the defibrillation discharge.

In children under 8 years of age and weighing less than 35 kg, energy-limited pads are used in order to prevent the discharge from injuring the heart.

Currently, defibrillators are so simple to use that placement in schools, stadiums, airports, and many other public places will be made compulsory.

Portable devices are available at a cost that also allows private citizens who want to keep them at home to purchase them.

Modern AEDs weigh little more than a kilogram and operate almost fully automatically.