1899

Defibrillator

Jean-Louis Prévost (1838–1927), Frédéric Batelli (Dates Unavailable), Frank Pantridge (1916–2004)

Imagine that you are walking down an airport concourse when a man in front of you suddenly clutches his chest and falls to the floor. He is experiencing sudden cardiac arrest. The good news is that many public buildings now have portable defibrillators. The fact that engineers have been able to shrink, simplify, and cut the cost of these lifesaving machines is a testimony to the engineering ethos. The concept of defibrillation dates back to 1899, when Jean-Louis Prévost and Frédéric Batelli, two physiologists at the University of Geneva, Switzerland, demonstrated the effect of electricity on the hearts of dogs. Portable defibrillators were not available until 1965, when Irish professor Frank Pantridge developed an early model weighing over 150 pounds (70 kg).

The portable units that we see at airports and malls are called AEDs or Automatic External Defibrillators, first used outside of a hospital in 1980. The goal of a defibrillator is to stop the fibrillation and reestablish a regular heartbeat. A defibrillator does this with a strong electric shock.

In sudden cardiac arrest, the heart has stopped its regular beating action for some reason. The human heart has its own independent nerve network that causes its regular beating, and if this network gets disrupted (for example by a suddenly clogged artery on the heart muscle), the heart can enter a cycle of fibrillation, where the nerve network goes off script and starts beating irregularly and rapidly.

After placing the self-stick electrodes on the patient’s chest, a microprocessor in the device analyzes the heart rhythm and detects if fibrillation is occurring. If it is, the defibrillator uses its internal batteries to load a capacitor with a high-voltage charge (e.g., 700 volts) and then delivers it to the patient. In many cases, a single charge is enough to start a normal heartbeat, but if not, the device can try multiple times.

The best way to treat sudden cardiac arrest is to use a defibrillator as soon as possible. What electrical engineers, software engineers, and industrial engineers have been able to do is create an inexpensive, lightweight, mass-produced package that can help treat a leading cause of death.

SEE ALSO Microprocessor (1971), Artificial Heart (1982), Kansai International Airport (1994).

While the first defibrillator was prohibitively massive, today lighter portable models are available in most public buildings.