indian heart journal 68 (2016) 246–247
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/ihj
Le Voyageur Temps
How to use an AED to help save a life 1.
Introduction
The widespread availability of automated external defibrillator (AED) represents one of the greatest applications of an engineering technology in medicine. These ubiquitous devices are now available everywhere: airports, office buildings, malls, gyms, libraries or any community center (Fig. 1). In just 2 decades, improvements in defibrillator design—in the efficacy of the waveform that delivers the electric shock, the way that the unit's energy is stored and delivered, and the AED's overall
ease of use—have made it so that a layman can operate it with ease. Occasionally, there may arise a situation when we are on an airplane and witness SCD and are required to defibrillate. Interestingly, while familiar with the hospital-based device, few cardiologists (what to speak of general physicians) know how to use an AED. Further, some are even afraid to use it out of fear of using the machine incorrectly. Therefore, it is imperative for us as cardiologists, nay healthcare professionals to be aware of workings of this device. This piece is an effort by IHJ to educate in this very important but frequently overlooked area, so that we are spared of some unwanted embarrassment.
2.
Fig. 1 – Automated external defibrillator.
How to use an AED device?
From the moment you open the AED's brightly colored box, audio instructions prompt you with simple commands (Fig. 2). First, they tell you to place two adhesive electrode pads on the patients (now) bare chest, following the diagrams on the pad wrappers. The defibrillator's built-in electrocardiograph automatically detects and analyzes the state of the patient's heartbeat, and its software judges whether to administer a shock. If the index heart is indeed in ventricular fibrillation, the AED will ask you to approve the delivery of a tailored burst of
Fig. 2 – How to use an AED device.
indian heart journal 68 (2016) 246–247
electric current. ‘‘Push the button,’’ will announce a firm voice emanating from the box. There is only one button, so you press it. If the normal rhythm is restored all is fine, if not, the box prompts you to push the button again after some time.
3.
How does the device function?
The device performs two main functions. First, it recognizes the cardiac rhythm as VF or not. Second, if so instructed, it delivers a 100-kilowatt shock to the heart, which may reset the electric conduction to normal.
4.
History of AED development
Some of the first dedicated research into the mechanisms of electric shock, however, emerged from actually its opposite effects, i.e. effect to kill. In early 1900s, when GE (the company co-founded by Thomas Edison), switched from DC to AC current transmission, linemen began to die from accidental electrocution. In response, GE funded research at several
247
universities to study what made electric current lethal. Two electrical engineering professors, William Kouwenhoven and Guy Knickerbocker, at Johns Hopkins University, in Baltimore, tested the phenomenon by shocking stray dogs to death. Serendipitously, they noticed that a second AC shock could sometimes actually bring an electrocuted dog back to life and thus started a whole field of research.
Sundeep Mishra K. Venugopal E-mail address: [email protected] (S. Mishra) Available online 1 April 2016 http://dx.doi.org/10.1016/j.ihj.2016.03.012 0019-4832/ # 2016 Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. on behalf of Cardiological Society of India. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/ihj
Le Voyageur Temps
How to use an AED to help save a life 1.
Introduction
The widespread availability of automated external defibrillator (AED) represents one of the greatest applications of an engineering technology in medicine. These ubiquitous devices are now available everywhere: airports, office buildings, malls, gyms, libraries or any community center (Fig. 1). In just 2 decades, improvements in defibrillator design—in the efficacy of the waveform that delivers the electric shock, the way that the unit's energy is stored and delivered, and the AED's overall
ease of use—have made it so that a layman can operate it with ease. Occasionally, there may arise a situation when we are on an airplane and witness SCD and are required to defibrillate. Interestingly, while familiar with the hospital-based device, few cardiologists (what to speak of general physicians) know how to use an AED. Further, some are even afraid to use it out of fear of using the machine incorrectly. Therefore, it is imperative for us as cardiologists, nay healthcare professionals to be aware of workings of this device. This piece is an effort by IHJ to educate in this very important but frequently overlooked area, so that we are spared of some unwanted embarrassment.
2.
Fig. 1 – Automated external defibrillator.
How to use an AED device?
From the moment you open the AED's brightly colored box, audio instructions prompt you with simple commands (Fig. 2). First, they tell you to place two adhesive electrode pads on the patients (now) bare chest, following the diagrams on the pad wrappers. The defibrillator's built-in electrocardiograph automatically detects and analyzes the state of the patient's heartbeat, and its software judges whether to administer a shock. If the index heart is indeed in ventricular fibrillation, the AED will ask you to approve the delivery of a tailored burst of
Fig. 2 – How to use an AED device.
indian heart journal 68 (2016) 246–247
electric current. ‘‘Push the button,’’ will announce a firm voice emanating from the box. There is only one button, so you press it. If the normal rhythm is restored all is fine, if not, the box prompts you to push the button again after some time.
3.
How does the device function?
The device performs two main functions. First, it recognizes the cardiac rhythm as VF or not. Second, if so instructed, it delivers a 100-kilowatt shock to the heart, which may reset the electric conduction to normal.
4.
History of AED development
Some of the first dedicated research into the mechanisms of electric shock, however, emerged from actually its opposite effects, i.e. effect to kill. In early 1900s, when GE (the company co-founded by Thomas Edison), switched from DC to AC current transmission, linemen began to die from accidental electrocution. In response, GE funded research at several
247
universities to study what made electric current lethal. Two electrical engineering professors, William Kouwenhoven and Guy Knickerbocker, at Johns Hopkins University, in Baltimore, tested the phenomenon by shocking stray dogs to death. Serendipitously, they noticed that a second AC shock could sometimes actually bring an electrocuted dog back to life and thus started a whole field of research.
Sundeep Mishra K. Venugopal E-mail address: [email protected] (S. Mishra) Available online 1 April 2016 http://dx.doi.org/10.1016/j.ihj.2016.03.012 0019-4832/ # 2016 Published by Elsevier, a division of Reed Elsevier India, Pvt. Ltd. on behalf of Cardiological Society of India. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
