Defribrillator Packet V2

Equipment*Packet:*Defibrillator*UMDNS*#:+15133+Date*of*Creation:+October+16,+2015+Creator:+Engineering+World+Health+(EWH)***Equipment*Packet*Contents:*This+packet+contains+information+about+the+operation,+maintenance,+and+repair+of+defibrillators.++Part*I:*External*From*the*Packet:** 1. An*Introduction*to*Defibrillators:*+PowerPoint+*Part*II:*Included*in*this*Packet:** 1. Operation*and*Use:*a. Brief+Overview+of+Defibrillators:+External,+Automated,+SemiMautomated+(p.+3M4)+b. Electrical+Activity+in+the+Heart+(p.+5M13)+c. Introduction+to+Defibrillators+(p.+14M19)+d. Automated+External+Defibrillators+(p.+20M22)+2. Diagrams*and*Schematics:*a. Figure+1:+The+Human+Heart+(p.+24)*b. Figure+2:+Placement+of+Defibrillator+Paddles+(p.+25)*3. Preventative*Maintenance,*Troubleshooting,*and*Repair:**a. Defibrillator+Troubleshooting+Flowchart+(p.+27M29)*4. Resources*for*More*Information*a. Resources+for+More+Information+(p.+31)+b. How+to+Build+a+Defibrillator+Tester+(p.+32M38)*c. Bibliography+(p.+39)** +** ****




*** 1. Operation*and*Use*of*Defibrillators*****Featured*in*this*Section:******Malkin,+Robert.+Medical!Instrumentation!in!the!Developing!World.+Engineering+World+Health,+2006.++*+ WHO.+“Defibrillator,+External,+Automated;+SemiMautomated.”+From+the+publication:+Core!Medical!Equipment.+Geneva,+Switzerland,+2011.+++Wikipedia.+“Defibrillation.”+Wikipedia,+p.+1M12.+Retrieved+from:+https://en.wikipedia.org/wiki/Defibrillation ++Wikipedia.+“Automated+External+Defibrillator.”+Wikipedia,+p.+1M5.+Retrieved+from:+https://en.wikipedia.org/wiki/Automated_external_defibrillator+*+* *




http://www.who.int/medical_devices/en/index.html
© Copyright ECRI Institute 2011 (not including the GMDN code and device name).


Reproduced with Permission from ECRI Institute’s Healthcare Product Comparison System.


© Copyright GMDN Agency 2011. GMDN codes and device names are reproduced with permission from the GMDN Agency.


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Health problem addressed
Fully automated external defi brillators (AEDs) deliver a high-
amplitude current impulse to the heart in order to restore normal
rhythm and contractile function in patients who are experiencing
ventricular fi brillation (VF) or ventricular tachycardia (VT) that
is not accompanied by a palpable pulse.


Product description
AEDs determine whether defi brillation is needed and
automatically charge and discharge to deliver a shock.
Semiautomated units analyze the ECG and charge in preparation
for shock delivery, but the operator activates the discharge.
AEDs typically include a memory module or PC data card,
disposable adhesive defi brillation electrodes, a display to give
status messages (patient and/or defi brillator), to display the
ECG waveform, or to prompt the user to initiate a shock.


Principles of operation
Automated defi brillators analyze the ECG rhythm to determine
if a defi brillation shock is needed; if it is, the defi brillator warns
the operator and automatically charges and discharges. Most
of these defi brillators use a single pair of disposable electrodes
to monitor the ECG and deliver the defi brillator discharge, but
some also incorporate ECG displays. The simple design and ease
of use of automated defi brillators requires very little training
and operational skill.


Operating steps
The operator attaches two adhesive defi brillator electrodes to
the cables or directly to the AED and applies the electrodes to
the patient. The AED will automatically analyze the rhythm to
determine whether defi brillation is necessary. In fully automatic
models, a shock is then automatically delivered when the rhythm
analysis determines it is necessary. In semiautomatic units the
user is prompted to deliver the shock.


Reported problems
Failure can be caused by defi brillator malfunction, poor
electrode application, inappropriate energy selection, a cardiac
physiologic state not conducive to defi brillation, or rechargeable
battery issues. First- and second-degree burns are especially
likely to occur during repeated defi brillation attempts (which
require successively higher energies) at the paddle or electrode
sites because a high current fl ow through a small area and/or
increased resistance (due to dried gel).


Types and variations
Portable, carrying case


Use and maintenance
User(s): Emergency medical services (EMS),
police offi cers, fi refi ghters, traditional
targeted responders (e.g., security guards,
fl ight attendants), nontraditional responders
(e.g., offi ce staff, family members), any
hospital staff trained in advance life support
(ALS) or basic life support (BLS).
Maintenance: Biomedical or clinical engineer/
technician, medical staff, out of hospital (e.g.,
airlines, shopping centers, emergency medical
servicers), manufacturer/servicer
Training: Initial training by manufacturer,
operator’s manuals, user’s guide


Environment of use
Settings of use: Hospital, emergency transport,
emergency medical services, patient homes,
public building or other public settings
Requirements: Fully charged battery/good
battery care and maintenance procedures
in place, uninterruptible power source (to
power and recharge batteries), proper sized
shock pads or electrodes, maintenance
procedures to monitor shelf life of shock pads
or electrodes, as well as errors returned by
internal testing trials.


Product specifi cations
Approx. dimensions (mm): 100 x 250 x 200
Approx. weight (kg): 2.5
Consumables: Batteries, cables, electrodes/
pads (with gel)
Price range (USD): 1,300 - 2,300
Typical product life time (years): 10
Shelf life (consumables): 1-2 years for
disposable electrodes/pads


Defi brillator, External, Automated; Semiautomated
UMDNS GMDN
17116
18500


Defi brillators, External, Automated
Defi brillators, External, Semiautomated


48049


48048


Non-rechargeable professional semi-
automated external defi brillator
Rechargeable professional automated external
defi brillator


Other common names:
AEDs, automated external defi brillators, automatic external defi brillators, semiautomated defi brillators, and shock-
advisory defi brillators, PADs, automated public-access defi brillators


WHO. “Defibrillator, External, Automated; Semiautomated.” From the publication: Core Medical Equipment. Geneva, Switzerland, 2011.


Brief Introduction to Defibrillators


3




http://www.who.int/medical_devices/en/index.html
© Copyright ECRI Institute 2011 (not including the GMDN code and device name).


Reproduced with Permission from ECRI Institute’s Healthcare Product Comparison System.


© Copyright GMDN Agency 2011. GMDN codes and device names are reproduced with permission from the GMDN Agency.


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n Health problem addressed
Defi brillators are lifesaving devices that apply an electric shock
to establish a more normal cardiac rhythm in patients who are
experiencing ventricular fi brillation (VF) or another shockable
rhythm.


Product description
The defi brillator charges with a large capacitor. For external
defi brillation, paddles are needed to discharge on the patient’s
chest. Disposable defi brillation electrodes may be used as an
alternative. For internal defi brillation small concave paddles are
used. An ECG monitor included is used to verify a shockable
rhythm and the effectiveness of treatment. Many defi brillators
can be equipped with optional monitoring capabilities, such as
pulse oximetry, end-tidal carbon dioxide and NIBP.


Principles of operation
Defi brillators typically have three basic modes of operation:
external defi brillation, internal defi brillation, and synchronized
cardioversion. (Sync mode uses a defi brillator discharge to correct
certain arrhythmias, such as VT; a shock is delivered only when
the control circuits sense the next R wave. The delivery of energy
is synchronized with and shortly follows the peak of the R wave,
preventing discharge during the vulnerable period of ventricular
repolarization.) An audible/visible indicator inform when the
capacitor is charged and the device is ready. ECG monitoring
can be performed before, during, and after a discharge, usually
through ECG electrodes, although most external paddles and
disposable electrodes have ECG monitoring capability. Many
defi brillators are equipped with optional monitoring capabilities
(SpO2, ETCO2, temperature, NIBP).


Operating steps
Apply the paddles to the patient’s chest and discharges the
defi brillator. Synchronized cardioversion (sync mode) uses a
defi brillator discharge to correct certain arrhythmias, such as
VT. After verifying that the sync marker pulse appears reliably on
the R wave, the operator presses and holds the paddle discharge
buttons; a shock is delivered only when the control circuits sense
the next R wave. The delivery of energy is synchronized with and
shortly follows the peak of the R wave, preventing discharge
during the vulnerable period of ventricular repolarization, which
is represented by the T wave.


Reported problems
Failure can be caused by defi brillator malfunction, poor
electrode application, inappropriate energy selection, a cardiac
physiologic state not conducive to defi brillation, or rechargeable
battery issues. First- and second-degree burns are especially
likely to occur during repeated defi brillation attempts (which
require successively higher energies) at the paddle or electrode
sites because a high current fl ow through a small area and/or
increased resistance (due to dried gel).


Use and maintenance
User(s): Physicians, nurses, other medical staff
Maintenance: Biomedical or clinical engineer/
technician, medical staff, manufacturer/
servicer
Training: Initial training by manufacturer,
operator’s manuals, user’s guide


Environment of use
Settings of use: Hospital, emergency transport
Requirements: Fully charged battery/good
battery care and maintenance procedures
in place, uninterruptible power source (to
power and recharge batteries), proper sized
shock pads or electrodes, maintenance
procedures to monitor shelf life of shock pads
or electrodes, as well as errors returned by
internal testing trials.


Product specifi cations
Approx. dimensions (mm): 250 x 300 x 250
Approx. weight (kg): 5.5
Consumables: Batteries, cables, paddles/
electrodes, gel
Price range (USD): 1,000 - 25,000
Typical product life time (years): 6-7
Shelf life (consumables): 1-2 years for
disposable electrodes/pads


Types and variations
Cart mounted, carry case


Defi brillator, External, Manual
UMDNS GMDN
11134 Defi brillators, External, Manual 37806 Manual external defi brillator


Other common names:
Battery-powered defi brillators, cardioverters, defi brillator/monitor/ pacemakers, external biphasic defi brillators, external
monophasic defi brillators, and monitor/defi brillators; DC-defi brillator, high-energy (including paddles)


WHO. “Defibrillator, External, Automated; Semiautomated.” From the publication: Core Medical Equipment. Geneva, Switzerland, 2011.


4




Defibrillation 1


Defibrillation


View of defibrillator position and placement,
using hands free electrodes.


Defibrillation is the definitive treatment for the life-threatening
cardiac arrhythmias, ventricular fibrillation and pulseless ventricular
tachycardia. Defibrillation consists of delivering a therapeutic dose of
electrical energy to the affected heart with a device called a
defibrillator. This depolarizes a critical mass of the heart muscle,
terminates the arrhythmia, and allows normal sinus rhythm to be
reestablished by the body's natural pacemaker, in the sinoatrial node of
the heart. Defibrillators can be external, transvenous, or implanted,
depending on the type of device used or needed. Some external units,
known as automated external defibrillators (AEDs), automate the
diagnosis of treatable rhythms, meaning that lay responders or
bystanders are able to use them successfully with little, or in some
cases no training at all.


History
Defibrillation was first demonstrated in 1899 by Prevost and Batelli,
two physiologists from University of Geneva, Switzerland. They discovered that small electric shocks could induce
ventricular fibrillation in dogs, and that larger charges would reverse the condition.


The first use on a human was in 1947 by Claude Beck,[1] professor of surgery at Case Western Reserve University.
Beck's theory was that ventricular fibrillation often occurred in hearts which were fundamentally healthy, in his
terms "Hearts are too good to die", and that there must be a way of saving them. Beck first used the technique
successfully on a 14 year old boy who was being operated on for a congenital chest defect. The boy's chest was
surgically opened, and manual cardiac massage was undertaken for 45 minutes until the arrival of the defibrillator.
Beck used internal paddles on either side of the heart, along with procainamide, an antiarrhythmic drug, and
achieved return of normal sinus rhythm.


These early defibrillators used the alternating current from a power socket, transformed from the 110-240 volts
available in the line, up to between 300 and 1000 volts, to the exposed heart by way of 'paddle' type electrodes. The
technique was often ineffective in reverting VF while morphological studies showed damage to the cells of the heart
muscle post mortem. The nature of the AC machine with a large transformer also made these units very hard to
transport, and they tended to be large units on wheels.


Closed-chest method
Until the early 1950s, defibrillation of the heart was possible only when the chest cavity was open during surgery.
The technique used an alternating current from a 300 or greater volt source delivered to the sides of the exposed
heart by 'paddle' electrodes where each electrode was a flat or slightly concave metal plate of about 40 mm diameter.
The closed-chest defibrillator device which applied an alternating current of greater than 1000 volts, conducted by
means of externally applied electrodes through the chest cage to the heart, was pioneered by Dr V. Eskin with
assistance by A. Klimov in Frunze, USSR (today known as Bishkek, Kyrgyzstan) in mid 1950s.[2]




Defibrillation 2


Move to direct current


A circuit diagram showing the simplest (non-electronically controlled) defibrillator
design, depending on the inductor (damping), producing a Lown, Edmark or Gurvich


Waveform


In 1959 Bernard Lown commenced
research into an alternative technique
which involved charging of a bank of
capacitors to approximately 1000 volts
with an energy content of 100-200
joules then delivering the charge
through an inductance such as to
produce a heavily damped sinusoidal
wave of finite duration (~5
milliseconds) to the heart by way of
'paddle' electrodes. The work of Lown
was taken to clinical application by
engineer Barouh Berkovits with his
"cardioverter".


The Lown waveform, as it was known,
was the standard for defibrillation until
the late 1980s when numerous studies
showed that a biphasic truncated waveform (BTE) was equally efficacious while requiring the delivery of lower
levels of energy to produce defibrillation. A side effect was a significant reduction in weight of the machine. The
BTE waveform, combined with automatic measurement of transthoracic impedance is the basis for modern
defibrillators.


Portable units become available
A major breakthrough was the introduction of portable defibrillators used out of the hospital. This was pioneered in
the early 1960s by Prof. Frank Pantridge in Belfast. Today portable defibrillators are among the many very important
tools carried by ambulances. They are the only proven way to resuscitate a person who has had a cardiac arrest
unwitnessed by EMS who is still in persistent ventricular fibrillation or ventricular tachycardia at the arrival of
pre-hospital providers.


Gradual improvements in the design of defibrillators, partly based on the work developing implanted versions (see
below), have led to the availability of Automated External Defibrillators. These devices can analyse the heart rhythm
by themselves, diagnose the shockable rhythms, and charge to treat. This means that no clinical skill is required in
their use, allowing lay people to respond to emergencies effectively.


Change to a biphasic waveform
Until the late 1980s, external defibrillators delivered a Lown type waveform (see Bernard Lown) which was a
heavily damped sinusoidal impulse having a mainly uniphasic characteristic. Biphasic defibrillation, however,
alternates the direction of the pulses, completing one cycle in approximately 10 milliseconds. Biphasic defibrillation
was originally developed and used for implantable cardioverter-defibrillators. When applied to external
defibrillators, biphasic defibrillation significantly decreases the energy level necessary for successful defibrillation.
This, in turn, decreases risk of burns and myocardial damage.


Ventricular fibrillation (VF) could be returned to normal sinus rhythm in 60% of cardiac arrest patients treated with a
single shock from a monophasic defibrillator. Most biphasic defibrillators have a first shock success rate of greater
than 90%.[3]




Defibrillation 3


Implantable devices
A further development in defibrillation came with the invention of the implantable device, known as an implantable
cardioverter-defibrillator (or ICD). This was pioneered at Sinai Hospital in Baltimore by a team that included
Stephen Heilman, Alois Langer, Jack Lattuca, Morton Mower, Michel Mirowski, and Mir Imran, with the help of
industrial collaborator Intec Systems of Pittsburgh[4] . Mirowski teamed up with Mower and Staewen, and together
they commenced their research in 1969 but it was 11 years before they treated their first patient. Similar
developmental work was carried out by Schuder and colleagues at the University of Missouri.


The work was commenced, despite doubts amongst leading experts in the field of arrhythmias and sudden death.
There was doubt that their ideas would ever become a clinical reality. In 1962 Bernard Lown introduced the external
DC defibrillator. This device applied a direct current from a discharging capacitor through the chest wall into the
heart to stop heart fibrillation.[5] In 1972, Lown stated in the journal Circulation - "The very rare patient who has
frequent bouts of ventricular fibrillation is best treated in a coronary care unit and is better served by an effective
antiarrhythmic program or surgical correction of inadequate coronary blood flow or ventricular malfunction. In fact,
the implanted defibrillator system represents an imperfect solution in search of a plausible and practical
application."[6]


The problems to be overcome were the design of a system which would allow detection of ventricular fibrillation or
ventricular tachycardia. Despite the lack of financial backing and grants, they persisted and the first device was
implanted in February 1980 at Johns Hopkins Hospital by Dr. Levi Watkins, Jr. Modern ICDs do not require a
thoracotomy and possess pacing, cardioversion, and defibrillation capabilities.


The invention of implantable units is invaluable to some regular sufferers of heart problems, although they are
generally only given to those people who have already had a cardiac episode.


Types


Manual external defibrillator


External defibrillator / monitor


The units are used in conjunction with (or more often have inbuilt)
electrocardiogram readers, which the healthcare provider uses to
diagnose a cardiac condition (most often fibrillation or tachycardia
although there are some other rhythms which can be treated by
different shocks). The healthcare provider will then decide what charge
(in joules) to use, based on proven guidelines and experience, and will
deliver the shock through paddles or pads on the patient's chest. As
they require detailed medical knowledge, these units are generally only
found in hospitals and on some ambulances. For instance, every NHS
ambulance in the United Kingdom is equipped with a manual
defibrillator for use by the attending paramedics and technicians. In the
United States, many advanced EMTs and all paramedics are trained to recognize lethal arrhythmias and deliver
appropriate electrical therapy with a manual defibrillator when appropriate.




Defibrillation 4


Manual internal defibrillator
These are the direct descendants of the work of Beck and Lown. They are virtually identical to the external version,
except that the charge is delivered through internal paddles in direct contact with the heart. These are almost
exclusively found in operating theatres, where the chest is likely to be open, or can be opened quickly by a surgeon.


Automated external defibrillator (AED)


An AED at a railway station in Japan. The AED
box has information on how to use it in Japanese,
English, Chinese and Korean, and station staff are


trained to use it.


These simple-to-use units are based on computer technology which is
designed to analyze the heart rhythm itself, and then advise the user
whether a shock is required. They are designed to be used by lay
persons, who require little training to operate them correctly. They are
usually limited in their interventions to delivering high joule shocks for
VF (ventricular fibrillation) and VT (ventricular tachycardia) rhythms,
making them generally of limited use to health professionals, who
could diagnose and treat a wider range of problems with a manual or
semi-automatic unit.


The automatic units also take time (generally 10–20 seconds) to
diagnose the rhythm, where a professional could diagnose and treat the
condition far more quickly with a manual unit.[7] These time intervals
for analysis, which require stopping chest compressions, have been
shown in a number of studies to have a significant negative effect on
shock success.[8] This effect led to the recent change in the AHA
defibrillation guideline (calling for two minutes of CPR after each
shock without analyzing the cardiac rhythm) and some bodies
recommend that AEDs should not be used when manual defibrillators
and trained operators are available.[7]


Automated external defibrillators are generally either held by trained personnel who will attend incidents, or are
public access units which can be found in places including corporate and government offices, shopping centres,
airports, restaurants, casinos, hotels, sports stadiums, schools and universities, community centers, fitness centers
and health clubs.




Defibrillation 5


An automated external defibrillator, open and
ready for pads to be attached


The locating of a public access AED should take in to account where
large groups of people gather, and the risk category associated with
these people, to ascertain whether the risk of a sudden cardiac arrest
incident is high. For example, a center for teenage children is a
particularly low risk category (as children very rarely enter heart
rhythms such as VF (Ventricular Fibrillation) or VT (Ventricular
Tachycardia), being generally young and fit, and the most common
causes of pediatric cardiac arrest are respiratory arrest and trauma -
where the heart is more likely to enter asystole or PEA, (where an
AED is of no use). On the other hand, a large office building with a
high ratio of males over 50 is a very high risk environment.


In many areas, emergency services vehicles are likely to carry AEDs.
EMT-Basics in most areas are not trained in manual defibrillation, and
often carry an AED instead. Some ambulances carry an AED in
addition to a manual unit. In addition, some police or fire service
vehicles carry an AED for first responder use. Some areas have
dedicated community first responders, who are volunteers tasked with


keeping an AED and taking it to any victims in their area. It is also increasingly common to find AEDs on transport
such as commercial airlines and cruise ships. The presence of an AED can be a particularly decisive factor in cardiac
patient survival in these scenarios, as professional medical assistance may be hours away.


In order to make them highly visible, public access AEDs often are brightly coloured, and are mounted in protective
cases near the entrance of a building. When these protective cases are opened, and the defibrillator removed, some
will sound a buzzer to alert nearby staff to their removal but do not necessarily summon emergency services. All
trained AED operators should also know to phone for an ambulance when sending for or using an AED, as the
patient will be unconscious, which always requires ambulance attendance.


Semi-automated external defibrillators


A Lifepak semi-automatic defibrillator/ECG
monitor mounted in an ambulance. These units


are designed for use only by healthcare
professionals and are capable of measuring blood
pressure and blood oxygen saturation in addition


to the primary functions


. These units are a compromise between a full manual unit and an
automated unit. They are mostly used by pre-hospital care
professionals such as paramedics and emergency medical technicians.
These units have the automated capabilities of the AED but also
feature an ECG display, and a manual override, where the clinician can
make their own decision, either before or instead of the computer.
Some of these units are also able to act as a pacemaker if the heart rate
is too slow (bradycardia) and perform other functions which require a
skilled operator.


Implantable cardioverter-defibrillator (ICD)


Also known as automatic internal cardiac defibrillator (AICD). These
devices are implants, similar to pacemakers (and many can also
perform the pacemaking function). They constantly monitor the
patient's heart rhythm, and automatically administer shocks for various life threatening arrhythmias, according to the
device's programming. Many modern devices can distinguish between ventricular fibrillation, ventricular


tachycardia, and more benign arrhythmias like supraventricular tachycardia and atrial fibrillation. Some devices may
attempt overdrive pacing prior to synchronised cardioversion. When the life threatening arrhythmia is ventricular




Defibrillation 6


fibrillation, the device is programmed to proceed immediately to an unsynchronized shock.


There are cases where the patient's ICD may fire constantly or inappropriately. This is considered a medical
emergency, as it depletes the device's battery life, causes significant discomfort and anxiety to the patient, and in
some cases may actually trigger life threatening arrhythmias. Some emergency medical services personnel are now
equipped with a ring magnet to place over the device, which effectively disables the shock function of the device
while still allowing the pacemaker to function (if the device is so equipped). If the device is shocking frequently, but
appropriately, EMS personnel may administer sedation.


Wearable cardiac defibrillator
A development of the AICD is a portable external defibrillator that is worn like a vest.[9] The unit monitors the
patient 24 hours a day and will automatically deliver a biphasic shock if needed. This device is mainly indicated in
patients awaiting an implantable defibrillator. Currently only one company manufactures these and they are of
limited availability.


Modelling defibrillation
The efficacy of a cardiac defibrillator is highly dependent on the position of its electrodes. Most internal
defibrillators are implanted in octogenarians, but a few children need the devices. Implanting defibrillators in kids is
particularly difficult because children are small, will grow over time, and possess cardiac anatomy that differs from
that of adults. Recently, researchers were able to create a software modeling system capable of mapping an
individual’s thorax and determining the optimal position for an external or internal cardiac defibrillator.
With the help of pre-existing surgical planning applications, the software uses myocardial voltage gradients to
predict the likelihood of successful defibrillation. According to the critical mass hypothesis, defibrillation is effective
only if it produces a threshold voltage gradient in a large fraction of the myocardial mass. Usually, a gradient of
three to five volts per centimeter is needed in 95 % of the heart. Voltage gradients of over 60 V/cm can damage
tissue. The modeling software seeks to obtain safe voltage gradients above the defibrillation threshold.


Early simulations using the software suggest that small changes in electrode positioning can have large effects on
defibrillation, and despite engineering hurdles that remain, the modeling system promises to help guide the
placement of implanted defibrillators in children and adults.


Recent mathematical models of defibrillation are based on the bidomain model of cardiac tissue. [10] Calculations
using a realistic heart shape and fiber geometry are required to determine how cardiac tissue responds to a strong
electrical shock.


Interface with the patient
The most well-known type of electrode (widely depicted in films and television) is the traditional metal paddle with
an insulated (usually plastic) handle. This type must be held in place on the patient's skin while a shock or a series of
shocks is delivered. Before the paddle is used, a gel must be applied to the patient's skin, in order to ensure a good
connection and to minimize electrical resistance, also called chest impedance (despite the DC discharge). These are
generally only found on the manual external units.


Newer types of resuscitation electrodes are designed as an adhesive pad. These are peeled off their backing and
applied to the patient's chest when deemed necessary, much the same as any other sticker. These electrodes are then
connected to a defibrillator. If defibrillation is required, the machine is charged, and the shock is delivered, without
any need to apply any gel or to retrieve and place any paddles. These adhesive pads are found on most automated
and semi-automated units, and are gradually replacing paddles entirely in non-hospital settings.


Both solid- and wet-gel adhesive electrodes are available. Solid-gel electrodes are more convenient, because there is
no need to clean the patient's skin after removing the electrodes. However, the use of solid-gel electrodes presents a




Defibrillation 7


higher risk of burns during defibrillation, since wet-gel electrodes more evenly conduct electricity into the body.


Some adhesive electrodes are designed to be used not only for defibrillation, but also for transcutaneous pacing and
synchronized electrical cardioversion.


In a hospital setting, paddles are generally preferred to pads, due to the inherent speed with which they can be placed
and used. This is critical during cardiac arrest, as each second of nonperfusion means tissue loss. However, in cases
in which cardiac arrest is suspected, patches placed prophalacticaly are superior,as they provide appropriate EKG
tracing without the artifact visible from human interference with the paddles. Adhesive electrodes are also inherently
safer than the paddles for the operator of the defibrillator to use, as they minimize the risk of the operator coming
into physical (and thus electrical) contact with the patient as the shock is delivered, by allowing the operator to stand
several feet away. Adhesive patches also require no force to remain in place and deliver the shock appropriately,
whereas paddles require approximately 25 lbs of force to be applied while the shock is delivered.[Citation Needed]


Placement


Anterio-apical placement of external defibrillator
electrodes (When defibrillation is unsuccessful,
anterior-posterior placement is also sometimes


attempted)


Resuscitation electrodes are placed according to one of two
schemes. The anterior-posterior scheme (conf. image) is the
preferred scheme for long-term electrode placement. One
electrode is placed over the left precordium (the lower part of the
chest, in front of the heart). The other electrode is placed on the
back, behind the heart in the region between the scapula. This
placement is preferred because it is best for non-invasive pacing.


The anterior-apex scheme can be used when the anterior-posterior
scheme is inconvenient or unnecessary. In this scheme, the
anterior electrode is placed on the right, below the clavicle. The
apex electrode is applied to the left side of the patient, just below
and to the left of the pectoral muscle. This scheme works well for defibrillation and cardioversion, as well as for
monitoring an ECG.


Popular culture references
As devices that can quickly produce dramatic improvements in patient health, defibrillators are often depicted in
movies and television. Their function, however, is often exaggerated, with the defibrillator inducing a sudden,
violent jerk or convulsion by the patient; in reality, although the muscles may contract, such dramatic patient
presentation is rare. Similarly, medical providers are often depicted defibrillating patients with a "flat-line" ECG
rhythm (also known as asystole); this is not done in real life. Only the cardiac arrest rhythms ventricular fibrillation
and pulseless ventricular tachycardia are normally defibrillated. (There are also several heart rhythms that can be
"shocked" when the patient is not in cardiac arrest, such as supraventricular tachycardia and ventricular tachycardia
that produces a pulse; this procedure is known as cardioversion, not defibrillation.)


In Australia up until the 1990s it was quite rare for ambulances to carry defibrillators. This changed in 1990 after
Australian media mogul Kerry Packer had a heart attack and, purely by chance, the ambulance that responded to the
call carried a defibrillator. After recovering, Kerry Packer donated a large sum to the Ambulance Service of New
South Wales in order that all ambulances in New South Wales should be fitted with a personal defibrillator, which is
why defibrillators in Australia are colloquially called "Packer Whackers".[11]




Defibrillation 8


See also
• Cardiopulmonary resuscitation (CPR)
• Advanced cardiac life support (ACLS)
• Cardioversion
• Automated external defibrillator
• Myocardial infarction (heart attack)
• Ambulance
• Wearable Cardioverter Defibrillator


References
[1] "Claude Beck, defibrillation and CPR" (http:/ / www. case. edu/ artsci/ dittrick/ site2/ museum/ artifacts/ group-c/ c-8defrib. htm). Case


Western Reserve University. . Retrieved 2007-06-15.
[2] Sov Zdravookhr Kirg.. "Some results with the use of the DPA-3 defibrillator (developed by V. Ia. Eskin and A. M. Klimov) in the treatment


of terminal states" (http:/ / www. ncbi. nlm. nih. gov/ entrez/ query. fcgi?cmd=Retrieve& db=PubMed& list_uids=5880446& dopt=Abstract)
(in Russian). . Retrieved 2007-08-26.


[3] Heart Smarter: EMS Implications of the 2005 AHA Guidelines for ECC & CPR (http:/ / www. jems. com/ data/ pdf/ AHA_Supplement. pdf)
pp 15-16


[4] http:/ / www3. interscience. wiley. com/ journal/ 118913850/ abstract?CRETRY=1& SRETRY=0
[5] Aston, Richard (1991). Principles of Biomedical Instrumentation and Measurement: International Edition. Merrill Publishing Company.


ISBN 0-02-946562-1.
[6] "Pacemaker Failure following External Defibrillation" (http:/ / circ. ahajournals. org/ cgi/ reprint/ 45/ 5/ 1144-a. pdf). Circulation: Journal of


the American Heart Association. 1972. ISSN 1524-4539. .
[7] editors Jasmeet Soar ...; Soar, J; Nolan, J;Perkins, G; Scott, M;Goodman, N;Mitchell, S (2006). Immediate Life Support: Second Edition.


Resuscitation Council (UK). ISBN 1-903812-12-7.
[8] Eftestol T, Sunde K, Steen PA. Effects of interrupting precordial compressions on the calculated probability of defibrillation success during


out-of-hospital cardiac arrest. Circulation 2002;105:2270-3
[9] "What is the LifeVest?" (http:/ / www. zoll. lifecor. com/ about_lifevest/ about. asp). Zoll Lifecor. . Retrieved 2009-02-09.
[10] Trayanova N (2006). "Defibrillation of the heart: insights into mechanisms from modelling studies". Experimental Physiology 91 (2):


323–337. doi:10.1113/expphysiol.2005.030973. PMID 16469820.
[11] "Defibrillation" (http:/ / medical-dictionary. thefreedictionary. com/ Packer+ Whacker). Farlex, Inc.. . Retrieved 2009-04-21.


• Picard, André (2007-04-27). "School defibrillators could be lifesavers" (http:/ / www. theglobeandmail. com/
servlet/ story/ RTGAM. 20070427. wxldefib27/ BNStory/ specialScienceandHealth/ home). The Globe and Mail.
Retrieved 2008-06-20.


External links
• Sudden Cardiac Arrest Foundation (http:/ / www. sca-aware. org/ )
• Center for Integration of Medicine and Innovative Technology (http:/ / www. cimit. org)
• American Red Cross: Saving a Life is as Easy as A-E-D (http:/ / www. redcross. org/ services/ hss/ courses/ aed.


html)
• FDA Heart Health Online: Automated External Defibrillator (AED) (http:/ / www. fda. gov/ hearthealth/


treatments/ medicaldevices/ aed. html)
• Resuscitation Council (UK) (http:/ / www. resus. org. uk)
• History of defibrillation (http:/ / efimov. wustl. edu/ defibrillation/ history/ defibrillation_history. htm)
• How an internal defibrillator is implanted (http:/ / heartcenter. seattlechildrens. org/ what_to_expect/ pacemakers.


asp) from Children's Hospital Heart Center, Seattle.




Article Sources and Contributors 9


Article Sources and Contributors
Defibrillation  Source: http://en.wikipedia.org/w/index.php?oldid=359342620  Contributors: 1337pino, Aatrek, Adw2000, Alansohn, AnnaFrance, Aruton, Badger151, Bongwarrior,
Bradjamesbrown, Bricaniwi, C3o, CambridgeBayWeather, Cburnett, Cimiteducation, Clarince63, Coralmizu, Countincr, Cygnosis, DefibrillatorHub, Delldude101, Discospinster, Dj stone,
Djinn112, Dnvrfantj, Dokane, Donfbreed, Dycedarg, Eastmain, Eh-Steve, Ehudzel, Emperorbma, Esperant, Firsfron, Footwarrior, Furrykef, Gene Nygaard, Geoffrey Wickham, Gilo1969,
Gnusmas, Heggyhomolit, Hehkuviini, Hugh2414, Iefimov, Infralap, Iridescent, J.delanoy, Jaapinwiki, Jackliddle, Jastewart, JessicaK15, Jet731, Jfdwolff, Joel7687, John Hill, Johnpnagy,
Jovianeye, Jpmizell, Kakofonous, Kchishol1970, Keilana, Kingturtle, Kitch, Kkailas, Ksheka, Kylu, LandruBek, Largoplazo, Lattucak, Lc3i, Lolmaster, Londonsista, Lwg9q, Lynbarn,
Maximillion Pegasus, Medicellis, Mi28, Michael Devore, Mikr18, Mild Bill Hiccup, Mnokel, Modster, Montrealais, MoodyGroove, Moscvitch, ObtuseMarginal, Owain.davies, Oxymoron83,
Pakaraki, Piano non troppo, Pixeltoo, Rama, Ravik, Rhezalouis, Richardcavell, Rjwilmsi, Rorynic, Rothbrad, RoyBoy, Rsabbatini, Sassf, Scottalter, Sdumont, Sfcollegeguy, Sgpsaros,
SiobhanHansa, SkyWalker, Snalwibma, Snorks1234, Snoyes, Someone else, Spitfire, Spra, Squiggle, Stadler981, Stare at the sun, Sumthingweird, SuperHamster, SwissArmyLight, TUF-KAT,
Tabuhan, Terra Green, Thumperward, Tjwood, TofuMatt, Trainspotter, Trevor Johns, Tristanb, UniQue tree, Uruiamme, Vegaswikian, Walden, WhyBeNormal, Wik, Wolfmankurd,
Wouterstomp, Xiner, Xkcd, Zephyrad, Zhang He, 225 anonymous edits


Image Sources, Licenses and Contributors
Image:Defibrillation Electrode Position.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Defibrillation_Electrode_Position.jpg  License: Creative Commons Attribution-Sharealike
3.0  Contributors: PhilippN
Image:Defrib.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Defrib.svg  License: GNU Free Documentation License  Contributors: Original uploader was Wolfmankurd at
en.wikipedia


Image:Defibrillator Monitor.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Defibrillator_Monitor.jpg  License: Creative Commons Attribution-Sharealike 2.5  Contributors:
User:Ernstl


Image:AED Oimachi 06z1399sv.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:AED_Oimachi_06z1399sv.jpg  License: BSD  Contributors: User:Cory
Image:AED Open.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:AED_Open.jpg  License: Public Domain  Contributors: User:Owain.davies
Image:lifepak.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Lifepak.JPG  License: GNU Free Documentation License  Contributors: User:Heggyhomolit
Image:Defib electrode placement.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Defib_electrode_placement.JPG  License: GNU Free Documentation License  Contributors:
Andersat, Glenn, Staph, Stevenfruitsmaak, 3 anonymous edits


License
Creative Commons Attribution-Share Alike 3.0 Unported
http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/




Automated external defibrillator 1


Automated external defibrillator


An automated external defibrillator,
open and ready for pads to be


attached


An automated external defibrillator or AED is a portable electronic device that
automatically diagnoses the potentially life threatening cardiac arrhythmias of
ventricular fibrillation and ventricular tachycardia in a patient,[1] and is able to
treat them through defibrillation, the application of electrical therapy which stops
the arrhythmia, allowing the heart to reestablish an effective rhythm.


AEDs are designed to be simple to use for the layman, and the use of AEDs is
taught in many first aid, first responder and basic life support (BLS) level CPR
classes.[2]


Usage


Conditions that the Device Treats


An automated external defibrillator is used in cases of life threatening
cardiac arrhythmias which lead to cardiac arrest. The rhythms that the
device will treat are usually limited to:


1. Pulseless Ventricular tachycardia (shortened to VT or V-Tach)[1]


2. Ventricular fibrillation (shortened to VF or V-Fib)


In each of these two types of shockable cardiac arrhythmia, the heart is
active, but in a life-threatening, dysfunctional pattern. In ventricular
tachycardia, the heart beats too fast to effectively pump blood. Ultimately, ventricular tachycardia leads to
ventricular fibrillation. In ventricular fibrillation, the electrical activity of the heart becomes chaotic, preventing the
ventricle from effectively pumping blood. The fibrillation in the heart decreases over time, and will eventually reach
asystole.


AEDs, like all defibrillators, are not designed to shock asystole ('flat line' patterns) as this will not have a positive
clinical outcome. The asystolic patient only has a chance of survival if, through a combination of CPR and cardiac
stimulant drugs, one of the shockable rhythms can be established, which makes it imperative for CPR to be carried
out prior to the arrival of a defibrillator.




Automated external defibrillator 2


Effect of Delayed Treatment
Uncorrected, these cardiac conditions (ventricular tachycardia, ventricular fibrillation, asystole) rapidly lead to
irreversible brain damage and death. After approximately three to five minutes,[3] irreversible brain/tissue damage
may begin to occur. For every minute that a person in cardiac arrest goes without being successfully treated (by
defibrillation), the chance of survival decreases by 10 percent.[4]


Requirements for Use
AEDs are designed to be used by laypersons who ideally should have received AED training. This is in contrast to
more sophisticated manual and semi-automatic defibrillators used by health professionals, which can act as a
pacemaker if the heart rate is too slow (bradycardia) and perform other functions which require a skilled operator
able to read electrocardiograms.


Bras with a metal underwire and piercings on the torso must be removed before using the AED on someone to avoid
interference.[5]


A study analyzed the effects of having AEDs immediately present during Chicago's Heart Start program over a two
year period. Of 22 individuals 18 were in a cardiac arrhythmia which AEDs can treat (Vfib or Vtach). Of these 18,
11 survived. More interestingly, of these 11 patients, 6 were treated by good Samaritan bystanders with absolutely
no previous training in AED use.[6] [7]


Placement and Availability


An AED at a railway station in
Japan.


Automated external defibrillators are generally either held by trained personnel
who will attend events or are public access units which can be found in places
including corporate and government offices, shopping centres, airports,
restaurants, casinos, hotels, sports stadiums, schools and universities, community
centers, fitness centers, health clubs, workplaces and any other location where
people may congregate.


The location of a public access AED should take in to account where large
groups of people gather, regardless of age or activity. Children as well as adults
may fall victim to sudden cardiac arrest (SCA)


In many areas, emergency vehicles are likely to carry AEDs, with some
ambulances carrying an AED in addition to manual defibrillators. Police or fire
vehicles often carry an AED for first responder use. Some areas have dedicated
community first responders, who are volunteers tasked with keeping an AED and
taking it to any victims in their area. AEDs are also increasingly common on
commercial airlines, cruise ships, and other transportation facilities.


In order to make them highly visible, public access AEDs often are brightly
colored, and are mounted in protective cases near the entrance of a building.
When these protective cases are opened or the defibrillator is removed, some will
sound a buzzer to alert nearby staff to their removal, though this does not
necessarily summon emergency services; trained AED operators should know to
phone for an ambulance when sending for or using an AED. In September 2008,
the International Liaison Committee on Resuscitation issued a 'universal AED
sign' to be adopted throughout the world to indicate the presence of an AED, and
this is shown at right.[8]




Automated external defibrillator 3


A trend that is developing is the purchase of AEDs to be used in the home, particularly by those with known existing
heart conditions.[9] The number of devices in the community has grown as prices have fallen to affordable levels.
There has been some concern among medical professionals that these home users do not necessarily have
appropriate training,[10] and many advocate the more widespread use of community responders, who can be
appropriately trained and managed.


Typically, an AED kit will contain a face shield for providing a barrier between patient and first aider during rescue
breathing; a pair of nitrile rubber gloves; a pair of trauma shears for cutting through a patient's clothing to expose the
chest; a small towel for wiping away any moisture on the chest, and a razor for shaving those with very hairy
chests.[11]


Preparation for operation
Most manufacturers recommend checking the AED before every period of duty or on a regular basis for fixed units.
Some units need to be switched on in order to perform a self check; other models have a self check system built in
with a visible indicator.


All manufacturers mark their pads with an expiry date, and it is important to ensure that the pads are in date. This is
usually marked on the outside of the pads. Some models are designed to make this date visible through a 'window',
although others will require the opening of the case to find the date stamp.


Mechanism of operation


The use of easily visible status indicator and pad
expiration date on one model of AED


An AED is external because the operator applies the electrode pads to
the bare chest of the victim, as opposed to internal defibrillators, which
have electrodes surgically implanted inside the body of a patient.


Automatic refers to the unit's ability to autonomously analyse the
patient's condition, and to assist this, the vast majority of units have
spoken prompts, and some may also have visual displays to instruct the
user.


When turned on or opened, the AED will instruct the user to connect
the electrodes (pads) to the patient. Once the pads are attached,
everyone should avoid touching the patient so as to avoid false
readings by the unit. The pads allow the AED to examine the electrical
output from the heart and determine if the patient is in a shockable
rhythm (either ventricular fibrillation or ventricular tachycardia). If the
device determines that a shock is warranted, it will use the battery to
charge its internal capacitor in preparation to deliver the shock. This
system is not only safer (charging only when required), but also allows
for a faster delivery of the electrical current.


When charged, the device instructs the user to ensure no one is touching the patient and then to press a button to
deliver the shock; human intervention is usually required to deliver the shock to the patient in order to avoid the
possibility of accidental injury to another person (which can result from a responder or bystander touching the
patient at the time of the shock). Depending on the manufacturer and particular model, after the shock is delivered
most devices will analyze the patient and either instruct CPR to be given, or administer another shock.


Many AED units have an 'event memory' which store the ECG of the patient along with details of the time the unit
was activated and the number and strength of any shocks delivered. Some units also have voice recording abilities to
monitor the actions taken by the personnel in order to ascertain if these had any impact on the survival outcome. All
this recorded data can be either downloaded to a computer or printed out so that the providing organisation or




Automated external defibrillator 4


responsible body is able to see the effectiveness of both CPR and defibrillation.


The first commercially available AEDs were all of a monophasic type, which gave a high-energy shock, up to 360 to
400 joules depending on the model. This caused increased cardiac injury and in some cases second and third-degree
burns around the shock pad sites. Newer AEDs (manufactured after late 2003) have tended to utilise biphasic
algorithms which give two sequential lower-energy shocks of 120 - 200 joules, with each shock moving in an
opposite polarity between the pads. This lower-energy waveform has proven more effective in clinical tests, as well
as offering a reduced rate of complications and reduced recovery time.[12]


Simplicity of use


Usual placement of pads on chest


Unlike regular defibrillators, an automated external defibrillator
requires minimal training to use. It automatically diagnoses the
heart rhythm and determines if a shock is needed. Automatic
models will administer the shock without the user's command.
Semi-automatic models will tell the user that a shock is needed,
but the user must tell the machine to do so, usually by pressing a
button. In most circumstances, the user cannot override a "no
shock" advisory by an AED. Some AEDs may be used on children
- those under 55 lbs (25 kg) in weight or under age 8. If a
particular model of AED is approved for pediatric use, all that is required is the use of more appropriate pads. Some
organizations, such as the American Heart Association, recommend that if pediatric AED pads are not available,
adult pads should be used to determine if the child is in a shockable rhythm. There is insufficient evidence to suggest
that a child, in a shockable cardiac arrest, can be "hurt" by an adult defibrillation energy setting.


All AEDs approved for use in the United States use an electronic voice to prompt users through each step. Because
the user of an AED may be hearing impaired, many AEDs now include visual prompts as well. Most units are
designed for use by non-medical operators. Their ease of use has given rise to the notion of public access
defibrillation (PAD), which experts agree has the potential to be the single greatest advance in the treatment of
out-of-hospital cardiac arrest since the invention of CPR.[13]


Liability
Automated external defibrillators are now easy enough to use that most states in the United States include the "good
faith" use of an AED by any person under the Good Samaritan laws.[14] "Good faith" protection under a Good
Samaritan law means that a volunteer responder (not acting as a part of one's occupation) cannot be held civilly
liable for the harm or death of a victim by providing improper or inadequate care, given that the harm or death was
not intentional and the responder was acting within the limits of their training and in good faith. In the United States,
Good Samaritan laws provide some protection for the use of AEDs by trained and untrained responders.[15] AEDs
create little liability if used correctly;[16] NREMT-B and many state EMT training and many CPR classes
incorporate or offer AED education as a part of their program. In addition to Good Samaritan laws, Ontario, Canada
also has the "Chase McEachern Act (Heart Defibrillator Civil Liability), 2007 (Bill 171 – Subsection N)", passed in
June, 2007,[17] which protects individuals from liability for damages that may occur from their use of an AED to
save someone's life at the immediate scene of an emergency unless damages are caused by gross negligence.




Automated external defibrillator 5


External links
• American Heart Association: Learn & Live [18]


• American Red Cross: Saving a Life is as Easy as A-E-D [19]


• FDA Heart Health Online: Automated External Defibrillator (AED) [20]


• Resuscitation Council (UK) [21]


References
[1] Kerber, Richard E; Becker, Lance B; Bourland, Joseph D; Cummins, Richard O; Hallstrom, Alfred P; Michos, Mary B; Nichol, Graham;


Ornato, Joseph P; Thies, William H; White, Roger D; Zuckerman, Bram D (March 18, 1997). "Automatic External Defibrillators for Public
Access Defibrillation" (http:/ / circ. ahajournals. org/ cgi/ content/ full/ 95/ 6/ 1677). Circulation (American Heart Association) 95
(1677-1682): 1677. PMID 9118556. . Retrieved 2007-06-28.


[2] "CPR Adult Courses" (http:/ / www. redcross. org/ services/ hss/ courses/ adultcpraed. html). American Red Cross. . Retrieved 2007-06-28.
[3] "Cardiopulmonary Resuscitation (CPR) Statistics" (http:/ / www. americanheart. org/ presenter. jhtml?identifier=4483). American Red Cross.


. Retrieved 2008-10-27.
[4] American Red Cross. CPR/AED for the Professional Rescuer (participant's manual). Yardley, PA: StayWell, 2006. (page 63).
[5] de Vries, Lloyd (2006-03-22). "Breathing Easier" (http:/ / www. cbsnews. com/ stories/ 2006/ 03/ 22/ opinion/ garver/ main1429483. shtml).


CBS News. . Retrieved 2009-04-22. "We got a short lesson in using an AED, which is an Automated External Defibrillator. We had the thrill
of yelling, "Clear!" Unfortunately this also brought on a little anxiety when Sean mentioned if the patient were a woman with a metal
underwire in her bra or with metal piercings on her torso, we'd have to remove them."


[6] Caffrey SL, Willoughby PJ, Pepe PE, Becker LB (October 2002). "Public use of automated external defibrillators". N. Engl. J. Med. 347 (16):
1242–7. doi:10.1056/NEJMoa020932. PMID 12393821.


[7] http:/ / beavermedic. wordpress. com/ 2010/ 02/ 10/ look-for-me-in-airportshockey-arenas/
[8] "ILCOR presents a universal AED sign" (http:/ / www. erc. edu/ index. php/ newsItem/ en/ nid=204/ ). European Resuscitation Council. .
[9] "Heartstart Home Defibrillator" (http:/ / www. heartstarthome. com/ content/ why_defibrillators/ why_defibs2_detail. asp). Philips


Electronics. . Retrieved 2007-06-15.
[10] Barnaby, Barnaby J (2005-05-03). "Do It Yourself: The Home Heart Defibrillator" (http:/ / www. nytimes. com/ 2005/ 05/ 03/ business/


03jolt. html?ei=5088& en=84d7afacd0fd7943& ex=1272772800& partner=rssnyt& emc=rss& pagewanted=all& position=). New York
Times. . Retrieved 2007-06-15.


[11] CPR/AED for the Professional Rescuer, supra, page 65 ("[a] safety surgical razor should be included in the AED kit.") The other items not
directly mentioned in this text but are used in AED preparation, such as the gloves (used throughout patron assessment) and the towel, as the
chest should be dried prior to AED pad attachment (id, at page 64).


[12] "AED Plus Biphasic Waveform" (http:/ / www. zoll. com/ product_resource. aspx?id=728). ZOLL Medical Corporation. . Retrieved
2008-10-27.


[13] Introduction to the International Guidelines 2000 for CPR and ECC (http:/ / circ. ahajournals. org/ cgi/ content/ full/ 102/ suppl_1/
I-1?ijkey=0ea84b1fa73ef72b72aef923e0f1adc6d4fd6ba5& keytype2=tf_ipsecsha)


[14] Laws on Cardiac Arrest and Defibrillators, 2008 update. (http:/ / www. ncsl. org/ programs/ health/ aed. htm) National Conference of State
Legislatures. Retrieved on 2008-03-23.


[15] State Laws on Heart Attacks, Cardiac Arrest & Defibrillators (http:/ / www. ncsl. org/ programs/ health/ aed. htm)
[16] Laws on Cardiac Arrest and Defibrillators (http:/ / www. ncsl. org/ default. aspx?tabid=14506)
[17] Health System Improvement Act, 2007 (http:/ / www. e-laws. gov. on. ca/ DBLaws/ Source/ Statutes/ English/ 2007/ S07010_e. htm)


Retrieved on 26 June 2007
[18] http:/ / www. americanheart. org/ presenter. jhtml?identifier=1200000
[19] http:/ / www. redcross. org/ services/ hss/ courses/ aed. html
[20] http:/ / www. fda. gov/ hearthealth/ treatments/ medicaldevices/ aed. html
[21] http:/ / www. resus. org. uk




Article Sources and Contributors 6


Article Sources and Contributors
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Alan012, Alexius08, AllureOfTheEarth, Andrewpmk, Anon lynx, BRUTE, Bdesham, Beao, Beetstra, Brat32, Brendandh, Byronbarny, CPRLongIsland, Captain Courageous, CarTitans, Cburnett,
Cdang, Cfparker, Chaimw21, Closedmouth, Cmichael, Coderedkyle, Compsign, Coralmizu, Cuvtixo, CyberDragon777, Darylcheng, Dbchip, Diderot, Discospinster, Editor at Large, Equendil,
Erich gasboy, Gabbe, GeeCee, Gnusmas, GraemeMcRae, Graham87, Gurch, Hashar, Heartguy, Hooperbloob, Hqb, Imroy, Islander, J.delanoy, Jclemens, Jpearson304, Justinfr, KPH2293, Kerttie,
Ketiltrout, Khalnath, Killing sparrows, Kjlewis, KnightRider, Kosebamse, Krisjag, Ksheka, Kubigula, Lifeguardmedical, LinguistAtLarge, Lschneid, Lungguy, Lwg9q, M7, MastCell,
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Sounddude, Stuston, Sultan Edijingo, The Thing That Should Not Be, Tide rolls, TimidGuy, Trusilver, Tsgttucker, Tupolev154, Underpants, Usanetsol, Veinor, VengeancePrime, VigilancePrime,
190 anonymous edits


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Andersat, Glenn, Staph, Stevenfruitsmaak, 3 anonymous edits


License
Creative Commons Attribution-Share Alike 3.0 Unported
http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/




Equipment found in the OR, ICU and ER


Page 38


2.8 Defibrillators


2.8.1 Clinical Use and Principles of Operation

A defibrillator is used to reverse fibrillation of the heart, restoring the heart’s normally
coordinated contractions. The uncoordinated contractions of the heart can take place in the
atrial, or upper, chamber of the heart as well as in the heart’s ventricular, or lower, chamber.
Atrial fibrillation (AF) is relatively common and can be well tolerated by the patient. Ventricular
fibrillation (VF) causes the heart to stop pumping blood immediately, and is therefore fatal if not
treated within minutes. Death from VF is often called a massive heart attack and is the most
common cause of death.

The defibrillator works by delivering a brief, very strong, electrical shock across the chest. The
typical pulse is 10 ms and as much as 3000 V. Energies ranging from 300 to 360 J are used
during external ventricular defibrillation. While treatment of ventricular fibrillation is the most
common use in the developing world, most hospital defibrillators can also treat ventricular
tachycardia, where the heart beats too quickly, but in a coordinated fashion. Energies for
treatment of ventricular tachycardia are typically below 200 J.

There are several different types of defibrillators. The most common in the developing world is
the manual defibrillator. The most common in the developed world is the automated external
defibrillators. The implantable defibrillator and the home defibrillator are very rare in the
developing world.




The manual defibrillator is a box about 1.5 cubic feet in size, weighing around ten pounds.
Cables connect two large metal paddles, which are used to apply the electric shock to the
patient. ECG leads can also be connected from the device to the patient. However, most can
monitor the ECG through the defibrillation paddles as well. When the ECG connections are used,
the ECG can be manipulated in many of the same ways as a bedside monitor.

Defibrillator paddles come in several types: external adult, external pediatric, internal (there are
several sizes, all used when the chest is open) and disposable or adhesive electrodes. The
external adult and pediatric defibrillators require a conductive gel to be added between the
patient and the paddle. The gel is used to assure conduction between the paddles and the chest
wall.

The defibrillator works by charging a capacitor, then discharging part of the stored energy in the
capacitor through the patient. Older defibrillators discharged through an LCR circuit to the


The manual defibrillator is commonly found
in the developing world. The unit on the
left includes an ECG monitor. The device
delivers a potentially lethal shock and
should be worked on with great care.


Malkin, Robert. Medical Instrumentation in the Developing World. Engineering World Health, 2006.


Operation and Use of Defibrillators


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Medical Instruments in the Developing World Malkin


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patient. In these devices, the pulse can be as high as 7,500 volts. These discharge circuits have
a characteristic waveform to the discharge current called an Edmark waveform. Edmark
waveform devices are still very common in the developing world. Because the Edmark waveform
can cause severe damage, even death, everyone should stand clear of the patient during the
delivery of the discharge of the capacitor. More modern defibrillators discharge the capacitor
through a transistor network to deliver a more effective, biphasic, waveform. The biphasic
waveform is less likely to cause damage, but the risk still exists.

All defibrillators have a battery back-up system. This way you can bring the defibrillator to the
patient, instead of bringing the patient to the defibrillator, which could add minutes to the time
until VF is treated. Batteries are often the reason that defibrillators are heavy. Unfortunately,
they are also, often, the cause of their failure in the developing world.


2.8.2 Common Problems

Defibrillators are highly reliable devices which require relatively little maintenance if properly
stored and used. The most common problem in the developing world is the batteries. Batteries
should be replaced every 24 months, or less, to assure proper operation of the defibrillator.
However, this is almost never done in the developing world. Refer to the battery chapter for
instructions on replacing and testing batteries.

If the batteries cannot be replaced, some defibrillators will not work. However, some will
function on mains power alone. If the defibrillator is destined for the OR, the need for batteries
is minimal. If the unit is destined for the ER, and won’t operate without batteries, it is better to
send it back with a very long extension cord, rather than deny ER their only defibrillator. For
EMT’s a defibrillator without functioning batteries has no value.

Some defibrillators will contain a synchronizer for atrial defibrillation. This is rarely used in the
developing world, but can cause problems if the user unwittingly engages the synchronizer. For
ventricular fibrillation, the synchronizer plays no role and should be switched off. If this feature
is broken, the synchronizer should be bypassed or its sensitivity increased to trigger the
discharge.


2.8.3 Suggested Minimal Testing

There are a few maintenance issues that you should take care of before releasing the defibrillator
to the floor. The gel will sometimes build up on the paddles and have to be cleaned. Alcohol will
soften the gel and make removal easy.

The external paddles should be inspected for pit marks; these could cause high current density
and leave burns on the chest. The marks can be removed using emery sand paper. Internal
paddles should be inspected to be sure that there are no breaks in the insulation around the
conductive part of the paddle. If breaks are present, attempt to repair them with epoxy or a dip
plastic. Tape will not withstand OR.

You should test the defibrillator before returning it to the floor. If the defibrillator is not
defibrillating, the patient may die. However, the defibrillator should never be discharged by
putting the two paddles or electrodes together and pushing the discharge switch. At a minimum
this will damage the paddles and potentially the unit.


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Equipment found in the OR, ICU and ER


Page 40


Ideally, you should discharge the defibrillator through a defibrillator tester. However, these are
rare in the developing world. Some defibrillators have an internal test load that you can use.
Engineering World Health has recently begun distributing limited-function defibrillator testers
free-of-charge. You can contact them to obtain one. However, in most cases, you will have no
tester and no internal test load.

If you find yourself without any testing equipment, you can try defibrillating through a large piece
of meat. While either chicken (or better turkey), pork or beef will work, you can often purchase
a freshly killed pig at very low cost in the developing world. Be sure to place the paddles on
opposite sides of the animal, at least six inches between the closest approaches of the paddles.
Also, be sure you are wearing gloves and no one else is touching the animal. Gel is required
between the paddles and animal, but be sure the gelled areas of the skin are no closer than six
inches A freshly killed pig will jump several inches when a defibrillation pulse is properly applied.
Large edemic (red) areas will quickly develop where the paddles where applied. The pig is safe
to eat after this procedure, after you remove the gel.

In the absence of freshly killed pig, the next best choice is a large piece of dead meat. You need
something large enough that the defibrillation paddles are never less than six inches apart at
their closest approach. Of course, the dead meat won’t jump. However, after ten 360 J shocks,
you should begin to see burn marks on the meat, typically outlining the electrode placement.
















Malkin, Robert. Medical Instrumentation in the Developing World. Engineering World Health, 2006.


22




2.*Diagrams*and*Schematics*of*Defibrillator****Featured*in*this*Section:******Openstax+College.+“Cardiac+Muscle+and+Electrical+Activity.”+From+the+publication:+Biology.+Rice+University:+2013,+pgs.+805M818.+ ***Wikipedia.+“Defibrillation.”+Wikipedia,+p.+1M12.+Retrieved+from:+https://en.wikipedia.org/wiki/Defibrillation * * *




Figure 19.2 Position of the Heart in the Thorax The heart is located within the thoracic cavity, medially between
the lungs in the mediastinum. It is about the size of a fist, is broad at the top, and tapers toward the base.


CHAPTER 19 | THE CARDIOVASCULAR SYSTEM: THE HEART 785


Figure 2: The Human Heart


Openstax College. “Cardiac Muscle and Electrical Activity.” From the publication: Biology. Rice University: 2013.


25






* 3.*Preventative*Maintenance,*Troubleshooting,*and*Repair*of*Defibrillators***Featured*in*this*Section:*****Cooper,+Justin+and+Alex+Dahinten+for+EWH.+“Defibrillator+Troubleshooting+Flowchart.”+From+the+publication:+Medical!Equipment!Troubleshooting!Flowchart!Handbook.+Durham,+NC:+Engineering+World+Health,+2013.+** ********** *




Defibrillator+Troubleshooting+and+Repair+


!Description+


Defibrillator Troubleshooting and Repair Flowchart


Cooper, Justin and Alex Dahinten for EWH. “Defibrillator Troubleshooting Flowchart.” From the publication: Medical Equipment Troubleshooting Flowchart


Handbook. Durham, NC: Engineering World Health, 2013.


28




45!*


Description*
! Text*Box! Comments!1! Start:!Defibrillator!Troubleshooting.!!!! Begin!diagnostic!process!for!a!work!order!on!Defibrillator!2! Is!the!defibrillator!free!of!any!external!damage/defects?! Inspect!defibrillator!for!external!cracks,!broken!switch,!knobs!and!indicators.!3! Identify!and!replace!damaged!switches,!indicators.! See!BTA!skill!set!on!Switches!and!Lighting/Indicators!to!identify!and!replace!damaged!switches!and!indicators.!4! Clean!casing,!pads!using!Alcohol.! Examine!casing,!pads!and!cables!of!defibrillator!for!gel!and!dirt.!Refer!BTA!skill!set!on!Cleaning!to!clean!the!defibrillator.!If!necessary,!address!damage!to!casing!with!BTA!skills!on!Casing.!5! Does!the!defibrillator!power!on!from!ac!power!line?! Power!the!device!from!ac!line!and!turn!it!on.!
6! Inspect!AC!adapter!cable!for!cuts,!broken!wires!and!replace!if!necessary.! See!BTA!skill!set!on!Connections!and!Connectors!for!identifying!and!replacing!damaged!cables.!7! Inspect!and!fix!broken!wires!or!bad!connections!inside!the!defibrillator.! Inspect!wires!and!connections!from!power!supply!circuit!board!to!other!boards!using!multimeter.!See!BTA!skill!set!on!Connections!for!identifying!and!fixing!broken!wires!and!bad!connections.!8! Identify!and!replace!blown!fuse.! See!BTA!skill!set!on!Fuse!to!identify!and!replace!blown!fuse.!9! Troubleshoot!power!supply.! Most!defibrillators!can!power!on!from!battery!and!ac!power!mains.!See!flowchart!on!Power!Supply,!and!BTA!skills!on!Power!Supply.!
10! Does!the!defibrillator!power!on!with!battery?!


Disconnect!defibrillator!from!ac!power!line.!Turn!the!device!on.!• If!battery/status!indicator!is!red!then!battery!needs!to!be!charged!or!replaced!(nondrechargeable).!• If!defibrillator!fails!to!power!on!then!battery!is!fully!depleted!or!damaged.!11! Recharge!battery!if!applicable!or!replace!it.! See!BTA!skill!set!on!Batteries!to!replace!and!identify!damaged!batteries.!12! Troubleshoot!charging!circuit!if!battery!doesn't!or!charges!very!slowly.! See!BTA!skill!set!on!Transformer!and!Regulators!to!troubleshoot!charging!circuit.!13! Run!the!defibrillator!selfdtest.! Power!the!device!from!ac!line!and!turn!it!on.!The!device!will!run!an!automatic!selfdtest.!14! Does!display!show!error!or!status!indicator!is!red?! The!result!of!the!selfdtest!will!be!displayed!(on!the!screen)!or!status!indicator!will!change!red/green.!15! Are!the!defibrillator!paddles!and!cables!damaged,!wet?! The!paddles!should!be!clean!and!dry.!Inspect!the!pad!cables!and!connectors!for!cuts!and!broken!wires.!16! Does!the!defibrillator!use!paddle!electrodes?! Paddle!electrodes!consist!of!a!metal!paddle!with!an!insulated!handle.!17! Clean!paddles!using!alcohol.!Identify!and!replace!damaged!paddles!and!cables.! Paddle!electrodes!are!reusable!and!should!be!cleaned!after!every!use.!See!BTA!skill!set!on!Connections!and!Connectors!for!identifying!and!replacing!damaged!cables.!
Cooper, Justin and Alex Dahinten for EWH. “Defibrillator Troubleshooting Flowchart.” From the publication: Medical Equipment


Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health, 2013.


29




46!*


Preventative*Maintenance*Common!Reasons!for!Failure:!
• Damaged!device!• Damaged!pads!or!cables!• Improper!power!supply!• Improper!functioning!of!internal!circuitry! !


18! Replace!the!Selfdadhesive!electrode.! Selfdadhesive!electrodes!should!be!replaced!after!every!use.!19! Does!the!hospital!have!a!defibrillator!tester?! Defibrillator!testing!can!be!done!on!a!commercial!tester!or!a!large!piece!of!meat.!
20! Test!defibrillator!using!the!defibrillator!tester.! Connect!pads!to!defibrillator!analyzer.!Select!energy!and!press!charge!button.!Once!charged!push!discharge!button.!Record!delivered!energy!from!display!of!defibrillator!analyzer.!Repeat!the!procedure!for!different!energy!levels.!
21! Is!delivered!energy!>=!limit!set!by!manufacturer!(refer!manual)!for!different!energy!levels?! Improper!functioning!of!internal!circuitry!if!the!defibrillator!delivers!less!or!no!energy!than!the!limit!set!by!manufacturer.!!
22! Test!the!defibrillator!using!a!large!piece!of!meat.! Set!energy!to!maximum!and!press!charge!button.!Once!charged!place!pads!on!a!large!piece!of!meat.!Press!discharge!button.!Repeat!the!procedure!10!times.!The!piece!of!meat!should!be!large!enough!so!that!the!defibrillator!paddles!can!be!placed!greater!than!6!inches!apart.!23! Are!there!no!burn!marks!on!the!meat!(after!10!shocks)?! Failure!of!internal!circuitry!if!no!burn!marks!are!found!on!the!piece!of!meat.!24! Refer!equipment!to!device!manufacturer.!!!! !Refer!equipment!to!device!manufacturer!for!possible!repair!and!replacement!of!internal!circuitry!components.!
25! Perform!preventive!maintenance!on!defibrillator.!Return!defibrillator!to!clinical!personnel.!!!!!!!!!!!!! Defibrillator!is!working!properly.!Perform!preventive!maintenance!before!returning!the!device!to!clinical!personnel.!!


Cooper, Justin and Alex Dahinten for EWH. “Defibrillator Troubleshooting Flowchart.” From the publication: Medical Equipment


Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health, 2013.


30




4.*Resources*for*More*Information*about*Defibrillators****Featured*in*this*Section:***Australian+Defibrillators.+“How+to+Use+an+AED+(Automatic+External+Defibrillator).”+Retrieved+from:+http://www.aeds.com.au/useManMaed.html+**University+of+Waterloo.+“Building+a+Defibrillator+Tester.”+Retrieved+from:+http://www.eng.uwaterloo.ca/~cube/building%20a%20perfMboard%20defib%20tester.pdf*+ *****+++




*Resources*for*More*Information:+*++External*Resources:*** 1. How*to*Build*a*Defibrillator*Tester:*This*document*demonstrates*how*to*build*a*homemade*defibrillator+tester.+University+of+Waterloo.+“Building*a*Defibrillator*Tester.”*Retrieved*from:*http://www.eng.uwaterloo.ca/~cube/building%20a%20perfVboard%20defib%20tester.pdf*++2. How*to*Use*an*AED*(Automatic*External*Defibrillator):*This+webpage+from+Australian+Defibrillators+explains+how+to+properly+use+an+automatic+external+defibrillator,+including+photographs+and+step+by+step+instructions.+Australian*Defibrillators.*“How*to*Use*an*AED*(Automatic*External*Defibrillator).”*Retrieved*from:*http://www.aeds.com.au/useVanVaed.html*+!! +++ +++++ +






Page 33




5 Building a Defibrillator Tester


5.1 Objective:

In this lab you will construct a device that tests the output of a defibrillator to ensure that it can
deliver a sufficient shock to restart a heart. This circuit was designed by undergraduate students
at Vanderbilt University.


5.2 Parts List:



12V 5mm LED soldering iron
1W, 3.9V Zener diode pliers
1.0M ohm, 3W resistor solder
1A, 50V rectifier perfboard, 15cm x 20cm
Diffused, round, long LED wire cutters
2W, 15V Zener diode super glue
63V, 4.7uF capacitor wire, roughly 1.2m
permanent marker multimeter


Figure 1: Parts for constructing the defibrillator tester.


How to Build a Defibrillator


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5.3 Procedures


5.3.1 Introduction to Defibrillators

A monophasic defibrillator is capable of delivering a 10-350 Joule shock across two paddles
or stick-on pads for a duration of about 40 milliseconds. Unlike popular culture's depictions of
the machine, defibrillators are not the preferred choice of treatment when a patient is “flat-lining”
or has no detectable heartbeat (continued administration of CPR is recommended in these
cases). Rather, these devices serve as an electrical reset for the heart and will be most effective
when the patient is undergoing ventricular fibrillation (uncoordinated heart muscle contractions).
The jolt from the machine clears the random electrical firing causing the lack of coordination,
essentially stopping the heart momentarily and allowing structures like the sinoatrial node to
regain control of the contractions.
The powerful shock presents several safety issues: when using defibrillators, never allow the
two paddles to touch each other; this could harm the operator and severely damage the device.
In a real life use of a defibrillator, no one should be in contact with the patient being shocked. A
small amount of gel should also be used on the paddles, lowering resistance of the body and
helping limit burns where the paddles are placed.


5.3.2 Defibrillator tester design theory
The circuit you will construct is designed to output a visual signal based on the power of the
defibrillator that is being tested. If, during the test, the defibrillator is outputting 11 Joules
(equivalent to 388V across the grids) in this circuit or less, neither of the two LEDs will light.
When a defibrillator's shock contains more than 11J but less than 150J (1410V), the 12V LED will
turn on. Unless the parts list has been modified, this 12V LED is the green LED. A shock with
more than 150J will activate both LEDs. The power values are relevant in understanding the
functionality of the defibrillator being tested. The equivalent voltages, derived based on the
circuit's construction, are relevant when the tester itself is being tested. Later in this lab, power
supplies will be used to ensure the defibrillator testers are lighting up near the appropriate
voltages.


5.3.3 Assembling the circuit
The circuit will be laid out on perfboard such that the electronic parts are in a central
column. The paddles of the defibrillator will be placed onto bare-wire grids on either side of this
column as show in the sketch below.





Figure 2: The general layout for the defibrillator tester.


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You will begin by laying out and soldering the electronics area. Before beginning, ensure you
keep track of the identity of each part during assembly. This is especially important for the 2W
Zener diode and the rectifier as the two components appear very similar.
The circuit should be laid out in a similar manner to Figure 3. Notice that two imaginary
columns of holes are visible in the perfboard and that the lead of every component falls into one
or both of these columns. Also note the polarities indicated in the text to the right of the figure.
The negative terminal of an LED is slightly shorter if the LED has never been clipped; the
negative end may also be identified by a slight flat area near the bottom of the plastic case of the
LED. Other diodes have their cathodes distinguished by a colored band.






Figure 3: Top layout of the circuit. The + and – symbols indicate the polarity of each piece.

A soldering job like that performed in the soldering lab can be completed on three of the
connections in the circuit. In these cases (seen for both leads of the rectifier and one lead of the
resistor) connections from one component are being directly soldered to the leads of another


University of Waterloo. “Building a Defibrillator Tester.” Retrieved from: http://


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part. Be sure to use the hook and hook connection technique.




The other connections require small jumper wires. These can be made from the piece of wire
in the parts list or they may be purchased. Seven small jumpers will be required. Figure 5
shows the completed “electronics column” from the top and bottom.





Figure 5: The front and back of the completed “electronics column.”


The circuit schematic in Figure 3 shows where power will enter the circuit. Two separate
meshes of exposed wires will be made in this step and then electrically connected to the column
of electronics. When a defibrillator is being examined, the paddles will be placed on the grids
and then the shock will be administered.
You will first need to remove the insulation from approximately 1 meter of wire; it might be
easier to do this with a knife rather than traditional wire strippers. Run the edge of the blade
down the length of wire until you can barely see the metal beneath the plastic. If you're nimble,
you should be able to pull back the plastic cover, separating it from the rest of the wire. Peel the


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covering back to the start of the cut, slice the plastic off, and repeat the process until the entire
wire is bare.
The mesh will be approximately 1.5” x 2.5” or 4cm x 6.5cm. To provide a more uniform
contact area between the device and tester, the longer wires should be woven in between the
shorter, horizontal wires. After the horizontal wires have been put in place, lay down the vertical
wire such that it alternates passing above and below the horizontal ones. All intersections should
be soldered together so the entire grid is electrically connected. A completed mesh can be seen
in Figure 6; remember to make one on the left of the electronics column and another mesh for
the right.





Figure 6: One of two completed meshes, the contact point for the defibrillator's paddles. Each
intersection is soldered above the board. The corners are soldered below the board to keep the
grid in place. The three vertical wires are woven among the seven horizontal wires to improve


the contact area's uniformity.


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Once the paddle meshes have each been made on the board, they will need to be connected
to the electronics column. This is accomplished via two more small jumpers. So long as the
schematic shown in Figure 3 is followed, the physical placement of the jumpers is irrelevant.
Figure 7 depicts the completed defibrillator tester.





Figure 7: After the paddle-to-electronics jumpers are installed, the board is complete.


5.3.4 Testing the circuit
The device you just completed needs to be tested to ensure the LEDs light up at the correct
voltages. If you have a defibrillator, simply check that the device lights up as expected (note
that it won’t necessarily work with the newer biphasic defibrillators).


If you don’t have a defibrillator, you can still test your device. Two tests will be used,
the first of which requires a completed power supply from another lab. If that section has not
yet been covered, perform the alternate test first and return to this lab when the power supply is
finished.
To verify that your tester works, take the negative lead of the power supply and place it on
the grid of wires that directly connects to the capacitor. (This is the negative grid; it is on the
right in Figure 7 and should be labeled with a negative symbol using a permanent marker. Also
label the right grid with a plus sign.) Make sure the power supply is off. The positive lead should
be placed on the capacitor's wire that is nearest the resistor (the left lead in Figure 7). While
keeping the leads firmly in place, turn on the supply at 0 volts, then increase the voltage across
the capacitor from 1V to around 25V. If the circuit is functioning correctly, the top LED should
light up and remain on above a certain voltage level. With the voltage continuing to increase,
the second LED should light as well.


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The second test makes use of the multimeter. Measure the resistance between the lead
of the capacitor nearest the resistor (this lead is on the left in Figure 7) and the positive
grid on the tester. The measurement should be close to the impedance of the installed
resistor, 1.0M ohms.


5.3.5 Instruction box
The image below should be cut out and super-glued to the back of your functional
defibrillator tester.

Engineering World Health www.ewh.org


University of Waterloo. “Building a Defibrillator Tester.” Retrieved from: http://


www.eng.uwaterloo.ca/~cube/building%20a%20perf-board%20defib%20tester.pdf


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Defibrillator*Bibliography:***Australian+Defibrillators.+“How+to+Use+an+AED+(Automatic+External+Defibrillator).”+Retrieved+from:+http://www.aeds.com.au/useManMaed.html++*Cooper,+Justin+and+Alex+Dahinten+for+EWH.+“Defibrillator+Troubleshooting+Flowchart.”+From+the+publication:+Medical!Equipment!Troubleshooting!Flowchart!Handbook.+Durham,+NC:+Engineering+World+Health,+2013.+* Malkin,+Robert.+Medical!Instrumentation!in!the!Developing!World.+Engineering+World+Health,+2006.++*+ +Openstax+College.+“Cardiac+Muscle+and+Electrical+Activity.”+From+the+publication:+Biology.+Rice+University:+2013,+pgs.+805M818.++++University+of+Waterloo.+“Building+a+Defibrillator+Tester.”+Retrieved+from:+http://www.eng.uwaterloo.ca/~cube/building%20a%20perfMboard%20defib%20tester.pdf*++ WHO.+“Defibrillator,+External,+Automated;+SemiMautomated.”+From+the+publication:+Core!Medical!Equipment.+Geneva,+Switzerland,+2011.+++Wikipedia.+“Defibrillation.”+Wikipedia,+p.+1M12.+Retrieved+from:+https://en.wikipedia.org/wiki/Defibrillation+++Wikipedia.+“Automated+External+Defibrillator.”+Wikipedia,+p.+1M5.+Retrieved+from:+https://en.wikipedia.org/wiki/Automated_external_defibrillator+++++++ *




Copyright 2016, Engineering World Health