RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
Wax nostalgic about and learn from the history of early electronics. See articles
from Electronics World, published May 1959
- December 1971. All copyrights hereby acknowledged.
Electric shock, depending on
severity, can range in damage from mere discomfort to body organ damage to instant death.
If you have experienced an electric shock, you know that avoiding another incident is
top priority when working around high voltages. My worst electric shock was either
when I got hit with a 3-phase 440 VAC supply on an industrial air compressor motor,
or the B+ vacuum tube plate supply on the air traffic control radar systems I worked on in the
Both were, thankfully, from finger to finger or finger to forearm (no vital organs in
the current path). I've been zapped a few other times, but nothing severe enough to require
being resuscitated. Neither have I ever witnessed anyone else being shocked to the point
of needing resuscitation. There are probably some gruesome electrocution videos on YouTube, but I don't
intentionally view images of real people being hurt or killed (except for a few terrorist
wipe-out missions taped from C-130's during the Gulf War).
in the video to the left is a riot as he subjects himself to various kinds of shocks
to determine the effect. Some of it looks choreographed, but he really is hurting
himself so that you don't have to wonder what to expect if it happens to you.
Most countries have some form of
law in place that shields well-meaning bystanders from legal liability when her/she
takes action to help an injured and helpless victim. More often than not, more good
must be done than harm, or the laws would probably not still exist. Someone with good
intentions can possibly worsen the situation due to improper application of life
saving procedures and/or improperly moving the unfortunate soul. We have all heard of
some doofus executing a precordial thump (not recommended anymore) and breaking the
victim's ribs, of bruising kidneys when doing the
maneuver (aka abdominal thrust) on a choking person. I have undergone CPR and
other emergency rescue training courses over the years (none recently), but cannot
say how competently I would perform when faced with a real situation.
Resuscitation for Electric Shock - A Proven Tool for Saying Lives
Thousands of lives have been saved by some of
the techniques described and illustrated in this article.
Editor's Note: We have run several articles recently on the subject of electrical
shock. Very little was said, however, about what to do for the shocked victim. The following
material, excerpted. from the "Resuscitation Manual," prepared by the Edison Electric
Institute, presents some of this information.
In cases where breathing has been suspended by accidental causes, the advantages of
manual artificial respiration are unchallenged. Records over the years show that thousands
of lives have been saved by those who knew how to apply it to persons who have stopped
breathing because of electric shock. Every year many additional lives are saved by properly
trained rescuers. Many thousands of individuals, and society as a whole, owe a debt of
eternal gratitude to the hundreds of public-spirited organizations and private companies
who have sponsored and promoted artificial respiration training and practice - a proven
tool for saving lives.
Conversely, many lives have been lost needlessly because those available did not know
how to apply artificial respiration in an emergency.
Effects of Electric Shock
The effect of electric shock on a human being is rather unpredictable and may manifest
itself in a number of ways:
a. Asphyxia: Electric shock may cause a cessation of respiration (asphyxia). Current
passing through the body may temporarily paralyze (or destroy) either the nerves or the
area of the brain which controls respiration.
b. Burns - Contact and Flash: Contact burns are a common result of electric current
passing through the body. The burns are generally found at the points where the current
entered and left the body, and vary in severity, the same as thermal burns. The seriousness
of these burns may not be immediately evident because their appearance may not indicate
the depth to which they have penetrated.
some accidents there is a flash or electric arc, the rays and heat from which may damage
the eyes or result in thermal burns to exposed parts of the body.
c. Fibrillation: Electric shock may disturb the natural rhythm of the heart beat.
When this happens, the muscles of the heart are thrown into a twitching or trembling
state and the action of the individual muscle fibers are no longer coordinated. The pulse
disappears and circulation ceases. This condition is known as "ventricular fibrillation".
and is serious.
d. Muscle Spasm: A series of erratic movements of a limb or limbs may occur due to
alternating contractions and relaxations of the muscles. This muscle-spasm action on
the muscles of respiration may be a factor in the stoppage of breathing.
Because a person may receive electrical shock in many different locations - on the
ground, in buildings, on poles, or on steel structures - it is neither possible nor desirable
to lay down definite methods of rescue. However, there are certain facts which should
1. Freeing Victim: Because of the muscle spasm at the time of shock, most victims
are thrown clear of contact. However, in some instances (usually low voltage) the victim
is still touching live equipment. In either situation, the rescuer must be extremely
careful not to get himself in contact with the live equipment nor to touch the victim
while he is still in contact. He should "free" the victim as soon as possible so that
artificial respiration can be applied without hazard. This may involve opening switches
or cutting wires so that equipment within reach is de-energized, or using rubber gloves
or other approved insulation to move the victim out of danger.
2. Applying Artificial Respiration: To be successful, artificial respiration
must be applied within the shortest possible time to a victim who is not breathing. The
graph (Fig. 1) shows the possibility of successful revival for each minute of delay.
Normally, the type of resuscitation in which the victim is placed on the ground or
floor is the best because the victim can be given additional treatment (stoppage of bleeding,
wrapping in blanket to keep warm, etc.) and the "rescuer" can be easily relieved without
an interruption of the breathing rhythm or cycle.
In choosing the type of resuscitation to be used, ·the rescuer must consider the obvious
injuries suffered by the victim. Broken ribs, for example, might make inadvisable the
use of certain types of resuscitation; burns on the arms or on the face might exclude
other types. However, no time should be lost in searching for injuries; artificial respiration
should be started at once.
There must be no delay to loosen clothing, warm the victim, or move him to a more
comfortable position. However, an immediate check of the victim's mouth should be made
by a quick pass of the fingers through the mouth to pull the tongue forward and remove
false teeth, tobacco, chewing gum, etc. After resuscitation is started, the victim's
belt, collar, and other clothing may be loosened, providing this doesn't interfere with
the resuscitation process. Artificial respiration should be applied with a smooth and
steady rhythm, as a person normally breathes this way. However, split-second timing is
After Resuscitation Is Started
a. As soon as artificial respiration has been started and while it is being continued,
an assistant (if available) should loosen any tight clothing about the victim's neck,
chest, or waist. Liquids are not to be given by mouth until the victim is fully conscious.
b. Resuscitation should be carried on at the nearest possible location to where the
victim was injured. He should not be moved from this location until he is breathing normally,
and then only upon his own volition and while lying down. Should it be necessary, because
of extreme weather conditions, to move the victim before he is breathing normally, resuscitation
should be carried on while he is being moved.
c. A brief return of normal breathing does not necessarily indicate that resuscitation
should be discontinued. Not infrequently the victim, after temporary recovery, stops
breathing again. He must be watched and if normal breathing stops, artificial respiration
must be resumed at once.
d. Artificial respiration must be continued (four hours or longer, if necessary) until
natural breathing is restored or rigor mortis (as determined by a doctor) sets in.
e. To avoid strain on the victim's heart when he revives, he should be kept lying
down and not be allowed to sit up or stand. If he revives before the doctor arrives,
he should be given a stimulant, such as inhalation of ammonia, or a hot drink such as
coffee or tea. The victim should be kept warm. However, when heating devices are applied
to an unconscious person, great care must be taken to prevent possible burns. The heating
devices should be tested on one's own body before use and if too hot, should be wrapped
in a towel or other suitable insulation or allowed to cool to the proper temperature.
Although there are many methods that have been employed for resuscitation, only two
are described here. These are the mouth-to-mouth and back pressure-arm lift methods.
Both techniques are highly effective and usually convenient to apply.
a. The victim should be laid on his back with his head placed as far back as possible
so that his neck is extended. If there is a slope, placing the victim's body with the
head slightly downhill is advisable.
b. The operator uses one hand to elevate the victim's jaw so that it juts out by inserting
a thumb between the victim's teeth, grasping the lower jaw at midline and lifting it
forcefully upward so that the lower teeth are higher than the upper teeth. He then closes
the victim's nose with his other hand (Fig. 2). When it is difficult to insert the thumb
into a victim's mouth, or when the thumb almost fills the mouth (such as on a child),
the operator lifts the jaw forcefully upward with both hands, places his fingers on both
sides of the jaw (near the ear lobes), and closes the victim's nose by pinching the nostrils
between the thumbs (Fig. 3).
c. After taking a deep breath, the operator places his mouth completely over the victim's
mouth with airtight contact. The victim's mouth should not be held open too wide as it
must be totally covered by the operator's lips. (On an infant, the operator's mouth should
be placed over the child's mouth and nose.)
d. The operator then breathes or blows into the victim's mouth, forcefully for adults
and gently for children (Figs. 4 and 5).
The victim's chest should be watched and as soon as it rises, the blowing should be
stopped and the operator's mouth quickly removed from the mouth of the victim, allowing
him to exhale passively.
e. The jaw must be held in an elevated position on both the inspiration and expiration
f. If the chest does not rise, the position of the head (paragraph a) and jaw (paragraph
b) should be improved and the blowing done more forcefully. If the victim's lungs are
still not ventilated, his airway may be obstructed. He should be placed in a face-down,
head-down position, his tongue pulled forward, and patted firmly on the back to dislodge
any foreign object.
g. The cycle of inflation and exhalation should be repeated 12 times per minute for
adults and 20 times per minute for infants and small children.
h. If the victim's stomach swells during resuscitation, air may be entering it. This
may be corrected by the operator gently pressing on the victim's stomach during exhalation.
Back Pressure-Arm Lift Method
a. The victim should be laid on his stomach with his elbows bent and his hands placed
(one upon the other) under his head. When the victim is found lying on his back, his
arms should be raised above his head and his body rolled over on his stomach by the operator
grasping the victim's clothing at the waist and thigh and pulling.
His head may be turned very slightly to one side, with the side of his chin resting
on the back of one hand. Do not turn the head too much as this may constrict the windpipe.
Air flow through the windpipe is dependent upon an unobstructed passage, which can be
promoted by bending the head backward and pulling the jaw forward. If there is a slope,
the body should be placed so that the head is slightly downhill.
The operator kneels at the victim's head on either knee, or on both knees. If on both
knees, he places one knee on each side and just above the head of the victim. If on one
knee, the knee should be close to the victim's forearm and the foot near the elbow of
his other arm (Fig. 6).
The hands should be placed flat on the victim's back so that the heels of the hands
lie just below an imaginary line running between the armpits, with the tips of the thumbs
just touching and the fingers spread downward and outward (Fig. 7).
b. The operator rocks forward until his arms are almost vertical, allowing the weight
of the upper part of his body to exert slow, steady, even pressure downward upon his
hands, keeping elbows straight (Fig. 8). About 40 to 50 pounds pressure should be applied
to the normal adult. This forces the air out of the lungs.
c. Then the operator rocks back slowly; in releasing the pressure he should avoid
a final thrust upon the victim's back. He places his hands under the victim's arms at
the elbows (Fig. 9).
d. Keeping the elbows straight, the operator continues rocking backward slowly, drawing
the victim's arms toward him and lifting until he feels the resistance of the victim's
shoulders (Fig. 10). This armlift expands the chest by pulling on the chest muscles,
arching the back, and relieving the weight on the chest. He now lowers the victim's arms
gently to the ground.
This completes a full cycle and should be repeated approximately 12 times per minute
at a steady uniform rate. The compression and expansion phases should occupy about equal
time, the release periods being of minimum duration.
Posted June 14, 2018
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