voltage (V)is the electromotive force moving those electrons from high concentration to low concentration . current or amperage (I) is the number of electrons flowingResistance to the electron flow (R) is a property of the medium through which they pass, measured in ohms (O). These three factors are related as shown in
Current is the most important determinant of tissue damage. Current passes through the tissues of least resistance, and this energy produces heat causing direct thermal injury. Tissue resistance varies throughout the body. Nerve cells are the most vulnerable, and bone is the most resistant to electrical current. Skin resistance depends on thickness and condition of the skin. The entrance and exit points are the most damaged. These are the locations where the current is concentrated and reconcentrated.
Drowning and electrical injuries
Done by: Al-Yaqdhan Al-Atbi
Senior clerkship medical
Outline the principles of Pre-hospital and ED
management and disposition of submersion
Differentiate between different mechanisms of
Describe the basic principles of management and
disposition of electrical injury patients
Drowning: is death from asphyxia due to suffocation
caused by water entering the lungs and preventing the
absorption of oxygen leading to cerebral hypoxia.
World Congress on Drowning in 2002 and
subsequently the WHO define drowning as:”
the process of experiencing respiratory impairment
from submersion/immersion in liquid”
Near drowning is the survival of a drowning event
involving unconsciousness or water inhalation and
can lead to serious secondary complications,
including death, after the event
According to the WHO, drowning is the 3rd leading
cause of unintentional injury death worldwide,
accounting for 7% of all injury related deaths.
96% of these deaths occurring in low- and middle-
In many countries, drowning is one of the leading
causes of death for children under 12 years old.
Drowning occurs more frequently in males and the
90% of drownings take place in freshwater (rivers,
lakes and swimming pools) and 10% in seawater
bathtubs or buckets of water
Most of these victims drown during a brief
(< 5 min) lapse in adult supervision.
Children aged 1-5 years
Residential swimming pools are the most
no physical barrier between the pool and
Young adults aged 15-19 years
Young adults typically drown in ponds,
lakes, rivers, and oceans
Alcohol or drugs
(MI) or syncopal episode
Water sports hazards
Cervical spine injury and head trauma associated with
surfing, water skiing, and jet skiing
Scuba diving accidents and other injuries (eg, bites,
the person has inhaled water which interferes with
respiration and causes the circulatory system to collapse.
Muscle spasms in the area around the voice box block
the airway. No water enters the lungs.
Lead to nigative pressure pulmonary edema (forced
inspiration against closed glottis) increase capillary
endothelium permeability occur with surfactant
disturbance ARDS or acute lung injury
often due to immersion in cold water.
Around 10% of drownings are dry drownings.
A group of teenagers was swimming at the lake,
when one of the boys failed to surface after diving
off platform. He was quickly found and rescued by
another swimmer from the lake bottom.
What should you do???
In the patient with an altered mental status, the airway should be
checked for foreign material and vomitus. Debris visible in the
oropharynx should be removed
Immediate Rescue Breathing (even before out of water)…
The abdominal thrust (Heimlich) maneuver has not been shown to be
effective in removing aspirated water; in addition, it delays the start of
resuscitation and risks causing the patient to vomit and aspirate. In
any event, ventilation is achieved even if fluid is present in the lungs.
Remove wet clothing, passive external rewarming
CPR (pulse check)
Supplemental oxygen, 100%, should be administered as soon as
available. Immediately place the patient on 100% oxygen by mask
Consider trauma: C-spine precautions
The patient noted to be apneic and CPR was
initiated by one of the bystanders.
After paramedics arrived, patient noted to have
spontaneous shallow respirations, weak palpable
pulse, GCS score of 7=(E1,V2, M4).
The paramedics intubate him and transfer him to
In ED patient vitals was BP 110/70, pulse 70/min,
RR 12/min, temp 35.6 C, GCS= 6 (E1,V1,M4),
What to do??
SpO2 92% on 100% FiO2
Emergency Department (ED):
Initial evaluation: ABCDEs and C-spine stabilization
Place the patient on monitors
Establish vascular access
Warm IV NS and warm adjuncts (heating blankets, overhead
Intubation and mechanical ventilation
Careful examination including a trauma survey.
Broncoscopy may be indicated in selected cases
Cardiac arrythmias should be corrected
Note: Patients with severe hypothermia may appear dead
because of profound bradycardia and vasoconstriction.
Resuscitation should continue while aggressive attempts are
made to restore normal body temperature
ECG: for dysrhythmias
Labs: electrolytes, renal function, CBC, glucose
although usually N
What are the complications associated with this
In all cases of wet Drowning there is
O2 deprivation, but also presence of
water in the lungs have direct effect on
Freshwater (isotonic) the pulmonary circulation by osmosis (dilution of
blood) haemolysis (bursting of red blood cells) elevation of plasma K+
level and depression of Na+ level alter the electrical activity of the heart
• animal experiments : capable to cause cardiac arrest 2 to 3
• Sea water (hypertonic to blood , more salty) Osmosis will instead
pull water from the bloodstream into the lungs, thickening the blood requires
more work from the heart cardiac arrest.
• animal experiments : capable to cause cardiac arrest 8 to 10
Mammalian diving reflex:
is a reflex in mammals which optimizes respiration
to allow staying underwater for extended periods of
Strong in aquatic mammals: seals, otters, dolphins,
Weak in human
Triggered only by diving in cold water <21C
Three principle effects:
Blood shift: major vital organs
Person submerge holding breath lead to hypoxia
and hypercapnia effect of Co2 in respiratory center
breathing hold breakpoint (PaCO2=55 mmHg)
The breath-hold break point can be suppressed or
delayed either intentionally or unintentionally
General: hypothermia, trauma
GI: vomiting (swallow >> aspirate)
+’ve pressure ventilation leads to gastric distention,
risk of aspiration.
Aspiration of particulate contaminants
Hypoxia from direct surfactant effects
CNS: initial hypoxic injury or secondary
reperfusion injury with resuscitation
Renal: ARF due to lactic acidosis,
prolonged hypoperfusion, rhabdo
Who can go home?
Asymptomatic on presentation
Maintains normal room air sat
No CXR or ABG abnormalities
…… D/C after 8 hour observation
Do we admit this
Control Alcohol/Drug Use
Same as infant/toddler
Precautions for water safety
Do not mix alcohol and water activities
Use personal flotation devices and life preservers
•Differentiate between different mechanisms
of Electrical injuries(AC,DC,lightening)
•Describe the basic principles of
management and disposition of electrical
Electricity is simply the flow of electrons.
Ohm’s law: I = V/R
The most harmful effects of electricity on the body
Heat = (amperage)2 * resistance *time
•Because amperage is squared, it contributes the most to tissue injury.
• In real accidents, the amperage is often unknown. Therefore, we use
voltage as an approximate indicator because high voltages are usually
associated with high amperages.
Electrical injuries present with a wide spectrum of
damage, from superficial skin burn to multisystem
injury and death.
Electricity-induced injuries are common and most
Electrical current type is either alternating current
(AC) or direct current (DC).
Alternating current (AC)
Bidirectional electrical flow that reverses direction in a
sine wave pattern forward to backward direction.
AC current can be low voltage or high voltage.
Low voltage (< 1000 V) is typically household AC current
that ranges in severity from minor injury to significant
damage and death.
High voltage (> 1000 V) is most often related to
occupational exposure and is associated with deep tissue
damage and higher morbidity and mortality.
Direct current (DC)
Unidirectional electrical flow (eg, that associated with
lightning, batteries, thermocouple, and automotive
It is more likely to cause a single intense muscle
contraction and asystole.
Differs from other high-voltage electrical shock in
that lightning is massive DC current of millions of
volts lasting a very brief duration (a small fraction of
Occurs when electrical difference between a
thundercloud and the ground overcomes the
insulating properties of the surrounding air
Current rises to a peak in about 2 µsec
HIGH-VOLTAGE ELECTRICAL INJURIES VS
1,000 to 10,000 volts
1 billion volts
deep (may appear
benign or superficial)
Minor and superficial
common and early
You are in the ED when two patient arrive by
paramedics. By report, two men in their twenties
were victims of lightning injury while playing
Eyewitnesses at the scene report that the victims
were standing several feet apart, when one of the
men was struck directly by the lightning that result
in both men immediately falling to the ground and
Rescuer should be cautious when treating victims
Persons who have been struck by lightning should be
treated as trauma patient.
Unlike other trauma, priority is givin people who
Assess and stabilize the patient (ABCDE)
close attention to C-spine immobilization
Continuous vitals monitoring
At least 1 large-bore IV crytalloid should be givin
VT, VF, and asystole standard ACLS protocols
Fractures and dislocations reduce and splinted
History and physical examination
Pulse oximetry, vitals monitor
Urinalysis: to check myoglobinuria
CBC, Serum electrolytes, cardiac enzymes
should be obtained even if asymptomatic
CT scan indicated in all patient with severe
lightning injury and those with abnormal
intubated by the paramedics
was found pulseless at the scene and CPR was initiated
extensive soft tissue burns over his back
No palpable pulse and ECG showed VF
remain unconscious for a several minutes
Pulse 80/min, BP130/80mmHg. RR 18/min, GCS 13/15
No identifiable external sign of injury
Mechanisms of Injury
Direct effect of electrical current
The extent of damage depends on the following factors:
Duration of exposure;
Voltage (high or low)
Standard household electricity is AC. Electricity in batteries and
lightning is DC. Low-frequency (50- to 60-Hz) AC can be more
dangerous than similar levels of DC because the alternating
current fluctuations can result in ventricular fibrillation.
Dry skin has high resistance, but sweaty or
wet skin has much less resistance.
Thermal (Burn) Injuries
Type & extent of injury depends on current intensity
High voltages: Severe electrical burns, because only a
fraction of a second of current flow is necessary for
severe damage to occur.
Low voltage: Burns are less common, because lowvoltage contact produces little heat energy in the skin
and other tissues.
Resistance varies significantly between tissues:
Tissues with high R (e.g., bone), generate more heat,
resulting in osteonecrosis and deep tissue periosteal
burns, especially surrounding long bones
Trauma can result from fall or muscle contraction
Tetanic Contractions :
Electric current can induce sustained muscular
contraction or tetany.
The overall effect varies according to type (AC or DC),
frequency, voltage, and extent of contact.
E.g. AC current flowing through the forearm can cause flexor
tetany of the fingers and forearm that overpowers actions of the
Forceful muscle contractions can cause fractures and
joint dislocations, especially around the shoulders.
Current flow through the trunk and legs may cause
brief, but strong, opisthotonic (arching) posturing and
Victims of electrical injury with no LOC, or physical
finding and have normal ECG can be safely
Indications for admission :
High voltage > 600 V
Symptoms suggestive of systematic injury
Evidence of neurologic or vascular injury to a digit or
Burns with subcutaneous tissue damage
Associated injuries requiring admission
Comorbid diseases (Cardiac, renal, neurologic)
Tintinali, Emergency Medicine Manual Book, 6th
Joseph J. Mistovich • Keith J. Karren, Prehospital
Emergency Care, Ninth Edition, 2010 by Pearson
Education, Inc., All rights reserved..
Markovchick. VN et al. Emergancy medicine secrets.
Simon T, Takenake B. Case Files emergancy
E-medicine website. ”lightning”
Plantz SH & Wipfler EJ. NMS, Emergancy Medicine.
Second edition. Lippincott Williams and Wilkins. 2007
Romano M, Sauve J etal; Emergency Medicine.