Page 1660 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 122: Electrical Trauma 1179

Compartment syndromes are a common manifestation of the electri- reach into the 30,000 to 50,000 amperes range for a duration of 5 to
cally traumatized extremity. Within minutes after injury, tissue edema 10 microseconds. Lightning arc temperatures reach up to 30,000 K,
begins to increase owing to increased vascular permeability with release which generates thermoacoustic blast waves commonly called thunder.
of intracellular contents into the extracellular space. Tense compart- Peak blast pressures reach 4 or 5 atmospheres in the immediate
ments on palpation and pain with passive movement are early findings of vicinity of a lightning strike, and up to 1 or 2 atmospheres 1 meter
compartment syndrome and should lead to immediate decompression. away. Clearly, substantial barotrauma can result. Lightning produces
Direct measurement of compartment pressure should be monitored if a high transient electrical field and resulting magnetic field. Because
clinical findings are equivocal. 11,14 of its high-frequency characteristics, the electric field only penetrates
Compartment pressures in excess of 30 mm Hg are abnormal and the outer surface of the body. However, the huge magnetic field can
indicate the need for decompressive fasciotomy. Measurement of pres- penetrate throughout. Victims of direct lightning strikes experience a
sure in smaller compartments such as that of the intrinsic muscles of multimodal injury. Superficial burns on the skin represent the current
the hand is notoriously unreliable. Exploration of the fascial compart- path along the skin surface. These injuries may create a ferning pat-
ments of the acutely swollen hand should be performed empirically tern on the skin of lightning strike victims. These patterns are known
whenever high-voltage trauma involves the hand and there is a high as Lichtenberg figures. The intense brief shock pulse seems to arrest
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index of suspicion of compartment syndrome. Fasciotomy of any all electrophysiologic processes. The victim may appear lifeless and
fascially bound muscle group may salvage an otherwise moribund prolonged CPR may be necessary. Muscle and nerve necrosis is rare in
muscle. Complete release may be facilitated by incising the epimysium survivors. Deeper injury results when the victim is in contact with a
of each muscle. large conducting object such as a truck or fence that has been struck by
All nonviable skin and irretrievable charred tissue should be debrided. lightning, which then will discharge over several milliseconds through
All noncharred nerves and tendons are preserved, as is marginal muscle the victim.
when intermixed with healthy muscle. We define healthy muscle as that In the past 25 years, lightening fatality in the United States has
which is of normal color and contracts with electrocautery stimulation. dropped from hundreds to less than 30 deaths. 30,31 Delay in resuscita-
Deciding which noncharred tissue is irretrievably injured and requires tion is the most common cause of death. Bystanders are usually afraid
debridement is often a difficult problem. to touch the victim while precious minutes pass. However, unless the
It is at this point in management that controversy exists. The victim is on an insulating platform, there is no residual electric charge
most widely practiced surgical approach is to reinspect the wound on the body after several milliseconds. When needed, CPR should be
and debride obviously necrotic tissue every 48 hours. Between given without hesitation. Victims should be cared for in an ICU until
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debridements, one must be careful to avoid tissue drying or desiccation. life-threatening CNS and cardiac injuries are ruled out. Late neurologic
Typically, moist dressings or allograft skin is applied to decompressed, and ophthalmologic sequelae often develop. Treatment of lightning
exposed, viable muscle, and a topical antimicrobial is applied to injury should follow the guidelines given for major electrical trauma. In
marginal tissue. Closure is usually delayed until the wound is in bac- addition to the electrical effects, one may expect tissue injury from the
teriologic balance and is free of all dead or marginal tissue. Whether a electrothermal-acoustic shock waves that also occur.
finding of additional nonviable tissue at each of the serial debridements Survivors of lightning injury are not likely to be the victims of a direct
represents progressive necrosis or progressive recognition of fatally dam- hit. Rather, they are likely to have been in the vicinity of the hit and to
aged tissue remains an unresolved question. have experienced surface burns and arc effects.
Based on the hypothesis that marginally viable tissue is potentially
salvageable if covered acutely with well-vascularized tissue, another
more aggressive therapeutic regimen exists for selected patients. After LATE SEQUELAE OF ELECTRICAL INJURY
decompression of tense compartments, debridement of obviously non- A full spectrum of central neurologic disorders has been described as
viable muscle and skin is performed. Exposed, devascularized tendons late sequelae of electric shock. Neurologic disorders may be classified as
and nerves, as well as marginal muscle, are covered acutely with well- cerebral syndromes (hemiplegia, striatal syndromes), spinal syndromes
vascularized tissue. Consideration is given to the replacement of injured (spinal atrophic palsies, spastic paraplegia), and peripheral nerve
major arteries and veins with healthy arterial or venous grafts before syndromes (isolated or multiple radiculopathies or neuropathies).
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they rupture or thrombose. Owing to the limited availability of suitable Persistent peripheral neurological, psychological, and neurocognitive
local tissue, distant flaps or microvascular free tissue transfers are gen- problems often require detailed evaluation and therapeutic intervention.
erally used for coverage. Maximal success of this approach has been Transient spinal cord complaints have been described in the literature
demonstrated when definitive closure is provided within 5 days. 25-28 An with the incidence of delayed spinal cord injury following high-voltage
additional indication for using a microvascular free tissue transfer is to electrical trauma ranging between 2% and 5%. Spinal cord injuries
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minimize shortening of an extremity, salvaging a proximal foot, hand, that appear early typically resolve within hours to days; the late appear-
elbow, or knee that would otherwise require amputation if standard, ance of injuries is associated with worse prognosis, although partial
nonmicrovascular techniques were used. recovery may occur. Clinical manifestations of spinal cord injury have
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The decision to salvage an injured extremity must involve careful been classified into immediate and delayed type—in cases with delayed
weighing of the potential morbidity and mortality. A cold, insensate, stiff presentation of spinal cord injury, the severity of dysfunction can range
extremity will be less useful to the patient than a functional prosthesis. from localized paresis to quadriplegia. Although unusual, cases of
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This decision of whether to attempt salvage or to amputate should be delayed spinal cord injury often presents with progressive symptomatol-
made as soon as possible, thereby minimizing the risks as well as the ogy, and results in paraplegia or quadriplegia, with complete recovery
physical and psychological efforts invested in salvaging an extremity that being rare. 37
will eventually be amputated. 20 The late sequelae of electrical injury generally result from the acute loss
or damage of tissue. The extent of tissue damage may not be recognized
LIGHTNING INJURY acutely. Neuromuscular problems are usually due to muscle fibrosis and
peripheral neuropathies coupled with loss of tissue from debridements
Injuries due to lightning are often fatal, and the pathophysiology is and joint stiffness. Sensorimotor neuropathies, paresthesias, dysesthesias,
relatively complex. Lightning injury is a powerful manifestation of arc- and reflex sympathetic dystrophy may manifest long after the wounds
mediated electrical contact. Arcing occurs when the voltage gradient have healed. Severely injured victims may require functional muscle
in air exceeds 2 million V/m. The arc consists of a hot ionized gas of and nerve reconstruction as well as correction of scar contractures. Cold
subatomic particles that is highly conductive. Peak lightning currents intolerance may persist for up to 2 to 3 years, and growth disturbances

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