0071643192.pdf

ENVIRONMENTAL EMERGENCIES

LIGHTNING INJURY

Lightning is a unidirectional currentofextremely high voltage. Fortunately

the duration of exposure is very briefand the majority of the current is trans-

mitted via external “flashover.”

Lightning strike victims who reach the hospital often have many external

findings, but minimal (excluding associated trauma) internal injury.

A comparison between lightning and high-voltage electrical injuries can be

found in Table 13.9.

PATHOPHYSIOLOGY OFLIGHTNINGINJURY

■ Direct contact

■ Current travels directly to victim.

■ Side flash

■ Current traverses through air from first object to victim.

■ Step or Ground current

■ Lightning hits ground →current travels via ground to nearby victims.

■ Blunt trauma

■ 2 °to fall or falling objects

■ Blast trauma

■ Victims suffer from pulmonary contusions, tympanic membrane rup-

ture (up to 50%) and conductive hearing loss.

■ Thermal burns

■ 2 °to fires

PATHOPHYSIOLOGY OFLIGHTNINGDEATH

■ Intense electrical stimulus →asystole (“primary death”)and apnea from

inhibition of brainstem respiratory centers.

TABLE 13.9. Key Differences in Lightning and High-Voltage Electrical Injuries

LIGHTNING HIGH-VOLTAGE

Duration Short Prolonged contact

Volts 10 million–2 billion 1000–10,000

Current DC AC

Side Flash Present Absent

Cardiac Asystole Ventricular fibrillation

Burns Minor and superficial More extensive

Myoglobinuria Infrequent Common

Fasciotomy Rarely indicated Common