Electrical trauma is a physiological reaction caused by electric current passing through the human body1 Electric shock occurs upon contact of a human body part with any source of electricity that causes a sufficient magnitude of current to pass through the victims flesh viscera or hair Ph ID: 1036081
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1. Electro Trauma
2. DefinitionElectrical trauma is a physiological reaction caused by electric current passing through the (human) body.[1] Electric shock occurs upon contact of a (human) body part with any source of electricity that causes a sufficient magnitude of current to pass through the victim's flesh, viscera or hair. Physical contact with energized wiring or devices is the most common cause of an electric shock. In cases of exposure to high voltages, such as on a power transmission tower, physical contact with energized wiring or objects may not be necessary to cause electric shock, as the voltage may be sufficient to "jump" the air gap between the electrical device and the victim.
3. What are the mechanisms of electrical injury?Direct and indirect.
4. 1. What are the mechanisms of electrical injury (direct and indirect)?
5. ElectrocutionDirect10 determinant of damage caused by direct effects of electricity is the amount of current flowing through the bodyother factors include voltage, resistance, type of current, current pathway, and duration of contact with an electrical source
6. High or LowElectrical shocks of 1000 V or more are classified as high voltagehousehold electricity has 110 to 230 V, and high-tension power lines are more than 100000 V. Lightning strikes are can produce 10 million V or more High-voltage electrical shocks are expected to result in more severe injury per time of exposure
7. CardiovascularArrhythmiasSudden cardiac death due to ventricular fibrillation is more common with low-voltage AC,asystole is more frequent with electric shocks from DC or high-voltage ACfatal arrhythmias are more likely by horizontal current flow (hand to hand); current passing in vertically(from head to foot) more commonly causes myocardial tissue damage
8. Lichtenberg figures are pathognomonic skin manifestations in persons struck by lightning
9. What are the most common causes of electrical injury?
10. In children usually occurs at home associated with electrical and extension cords (in about 60–70%) and with wall outlets (another 10–15%)Most deaths in adults due to electrocution are work related (5–6% of all workers’ deaths)Miners and construction workers account for most of these cases, with rates of 1.8 to 2.0 deaths per 100 000 workers
11. Evaluation of Our PatientParamedics report that he was initially not moving much beyond shallow respirations. (protective when slung over a branch 15 feet above asphalt) However, his overall LOC has deteriorated somewhat.His clothes are cut off, revealing extensive burnt skin from the remains of his right hand, along his arm, involving his torso and left thigh.
12. BreathingHow might his initial assessment (on scene) have been clouded by his electrical injury?What are the effects of electrocution on skeletal and respiratory muscles?
13. “Keraunoparalysis”2dary to massive catecholamine releaseTypically after lightening injuryClinical manifestationParaplegia/quadriplegiaAutonomic instabilityHypertensionPeripheral vasospasmMydriasis and anisocoriaResolves within a few hoursCritical Care Clinics 1999;15(2)
14. Respiratory failureUsually no specific injury from the electric current to the lung or airwaysCauses of respiratory arrest:Blunt traumaInjury to the respiratory control center as a result of electrical current through the brainSpinal cord injury C4 to C8 (hand-to-hand) leads to indefinite refractory state of the NMJTetanic contractionsuffocate
15. Skeletal systemCurrent:DC: causes single muscle contractionAC: causes repetitive tetanic muscle contractionprolonged electrical exposureMuscle:Tissue necrosisCan lead to compartment syndrome and rhabdo
16. Skeletal SystemBone has the highest resistancehighest electrothermal injuriesPeriosteal burns OsteonecrosisLong bone fractures from muscle contraction
17. In the field:Provide a safe environment; disconnect electricity if necessary.ABCsArrhythmia management as per ACLS guidelines.may also cause fixed dilated pupils due to autonomic effects; do not cease resusc.Immobilize C-spine and splint other fractures prior to transfer.
18. In the E.R.Aggressive fluid resusc. for significant electrical injury through large bore IV.Less fluid usually required for lightning injury.Complete Hx, including nature of electrical contact, voltage, duration of contact, and any resulting fall have obvious implications.Complete Px looking for associated (esp. spinal cord) injuries, as well as entry, exit wounds, and blunt thoracic and abdominal trauma.
19. After initial resuscitation:Most common complication is cardiac arrhythmia. Although most run a benign course, particularly with transthoracic injuries, cardiac monitoring for up to 24 hours is appropriate.R/O spinal cord, C-spine injury with appropriate imaging.Keep this in mind in event of impaired motor function.
20. Serial evaluation of liver, pancreatic,and renal function for traumatic and anoxic/ischemic injury (in case of cardio-respiratory arrest), supplemented by appropriate imaging studies (e.g., CT or abd. U/S) as necessary.CT scan of the head is indicated in all severe cases of lightning injury, of injuries due to a fall, and if there are persistent abnormal findings in the neurologic examination.Evaluation of the limbs for compartment syndrome that may require fasciotomy (rare in lightning injury).Nutritional support due to increased energy expenditures.Ophthalmologic and otoscopic evaluation (injury common in cases of lightning injury).
21. Fluid resuscitationAny concerns about crystalloid volume?
22. Fluid ManagementTraditional formulas use %BSA
23. So how do you decide how much fluid to give?Titrate to normal urine output (0.5 cc/kg/hr)How much is too much?Klein et al. 5ml/ % BSA = increased pneumonia + deathCompartment syndromesAbdominalExtremityOcularPhysicians tend to over resus follow BP, unwilling to decrease when good U/O
24. Fluid ResuscitationIn high voltage injury, risk of rhabdo is high.Maintain u/o 70-100 cc/h until clear of pigment, then 50 cc/h.Alkaline diuresis with intravenous sodium bicarbonate may improve clearance of myoglobin. Osmotic diuresis with mannitol can be tried in patients who have increased pigment. If compartment syndrome has been excluded, early amputation may be necessary when there is persistent myoglobinuria. The fluid requirement is approximately 1.7 times the calculated fluid requirement for the percentage of body surface area burnt by standard formulas. Because of large fluid shifts, close monitoring of electrolytes is also necessary with replacement as needed.
25. Later, in ICUHis spine imaging is clear.Seen by plastics, who plan to take him to OR within 24 hours.VS after volume resus:HR 110, BP 115/65, RR 18 on PSV FiO2 .35U/O approx 1 cc/kg/hrRequiring MS and midaz to allow for ventilation.Admission labs come back…
26. Differential for lactic acidosis
27. Compartment syndrome in electrical injuriesSmall vessels do not dissipate heat from electrical current as efficiently as larger vessels, and undergo coagulative necrosisThe electrical current may also cause direct injury to the muscle fibersThese factors lead to myonecrosis and swelling which can then cause a compartment syndrome with secondary ischemic injury.
28. Prevention of compartment syndrome:“when in doubt…”Surgeons historically advocated early surgical exploration with fasciotomy and debridement within the first 24h.Theorized to prevent secondary tissue loss from massive edema and compartment syndromeThis was followed by serial debridement of necrotic tissue until the wound was suitable for closure with skin grafts.
29. Prevention of compartment syndrome: being more selective Mann R.,et al. Is immediate decompression of high voltage electrical injuries to the upper extremity always necessary? J Trauma. 1996 Apr;40(4):584-7
30. Prevention of compartment syndrome: guidelinesRecent guidelines from the American Burn Association recommend that surgical decompression (fasciotomy +/- carpal tunnel release) be performed in the setting of:Progressive neurological dysfunctionVascular compromiseIncreased compartment pressure ( > 30 mmHg)Clinical deterioration from suspected myonecrosisArnoldo B. et al. Practice guidelines for the management of electrical injuries. J Burn Care Res. 2006 Jul-Aug;27(4):439-47.
31. That was closePlastics whisks him to the OR, where R upper arm fasciotomy and amputation of his hand are performed.Returns to ICU with essentially normal ABG and HR 88, BP120/60 unsupported.
32. Any particular feeding strategy?Burn pts are among the most hypermetabolic in the ICUThe extent of open wound area can be used to estimate energy requirements for burn patientsHill, Bruns Patient 2005
33. Trigger of physical, hormonal, metabolic and inflammatory responseHill, Bruns Patient 2005
34. Caloric estimationIndirect calorimetryIndividualize requirementPrevents over/under-feedingModality of choice to estimate caloric needHill, Burns Patient 2005
35. Amino acids needed for tissue repairAcute phase protein productionCellular immunityGluconeogenesisRecommend 2 to 3 gm/kgHill, Burns Patient 2005
36. When to start?Start feeding as early as possibleAvoid catheter associated morbidity and depression of gut functionConsult a dietician near you…Burns,2007;33:14-24
37. What is the most likely cause of his oliguria? What can be done about it?
38. Rhabdomyolysis and myoglobinuriaRare in lightning strikes and low-voltage injuries.Lowest voltage that caused myoglobinuria in a 26-year retrospective review in Boston (N=211), was 600 volts (2 cases involving subway rails)Risk factors associated with myoglobinuria were: High voltage (> 1000 V)Pre-hospital cardiac arrestFull thickness burnsCompartment syndrome Rosen CL, et al. Early predictors of myoglobinuria and acute renal failure following electrical injury. The Journal of Emergency Medicine. 1999;17(5): 783-789
39. Treatment of rhabdomyolysisEarly aggressive fluid resuscitation with salineShown to minimize the risk of ARF when started within 6h of admissionVarious authors suggest target urine-outputs from 70 to 300 cc/h2. No clear evidence for urine alkalinization or mannitol but…? Benefit in pts with CK elevations > 30 000Huerta-Alardin AL, et al. Bench-to-bedside review: Rhabdomyolysis – an overview for clinicians. Critical Care. 2009; 9(2): pp158-169
40. Treatment of rhabdomyolysisDialysis may be necessary in cases where forced diuresis fails. Persistent myoglobinuria should prompt surgical exploration for necrotic tissue
41. 7 days laterThe electrocuted patient is transferred out of ICU, to be followed by nephrology re: dialysis. He vows never to go near power lines again.The news is on in the lounge as you walk by…
42. How can electrical injuries cause cardiac arrest?What conditions contribute to the risk of cardiac arrest in patients with electrical injuries?
43. Cardiac injuryPathway:Horizontal pathways:Hand-to-handHigh potential for fatal arrhythmiasVertical pathways:Are at higher risk for myocardial tissue damage
44. ArrhythmiaUp to half of electrical shock survivors experience some form of arrhythmia Can have delayed arrhythmia up to 12 hours post electrical injuryCommon Arrhythmia:Sinus tach PVCAfibVT
45. Conduction abnormalitiesSinus and AV node especially vulnerable to AC current?RCA being close to the chest wallvasospasmCan have permanent heart block
46. Myocardial InjuryThermal injury of the myocardium results in patchy band necrosisCoronary spasm leading to ischemiaMyocardial contusionSecondary hypoperfusion from shockECG: Non specific ST changes that resolve spontaneouslyCK-MB elevation, not helpful in determining injury
47. Cardiac monitoringProlonged monitoring required if:History of arrest or loss of consciousnessCardiac arrhythmia in the field/ERAbnormal ECG on admissionAdmission for extent of burn or age of ptMonitor for ~24hoursCritical Care Clinics, 1999;15(2)