Retrospective evaluation of admission criteria for paediatric electrical injuries

Burns Vol. 21, No. 8, pp. 590-593, 1995 Copyright 0 1995 Elsevier Science Ltd for ISBI Printed in Great Britain. All rights reserved 0305-4179195 $r0.00+ 0.00

0305-4179(95)00064-X

Retrospective evaluation of admission paediatric electrical injuries B. H. Wallace, J. B. Cone, R. D. Vanderpool,

criteria

for

P. J. Bond, J. B. Russell and F. T. Caldwell

Jr

Arkansas Children’s Hospital Bum Center and University of Arkansas Medical SciencesCampus,Little Rock, Arkansas, USA

In the medical community, the practice of admitfing all electrical burns for 24-48 h of observafion, monitoring and laboratory evaluation is widespread. This retrospective review of paediatric electrical burns was conducted to determine which pafients may safely be treated as oufpafients. Retrospective analysis of all paediatric burns admitted between 1980 and 1991 identified 35 patients with electrical injuries. Putienfs were divided into two groups for analysis: those burned by exposure to household voltages (120-240 V; n = 26) and those exposed lo high voltages, in excessof 1000 V (n = 9). The majority of household electrical injuries occurred secondary to contact with the household 120 V (21126). Contact with an extremity accounted for the largest number of these injuries(18126). The moufh was fhe second mosf frequent site of injury (7/26). Most of these patients (20/26) had < 1 per cent BSA burn. No patient in the household-voltage group had an arythmia that required treatment, nor were fhere any rdenfified examples of comparfment syndrome or other vascular complications. Seven patients did require minimal skin gruffing. No deaths occurred in either group. The pafients in the household-voltage group were signijicantly younger. High-voltage electrical injuries occurred in an older patient population and required more aggressive care and surgical infervention. This was evident at the time of initial evaluation. Based on fhese data, healthy children with small partial-thickness electrical burns and no inifiul evidence of cardiac or neurovascular inju y do not appear to need hospital admission.

Bums, Vol. 21, No. 8,590-593,1995

Introduction Electrical injuries in children account for substantial morbidity and mortality. Annually, thousands of patients require emergency treatment for electrical injury; however, the percentage of all bum admissions secondary to electrical injury is usually low, ranging from 2 to 4 per cent of admissions’-3. To underscore the magnitude of the resourcesrequired to treat thesepatients and the interest in this subject, since 1966 over 1200 publications have addressedissuesconcerning the epidemiology, management and treatment of electrical bums. Electrical injuries are often deceiving. Benign-appearing

wounds can be associated with life-threatening cardiac arrhythmias, limb-threatening vascular compromise and acute renal failure secondary to myoglobinuria. These concerns have led to the widespread practice and recommendationsfor admissionof all electrical bums for 24-48 h of observation, cardiac monitoring and laboratory evaluation, with no distinction between patients injured by low-voltage versus high-voltage injury4-7. However, medical economicsnow dictates that we be more circumspect in the utilization of hospital beds and that we evaluate routine medical practice to determine costefficient strategies for delivery of quality care. Bum injuries occurring as a result of electrical current frequently constitute a dilemma for the admitting physician. What are the objective criteria for admission, and which patients can be safely discharged?

Methods In an attempt to evaluate patients with electrical injuries and identify those who may be safely treated as an outpatient, a retrospective review of medical records was conducted for all inpatient paediatric electrical bums at Arkansas Children’s Hospital Bum Center during the years 1980-91. This review included all patients less than 21 years old. Data were statistically analysed using Student’s t-test and chi-squareanalysisa.

Results Thirty-five patients were identified with electrical injuries. The patients were divided into two groups, those injured as a result of household voltages, which in the USA are 120 V or 240 V (60 Hz AC), and those patients injured asa result of high voltages. High voltage was defined as that greater than 1000. While an uncommon paediatric injury, high voltage produces devastating damage. Low-voltage injuries rarely causedeep tissuedestruction, but prolonged contact can causesufficient injury to require amputation9. The criteria for admission of low-voltage injuries is not uniform in the literature4-7’9-12.For high-voltage injuries, admissionis indicated in virtually all cases9-“. There were 26 patients in the household-voltage group and nine in the high-voltage group. Those injured by

Wallace

et al.: Admission

criteria

for paediatric

electrical

injuries

Table I. Patientcharacteristics andlength of hospitalstay

591 Table II. %BSAburn, %FT bum, voltage, electrocardiographic

(ECG)resultsand creatinephosphokinase (CPK)levels(u/l),

Age W P s.d. Sex Males Feinales % Full-thickness i s.d.

6.2 6.1

16.4” 4.7 8 1

burn

Length ii s.d.

of stay (days)

Values

are expressed

P=

High voltage (n=9)

16 IO

% BSA burn R s.d.

l

Household voltage (n = 26)

0.6 0.9

7.7’ 9.8

1.2 1.2

14.7’ 17.7

7.6 12.9

36.0’ 28.5

as mean *s.d.

0.0001.

household voltages were significantly younger (P= 0.0001): 6.2 years vs. 16.4 years (TableI). The sex ratio between the two groups was not significantly different. Most of the patients in the household-voltage group had bum sizes less than 1 per cent of the body surface area (BSA). The average percentage full-thickness bum injury was 0.6 per cent BSA in the household-voltage group and 7.7 per cent in the high-voltage group. The total body surfacearea bum was 1.2 per cent in the household-voltage group and 14.7 per cenkin the high-voltage group; these differences are significant at the 0.0001 probability level. Twelve patients in the household-voltage group and one in the high-voltage group were hospitalized for 24 h. The average length of stay for the household-voltage group was 7.6 days, and 36 days for the high-voltage group; these differences are highly significant (TableI). Of the 13 patients in the household-voltage group with a length of stay greater than 1 day, seven required one or more surgical procedures and six were observed for bums to the oral commissure. Only three patients in the household-voltage group had lengths of hospital stay in excessof 10 days. In retrospect, we cannot assessthe role that social circumstancesmay have played in the length of hospital stay. The aetiology of the injuries in the household-voltage group included eight patients who bit an electrical cord; four who grasped a non-insulated electrical cord; three who inserted a metal object into an outlet; three who were burned when a cord shorted and arced; six who were burned by miscellaneouscauses;and one patient who touched a 240-V line with the side of his head. The aetiology of the injuries in the high-voltage group included three patients who were working from a ladder and made contact with a high-voltage power line and fell 6-9 m to the ground; three who came in contact with high-voltage lines that were ‘down’ after a storm; one who touched a power line with a metal pole and one patient who was operating a large crane and came in contact with a 70 000-V source. An abnormal electrocardiogram (ECG) was identified in only one of the 17 patients in the household-voltage group in which an ECG was obtained. This one patient had non-specific ST changes on admissionwhich resolved to normal sinusrhythm within 24 h. One abnormal ECG was

%BSA 1 1 1 :, 1 1 1 1 1 56 ‘N = normal;

%FT

Voltage

0 0 0 0 0 0 0 0 0 0 30

120 120 120 120 240 240 120 240 120 8000 70 000

ECG N N N N N N A N N N A

l

CPK 115 175 144 1173 237 181 698 852 116 127 70 000

A=abnormal.

identified in the high-voltage group (ST changes and premature ventricular contractions (PVCs) which resolved to normal sinus rhythm by 24 h. There were no arrhythmiasthat required treatment. No seriousarrhythmias were detected in any patient with a normal ECG on admission. In the household-voltage group, the total creatine phosphokinase(CPK) level was elevated above the upper limits of normal in nine of the 10 patients in which it was measured (TableII). In a high-voltage group, CPK was elevated in two of the three patients in which it was measured. The CPK levels did not correlate with the voltage of the energy source causing the injury; CPK did not correlate with electrocardiographic changes;and CPK did not correlate with the percentage of full-thickness injury (the one exception to thesestatementsis the patient with the 30 per cent full-thickness bum, receiving a 70000-V injury). The majority of the household-voltage injuries occurred secondary to contact with 120V in (21/26) or 81 per cent of the cases.Those injured by high voltage ranged from 8000 to 70 000 V. In the household-voltage group, electrical contact with an extremity accounted for the largest number of injuries (W26 or 69 per cent): 15 hands, one arm, one foot and one leg. The mouth was the secondmost frequent site of injury (8/26 or 31 per cent). The ear was the point of contact for one patient in the household-voltage group. In the high-voltage group, all injuries resulted from contact with an extremity. In the household-voltage group, seven patients (27 per cent) required skin grafting, and in the high-voltage group, six of nine (67 per cent) required skin grafting, In the high-voltage group, a total of four limb amputations occurred in three patients, orchiectomy in two patients and an evisceration secondary to an abdominal ‘blowout’ exit injury in one patient. One patient in the household-voltage group required amputation of a toe. The current pathway through the body or extremity determinesthe severity of tissuedamage,which is proportional to current density6. A small area of contact on a digit may lead to more damage than a broad contact with the dorsum of the hand. Of the 15 hand bums in the household-voltage group, five required debridement and grafting. Two required arthrodesis.No deaths occurred in either group. Table111shows the data of all 16 patients with exclusively partial-thickness bums who were injured as a result of exposure to household voltages. These patients did not have any obvious full-thickness injury at the time of admission. In this subset of patients, there was one

Burns: Vol. 21, No. 8, 1995

592 _l__l___l

Table III. Patients injured by household

---

voltages with only partial-thickness

-l_-^--llll-.

burns -_____

%8SA -.-__-_--

%fT

LOS

Voltage

ECG

1 1 1 1 1 1 1 0 1 0 1 1 1

0 0

1 I

0 0 0 0 0 0 0 0 0 0

1

1

0

5

1 1

0 0

7 7

120 120 120 120 120 120 120 240 240 120 1 20 120 240 120 120 120

WNL WNL WNL WNL WN L WNL WNL WNL WNL WNL WNL ST WNL WNL WNL WNL

0 1 1 1 t ! 1 1 2

CPK 1;s 175 144 iQ0

.-..-

Myoglobm

site

Negatwe

l’hlgh

Hand I-land Hand Hand &n-r: Wand Hand Foot 4rn / I-lands Motith

Negatwe 1r73 237 7 81 Negatwe 698 852

Negative

Hand

Negative

kAou?h Hard

116

.-

!-hid

_--

.--_

_...- ._.._-

Note: there were no complications in any of the patients studied. %BSA=%body within normal

surface area burned; %FT=%fflll limits and ST is a sinus tachycardk,

thickness burn; CPK = creatine

LOS = length of hospital stay; ECG = electrocardiogram, phosphokinase

where WNL IS

(U/I).

abnormal ECG. Myoglobin was negative in all five of the patients in whom it was measured.All the measuredCPKs were abnormal (n = 10). The abnormal CPKs did not correlate with outcome. In this subset of patients, there were two arm burns, nine hands, two mouths, one thigh and one foot burn, and it hashistorically been our practice to admit all bums to the hand, face, feet and perineum. However, it appearsthat these very small superficialbums do not require hospitalization. None of these patients had any subsequentcomplications or required readmission.

surgical intervention. This was evident at the time of’ mitial evaluation. All patients who are injured secondary to high voltage should be admitted, until the full extent of injury is determined. Based on these data, healthy children with householdvoltage injuries which are smallpartial-thickness burn, and who have no evidence (over the first few hours) of cardiac or neurovascular injury, do not appear to need hospital admission.

Discussion

References

Total CPK was elevated in the group of patients exposed to household voltages. Nine out of ia of the patients with very small superficial bums had elevated values, but these did not correlate with any negative outcome or complication. Therefore, it could be inferred that a modest elevation in total CPK level is not a diagnostic indicator of muscle injury in the electrical burn patient with smallsurface area bums. Isoenzyme levels were not obtained. One patient in the household-voltage group made electrical contact with his head. After long-term follow-up, this patient developed a cataract which is a common complication of electrical injury. The work of Boozalis and associates13underscores the necessity For ophthalamic consultation and careful follow-up for this possiblecomplication. In both of our groups of patients, the two ECG abnormalities noted on admission rapidly resolved. Our findings are consistent with those of Gordon and associates14,who noted that all those patients who had ECG changeson admissionrecovered completely. We echo the question posedby Purdue and Hunt15, and askif continued monitoring is necessaryif the initial ECG is within normal limits. Seven of the eight bums to the mouth were allowed to heal by contracture, and one was excised and closed. Of the seven patients allowed to heal spontaneously, there was no seriousbleeding, and only one patient requesteda late revision of the oral commissure.The early excision result was not superior to delayed healing. High-voltage electrical injuries occurred in an older patient population and required more aggressive care and

----

L Wallace BH, Caldwell

FT, Meadors

FA, Stewart

C.L An

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9 Biiiowitz EB.Electricalinjuries.In: SchwartzGR,Cayten CC. MangeisenMA, Mayer TA, HankeBK feds).Principle.5 atui Prucfice uf Emergency Medicine, 3rd edn. Philadelphia: Lea & Febiger, 1992; p 2847. 10 Cooper MA, Johnson K. Electrical injuries. In: iiosen P,

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Wallace II

et al.: Admission

criteria

for paediatric

electrical

injuries

Barkin RM, Rosen P (eds). Emergency Pediatrics, a guide fo ambulatory care, 4th edn. St Louis: Mosby, 1994; p 303. 12 Saunders CE, Ho MT (eds). Current Emergency Diagnosis and Treatmenf, 4th edn. Norwalk: Appleton & Lange, 1992; p 714. 13 Boozalis CT, Purdue GF, Hunt JL, McCulley JP. Ocular changes from electrical bum injuries. A literature review and report of cases. ] Burn Care Rehabil 1991; 12: 458-462. 14 Gordon MW, Reid WH, Awwaad AM. Electrical burns incidence and prognosis in Western Scotland. Burns 1986; 12: 254.-259.

593 15 Purdue GF, Hunt JL. Electrocardiographic monitoring after electrical injury: necessity or Juxury? J Trauma 1986; 26: 166-167. Paper accepted

after revision

Correspondence should Professor of Surgery, Campus, Department Markham Street, Little

27 March

1995.

be addressed to: Dr J. B. Cone, Associate University of Arkansas Medical Sciences of Surgery, Mail Slot 520, 4301 West Rock, Arkansas 72205-7199, USA.