Download Thermal Burns

Thermal Burns
Todd Ring
Nov. 27/03
You will know…

Types, severity, and extent of thermal burns
 Pre-hospital management goals
 Smoke inhalation injury and treatment
 Evidence behind the Parkland formula and
fluid resuscitation goals
 Treatment of major and minor burn wounds
 Issues regarding burns in the pediatric and
pregnant patient
Case 1: Mr. Crispy
A 55 yo. male is brought into the ED after lighting
himself on fire. He has sustained burns to his face,
anterior thorax and anterior aspect of his right arm
and leg. The burns on his face are red with blisters
while those on his trunk and extremities are white.
 What features distinguish the depth of the burn?
 What percentage of his body has been burned?
 Does this patient require admission to a burn unit?
Burn Zones
Burns consist of three
geographic zones



Zone of coagulation:
center of burn; greatest
heat transfer
Zone of stasis:
pronounced inflammation
and vascular injury; cell
survival tenuous
Zone of hyperemia: tissue
injury minimal; expected
recovery
Burn Classification

Assessment should include an assessment of depth
and total body surface area (TBSA) burned
 First degree burn: involves epidermal layer of
the skin but not dermis; characterized by pain,
erythema and lack blisters; generally heals without
scar; not considered in TBSA
 Second degree burn: divided into superficial and
deep partial thickness
Superficial partial thickness burn involves the
papillary dermis; painful; blisters are present or
may develop; heal over 2-3 weeks with no scar
Burn Classification
Deep partial thickness burn damages both
papillary and reticular dermis plus deeper sweat
glands and follicles; may or may not be painful; 3
or more weeks to heal and often will scar
 Third degree or full thickness: involve all layers
and may destroy subcutaneous tissue; white or
charred; insensate; require skin grafting
 Fourth degree: involve structures below the
subcutaneous fat including muscle and bone
Degree of Burn Wound
Depth
Burn Shock

Severe burn injury results in a physiologic
response throughout the body to increase
capillary permeabilitythird spacing of
fluid in tissues surrounding burn
 Damaged skin also no longer able to retain
H2O and consequently large evaporative
losses
 Combination results in hypovolumeic shock
Metabolic Complications

Directly related to extent of burn
 Initial ebb phase with decreased CO and
metabolic rate (MR)
 Followed by flow phase with increased MR
and core temp reset to 38.5 C
Wound Assessment:
Rule of Nines
Head
9%
Arm
9%
Front
18 %
Back
18 %
Leg
18 %
Perineum 1 %
*palm of hand 1 %
Pediatric Burn Assessment
Rule of 9’s not
applicable b/c head
relatively larger than
legs
 Lund-Browder or
Berkow chart divides
chart into smaller units
and makes age
appropriate
corrections

Burn Severity Classification
MINOR
• Less than 15% TBSA burns in adults or less than 10% TBSA burns in children or the elderly with less than 2%
full-thickness injury
MODERATE
• Partial- and full-thickness burns of 15-25% TBSA in young adults, 10-20% in children younger than 10 and
adults older than 40
• Full-thickness burns less than 10% TBSA, not involving special care area
MAJOR
• Greater than 25% TBSA burns in young adults or greater than 20% TBSA in children younger than 10 and
adults older than 40.
• Full-thickness burns of 10% or greater. All burns of special care areas that are likely to result in either
functional or cosmetic impairment (i.e., face, hands, ears, or perineum).
• All burns complicated by inhalation injury, high-voltage electrical injury, or associated major trauma. High-risk
patients include infants, the elderly, and patients with complicated medical problems.
Adapted from: American Burn Association 1984 Guidelines for Service Standards and Severity Classifications in
the Treatment of Burn Injury.
Pre-hospital Management

Typical measures including primary and secondary
survey, initial stabilization (i.e.. c-spine, splinting
other injuries)
 High flow O2 or intubation if inhalation injury
suspected
 Removal of burned clothing and jewelry
 Small burns should be covered with wet dressing
as decrease pain and thermal injury if initiated in
1st 40 min
Pre-hospital Management

Large burns (> 20 %TBSA) should be covered
with clean dry dressings b/c risk of hypothermia
 IV should be initiated if it doesn’t delay transport
– Adult and adolescent 500cc/hr RL
– Child (5 –15) 250 cc/hr
– < 5yrs do not attempt IV as may prevent transport delay
(as per burn life support protocol)
Case 2: Mr. C.O.
A 33yo male is involved in a confined gas plant
explosion. EMS patches in that the patient has
extensive burns on his face and neck and is
stridourous. His O2 sat is 98 %.
 What features on history and physical exam
suggest an inhalational injury
 How would you manage this patients airway?
 Why may the O2 sat be unreliable?
Inhalation Injury

Smoke inhalation accounts for more than 50% of
fire-related deaths
 Most injuries occur from inhalation of smoke but
rarely superheated air produces direct thermal
injury (especially steam)
 Three phases of acute smoke inhalation:
– 1st 36 hours: acute pulmonary insufficiency
– 2 – 5 days: post resuscitation
– > 5 days: post injury period

Smoke inhalation is a combination of direct
pulmonary injury and systemic and metabolic
toxicity
Smoke Lung Injury

Depends on fuels, intensity, duration, confinement
 Unless steam, direct heat injury to airway is
supraglottic
– Obvious concern re: obstructive edema, thermal
trachetitis, hemorrhagic edema of bronchi

Gas phase constituents of smoke include CO,
cyanide, acid and aldehyde gases, oxidants
 Direct damage to muco-ciliary elevator, bronchial
vessel permeability, alveolar destruction and
secondary mucous and edema
Clinical Assessment

History of explosion or trapped in building
 Physical examination demonstrates facial
burns, singed eyebrows or nasal hair,
pharyngeal burn, carbonaceous sputum or
impaired mentation
 Changes in voice, stridour or wheeze
alarming
Management

Natural history of upper airway burn is edema that
narrows the airway over 12 –24 h
– Intubation recommended in patients with stridour,
wheeze, voice changes

Serial bronchoscopy option in stable patient or to
assist in intubation
 Burns to the neck can result in tight eschar
formation that combined with pharyngeal edema
 pulmonary insuff.
 Neck escharotomy: vertical incision from sternal
notch to chin
Carbon Monoxide Poisoning





CO much higher affinity for Hgb than O2
Pulse oximetry overestimates hemoglobin O2
saturation
ABG measurement for carboxyhemoglobin value
Patients exposed to CO should receive 100% O2
by nonrebreather (CO ½ life decreased from 240 –
60 minutes
HBO therapy if CO level >25 %, myocardial
ischemia, dysrhythmia; CO level > 15 % in
pregnant women or young child
Cyanide Poisoning

Cyanide is released when natural and synthetic
polymers such as wool, vinyl and plastics are
burned
 Cyanide causes tissue hypoxia by uncoupling
oxidative phosphorylation in mitochondria aa3
 Consider Rx in patients with unexplained severe
metabolic acidosis associated with elevated central
venous O2 (therefore patients are clinically not
cyanotic), normal arterial O2 content and low CO
Hgb
Treatment of Cyanide
Poisoning
1.
2.
3.
4.
5.
100% O2
Amly nitrite, crack vial and inhale (not
necessary if IV in place)
Sodium nitrite: 10 ml IV*
Sodium thiosulfate: 50 ml IV*
Repeat at ½ doses if symptoms persist
*Above available as kit
Case 3: Jeremy “Shocky”




A 22 yo male was lighting his BBQ in the house
(minus 20 outside). The BBQ exploded causing 3rd
degree burns over 40 % of his body, 2nd degree
burns over 10 % and 1st degree burns over 10 %.
His HR is 115 and BP 95/60.
Who is Jeremy Shocky?
What solution, and at what rate, do you want to
resuscitate him at (assume 70 kg).
What evidence is there for the Parkland formula?
Is there a role for colloids?
Parkland Formula

Formula derived in 1960s and 1970s based on
primate and subprimate models
 Prior burn formula recommended maximum
volumes of 10% body weight
 Demonstrated decreased mortality with volumes
of 32 % body weight
 Derived widely quoted Baxter (Parkland) formula
– 4ml/kg/%TBSA; ½ in first 8 h and ½ in remaining 16h

Original formula also recommended colloid in
forth 8 hour period (.3-.5 mg/kg/%TBSA)
Resuscitation Volume

Situations in which more fluid required
– Inhalation injury, associated mechanical or electrical
trauma, large burns with delay in initiating treatment

Baxter recommended monitoring MAP (>70) and
u/o (.5-1ml/kg/hr)
 Invasive monitoring (PA cath) rarely used in burn
patients
– 8 % of burn units with burns >30% TBSA from 250
burn units used PA caths in > 50% of patients
– Only few centers use data from PA cath to direct Rx
Mansfield et al. Burns. 1996; 22: 549-51
Resuscitation Volume

Well known that BP, HR, and u/o have poor
correlation with invasive measurements
– Compensated shock can give relatively normal
parameter but ongoing tissue damage

Majority of studies using invasive monitoring
have reported significantly higher volumes (4.5 –
9.2 ml/kg/TBSA/24h)
Holm et. al. Resuscitation 2000; 44:157-64

No RTC’s comparing Baxter formula to invasive
monitoring
Resuscitation Volume

Schriller et al. in a non-prospective,
nonrandomized study compared survival rate
using standard vitals vs. invasive monitoring
– Survival rate 48% PA cath vs. 32% standard

It seems that many burn centers which are using
MAP and u.o as goals are already exceeding
Baxter formula
– Kemalyan et al. demonstrated rates 40 – 80 % more at 7
burn centers using u/o to direct resuscitation

No evidence to support claim that aggressive
resuscitation results in cardiopulmonary overload
Colloid vs. Crystalloid



Theoretical advantage of colloid administration
keeping fluid intravascualar
Baxter recommended delayed (>12 – 24 h post injury)
administration because of increased pulmonary
permeability early on however recent studies do not
support this claim
Cochrane collaboration conducted a review on the use
of albumin in burns
– 1419 patients; 30 RTCs
– Increased mortality in albumin group (NNH 17)
– ? Secondary to coagulation effect of albumin

Despite Cochrane findings many burn centers still
advocate use of colloid
Conclusion on Fluid
Resuscitation





Fluid Resuscitation is essential
Immediate resuscitation advocated
Despite 3 decades since Baxter developed original
formula still no conclusive evidence re: what kind
of fluid; when to give; and how much
Parkland formula tends to underestimate
resuscitation volumes
Some evidence to support invasive monitoring
Pain Control

Pain requirements inversely proportional to depth
of burn
 Full thickness burns are painless because sensory
nerves damaged
 Partial thickness burns have intact nerves and are
extremely painful
 Morphine advocated for pain management
– Low protein binding
– Metabolized by liver and excreted in urine

Rapid elimination may result in doses > 50mg/h
GI/GU Complications

Foley catheter should be placed to monitor
fluid resuscitation
 Perineal burns should also have foley
placed to decrease urinary soilage
 Gastric ileus is common involving burns
more than 20 %; NG tube should be placed
 Gastric ulcers may occur in patients with
severe burns; GI prophylaxis necessary
Burn Wound Care: Major
Burns

Full thickness circumferential burns can result in
vascular compromise necessitating escharotomy
– Performed on medial and lateral aspect of extremity and
extend length of constricting eschar
– Can use scalpel or electo-cautery

Following escharotomy tissue edema can result in
compartment syndrome necessitating fasciotomy
Escharotomy
Major Wound Dressing

Gentle cleansing with saline or commercial
product (Shur-Clens)
 Debridement of devitalized tissue and blisters
(except those on palms and soles)
 Application of topical antimicrobials (flamazine)
or bacitracin/polysporin
– Polysporin less bactericidal than flamazine but also less
toxic to skin

Transfer to burn center
Burn Wound Care: Minor
Burns

Proper patient selection and appropriate follow-up
 Care with burns involving critical areas of the
body (i.e. face, hands, perineum)
 Minor burns are not associated with
immunosuppression, hypermetabolism or
susceptibility to infection
 Adequate pain control essential
– NSAIDs mainstay of treatment
Minor Burn Care

General Care. Clean with soap and water.
Leave hair intact. Debride devitalized tissue
and ruptured blisters. Tetanus booster.
 Blisters. Management controversial. Poor
evidence either way. Generally leave intact.
If large or tense decompress with needle
aspiration.
Blister Management

Poor evidence, mixed results
 Andrejak et al. conducted a non-controlled
prospective trial, 202 patients allocated to of three
groups
 Blister fluid analyzed for colonization of any
bacteria and for Staph aureus
 Significantly (p<.05) less colonization of any
bacterium and staph aureus in patients with intact
blister vs. aspirated vs. deroofed
– Any bacterium 15% vs. 70% vs. 76%
– Staph aureus 2% vs. 18% vs. 45%
Minor Burn Care

Dressings. Some minor burns can be left
open (i.e. face neck). Wash twice daily with
soap. Care in sun b/c of hyperpigmentation.
Most minor burns are dressed. Dressing
should be changed daily or every other day.
Burn should be cleaned with soap and water
with dressing changes.
Minor Burn Care

Topical antibiotics. Continued debate. Decrease
infection in serious burns with 50 % mortality
reduction. Agents include sulfazidine (flamazine),
mafenide acetate, silver nitrate. No evidence that
these medications offer any benefit in 1st degree or
partial thickness injury. Most experts agree that
topical antimicrobials useful in large, deep partial
or full thickness burns. Aloe vera may also be
beneficial
Minor Burn Care

Synthetic dressings. Include tegaderm, duoderm,
etc. Useful for partial thickness burns promoting
healing, decreasing pain and requiring less
frequent dressing changes. Not indicated for full
thickness burns and should not be applied to
infected burns. Blisters and devitalized tissue need
to be debrided. Can only be applied on fresh burns
1-2 cm over burn margin and needs to be changed
daily
Hot Tar Burns

Tar heated to the liquid form that inadvertently
comes in contact with skin transfers sufficient heat
to cause burn injury
 As the tar cools it solidifies making removal
challenging
 Two distinct forms of tar:
– Coal pitch
– Petroleum-derived asphalts

Both used for paving and roofing
 Higher temperatures needed for roofingdeeper
burns
Hot Tar Burns: Management

H2O should be applied immediately at
scene to cool tar limiting injury and further
damage; continue cooling until tar hardens
 Adherent tar should not be removed at
scene
 Adherent tar should be removed in the ED
to prevent underlying bacterial growth
converting partialfull thickness burn
Hot Tar Burns: Management





Asphalts susceptible to aromatic and aliphatic
hydrocarbons (HC’s)
Coal tars are susceptible to aromatic HC’s
Aromatic HC’s have serious potential systemic
side effects
Long chain HC’s may also be effective without
serious side effects
Multiple applications of various agents may be
required
Mr. Little
An 18 month toddler is brought into the ED
after suffering 3rd degree burns to his right
arm and leg following a boiling grease spill.
 What special fluid requirements does this
toddler need?
 What is your goal u/o for resuscitation?
Pediatric Burns

1/3 of burn unit admissions are children <
15 years
 1/3 burn deaths involve children; 2nd
leading cause of death in children > 1 year
 Scalds (50-60%), flame (30%), hot solids
(10%), chemical and electrical (<2%)
 Child abuse 10%
Special Considerations in
Pediatric Burns

Children < 2 years have high SA/mass ratio, thin
skin and lower physiologic reserve
– High morbidity and mortality

Pre-existing diseases can complicate care
 Infants and toddlers require maintenance fluid in
addition to Parkland formula
 Goal u/o is higher in kids (1mg/kg/hr)
 Infants are susceptible to hypoglycemia
– Frequent monitoring of blood sugar and glucose
containing solutions
Burns in Pregnancy

Limited literature from developed countries
(primarily case reports)
 Special maternal physiological changes
 Sydney et al. conducted a case report on 8
patients plus review of literature
Sydney et al. Management of burns during pregnancy. Burns 2000. 27:
394-7.
Burns in Pregnancy

All women should have pregnancy test
– Minimize teratogenic meds and imaging

Pregnancy associated with hyperdynamic CV state
and expanded blood volume
– Timely and aggressive fluid resuscitation essential for
placental perfusion
– O2 administrating and upright maternal posture
increase fetal oxygenation

Diminished FRC and EEV; increased oxygen
requirements
– Do not delay ventilatory assistance
– Maternal delivery can occur while on MV
Burns in Pregnancy

Fetal outcome dependent on fetal age and maternal
injury
 In second trimester fetal survival is highly
dependent on maternal survival
– Consider tocolysis; conservative management unless
maternal dictates delivery

In the third trimester if there is significant
maternal injury then early delivery recommended
– Post delivery maternal physiological changes rapidly
reverse and aggressive management can be undertaken

Hypercoaguable states in pregnancy and post burn
– Unclear whether anti-coagulation beneficial/required
What you now know…






The rule of 9’s in adults, its limitations in
pediatrics, comparable tables for pediatrics
Burn severity scoring: mild/moderate/severe
Smoke lung injury and related inhalational injuries
Fluid resuscitation goals and limitation of
Parkland formula
Treatment of major and minor burn wounds
Resuscitation issues in pediatrics and the pregnant
patient