Download - Catalyst

Burn Care: Pediatric
Considerations
Judah Slavkovsky
April 24th, 2014
Today in 1184 BC:
The Greeks sack Troy
Introduction
• Burns declining steadily over last 20yrs
– 1.24 million burns yr, 1/3 children
– 60-80K hospitalizations, 30K children
– 4K deaths, 1K children
• Likely to be hospitalized, unlikely to die
Two Mechanisms:
• House fires:
– Leading cause of burn related deaths in children
– Esp. 0-5y
– Preschool also high (2x national average)
Two Mechanisms Cont.
• Scalds
– V common, under 3y
– Both accidental and
non-accidental
– Reaching, pulling
appliance cords,
climbing into hot baths
Real and durable progress last 20yrs
• Advances:
– Fluid resus
– Early excision and grafting
– Infection control
– Tx of inhalation injury
– Nutritional support
– Management of the hypermetabolic state
Real and durable progress
• Largest improvement in burn mortality has
been in children (0-14y)
• 1949 – 50% mortality with 49% TBSA
• 2014 – 50% mortality with 98% TBSA
Mortality Predictors in >80% TBSA
Burns
•
•
•
•
TBSA >95%
Children under 2y
Inhalation injury
Delay in IV access
IV Access
• Need IVF w/i 1st hr – delay major driver of
mortality
Pediatric Resuscitation Considerations
- Get access FAST
• Systemic capillary leak – pronounced for first 1824hrs
With small circulating volume, access delay of > 30m
- Profound shock
• Peripheral IV best, through burn - OK
• Central lines OK – femoral often easiest with edema
• Low threshold for IO – OK for all ages
Peds Resus
• Hyponatremia – V. frequently observed in first
48hrs
– High urinary Na losses
– Check frequently
• Potassium replacement: Oral K phos
– Hypophosphatemia ->frequent
• Neonates: small glucose stores
– Separate maintenance IVF w dextrose
Peds Resus cont
• Children much more prone to vasogenic
edema – over exuberant catecholamine and
chemokine response to burn
• Parkland Formula – underestimation esp. with
deep, electrical, inhalation injury
• Capillary leak omnipresent
– Albumin use more frequently
– 8hrs after - burn albumen remains in circulation
• Maintain serum levels >2.5
Over Resus
• Pulm edema, ARDS,
compartment
syndromes
• Cerebral edema
– Head of bed elevation
– 1st 24-48hrs
Resus guideposts
• UOP
– 1ml/kg/hr children, 2ml/kg/hr infants
• Pulse pressure, distal extremity color, capillary
refill
• MAP, base deficit, lactate
• All parameters can be erroneous - Data
review: No better markers
• New:
– Thermal dilution catheters (PiCCO)
The PiCCO Catheter
• Pulse Couture Cardiac Output
– Arterial line – Femoral in
children (6cm – 3F)
– Calibrated with thermodilution
(like pulmonary artery cath)
– Arterial pressure wave form
used to establish stroke volume
with mathematical algorithm
• CO
• SVR
• Stroke volume variability
A few words on inhalation injury
• Flow: r4
• Peds mortality: isolated burn:
1-2%
- presence of
inhalation inj:
40%
• Nebulized heparin
and acetylcysteine
The Burn Wound
• Early tangential excision
and grafting: Pillar burn
care
– Zora Jansekovic 1960s
(Yugoslavia)
– Originated in children
Unable to tolerate infections
and metabolic derangements
of autolysis
Coverings
• Autografts
• Xenografts
• Allografts
Dermatome at
scalp
xenoderm
New(er) techniques
• Large full thickness burns with loss of dermis
– more prevalent in children
• Nearly all structural skin properties – dermis
– Flexibility, elastic recoil, strength
• Dermal substitutes
Integra
• MGH and MIT
• Dermal analog
– Porous matrix of cross-linked bovine collagen
and glycosaminoglycan
– “Scaffolding” organizes cellular invasion and
capillary growth
– Silicone overlay – humidity and bacterial barrier
• Incorporates into wound bed
– 2-3w later thin STSG layered over
5 picute figure of
boy
AlloDerm
• Cryopreserved allogeneic dermis
• Obtained from cadaver donors
– Hypertonic saline, epithelium removed
– Detergent inactivate cellular and viral components
– Freeze dried – rehydrated before use
• Basement membrane proteins intact
– Combined with thin overlying epithelial autograft at
time of closure
• Limited use – but animal models suggest least scar
contractures of available dermal substitutes
Scalds
• Most common form of
burn, esp <4y
• Exception to rule of
early excison
– Less area excised and
blood loss – with delayed
surgery (2nd, 3rd week)
– Often difficult to judge
depth of tissue injury
– If under 20-30%TBSA Wait
Teen age
shald
Scalds
• Prolonged period of dressing
changes
• Synthetic and biosynthetic
membranes
– Biobrane
• Nylon/silicone bilaminated
neoepidermis, w/ porcine type I
collegen
• No increase in infections, fewer
dressing changes, reduced pain med
use
– Suprathel
• Copolymer of D&L – lactide
• Derived from starch
• Less pain – similar healing times
Boy scald
Hypermetabolic Response: developing
field
• Major cause of poor outcome in children –
seem to have an overly robust response.
• Severe alterations in metabolism of
– Glucose, lipids, amino acids
• Severe Catabolism
– Protein loss from muscle and organs
– Multiple organ dysfunction
• Hypermetabolism linked to organ function and
survival
Cause
• Not entirely clear
– Thousands of identified genes w/ altered expression after major
burn
• Many w roles in mitochondrial and immune function
– Hypothymic thermoregulatory “reset”
• Increased heat production, HR, cardiac output
• Persistent increases in:
–
–
–
–
–
Catecholamines
Glucocorticoids
Glucagon
Dopamine
Additional players: nitric oxide, complement cascades,
neutrophil-adherence complexes, reactive oxygen species, and
endotoxins
Persists
• Thought to resolve after wounds closed
• Accumulating evidence process lasts much
longer
– 3 yrs +
• At 3 yrs all higher than baseline
– Energy needs, circulating catecholamines, urine
cortisol
– Insulin resistance, impaired glucose intolerance
Growth
• Near complete lack of bone growth for 2y
– Endogenous glucocorticoids, Vit D
– Long term osteopenia
– Possible reductions in peak bone mass
– Linear growth delay (height and weight) 1 yr after
burn
• Slowly resolves to near nml rate by post burn yr 3.
• Never catch up
Loss of growth (velocity)
All pts: >40% TBSA
Same pattern true of girls – but fewer data points
Fat redistribution
• Multiple organs infiltrated
• Best studied: Liver
– Children w/ major burns: 3-5 fold increase in
hepatic triglycerides
• Increases subsequent risks:
– Infection
– Progression to sepsis
Treatments of Hypermetabolic
Response: Unsolved problem
• Early and accurate feeding
– Initiate w/i 1st 12hrs
• Glutamate?
• Keep room warm
– 77ᵒF to 91ᵒ
– Reduced energy expenditure from 2
to 1.4 times predicted need
• Exercise early
– Resistance
– Rigorous play
Pharmacologic Aids
• Propranolol
– Effects on tachycardia
– Slows catabolism of skeletal muscle
– Reduces fatty liver: inhibits peripheral lipolysis
– Reduces bone demineralization
– Reduces hypertrophic scaring
More Meds:
• Recombinate Growth Hormone
– No improvement over exercise alone
– Interest in using for growth catch up
• Oxandrolone – anabolic steroid
– Augments exercise effect
– Improves bone rates of growth
Conclusions
• Children are over represented
in burn care
• Nearly all survive
• Any delay in resuscitation
affects mortality
• Evolving approaches to cover
large wounds
• Scalds are often smaller than
first appear - wait
• Hypermetabolism after burns is
profound, long lived and a
largely unsolved riddle in burn
care.