Anesthesia for Burn injuries Flashcards
Functions of the skin include
barrier- body fluids & infection temperature elasticity appearance sensory organ
Anatomy of the skin includes
the hair follicle and nerve fibers are in the dermis
Types of burn injuries include
thermal- flash, flame, & scaled
chemical
electrical
radiological
Regardless of the etiology, burns are classified according to
depth- extent of skin & tissue destruction- superficial, partial thickness, & full thickness
total body surface area involved- rule of nines
Describe the depth of superficial burns
1st degree
destruction of epidermis
Describe pain level of superficial burns
very painful
Describe appearance of superficial burns
red
Describe characteristics of superficial burns
dry, flaky
will heal spontaneously in 3-5 days
Describe depth of partial thickness burns.
2nd degree
superficial or deep
-epidermis up to deep dermal element
Describe pain level of partial thickness burns
very painful
Describe appearance of partial thickness burns.
bright cherry red, pink or pale ivory, usually with fluid filled blistering
Describe characteristics of partial thickness burns
hair follicle intact- may require skin graft
Describe depth of full thickness burns.
all of the epidermis, dermis, down into the subcutaneous tissue
Describe the pain level of full thickness burns
little or no pain- in a trauma situation a SNS response still may cause lots of pain due to psychological component
Describe the appearance of full thickness burns.
khaki brown, white, or charred/cherry red is pediatrics
Describe the characteristics of full thickness burns.
loss of hair follicles will require skin graft
Describe a fourth degree burn.
full thickness extending into muscle and bone
will require skin graft and possible amputation
Describe depth, appearance, causes, level of pain, healing time, and scarring for a first degree burn.
Depth- epithelium appearance- no blisters, dry pink causes- sunburn, scald, flash flame level of pain- painful, tender, & sore healing time- two to five days; peeling scarring- no scarring; may have discoloration
Describe depth, appearance, causes, level of pain, healing time, and scarring for second degree burn.
depth- epithelium and top aspects of the dermis
appearance- moist, oozing blisters, moist, white to pink, to red
causes- scalds, flash burns, chemicals
level of pain: very painful
healing time: superficial- 5 to 21 days; deep 21-35 days
scarring: minimal to no scarring; may have discoloration
Describe depth, appearance, causes, level of pain, healing time, and scarring for third degree burn.
depth- epithelium & dermis
appearance- leathery, dry no elasticity; charred appearance
causes- contact with flame, hot surface, hot liquids, chemical, electric
level of pain: very little pain or no pain
healing time- small areas may take months to heal; large areas may need grafting
scarring- scarring present
Describe the rule of nines.
head= 9% TBSA
Upper extremities= 18% TBSA- each arm= 9%
trunk= 36%TBSA; front/back= 18% each
lower extremities= 36% TBSA; each leg= 18%
pediatric is exception
Burns that should be transferred to a burn center include
full thickness burns in any age group
partial thickness >10% TBSA
Burns of special areas
-at extreme of age
-burns of face, hands, feet, perineum, or major joints
-inhalation, chemical, & electrical burns
-those burns associated with co-existing disease
The National Burn Registry states the mortality of burns is as follows:
if the age of the patient plus the TBSA is >115 the mortality is greater than 80%
Mortality is increased with
associated injury- inhalation injury & other trauma
pre-morbid condition
The resuscitative phase of burns involves
-initial treatment of the burn patient should involve- airway, breathing, circulation, and coexisting trauma
Closed space thermal injury equates to
airway injury**
Open space “accidental injury (campfire), motor vehicle crash equates to
multiple co-existing injuries
Electrical injury may lead to occult
severe fracture hematoma visceral injury skeletal cardiac injury neurologic injury
Diagnosis of airway injury in the burn patient is made by
history & physical exam (DVL or fiberoptic bronchoscopy)
Airway management in the burn patient includes aggressively ruling out
upper airway injury in patients at risk (closed space injury, unconsciousness)
Signs & symptoms of airway complications include
singed facial hair, facial burns, dysphonia/hoarseness, cough/carbonaceous sputum, soot in mouth/nose, swallowing impairment, oropharynx inflammation, CXR initially normal (until pulmonary edema or infiltration develops)***
Inhalation injury refers to
damage to the respiratory tract or lung tissue from heat, smoke, or chemical irritants carried into the airway during inspiration
Upper airway inhalational injury presents as
thermal damage to soft tissues of the respiratory tract and trachea can make intubation difficult
thermal injury plus fluid resuscitation
increases the risk for glottic edema
Lower airway inhalational injury presents as
pulmonary edema/ARDS develops 1-5 days post-burn
pneumonia and pulmonary embolism >5 days post burn
Smoke inhalation occurs in conjunction with
face/neck burns and closed space fires
______ occurs after smoke/toxic fume inhalation
chemical pneumonitis similar to gastric aspiration
Smoke inhalation may present as
honeymoon period 1st 48 hours with clear CXR
decreased PaO2 on room air is 1st sign
increased sputum with rales/wheeze
In regards to hypoxia in the burn patient with inhalational injury, the first 36 hours equates to
high risk of pulmonary edema
Hypoxia in the burn patient with inhalational injury will see the following in days 2-5
expect atelectasis, bronchopneumonia, airway edema maximum secondary to sloughing of airway mucosa, thick secretions, distal airway obstruction
Hypoxia in the burn patient with inhalational injury will see the following after >5 days post-burn
nosocomial pneumonia, respiratory failure, ARDS
Circumferential burns of chest & upper abdomen may cause
restricted chest wall motion as eschar contracts & hardens
If inhalation injury or facial burns occur
intubate & secure the airway early!
Airway management in the burn patient includes
patent airway= maximum FiO2 via facemask
The following should be performed in patients with suspected inhalational airway injury
serial larygoscopic/bronchoscopic exams, CXR, ABGs, and PFTs
An ETT is indicated in airway management in the burn patient if the following occur
massive burn stridor respiratory distress hypoxia/hypercarbia altered level of consciousness prophylactic intubation if deterioration likely
Intubation technique for the airway management in the burn patient depends on
patient factors
extent of airway damage
age
co-existing disease
The safest approach for airway management in the burn patient is
fiberoptic intubation under adequate topical anesthesia is safest approach
For the pediatric patient with suspected inhalational or burn injury,
there is a low threshold for intubation due to small diameter airways
Treatment of hypoxia in burn patient with inhalational injury includes
PEEP airway humidification bronchial suctioning/lavage bronchodilators antibiotics chest physiotherapy
Restriction of respiratory excursion may necessitate
escharotomy
Smoke inhalation and ______ are usually found together
CO poisoning
Carbon monoxide has 200 times the affinity
for hemoglobin as O2
CO shifts hemoglobin dissociation curve
LEFT***** impairing O2 unloading to the tissue
CO interferes with
mitochondrial function
uncouples oxidative phosphorylation
reduces ATP production
resulting in metabolic acidosis*****
CO may act as a
myocardial toxin & prevent survival of cardiac arrest
With carbon monoxide toxicity, the following signs & symptoms may appear
SaO2 may be normal
respiratory effort may appear normal
“Cherry-red” blood color may NOT be present if CO is <40% and/or the patient is cyanotic & hypoxic
Management of patients with suspected carbon monoxide toxicity includes
high FiO2 on all burn patients until CO toxicity is ruled out
COHbg >60% is
incompatible with life
DEATH
Hyperbaric chamber is recommended for patients with carbon monoxide if
COHgb is >30% & patient is hemodynamically & neurologically stabilized
Carbon monoxide levels of <15-20% may appear as
headache, dizziness, confusion
Carbon monoxide levels of 20-40% may appear as
nausea, vomiting, disorientation & visual impairment
Carbon monoxide levels of 40-60% may appear as
agitation, combative, hallucinations, coma & shock
Cyanide is produced as
synthetic materials burn
-victims inhale & absorb it through mucous membranes
______ results with elevated lactate levels as a result of cyanide toxicity
metabolic acidosis
Cyanide toxicity may present as
altered LOC with agitation, confusion or coma
CV depression/arrhythmia risk
Blood cyanic levels of _____ confirm diagnosis
> 0.2 mg/L
1.0 mL/L is lethal
The treatment of choice for cyanide poisoning is
oxygen
Cyanide has a half-life of
60 minutes
Other treatments for cyanide toxicity include
hydroxycobalamine (Vitamin B12), amyl nitrate, sodium nitrate, thiosulfate
Release of inflammatory mediators locally at the burned tissue and systemically contribute to
edema associated with burn injury
Increase in microvascular permeability lead to
fluid leak loss of proteins
Additional systemic effects of burns include
increased intravascular hydrostatic pressure/decreased interstitial hydrostatic pressure
interstitial osmotic pressure increases
__________ can perpetuate this mediator-induced systemic inflammatory response that may lead to multiple organ failure
surgery & infections
Overall systemic results of burn injuries include
immune suppression activation of the hypothalamo-adrenal axis and the renin-angiotensin/aldosterone system hypermetabolism protein catabolism sepsis multi system organ failure
In regards to cardiovascular stresses with burn injury, after 24-48 hours, the body has a
hyperdynamic state (high output CHF)- increased BP, HR, CO 2x normal
In regards to cardiovascular stressors, _______ lasts for the first 24 hours
severe decrease in cardiac output
Circulating tumor necrosis factor leads to
myocardial depression
Increased microvascular permeability leads to
hypovolemia
Cardiovascular stressors related to burn injuries include
diminished response to catecholamines
increased microvascular permeability–> hypovolemia
intense vasoconstriction compensation
decreased tissue O2 supply and coronary blood flow
hemolysis of erythrocytes
Increased metabolic rate is proportional to
TBSA burned (can double in 50% TBSA)
________ reflects increased metabolic state
increased core body temp
Loss of skin leads to
loss of vasoactivity, piloerection, insulation functions
Daily evaporative loss of burn patients is
4000 mL/m2
________ is increased in burn patients as a result of increased metabolism
caloric consumption
End organ complications related to GI include
ileus, ulceration, cholecystitis
End organ complications related to the renal system include
decreased GFR, RBF, loss of Ca, K, Mg with retention of Na, H2O
End organ complications related to blood & coagulation include
increased viscosity-> increase in clotting factors including fibrinogen, V & VIII, fibrin split products at risk of DIC development, HCT usually decreases (RBCs decreased half-life)
End organ complications related to endocrine include
increased corticotropin, ADH, renin, angiotensin, aldosterone, increased glucagon, insulin resistance, hyperglycemia (at risk nonketotic hyperosmolar coma esp. TPN).
Loss of fluid from vascular compartment occurs in
1st 24 hours–> replaced with 2-4 mL/kg for each 1% TBSA burned
Fluids should be titrated to
urine output of 0.5-1.0 mL/kg/hr.
Over aggressive fluids can worsen
airway edema, increase chest wall restriction and contribute to abdominal compartment syndrome
Fluid type in the first 24 hours should be
crystalloid only
> 24 hour fluid administration can consider
colloids at 0.3-0.5 mL/kg/% burn with 5% dextrose in water
Describe the Parkland formula
4.0 mL LR/kg/% burn/1st 24 hours
with 50% admin in 1st 8 hr.
25% 2nd 8 hr.
25% 3rd 8 hr.
Describe the modified Brooke formula
2.0 mL LR/kg/% burn/1st 24 hours
with 50% admin in 1st 8 hr.
25% 2nd 8 hr.
25% 3rd 8 hr.
Goals of fluid resuscitation include
urine output= 0.5-1.0 mL/kg/hr HR= 80-140 (consider age) MAP= adults >60 mmHg Base deficit= <2 normal Hct
If perfusion/urine output is inadequate despite >6 mL/kg/% TBSA burn & the patient has normal or high CVP
consider low dose dopamine 5 mcg/kg/min
consider other vasopressors
Major areas of concern related to repeat surgeries for burn patients includes
maintain Hct: multiple transfusions
coagulopathy
temperature
fluids & electrolytes
hypermetabolic state= increase O2, ventilation, nutrition
increased risk for GI ileus- aspiration/hyperalimentation
Describe blood loss per excision of skin
200-400 mL of blood loss for each % area that is excised
conservation can be by epi or thrombin soaked sponges
Challenges related to monitoring of the burn patient includes
burned tissue= limited access for ECG, SaO2, PNS, NIBP- consider a-line
Blood loss for burn patients can be minimized by
topical/SQ epinephrine, only 15-20% TBSA q procedure, tourniquets
Challenges for the burn patient include
need large bore IV access- may consider alternative areas for placement
compensate for evaporative/exposure heat loss- room temp 28-32 degrees C
treat the complications of massive transfusion (coagulopathy & hypocalcemia
Preop evaluation of the burn patient includes
airway phase of resuscitation monitoring intravascular access equipment
Anesthesia considerations for the high voltage electrical injury include
follows path of least resistance; bone most resistant
cardiac arrhythmias
respiratory arrest
seizure
fractures
muscle damage–> myoglobinurea–> renal failure
Patients with burns require HIGH
opioid requirements
-ideal anesthetic choice is isoflurane+ large dose opioid
Serial debridements may require
ketamine in incremental doses
regional anesthesia
Describe the use of muscle relaxants for burn patients
1st 24 hours- unaltered response to depolarizing & non-depolarizing muscle relaxants
24 hours to 1 year post burn avoid succinylcholine due to massive release of K+–> may be due to the proliferation of acetylcholine receptors along the entire muscle membrane
-resistance to most NDMR if >30% TBSA burned
