Burn pathophysiology, immunology, nutrition and resuscitation Flashcards
(23 cards)
Whata re 3 phases of burn metabolism in the burn patient
- Acute phase: Acut ephase proteins, cytokines, insulin, cortisol, catecholamines
- Hypermetabolic: insulin resistance, high glucose production, lipolysis, catabolism
- Recovery: scar formation, muscle building
What happens to caloric requirement with burn injury
- 20% TBSA - results in 50% increase in caloric needs
- 40% TBSA - results in 100% increase in caloric needs
How do you assess energy expenditure or energy expenditure?
- Anthropometry / body weight
- Blood test: urea nitrogen
- Indirect calorimetry
- Respiratory Quotient : Co2 produced/O2 consumed, normal 0.7-0.85. If RQ >0.85 = high caloric intake, if <0.7 = inadequate calories
- Predictive formulae
- Currerri Adult total EE: 25kcal/kg + 40kcal/%TBSA
- Currerri kids total EE: 40kcal/kg + 40kcal/%TBSA
What is an estimate of protein requirement for a burn patient?
- Adult = 1g/kg ideal BW + 1g/%TBSA
- Kids = 3g/kg ideal BW + 1g/%TBSA
List supplements for burn patients and their function
Anti-catabolics
- ornithine
- oxandralone (decrease APP) 10mg bid for TBSA>40%
- propanolol
Immune enhancing
- Glutamine 40G daily
- ornithine
- Arginine
Wound healing
- Vitaminc 500mg bid
- vitamin a 10 000IU daily
- omega 3 fatty acid - anti cytokines/PGE2
- Zinc
What are indications and benefits of enteral feeding and indications for TPN
INDICATIONS FOR ENTERAL FEEDING
- TBSA>20%
- inadeaute oral intake/preburn nutritional deficiency
BENEfits of enteral feeding
- reduce gut atrophy, bacterial trasnlocation
- ulcer prophylaxis by normalizing gut pH
- improved wound healing
Indication for TPN
- ileus
- electrical burn with GI involvement
What are complications of TPN
- hyperglycemia
- hyperosmolarity
- hypoKalemia hypophosphetemia
- FA deficiency
- fluid imbalance
What are criteria for trasnfer to a burn unit
- >10%TBSA partial thickness burn
- any 3rd degree burn
- burns involving face, hand/feet, genitalia, major joints
- electrical burn
- chemical burn
- inhalational injury
- burn w concomitant trauma where burn is sourc eo fmorbidity
- preexistin comorbidity that could affect mortality
- facility where personel/equipment not sufficient for kids
- patients who will require social/emotional/psychological support
How do you predict mortality
Modified Baux score
based on age, TBSA, presence of II
- Age + TBSA% + II (17) >100 => 50% mortality
- Age + TBSA% >110 => 50% mortality
What are indications for prophylactic intubation
- Inhalational injury - or strong suspicion
- facial/neck burns
- large volume of fluid resus anticipated =>35TBSA
- close range explosion
- steam inhalation
- long transport
- respiratory failure
What is the parkland formula, when is it used and in what circusmtances is parkland inadequate
- Formula is to guide fluid resusicitation in primary survery
- RL 4cc/kg/%TBSA, with half volume igven in first 8 hr and second half in next 16hrs
- Titrate to urine output for o.5cc/hr adult, 1cc/hr kids
Fluid resuscitationr equired when
- >15%TBSA 2’ and 3’
- >10%TBSA for kids <10 and adults >50
When parkland may be inadeqaute
- Inhalational injury (50% increased needs)
- children
- high voltage electrical injury
- delayed resuscitation
- alcohol intoxication
- polytrauma
- deep burns 2’ vs 3’ because of increased zone of stasis
What are principles for pediatric lfuid resuscitation
- normal blood volume is 80cc/kg
- higher requirements compared to adults
- parkland for peds: Parkland (RL) + Maintenance fluid D5W
What are end points of fluid resuscitation
- urine output 30-50cc/hr
- base deficit normalization (<3mmol/L)
- lactate clearance <2mmol/L)
- MAP >65mmHg
- HR normalized
What is fluid creep
Complications of edema secondary to fluid resuscitation
- abdominal compartmen syndrome
- pleural effusion, pulmonary edema
- CHF
- compartment syndrome of extremities
- pericardial effusion
- increased intra-ocular pressures
- H&N edema leading to airway compromise
What are 4 clinical signs of abdominal compartmnet syndrome and RFs for ACS
ALso what is the differene b/w A HTN and ACS
- oliguria
- high airway pressure
- hemodynamic instability
- metabolic acidosis
Risk factors
- circumferential abdominal/chest burn
- TBSA>40%
- large fluid resuscitation (>200cc/kg in last 24hr)
- inhalation injury
- burn sepsis
- hemo/myoglobinuria
Diangosis:
- Intrabdominal pressure determined with transduction catheter inside bladder
- IAHTN: Pbladder >12mmHg
- ACS: Pbladder >20mmHg + new organd failrue (eg. oliguria, hypotension, oxygentation/ventilation hypoxemia, high A/W, drop in Vt)
Diangosis: increased bladder pressure trasnduction: >20mmHg
What is the treatment for ACS
Conservative
- reduce IV rate
- pharmacologic paralysis,
- neuromuscle relaxants + sedation
- escharotomy
- peritoneal dialysis
- diuresis
Operative
- decompressive laparotomy
How does burn injury lead to immunosppression?
Burn leads to thermal/tissue damage =>
- proinflammatory cytokine activation (TNFa, IL-1 IL-6)
- AA cascade (PGE2, TXB2, TXA2)
- neuroendocrine dysfunction
- immune cell dysfunction (macrophage, IgG, APC)
What are management strategies to improve immune function
- early E&G
- early enteral feeding
- adequate resuscitation
How do you define SIRS
2 or more of the following
- Temp: <36, >38
- HR >90
- RR >20/min, PaCO<32mmHg
- WBC <4 or >12
What is the cytokine cascade and its role in immunosuppression in the burn patient
- Tissue damage stimulates cytokine relase
- IL-1, IL-6, TNFalpha
- released by macropahges
When do you consider using colloids and why?
- TBSA>40%
- to reduce amountof crystalloid given
- start 8-12hr post-burn (reduced leak in non-burns areas)
- 100cc/hr IV 5% albumin or 1/3 rate of crystalloid
When do you consider hypertonic solution
- to reduce overall fluid form taking from ISF to plasma
- 3% HTS 200cc over 2hrs
- risk hypernatremia, hyperchloremia, AKI
