81. Burns Flashcards
Thermal burns occur during heat or cold transfer. What are ways heat is transferred?
- Conduction–direct contact2. Convection–airborne3. Radiation–electromagnetic energy interaction(also evaporation chapter 23–anesthesia)
Surface area classification of wounds
Rule of 9sHead/neck 9, ea forelimb 9, ea hindlimb 9Dorsal trunk 18Ventral trunk 18Burn card= 45cm2(# cards x .45)/ m2 (standardized body weight to surface area)
Local response to thermal burn injuryZones
Zone of coagulation– inner, irreversible, nonviable, necrosis, destructionZone of stasis– poor perfusion, vulnerableZone of hyperemia–outer, viable
Why are burns more likely to heal slowly
They have < 5% of normal levels of fibroblast growth factor 2And lack endothelial chemotactic activity
Generalized cardio effects from smoke inhalation
Vascular permeability of fluid and albumin–overwhelms lymphaticsOther fluid loss through evaporation (direct loss from skin)RBC deformability both extravasation and evaporation lead to hypovolemia= hyperviscosity, poor perfusion, hypoxemia20% TSA burn cause 28% loss of plasma volume w/in 6 hr
Myocardial effects from smoke inhalation
Carbon monoxide toxicity causes myocardial damage and decreased cardiac outputOxidative injury to sarcolemma causes incr myocyte intracytoplasmic CaThermal injury also injures Na/Ca channels causes incr myocyte intracytoplasmic CaLeads to decrease left ventricular contractility and CO
Burn anemia
10 % RBCs become trapped and destroyed in large burn RBC fragility and membrane damage Intravascular hemolysisReduced erythropoiesis from decreased iron stores despite EPO release
Pharmacological therapy for smoke inhalation
Aerosolized sympathomimetic bronchodilators–epinephrine Nacetylcysteine–mucolytic that forms free sulfhydryl radicals that break down disulfide bonds in muco proteins but can cause bronchospasms ; Nacetylcysteine l lysinate is an improved formLow molecular wt dextran— makes mucus bonds weaker
3 types of pain w burn injury
- Procedural pain–most intense, during tx, sharp, burning, stinging, most likely under treated2. Background pain– prolonged relatively constant pain, burning, throbbing, usually during immobility3. Breakthrough pain– transient worsening of pain usually associated w movement, stinging, shooting (treated with CRI or shortening the dosing interval)
How to treat a doxorubicin extravasation
Not neutralized during run therefor continually causes local rxn1. Local excision2. Local injection of hyaluronidase ( to promote vascular uptake of drug)3. Infiltration of dexrazoxane (dimethyl sulfoxide) as free radical scavenger by binding iron
initial response to tissue trauma from burn
vasodilation (under cytokine control)NO, PGE2, Histamine, Substance P
toxic substances in smoke inhalation
250 toxic substance–Carbon monoxide–binds w Hb to make carboxyhemoglobin wh reduces o2 carrying capacity and causes left shift of oxyhemoglobin dissociation curve reducing o2 delivery to tissues; also binds w Mb reducing o2 available to muscle –Hydrogen cyanide– disrupts cellular respiration –hydrochloride–irritants leading to laryngeal and broncho spasms
initial first aid for burns
cool to cold running water NOT ICEoptimum temp 15 degrees Ccooling with ice causes extreme drops in sub dermal temperature
goals of bronchial hygiene for treatment of smoke inhalation
- minimize ongoing pulmonary inflammation2. improve gas exchangeinclude oxygen, nebulization and coupage
benefits of oxygen for tx of smoke inhalation
supplemental oxygen speeds the removal of carbon monoxide from bloodaffinity of Hb for carboxyHb is 240x higher than affinity for oxygen, need to saturate blood with oxygen to overcome difference in affinity
