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Chemical Burns. Chemical Burns – Epidemiology. 2.5-4% of all burn admission Male >> female, adults Industrial chemicals Chemical stored in households Military injuries Criminal assault. Chemical Burns - Pathophysiology. As in thermal burns involves protein denaturation
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Chemical Burns – Epidemiology • 2.5-4% of all burn admission • Male >> female, adults • Industrial chemicals • Chemical stored in households • Military injuries • Criminal assault
Chemical Burns - Pathophysiology • As in thermal burns involves protein denaturation • Injury contnues as long as chemical exists in tissue • Chemical nature determines damage • The concentration and time of exposure has a crutial role
Chemical Burns – Mechanisms of Action • Reduction • Oxigenation • Corrosive • Protoplasmic poison • Desiccants • Vesicants
Chemical Burns - Management • Tend to be deeper than appear at first • Usually not very wide (< 10% TBSA) • Thick eschar • Heal more slowly- hospital stay +30%
Chemical Burns – Emergency Care • Remove immediately all clothing • Dilution - copius water irrigation • Drain first lavage fluid • Moniter lavage fluid pH (if possible) • Identify assaulting chemical • Specific neutralizing solutions
Chemical Burns – Emergency Care • Metabolic monitoring and support -ABG’s and electrolytes • Airway management, oxygenation amd ventilation • Analgesia • Hypothermia
Chemical Burns - Management • Tangential excision + STSG after extent is obvious • Excision and primary closure of trickling • Enzymatic or laser debridement
Chemical Burns - Classes • Acids • Bases • Organic compounds • Inorganic agents
Chemical Burns – Acids • Tungstic, picric, sulfosalycylic, trichloric – renal and hepatic damage • Oxalic acid – lethal at 0.5 gr/kg • Apply Ca salts to site • Iv Ca-gluconate/chloride if systemic Ca2+ • Sulfuric acid – release heat, black eschar • Limited yet deep excision +STSG
Chemical Burns –Hydroflouric Acid • Silica dissolvent, petrollium, semiconductors • Dehydration and corrosion as an acid • F- entrap Ca2+ and Mg2+ • Concentration dependent
Chemical Burns –Hydroflouric Acid • Local - necrosis and bone decalcification • PAINFULL • Systemic – hypocalcemia, hypomagnesemia, hyperkalemia • Cardiac arrhythmias – refractory VF
Chemical Burns –Hydroflouric Acid Treatment • Topical and local injections of Ca-gluconate • Cardiac monitoring, frequent elctrolyte evaluation • Dialysis
Chemical Burns –Hydroflouric Acid Specific injuries • Hand – radial artery administration Ca-gluconate • Eye – immediate NS irrigation, Ca-gluconate q2-3h • Inhalation – Ca-gluconate inhalation, C-PAP, steroids
Chemical Burns - Alkali • NaOH, KOH, Lime • Mechanism • Fat saponification • Hygroscopic qualities • Alkaline proteinates Further reactions • Rapid dry eschar formation • Ocular damage – topical anasthesia, cycloplegia, Abx , cysteine, topical steroids
Chemical Burns - Cement • Alkali • Anterior leg • Abrasive if mixed with gravel or sand • Exothermic • Hygroscopic • Painless
Chemicl Burns - Assault • Male 70-80 %, 30’s • Usually sex partner • Facial and genital injuries • Cheap household chemicals (lye, sulfuric acid) • Almost never adequate lavage
Chemical Burns – Organic Compounds Petrolium • superfacial burns, heal spontaniously • Fluid resuscitation - Parkland • Acute renal failure –dehydration + direct tubuloglomerular damage • Lung injury from petrolium fumes, surfactant production inhibited
Chemical Burns – Organic Compounds Phenol • Dermatits, depigmentation, necrosis • Acts as local anasthetic • Local treatment - water, PEG, soap, oil • Albumin bound • Cardiac arrhythmias, hemolysis
Chemical Burns- Chrome Deriviates • Chromic acid, chromic salts • Yellow coagulum , blisters, ulceration • VERY toxic : gastritis, muscle cramps, vertigo, vascular collapse,nephritis coma • Acid – buffered phosphate rinse, demercaprol IM injection • Salt - 2% hyposulfite or buffer phosphate
Chemical Burns - Phosphorus • Military, fireworks, farmers • Ignites in contact with air • Painful, necrotic, yellowish, garlic odor • Water soaked dressing + CuSO4 0.5% irrigation • Hypocalcemia, hyperphosphatemia, ECG changes, arrhythmias
Chemical Burns - Vesicants Nitrogen/sulfur mustard, Lewisite • Immediate – ocular and throat burning • 4-48 hrs – erythema, blistering, pruritus, ulcers • Days – Bone marrow suppression, GI, CNS, pneumonits, superimposed infection • Late - Respiratory mucosal injury, recurrent corneal ulceration and chronic conjunctivits
Chemical Burns – Mustard Gas • Lipophilic but activated in aqueous solution • 12-50% react in the skin • Alkylation of DNA, targeted at TAC • Deplition of thiol oxidative stress • Late hyperpigmentation • Slowing wound healing process
Chemical Burns - Vesicants • Protective garments • Eye - NS or 1.26% bicarbonate • Debride blisters + antimicrobial ointment • Lewisite burns – topical chelator dimercaprol/DMSA • Deep ulcers Tx as thermal injury • Fluid replacement, electrolyte management, G-CSF
Topical skin protectants Perflouroalkylpolyether (PFAPE) Polytetrafluoroethylene (PTFE, teflon) Chloramide Post contact Vandillylate neropeptide inhibitors Bimoclomol Chemical Burns - Vesicants