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Environmental Injury

Environmental Injury. Emergency medicine - 4 -. Topics. Burns and frostbite C arbon Monoxide Poisoning Hypothermia Heat Emergencies N e ar Drowning and Dysbarism High Altitude Medical Problems Disaster Medicine. Burns. Classification Epidemiolog y P at h o physio log y

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Environmental Injury

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  1. Environmental Injury Emergency medicine - 4 -

  2. Topics • Burns and frostbite • Carbon Monoxide Poisoning • Hypothermia • Heat Emergencies • Near Drowning and Dysbarism • High Altitude Medical Problems • Disaster Medicine

  3. Burns • Classification • Epidemiology • Pathophysiology • Clinical features • Inhalation injury • Treatment: • prehospital • Emergency department • Hospital - Admission or transfer to specialized burn center

  4. Burns: Classification, epidemiology • Burns: • thermal • chemical • electrical • Epidemiology: 1,25 mil./year (USA) • Age: 18-35 year-old group, hot liquids-children 1-5 years of age and in the elderly • Mortality rate: 4 % (USA)

  5. Burns:pathophysiology • Thermal injury is a progressiv injury: • Local: • Liberation of vasoactive substances • Disruption of normal cell membrane function (Na pump) • Edema formation • Systemic response: • neurohormonal ( histamine, kinine, serotonin, arahidonic acid metabolites,free O2 radicals) • Hypovolemic shock,heart-myocardial depression,acidosis,renal failure) • Factors may influence prognosis:the severity of the burn, presence of inhalation injury, associated injuries, patient’s age, preexisting disease

  6. clinical features • Burn Size: body surface area • “9” method - A. B. Wallace

  7. Burns-clinical • Burn depth: First degree–involve only epidermal layer of skin: the burned skin is red, painful and tender /heal in 7 day Second-degree- extend into the dermis, are divided into superficial partial-thickness and deep partial–thickness burns- there is blistering the skin, the derm is red and very painful to touch- heal with ’’ restitutio ad integrum” in 14-21 d Third degree involve the entire thickness of the skin,all epidermal and dermal structures are destroyed, the skin is charred, pale, pailess and leathery, heal “per secundam intentionem”, needs surgical repair and skin grafting. Fourth-degree burns extend through the skin to the subcutaneous fat, muscle, and even bone-amputation or extensive reconstruction.

  8. Major burns I-II, > 25 %, 10-50 year I-II, > 20 %, < 10 sau > 50 ani III-IV, > 10 % Hands,face,feet, perineum Burns crossing major joints Circumferential burns of an extremity Inhalation injury Burns complicated by fractures and other trauma Electrical burns Burns in infants and the elderly Poor-risk patients Moderate I-II, 15-25 %, 10-50 ani I-II, 10-20 %, < 10 sau > 50 year III-IV, < 10 % Minor I-II, < 15 %, 10-50 year I-II, < 10 %, < 10 sau > 50 year III-IV, < 2 % American Burn Association Criteria

  9. Inhalation injury • Smoke- small particles, reach the terminal bronchioles- bronchospasm, edema,decreases alveolarsurfactant activity,airflow obstruction, atelectasis • CO poisoning: produces brain hypoxia and coma • Diagnosis:history,physical signs: facial burns, singed nasal hair,soot in the mouth or nose, hoarseness,carbonaceous sputum, expiratory wheezing • Endotracheal intubation: • Full-thickness burns of the face or perioral region, • Circumferential neck burns, • Acute respiratory distress, • Progressive hoarseness or air hunger , • Respiratory depression or altered mental status, • Supraglottic edema or inflammation on bronhoscopy

  10. Prehospital treatment • Stop the burning process • Establish airway • Oxigenoterapy • Fluid resuscitation • Relive pain • Protect the burn wound • Transport

  11. Burns:treatment • ABC • Fluids (cristaloids): Lactated Ringer’s 4 ml x weight(kg) x BSA (%), over initial 24 h ( ½ over the first 8 h, ½ over the subsequent 16 h) • Monitoring BP, HR, capillary refill time,mental status , urinary output(0,5-1ml/kg/h) • CBC, electrolytes, BUN, creatinine, glucose, • Arterial blood gases,chest radiograph, carboxiHb, ecg, bronhoscopy • Tetanus immunization • Pain: narcotic analgesis, anxiolytic

  12. Burns: local treatment • Initially: clean, dry sheet Small burns: moist saline-soaked dressing, local cooling (reduces histamine release, kinin formation, Tx B2 production) • Large burns: sterile drapes, transfer • Circumferential deep burns: escharotomy • Antibiotics

  13. Chemical burns • Home, agriculture, industrial, research laboratories, military, • Acids (organics and anorganics)- coagulation necrosis • Alkalis- liquefaction necrosis • others- local and general injury • Thermal injury (erithema, blistering,full-thickness ,necrosis)is determined by:strength/concentration of the agent ,quantity,duration of contact, mechanism of action, extent of penetration.

  14. Chemical burns- treatment • Dilution,irrigation to avoid the agent • Irrigation-continued for hours in the case of alkali burns • Topical antimicrobial agents • Dilution of phenol and oxid de Ca with water may enhance penetration • General treatment if burns>20% • Local treatment:autografts,heterografts,homografts

  15. Electrical burns • Factors associated with severity of electrical injuries: • Current Intensity (A) • Electrical potential (V) • Type of current (AC sau DC) • Tissue resistance • Duration of contact • Current pathway( vertical, horizontal) • Enviromental circumstances • Clinical features: • Local:cutaneous burns at the point of entry and exit • General: Cardiac arrest (FV, asistola), neurological, vascular injury, muscular injury, mioglobinury

  16. Electrical burns- treatment • ABC with spinal immobilization • Cardiac arrhythmias-ACLS protocol • Fluids resuscitation: Ringer’s lactate or normal saline 20-40 ml/kg over the first hour • rhabdomyolysis: 50 mEq bicarbonat/l of fluid • Wound care: excision,etc • Tetanus immunization • Prophylactic administration of parenteral antibiotics

  17. Frostbite and cold related injury • Def: tissue injuryafter cold exposure • Hystory: Hannibal(losing half his 46000 man crosing the Pyrenean Alps), Napoleon’s surgeon -Larrey,World War l-trench foot • Factors:duration of contact, humidity,wind, altitude,clothing,medical condition,behavior • Patophysiology • Clinical features • Treatment: prehospital, emergency department

  18. Frosbite patophysiology • Prefreeze State: tissue cooling, increased viscosity,capilary constriction-dilatation cycle • Frozen state:extracellular ice crystal formation, intracellular dehydration and hyperosmolarity,fluid crossing cell membrane • Ischemic and vascular complications: reperfusion injury,endothelium leaky , cogulation from stasis, leakage of destructive prostaglandins and oxigen free radicals, vasoconstriction and arteriovenous shunting, necrosis demarcation and gangrene

  19. Frostbite severity • I degree: partial skin freezing,erythema,edema,hyperemia,no blisters or necrosis, occasional skin desquamation( 5-10 d later) • II degree:full-thickness injury, erythema, substantial edema, vesicles with clear fluid,blisters that desquamate and form blackened eschar • III degree:full-thickness skin and subcutaneous freezing , violaceous or hemorrhagic blisters, skin necrosis, blue-gray discoloration • IV degree: full-thickness skin,subcutaneous tissue, muscle, tendon,and bone freezing,little edema,initially mottled,deep red or cyanotic, eventually dry, black, mummified

  20. Treatment • prehospital: wet and constrictive clothing should be removed,the involved extremities should be elevated and wrapped in dry sterile gauze • Hospital: bath at 40-42 C for 10-30 min with active motion, parenteral analgesics(morphin 0,1 mg/kg, meperidină 1-1,5 mg/kg) • Local: • debride clear blisters, • leave hemorrhagic vesicles intact,dress with aloe vera • Tetanus prophylaxis, penicilina G (500.000/6 h), ibuprophen 400mg,begin daily hydrotherapy • Surgery

  21. Carbon monoxide poisoning • Epidemiology: mediu industrial, casnic, incendiu • patophysiology • clinical • Diagnosis • Treatment

  22. Pathophysiology • CO forms a ligand with respiratory pigmentsand enzymes: • Hb • Reduces the O2 carriage • Transform the oxyhemoglobin dissociation curve • Formation of HbCO – “chemical anemia” • Myoglobin (miocardică) • Cytochrome P-450 • Cytochromeaa3 • Direct toxic efects

  23. Carbon monoxid poisoning: diagnosis • Hystory • Physical exam: neurological examination, skin color • Paraclinic: co-oximetry, HbCO level • Lab:CBC, metabolic acidosis, serum bicarbonate level, serum lactate level, serum electrolytes • Ecg: myocardial ischemia • Serum CK and CK-MB,myoglobin, urine toxicology • Chest -ray • CT / IRM: cerebral ischemic injury

  24. CO poisoning: treatment • ABC , CPR in cardiac arrest • Mild CO toxicity: • Normobaric oxygen 100 % by mask for 4 h/ventilatory assistance: bag-valve-mask ventilation or endotracheal intubation • Serious CO toxicity: • Hyperbaric oxigen 100 % at 2,4 – 2,8 AT 90 min

  25. Hypothermia • Definition • Classification • Etiology • Diagnosis • Ecg changes • Treatment

  26. Hypothermia-definition • Core (Central) temperature< 35 C( esofagian/ rectal • clasification: • mild 35-32 C • medium 32-28 C • severe< 28 C

  27. Hypothermia-causes • “Accidental”(enviromental) • Metabolic:hypothyroidism, hypoadrenalism,hypopituitarism, hypoglicemia • Hypothalamic andCNS dysfunction (trauma, tumori,AVC,B. Wernicke) • Sepsis • Dermal disease • Iatrogenic (fluid resuscitation) • Acute incapaciting illness • Toxics (drogs,etanol, fenotiazin,sedativs, hypnotics)

  28. Hypothermia-efects • Cardiovascular: inotrop and cronotrop negativ, hypovolemia, life-threatening dysrhymias; • Respirator: tachypnea, decrease in respiratory rate and tidal volum, depression of cough and gag reflexes (aspiration pneumonia); SNC:depression, confusion, lethargy, coma; • Renal: “cold diuresis ”,significant volume losses, rhabdomyolysis, acute tubular necrosis, renal failure (myoglobinuria, renalhypoperfusion); • CID (hemoconcentration, increase in blood viscosity, coagulopathy); • acid-base disturbances: acidosis(CO2 retention),alcalosis(diminished CO2 production).

  29. ECG: J wave Osborn • PR, QRS, QT prolongation, T-wave inversions • Sinus bradycardia , nodal rhythms • PVCs, AV block • Atrial fibrillationor flutter • VF, asystola

  30. Hypothermia- treatment • CPR • Passive rewarming: removal cold environment • Active external rewarming:warm water immersion,heating blankets, radiant heat, forced air • Active internal rewarming: • Ventilation with warm O2, • Heated i.v. fluids, • Gastrointestinal tract lavage,bladder lavage, pleural lavage,pleural lavage, extracorporeal rewarming, mediastinal lavage via thoracotomy

  31. Heat emergencies • Definition, epidemiology • Risk factors • Pathophysiologie • Clinical forms • Clinical and paraclinical diagnosis • Complications • Treatment • Prognosis

  32. Heat emergency: def., epidemiology • USA:390 deaths/year caused by the effects of heat and excessive heat exposure; • The second leading cause of death among young athletes; • Risk group:elderly with cardiopulmonary illnesses • Environmental fators: • Temperature; • Humidity; • Sun exposure • The wind;

  33. RiskFactors for serious heat injury • Dehydratio • Obesity • Heavy or impermeable clothing • Lack of aclimatization

  34. Heatstroke • Central temperature> 40,5 C; • Mental status; • Mortalitality 10 %; • Endotoxin and citokin action

  35. Clinics • Temperatură centrală (esofagiană, rectală, vezicală) > 40,5 C; • Tahicardie, tahipnee, hipotensiune; • Iritabilitate, confuzie, obnubilare; • Convulsii, stare de comă,hemiplegie; • Echimoze, epistaxis, hematemeză, hematurie (CID).

  36. Chest x-ray Pulmonary edema, pulmonary congestion, adult respiratory distress syndrome EKG Conduction abnormalities, nonspecific ST-T wave changes, arrhythmias, myocardial infarction ABG Respiratory alkalosis, oxygenation status Cardiac isoenzymes Myocardial injury CBC Leukocytosis, elevated hematocrit Fibrinogin, fibrin split products Coagulopathy, disseminated intravascular coagulation LDH, AST, ALT, CK, potassium, BUN Elevated in renal or hepatic injury Lactate Commonly elevated in exertional heat stroke, predicts poor prognosis in classic heat stroke Calcium, phosphorus, glucose Decreased Urinalysis Myoglobin casts, red blood cells Paraclinics

  37. Near Drowning • Drowning- death from suffocation after submersion • Near drowning- survive, at least temporarily after suffocation by submersion • Epidemiology- children <4 years, teenagers

  38. Associatead risk factors • Alcohol or drug use • Traumatic injury – spinal injury • Hypothermia

  39. Pathophysiology • Water – airway- flooding of alveoli- impairment of gas exchange • Initial hypoxemia • Respiratory failure • Ischemic neurologic injury

  40. Pathophysiology • Noncardiogenic pulmonary edema • Poor perfusion and hypoxemia • Metabolic acidosis • Electrolyte abnormalities • Disseminated intravascular coagulation • Acute tubular necrosis

  41. Prehospital care • Rapid , cautious removal of the victim from the water • Spinal precautions • Cardiopulmonary resuscitation • Supplemental oxygen on all patients • ETT and assisted ventilation • No postural drainage • No Heimlich maneuver

  42. Hospital care • Clear spine • Pulmonary support: O2 or supplemental oxygen • Monitor • Laboratory studies: CBC, electolytes, glucose, pulse oximetry, arterial blood gases, chest x-ray, ecg • Nasogastric tube, Foley catheter

  43. Arrhythmias; Aspiration pneumonia , irreversible lung injury; Sepsis; Neurologic deficits; Vary with the time of hipoxia; Cardiac arrest – mortality rate 35 - 60 %; Neurologic deficit 60 – 100 %; Complications Prognosis

  44. Dispositions • I-Patients with no evidence of significant submersion may be discharged • II- asymptomatic or mild symptoms – observed in ED, chest x ray, arterial blood gases, pulse-oximetry; • III- mild and moderate hypoxemia- oxygen therapy- admitted or discharged; • IV-intubation and mechanical ventilation – neurologic status and pulmonary injury

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