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244 Current Essentials of Critical Care Warfarin Poisoning Essentials of Diagnosis • Bleeding from single or multiple sites, with bruising, epistaxis, gingival bleeding, hematuria, hematochezia, hematemesis, men-orrhagia • Prolonged PT, normal or prolonged PTT, normal thrombin time, normal fibrinogen level • Can occur either by ingestion of warfarin (drug) or ingestion of rodenticides containing similar agents (most rodenticides con-tain small amounts of anticoagulant and rarely associated with significant toxicity) • Allopurinol, cephalosporin, cimetidine, tricyclic antidepressant, erythromycin, NSAIDs, ethanol increase anticoagulant actions of warfarin and contribute to toxicity Differential Diagnosis • Other causes of coagulopathy, including liver disease, vitamin K deficiency, disseminated intravascular coagulation, sepsis-re-lated coagulopathy Treatment • Gastric decontamination within 1 hour of ingestion • For life-threatening bleeding, immediate reversal with fresh frozen plasma, IV vitamin K • For non-life-threatening bleeding, oral or IV vitamin K in pa-tients not requiring long-term anticoagulation • For non-life threatening bleeding in patients requiring subse-quent long-term anticoagulation, partial correction with fresh frozen plasma • For prolonged PT without bleeding, observation alone usually sufficient Pearl Warfarin can be associated with several skin abnormalities including urticaria, purple toe syndrome, and skin necrosis. Reference Ansell J, et al: Managing oral anticoagulant therapy. Chest 2001;119(1 Suppl):22S. [PMID: 11157641] 17 Environmental Injuries Carbon Monoxide (CO) Poisoning.................................................. 247 Electrical Shock & Lightning Injury................................................ 248 Frostbite.......................................................................................... 249 Heat Stroke..................................................................................... 250 Hypothermia................................................................................... 251 Mushroom Poisoning..................................................................... 252 Near Drowning................................................................................ 253 Radiation Injury.............................................................................. 254 Snakebite........................................................................................ 255 Spider & Scorpion Bites................................................................. 256 245 This page intentionally left blank Chapter 17 Environmental Injuries 247 Carbon Monoxide (CO) Poisoning Essentials of Diagnosis • Headache, confusion, neuropsychological impairment, general-ized malaise, fatigue, nausea, vomiting, chest pain • Tachycardia, hypotension, focal and non-focal neurological findings; patients do not have cyanosis; if severe, shock, stupor, coma • Electrocardiogram (ECG) changes of ischemia in susceptible pa-tients • May be accidental (operation of motor vehicles in enclosed space, malfunctioning furnaces), concomitant with smoke in-halation, deliberate suicide attempt • Alcohol, drugs associated with poisoning and death; most com-mon poison-related death in United States • CO binds to tightly to hemoglobin, also increases O2 affinity to hemoglobin, resulting in impaired O2 delivery; also may be in-tracellular toxin Differential Diagnosis • Drug overdose • Hypoxemia • Cyanide toxicity • Effects of smoke inhalation Treatment • Supportive care, especially if cardiovascular compromise, smoke inhalation, burns • High concentration of inhaled oxygen speeds elimination of car-bon monoxide (use non-rebreather O2 mask or endotracheal in-tubation with 100% O2) • Hyperbaric 100% O2 increases rate of CO elimination; clinical value unclear • Transfusion of packed red blood cells may be helpful; consider exchange transfusions in severe toxicity Pearl The pulse oximeter is unable to distinguish carboxyhemoglobin from oxyhemoglobin; blood must be sent for carboxyhemoglobin concen-tration. Reference Gorman D et al: The clinical toxicology of carbon monoxide. Toxicology 2003;187:25. [PMID: 12679050] 248 Current Essentials of Critical Care Electrical Shock & Lightning Injury Essentials of Diagnosis • Burns: partial or full thickness skin damage • Household current shock: transiently unconscious, headache, cramps, fatigue, paralysis, rhabdomyolysis, atrial or ventricular fibrillation, nonspecific ST-T ECG changes • Lightning strike: para- or quadriplegia, autonomic instability, hypertension, nonspecific ST-T ECG changes; blunt trauma due to falls; burns typically superficial • Degree of injury depends on conducted current of electricity • Alternating current (household) more dangerous than direct cur-rent (lightning); high voltage injury defined as .1000 volts Differential Diagnosis • Cardiac arrhythmia • Thermal or chemical burns • Blunt traumatic injury • Toxin or smoke inhalation Treatment • Intubation and mechanical ventilation for respiratory compro-mise • Fluid resuscitation • Most immediate risk from cardiac arrhythmia, particularly if electric shock passed through the thorax; most arrhythmias self limited, but may require antiarrhythmic drugs • Local care for skin wounds; transfer to burn unit if extensive burns • Monitor creatine kinase levels for rhabdomyolysis; if present, consider alkalinization of urine Pearl Lightning generates massive peak direct current of 20,000–40,000 am-peres for 1–3 microseconds. Despite this, patients surviving the im-mediate event typically have few complications and often only require observation. Reference Koumbourlis AC: Electrical injuries. Crit Care Med 2002;30(11 Suppl):S424. [PMID: 12528784] ... - tailieumienphi.vn
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