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Abstract Summary Major burns are burns to over 20% of total body surface area (TBSA) in adults, more than 10% TBSA in children and elderly patients, or full thickness burns to >5% TBSA . Burns involving the face, airway, or genitalia are also classified as major burn injuries regardless of the percentage of TBSA affected. Major burns result in very serious systemic pathophysiological changes mainly due to release of inflammatory mediators .Systemic pathophysiological changes can be categorized in two main phases ; the early phase known as the emergent or ebb phase, is at maximum 12 h into the post burn and usually lasts for up to 72 h and the late phase known as hypermetabolic phase that may last to years after the burn injury . The early phase is characterized by hypervolemia , decrease in patient cardiac output with decrease hepatic and gastrointestinal tract perfusion , airway obstruction and oedema that may progress to acute lung injury or acute respiratory distress syndrome , carbon monoxide poisoning , hemoconcentration and thrombocytopenia and increase incidence of cerebral odema. The hypertmtabolic phase is mainly due massive surge in catecholamines and corticosteroids and is characterized by increased cardiac output , tachycardia , increased systemic vascular resistance , increased metabolic rates , increased core body temperature , increased muscle catabolism that leads to weight loss and hyperglycemia. Both phases requires special attention when anesthesia is considered to be given. Role of anesthesiologist in cases of major burn begins early in the emergency department in form of rapid initial assessment of respiratory and cardiovascular status, establish the extent and depth of burn injury, and determine the need for special procedures. Care of airway is very important as endotracheal intubation is indicated in certain circumstances example if there is physical evidence of airway affection. Also mechanical ventilation is considered in certain circumstances. There are different modes of ventilation mainly aim to protect lung. Aim of cardiovascular support is to provide enough fluid replacement to Page 85 maintain perfusion without causing fluid overload ,so different resuscitation formula are created for fluid replacement including for example Parkland (Baxter) formula . For preoperative management routine laboratory tests is considered enough. Additional laboratory test that is considered include arterial blood gases and frequent venous blood gases. Preoperative medications includes sedatives, drugs that reduce gastric acidity. Preoperative preparing of blood products is essential. During early phase lower doses of agents are typically required. During hypermetabolic phase anesthetic requirements are generally increased . Intravenous induction of anesthesia with ketamine shows many advantages especially for hypovolemic burned patients. Inhalation induction is indicated when there is actual or potential airway obstruction. Sevoflurane is a good agent for inhalation induction . Burn injury shows increased resistance to nondepolarizing muscle relaxants and increased sensitivity to depolarizing muscle relaxants (i.e, succinylcholine). For Maintenance of anaesthesia; Volatile anaesthetics are routinely used during maintenance of adult ,but dose-dependent vasodilation and cardiac depression may limit volatile anaesthetics as sole agents. Total intravenous anesthetic technique should be considered in patients managed with nonconventional ventilators . Advantages of regional anaesthesia include avoiding deep sedation. The coagulopathy, sepsis and burns at site of introducing regional anesthesia are the limiting factors for this technique. Pain is a serious problem as pain and anxiety affect outcome and progress of healing ,so pain management is started early in emergency room . Opioids remain the main drugs used to manage pain of burned patients although their side effects . Because of these side effects of opioids other analgesics are used in combination with opioids aiming to Page 86 decrease doses of opioids. Relieving anxiety with benzodiazepine and tricyclic anti-depressant is essential is essential The provision of the right balance of macro and micronutrients, along with additional antioxidants is essential to mitigating the hypermetabolic and hypercatabolic state. The enteral nutrition route of nutritional support is associated with many advantages. The metabolic rate is reported to increase proportionally to the increase in burn size so weight loss is noticed in all burned patient and adequate energy and caloric intake should be managed with close eyes also to avoid overfeeding. Many formulas are used to asses caloric requirement for burned patient (e.g Toronto equation). 60 to 70 % of caloric requirement should be given as carbohydrate. Use of topical antibiotics is more essential to protect against infection more than systemic antibiotic , although prophylactic systemic antibiotics may be needed are used in many burn unit |