الفهرس 
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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
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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
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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