TRAUMA

Dr Abdollahi

Trauma and associated life-threatening injuries account

for 10% to 15% of all patients hospitalized. Rapid

transport of a trauma victim to a trauma center rather than to the nearest hospital has resulted in improved outcome for the victim.

A level I trauma center is characterized by the

immediate availability of medical and nursing personnel

(emergency medicine physician, trauma surgeon, neurosurgeon, orthopedic surgeon, plastic surgeon, anesthesiologist,critical care specialist, radiologist, and nurses), as well as the facilities needed to treat trauma patients (emergency room, operating rooms, radiology suite, intensive care unit [ICU], central laboratory, and blood bank).

INITIAL EVALUATION

On arrival at the hospital, the patient's airway, breathing, circulation, and neurologic status (Glasgow Coma Scale, computed tomography [CT], magnetic resonance imaging) must be rapidly evaluated with the advanced trauma life support (ATLS) protocol. The first priority is establishment

of an airway and administration of oxygen.

Occasionally, the trauma victim's trachea has been intubated by the paramedic before arrival at the hospital.

Confirmation of tube placement as reflected by a sustained end-tidal CO2 waveform needs to be established and documented immediately on arrival at the hospital.

Early tracheal intubation in selected patients has been

a major factor in decreasing mortality from trauma.

Nasotracheal intubation should not be attempted if there

is the possibility of a basal skull fracture. If airway obstruction exists and tracheal intubation cannot be accomplished, emergency cricothyrotomy or tracheostomy is indicated.

All trauma victims are assumed to be at risk for pulmonary aspiration of gastric contents .

Cervical Spine Injury

In patients with a possible cervical spine injury (present

in 1.5% to 3% of all major trauma victims), orotracheal intubation should be attempted only with the patient's head stabilized in a neutral position (a rigid collar decreases flexion and extension to about 30% of normal and rotation and lateral movement to about 50% of norma!).

CT is the best way to diagnose cervical spine injury, although two thirds of all trauma victims have multiple injuries that may interfere with the ability or safety of performing routine CT.

Thoracic Trauma

Thoracic trauma may involve the lungs or cardiovascular system, or both. An upright inspiratory chest radiograph is preferred for visualization of a pneumothorax (high index of suspicion if rib fractures are present), although the more likely radiograph will be an anteroposterior supine film.

Pneumothorax or hemothorax is treated with a tube thoracostomy (tube placed in the fourth or fifth interspace in the midaxillary line and directed posteriorly and attached to suction). Intrathoracic vascular injury is suggested by a widening mediastinum, whereas lung contusion is predictable when a flail chest is present.

Abdominal Trauma

Abdominal injuries after blunt trauma are most often splenic rupture or laceration of the liver, with both resulting in profound hemorrhage. Intra-abdominal hemorrhage is diagnosed by diagnostic peritoneal lavage (DPL), abdominal ultrasound, or CT. Continued hematuria after placement of a bladder catheter indicates a possible bladder injury and the need for a cystogram or intravenous pyelogram.

Orthopedic Trauma

If suspicion of a pelvic fracture is entertained, the patient should be placed in a pelvic binder and transferred to interventional radiology for an emergency angiogram and possible intravascular embolization instead of rushing the patient to the operating room.

Evaluation of the extremities includes palpation of distal pulses and visual inspection for symmetry of the extremities to detect evidence of bleeding, especially in the thighs after femur fractures. Early immobilization of fractures is indicated.

Management of Anesthesia

General anesthesia is necessary for most trauma patients who require surgical intervention. A "trauma operating room" should be designated and appropriately equipped . There is no ideal anesthetic drug or technique for a trauma patient.

If the patient's trachea has not already been intubated, rapid-sequence induction of anesthesia is indicated. In the presence of hypovolemia, etomidate (0.1 to 0.3 mg/kg IV) or ketamine (1.0 to 3.0 mg/kg IV) is often selected for induction of anesthesia because these drugs are usually able to maintain stable hemodynamics. In patients with suspected or known cervical spine injury, avoidance of excessive head movement during direct laryngoscopy is necessary.

Frequently, the dose of anesthetic tolerated by the

patient is too small to prevent movement, thus necessitating skeletal muscle paralysis with a neuromuscular blocking drug. In this regard, some patients may experience recall of intraoperative events.

Hemodynamic stability results from control of surgical bleeding and restoration of the patient's blood volume. Arterial blood gases, pH, and hematocrit are measured at frequent intervals during anesthesia and surgery. On a less frequent basis, it may be useful to analyze blood for electrolytes, glucose, and coagulation factors.

Fluid Resuscitation

Hypotension plus cellular hypoxia as a result of massive hemorrage is the resone for production of lactic acid . Goal-directed fluid resuscitation should be initiated immediately after the establishment of venous access because it serves to improve poorly perfused organs, including the liver and skeletal muscles.

Initially, administration of a crystalloid solution such as lactated Ringer's or Plasma-Lyte solution restores intravascular fluid volume to help maintain venous return and cardiac output.

SELECTION OF INTRAVENOUS FLUIDS

There is no advantage in using colloid for initial

resuscitation. When hemorrhage is extreme, it will be

necessary to eventually administer blood products.

Dilutional thrombocytopenia may accompany the massive blood transfusion necessary to reestablish intravascular fluid volume, whereas disseminated intravascular coagulation may accompany persistent hypotension.

Rarely, transfusion-related acute lung injury (ALI) can also occur in trauma victims receiving blood transfusions. A fluid warmer device should be used for all intravenous fluids to minimize the likelihood of hypothermia. The ambient operating room temperature should be kept warm. A massive transfusion protocol should be established.

Invasive monitoring, including an intra-arterial and

central venous pressure catheter, is recommended

Transport from the Operating Room

Severely injured patients often require continued postoperative support of major organ function in an rcu, especially mechanical ventilation of the lungs. Patients usually remain intubated, sedated, and paralyzed during transport to the Icu. Appropriate and necessary drugs and equipment should accompany the patient to the Icu. A transport ventilator is preferred if the patient's oxygenation or ventilation (or both) needs to be continuously supported.

Head Injuries

Depressed Linear

Stellate

BasilarSkull Fractures

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TRAUMATIC BRAIN (HEAD) INJURY

Traumatic brain injury (TBl) reflects an insult to the brain

from an external mechanical force (high-energy acceleration or deceleration) that might cause a temporary or permanent impairment of physical and cognitive functions along with changes in mental status. TBl resulting from head injury is the leading cause of death in individuals younger than 45 years and accounts for approximately 40% of all deaths from acute injuries in the United States.

Recognition

The hallmark of closed head injury is loss of consciousness.

CT should be performed early because it is the most important diagnostic test (evidence of increased intracranial pressure [ICP], types of hematoma, and hemorrhage), and the level of consciousness should be classified according to the Glasgow Coma Scale .

Patient age, imaging studies, pupillary response, mean arterial pressure, and initial Glasgow Coma Scale score have been used to predict the overall outcome in TBI patients.

Head Trauma Assessment

Glasgow Scale

Eye Opening

Motor Response

Verbal Response

Head Trauma Assessment

Glasgow Scale--Eye Opening

4 = Spontaneous

3 = To voice

2 = To pain

1 = Absent

Head Trauma Assessment

Glasgow Scale--Verbal

5 = Oriented

4 = Confused

3 = Inappropriate words

2 = Moaning, Incomprehensible

1 = No response

Head Trauma Assessment

Glasgow Scale--Motor

6 = Obeys commands

5 = Localizes pain

4 = Withdraws from pain

3 = Decorticate (Flexion)

2 = Decerebrate (Extension)

1 = Flaccid

Hypotension, hyperthermia, hypoxia, and elevated ICP

are strong predictors of a poor outcome. Patients with a

Glasgow Coma Scale score of less than 8 by definition

have severe TBI, and the mortality rate is about 33% to

55%. In contrast, the mortality rate is lower (around 2.5%) in patients with mild to moderate TBI (Glasgow Coma Scale score of 8 or greater).

CriticaL Care

Critical care of a head-injured patient is based on recognition and treatment of hazardous increases in ICP.Interventions designed to provide cerebral protection and resuscitation have been successful in patients who experience TBI. Invasive monitoring, including intraarterial and central venous catheter, is recommended. Fluid resuscitation to maintain adequate hemodynamics is important.

Low-volume resuscitation with hypertonic solution saline, dextran, or a hemoglobin-based oxygen carrier may be favored over conventional crystalloid therapy. Jugular venous oxygen saturation (Sjo2), potentially representing cerebral tissue oxygenation, may be used to guide therapy.

Administration of barbiturates is recommended when

ICP remains increased despite traditional therapy.

MANAGEMENTOF INTRACRANIAL PRESSURE

A catheter placed through a burr hole in a cerebral ventricle or a transducer placed on the surface of the brain is used to monitor ICP. Normally, ICP is around 15 mm Hg. Cerebral perfusion pressure is the difference between mean arterial pressure and ICP. Patients with a Glasgow Coma Scale score less than 8 should probably have their ICP monitored in a neurosurgery ICU.

An abrupt increase in ICP during continuous monitoring is known as a plateau wave . Painful stimulation in an otherwise unresponsive patient can initiate a plateau wave. Hence, the liberal use of analgesics to avoid pain is indicated even in unresponsive patients. Efforts to minimize the secondary injury from hypoxia or decreased cerebral perfusion will ultimately be the main goal for the care ofTBI patients.

Head Trauma Assessment

Cerebral Perfusion Pressure = Mean Arterial Pressure - Intracranial Pressure

CPP = MAP - ICP

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TREATMENT

Early tracheal intubation plus mechanical ventilation of

the patient's lungs to avoid arterial hypoxemia has been

shown to improve outcome in the presence of TBI.

Hyperventilation may be deleterious because of cerebral vasoconstriction.

Methods to decrease ICP

1. Posture;

2. Administration of osmotic diuretics,

3. Hypertonic saline,

4. Barbiturates;

5. Institution of cerebrospinal fluid drainage;

6. Craniectomy, lobectomy, and craniotomy.

A frequent recommendation is to treat sustained increases in ICP greater than 20 mm Hg. Treatment may be indicated when ICP is less than 20 mm Hg if the appearance of an occasional plateau wave suggests low intracranial compliance.

POSTUR

Elevation of the head to about 30 degrees is useful in the care of head-injured patients to encourage venous outflow from the brain and thus lower ICP. It should also be appreciated that extreme flexion or rotation of the head can obstruct the jugular veins and restrict venous outflow from the brain. Placement of a central catheter via the subclavian or the internal jugular vein should be guided by the ultrasonic technique.

If central venous pressure monitoring is needed, the patient's neck should be prepared and draped before the patient is placed in the Trendelenburg position. The procedure should be terminated if ICP increases during placement.

Hyperventilation

In the past, deliberate hyperventilation of an adult patient's lungs to a Paco2 between 25 and 30 mmHg to decrease ICP has been recommended. It was presumed that the beneficial effects of hyperventilation of the lungs on ICP reflect decreased cerebral blood flow and resulting decreases in intracranial blood volume.

However, deliberate hyperventilation as a treatment to lower ICP has been questioned because of data showing an increase in mediators, lactate, and glutamate, even with a short period of hyperventilation.

.

Hyperventilation of a head-injured patient's lungs as a technique to reduce ICP is recommended only

in the presence of a mass lesion and impending herniation before definitive surgical intervention

Osmotic Diuretics

Administration of hyperosmotic drugs, such as mannitol

(0.25 to 1 g/kg IV over a period of 15 to 30 minutes),

decreases ICP by producing a transient increase in the

osmolarity of plasma, which acts to draw water from

tissues, including the brain.

However, if the blood-brain barrier is disrupted, mannitol may pass into the brain and cause cerebral edema by drawing water into the brain. The duration of the hyperosmotic effect of mannitol is about 6 hours. The brain eventually adapts to sustained increases in plasma osmolarity such that chronic use of

hyperosmotic drugs is likely to become less effective.

The diuresis induced by mannitol may result in acute

hypovolemia and adverse electrolyte changes (hypokalemia, hyponatremia), thus emphasizing the need to replace intravascular fluid volume with infusions of crystalloid and colloid solutions. A rule of thumb is to replace urine output with an equivalent volume of crystalloids, most often lactated Ringer's solution.

Glucose and water solutions are not recommended because they are rapidly distributed in total-body water, including the brain. If the blood glucose concentration decreases more rapidly than the brain glucose concentration, the brain water becomes relatively hyperosmolar, and water enters the

central nervous system and exaggerates the existing

cerebral edema.

Hypertonic Saline

Hypertonic saline decreases ICP, improves cerebral

perfusion pressure, and enhances hemodynamic function in TBI patients. In addition to its osmotic effect on edematous brain tissue, hypertonic saline also has vasoregulatory, neurochemical, and immunologic effects.

Nevertheless, there is no significant outcome difference

in patients who receive either 7.5% hypertonic solution

or 20% mannitol.

Corticosteroids

Corticosteroids such as dexamethasone or methylprednisolone have been used to decrease ICP for more than 30 years. The mechanism for the beneficial effect of corticosteroids is not known, but it may involve stabilization of capillary membranes or a decrease in the production of cerebrospinal fluid, or both.

Nevertheless, there is no reduction in mortality in patients treated with methylprednisolone in the first 2 weeks after TBl, thus suggesting that steroids should no longer be routinely administered to these patients.

Decompression Craniectomy

Emergency decompression craniectomy is a surgical procedure performed to resolve the elevated ICP and prevent herniation after head insults, especially severe TBI.

Barbiturates

Administration of barbiturates may be recommended

when ICP remains increased despite deliberate controlled hyperventilation of the lungs and drug-induced diuresis.

.

This recommendation is based on the predictable ability

of these drugs to decrease ICP, presumably by decreasing cerebral blood volume secondary to cerebral vasoconstriction and decreased cerebral blood flow. The goal of barbiturate therapy is to maintain ICP at less than 20 mm Hg without the occurrence of plateau waves

Discontinuation of the barbiturate infusion can be considered when ICP has remained in a normal range for 48 hours.

Failure of barbiturates to decrease ICP is a grave

prognostic sign.

A hazard of barbiturate therapy to lower ICP is hypotension, which can jeopardize the maintenance of adequate cerebral perfusion pressure.

Such hypotension is particularly likely in the presence

of decreased intravascular fluid volume. Dopamine

or dobutamine may be necessary in the event of

barbiturate-induced hypotension secondary to myocardial depression. Transthoracic echocardiography can be useful for evaluating cardiac function in head injured patients.

Blunt Cardiac Injury

CHEST INJURIES

Chest injuries are a significant cause of mortality in injured patients and account for 20% of trauma-related deaths in the United States. Both blunt and penetrating chest injuries are treated with similar principles of management. The initial evaluation of patients with chest injuries should emphasize the presence of an adequate airway and ventilation.

Thoracic Trauma

Penetrating Chest Injuries• Majority are stab wounds

or gunshot wounds (GSW)

• Lower mortality rates--less likely to include multiorgan injury

• 85% of penetrating chest wounds can be treated with tube thoracostomy and supportive measures

Penetrating Chest Injuries

• 25,000 deaths per year in the U.S. due to GSWs to the chest

Penetrating Chest Trauma

• Wounds that enter or exit inferior to the nipple or the posterior tip of scapula may perforate the dome of the diaphragm.

• Any penetrating wound such as this should be considered to have an abdominal component until proven otherwise.

Work-up of Penetrating Chest Trauma

• Physical examination– Look, Listen, Feel– Contusions, diminished or absent

breath sounds, SQ emphysema can readily be found

• CXR- best, least expensive and fastest initial evaluation

• Ultrasound-may soon replace CXR as initial radiographic study in chest trauma

• Angiography- to look for great vessel injuries

• CT Scan: for better evaluation of chest wall and parenchyma

• Transesophogeal Echocardiography

Penetrating Chest Injuries

• Operative intervention required for:– Massive or persistent

bleeding– Massive air leak– Tracheobronchial injuries– Esophageal perforation– Cardiac or great vessel

injuries– Post-traumatic empyema

Penetrating Chest Trauma

Wounds that enter or exit inferior to the nipple or the posterior tip of scapula may perforate the dome or the diaphragm.

Any penetrating wound such as this should be considered to have an abdominal component until proven otherwise.

Penetrating Chest Trauma:Indications for Mechanical Ventilation

Intrapulmonary Foreign Bodies

• When left in lung:– 20% developed into

chronic bronchitis– 6% : lung abscess– 10%:

bronchopleural fistula

– 5%: Empyema

Pulmonary Parenchymal Laceration

Massive air leaks and hemorrhage require immediate operation

High Velocity Missile Injuries

• Wounds due to high velocity missiles that travel > 25,000 ft/s are being seen with ever-increasing frequency

• Military and civilian

Operative Intervention for Hemothorax

• As noted previously

• Hemothorax: massive = initial drainage more than 1,000 cc or

• Continuous bleeding of 200 cc/hr for 2 hrs

Blunt Cardiac Injury

EKG (for any blunt chest injury, persistent tachycardia, ST-T changes or ectopy)

Cardiac enzymes (CPK, CK-MB and Troponin I)

Echocardiography (TEE)

Categories of chest wall injuries

• Scapular fractures– 3% of blunt trauma cases– 54% have pulmonary

contusions– 11% have associated

ipsilateral subclavian, axillary or brachial artery injury

• Over 1/3 are missed on initial evaluation

Categories of chest wall injuries

• Flail chest– Fx of at least 4

consecutive ribs in 2 or more places

– Incompetent segment of chest wall large enough to impair respirations

– Paradoxic motion hinders creation of the expected ipsilateral negative inspiratory force

Categories of chest wall injuries

Flail chestCombination of pulmonary contusion and flail

chest has a mortality of 42%

Pulmonary contusion with flail chest: 75% require ventilation

Flail chest ALONE: 48% require ventilation tx

Aggressive respiratory txs and IS with pain control

Pulmonary Contusion

Increase in pulmonary vascular resistance and A-aO2 difference

Diagnosis:

Dyspnea

Tachypnea

Hemoptysis

Cyanosis

Hypotension

Pulmonary Contusion

Treatment

Oxygen to maintain PaO2 above 60 mmHg

Vigorous chest physiotherapy

Use colloids instead of crystalloids when rapid volume replacement is needed

Place PA catheter when large or rapid volume replacement is needed

Use of steroids and antibiotics are controversial

Intra-thoracic Trauma: Great Vessel and Mediastinal Trauma

Aorta

Pulmonary vessels

Tracheobronchial lacerations

Esophageal lacerations

Intra-thoracic Trauma: Great Vessel and Mediastinal Trauma—

Work-upPlain CXR to identify thoracic aorta injuries

Look for air in the mediastinum

Persistent airleak should cue into:

Bronchopulmonary or tracheobronchial injury

Mediastinitis, tube feedings in chest tube or saliva in chest tube should cue into:

Esophageal injury

Intra-thoracic Trauma: Great Vessel and Mediastinal Trauma—

Work-upBronchoscopy

Esophagoscopy

CT

Serial CXR

Initial CXR of Concern

Indications for Angiography

Lateral deviation of the NGT in esophagus

Widened mediastinum (>8cm)

Loss of visualization of the aortic knob

Hematoma of the Left cervical pleura (pleural cap)

Depressed left main stem bronchus

Rt lateral deviation of the trachea

Indications for Angiography

• Widened mediastinum (>8cm)

Indications for Angiography

• Forward displacement of the trachea on the lateral CXR

• Fx of the 1st or 2nd rib• Massive chest trauma w/

multiple rib fx• Fx or dislocation of the

thoracic spine• Major deceleration injury

The chest radiograph is analyzed for the presence

of pneumothorax, hemothorax, pulmonary contusion,

deviation of the tracheobronchial tree, widening of the

mediastinum, and abnormal mediastinal shadows. These findings determine the need for additional diagnostic or therapeutic interventions.

Tension Pneumothorax

Tension pneumothorax is a relatively common cause of

respiratory distress in a patient with chest trauma. Placement of a chest tube without waiting for a chest radiograph is warranted in patients with penetrating chest trauma who are in significant respiratory distress or have systemic hypotension. Patients with chest trauma may also have significant hemorrhage that requires prompt administration of crystalloid solutions and blood.

Urgent Thoracotomy

The need for urgent thoracotomy because of chest trauma is rare. In fact, because lobectomy and pneumonectomy are associated with high mortality in trauma patients, treatment techniques have been developed that emphasize rapid and minimal lung resection.

Guidelines for the need for emergency thoracotomy include an initial blood loss of 1500 mL on placement of the chest tube and continued bleeding of 200 to 300 mL/hr. Additional indications for thoracotomy consist of injuries to the heart or great vessels and tracheal, bronchial, or esophageal injuries. Diaphragmatic repair is usually performed via an

abdominal approach.

MANAGEMENT OF ANESTHESIA

Before induction of general anesthesia for trauma

patients undergoing emergency thoracotomy, it is

critical to exclude the presence of a pneumothorax that

could become a tension pneumothorax with the institution of mechanical ventilation of the patient's lungs.

Management of these patients often includes an intra arterial and central venous pressure catheter, as well as peripheral large-bore intravenous catheters placed above the diaphragm. Because of the presence of lung injury, these patients' lungs need to be ventilated with low tidal volume ventilation (6 mL/kg ideal body weight) and a small amount of positive end-expiratory pressure.

Placement of a double-lumen endotracheal tube to

perform one-lung ventilation may be warranted for lung

resection or repair of the esophagus or large intra thoracic vessels. These patients are usually transferred to the Icu with the trachea intubated and the lungs mechanically ventilated.

ABDOMINAL INJURY

Abdominal injury accounts for a small, but significant

number of trauma-related deaths, especially when the

abdominal injury is not recognized. One of the major

reasons for a fatal outcome is that the peritoneal cavity

and retroperitoneal space are potential reservoirs for

large and occult blood loss.

During initial evaluation of the trauma victim, peritoneal signs of abdominal trauma are often subtle and difficult to diagnose because of the intense pain associated with extra-abdominal injuries or

because of the presence of TBl and altered mental status.

Thus, during the initial evaluation of a severely traumatized patient, the first step is to diagnose the presence of abdominal trauma.

Classification

Traumatic abdominal injuries are classified as penetrating or blunt injuries. Penetrating injuries associated with overt signs of peritoneal irritation or acute blood loss (or both) are clear indications for surgery.

If there is no violation of the peritoneum, local exploration is usually sufficient. Blunt trauma is generally caused by collisions or falls. The severity of the injury is determined by the acceleration-deceleration process sustained by the victim.

The organs most commonly injured are the liver, spleen, and kidneys.

Diagnosis

Ultrasound performed in the emergency department is

an important diagnostic tool for detecting the presence

of an abdominal injury, including the presence of blood

in the abdomen. Diagnostic peritoneal lavage (DPL) is a

sensitive method for detecting the presence of serious

intra-abdominal bleeding.

The classic indication for DPL is suspicion of intra-abdominal bleeding associated with arterial hypotension. In stable patients, an abdominal

CT scan with radiocontrast is often performed instead of

DPL. A CT scan allows the clinician to detect the location and magnitude of intra-abdominal injuries in hemodynamically stable patients.

CT may also be important for investigating genitourinary injuries when intravenous radiocontrast is used.

Management of Anesthesia

Severe abdominal injuries require general anesthesia and often placement of an intra-arterial and central venous pressure catheter. In many institutions, a large-bore catheter is placed in a femoral vein on arrival at the emergency department..

It is important to recognize that the femoral venous catheter should not be used for rapid blood transfusions when abdominal venous injuries are suspected.

It is good practice to place an additional large-bore catheter above the diaphragm for rapid intravenous administration of volume to these patients

PELVIC FRACTURES

Pelvic fractures are the third most frequent injury in

victims of motor vehicle accidents and are often associated with other abdominal injuries. The overall mortality from pelvic fractures is between 15% and 50%, depending on the extent of the injuries. The combination of pelvic fracture and severe TBI has high mortality..

The initial treatment of pelvic fractures associated with bleeding is nonoperative, and they are managed by angiographic embolization.

In addition to this treatment, patients may require external fixation of the fractures to allow mobilization.

Alternatively, stabilization of the pelvis can be

achieved with the use of military antishock trousers (MAST).

The anesthesiologist has a critical role to play during the initial resuscitation of patients with severe pelvic fractures.

These patients frequently require the administration

of large volumes of blood, thus necessitating activation of the massive transfusion protocol. As with other abdominal injuries, it is also imperative to place large-bore intravenous catheters above the diaphragm.

BLUNT SPLENIC AND LIVER INJURIES

There has been a change in the management of blunt

splenic and liver injuries toward a more conservative

approach. Patients without signs of hemodynamic instability or intra-abdominal bleeding can be monitored closely in the ICU after the initial evaluation and placement of large-bore intravenous catheters.

Usually, it is mandatory to obtain sequential hematocrit measurements during the first 24 hours and to frequently examine these patients for detection of any signs of new intra-abdominal bleeding.

Furthermore, these patients are at risk for abdominal

compartment syndrome because of the increased vascular permeability associated with severe trauma.

Thermal (Burn ) injury

Continuous improvement in the care of burned patients

for the last 30 years has resulted in an increase in survival after the initial insult. It is not uncommon to see patients with burns affecting 70% to 80% of the total body surface area to survive this injury.

Critical factors that affect mortality in these patients include age older than 60 years, third-degree burns over more than 40% of the total body surface area, and smoke inhalation. Mortality increases in proportion to the number of risk factors present. In addition, the mortality rate of burned patients is also affected by the presence of significant coexisting diseases and delays in treatment.

Initial Evaluation

The initial clinical evaluation of an acutely burned patient includes a careful analysis of the burned body surface area, the depth of the burns, the mechanisms of injury (electrical, smoke inhalation), and the presence of associated traumatic injuries . Furthermore, information should be obtained as soon as possible about the presence of significant comorbid conditions that may affect the survival of a severely burned patient.

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Initial Fluid Resuscitation

The initial treatment of burned patients includes an

assessment of the fluid resuscitation requirements for the first 24 hours. The most commonly used guideline for calculation of fluid replacement needs is the Parkland formula (4 mL/kg/% burn); the replacement fluid is given as lactated Ringer's solution. Half the volume should be given during the first 8 hours and the other half during the following 16 hours.

After the first 24 hours, protein repletion is frequently needed and is typically provided by 5% albumin (0.3 to 0.5 mL/kg/total body surface area of burned tissue). In addition to colloid replacement, a

burned patient should receive maintenance fluid, which

can be estimated as basal maintenance (1500 mL/m2 +evaporative water loss [(25 + % burn) x m2 x 24]).

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Clinical evidence of adequate fluid resuscitation includes normalization of systemic blood pressure, urine output (> 1 mL/kg/hr), and values for blood lactate, base deficit,plasma sodium concentration, and central venous pressure

Urine output is not a reliable guide to the adequacy of

resuscitation after the first 24 to 48 hours following a

burn injury because of the presence of osmotic diuresis

associated with glucose intolerance and high caloric feeding.

Furthermore, a non-anion gap arterial base deficit may

reflect the excessive intravenous administration of 0.9%

sodium chloride solution.

In elderly patients or those with significant preexisting cardiac disease, hemodynamic parameters should be monitored carefully, possibly with placement of a pulmonary artery catheter, to prevent the

development of acute congestive heart failure as a result of vigorous fluid resuscitation. Rapid fluid resuscitation can be associated with the development of severe tissue edema compromising limb perfusion or an abdominal compartment syndrome.

Management of Anesthesia

Burned patients will require general anesthesia, initially

for escharotomy of the limbs, thorax, and/or abdomen and later for excision of the burned skin and grafting. If the injuries do not preclude conventional airway management, standard anesthesia induction and tracheal intubation procedures are appropriate.

However, succinylcholine should not be administered when the burn injury is older than 24 hours because drug-induced hyperkalemia may result in cardiac arrest. The trachea of a severely burned patient should remain intubated after the initial escharotomies because the aggressive fluid management that occurs during the following 24 to 48 hours to compensate for the burn shock often causes airway edema and compromise.

The patient's lungs should be ventilated with low-tidal volume ventilation (6 mL/kg ideal body weight)

if smoke inhalation injury or acute lung injury from another origin is present. Placement of an intra-arterial and central venous catheter should be done under sterile conditions.

.

Particular attention should be paid to the impaired

temperature regulation associated with severe burns.

Excision of burned skin is accompanied by substantial

blood loss, which can be estimated at 0.5 mL/cm2 of burned area

At the conclusion of surgery, transport of severely

burned patients to the ICU should be planned carefully

because accidental extubation during the transport of

these patients may result in an inability to ventilate the

patient's lungs by mask because of face and neck burns.

Lean body weight or mass

Ideal Body Weight (men) = 50 + 2.3 ( Height(in) - 60 ) ( Devine formula)

Ideal Body Weight (women) = 45.5 + 2.3 ( Height(in) - 60 ) (Robinson formula)

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Lean body weight or mass

Ideal Body Weight (men) = 50 + 2.3 ( Height(in) - 60 ) ( Devine formula)

Ideal Body Weight (women) = 45.5 + 2.3 ( Height(in) - 60 ) (Robinson formula)

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