Thursday 29 November 2012

Multiple trauma-2

  • A revised trauma score results from the sum of respiratory rate, systolic blood pressure, and Glasgow coma scale and can be used to decide which patients should be sent to a trauma center (Table 2.2).
    Table 2.2. Revised trauma score: trauma scoring systems
    Revised Trauma Score (RTS) Rate Score
    A. Respiratory Rate (breaths/min) 10–29 4
    >29 3
    6–9 2
    1–5 1
    0 0
    B. Systolic Blood Pressure (mm Hg) >89 4
    76–89 3
    50–75 2
    1–49 1
    0 0
    C. Glasgow Coma Scale (GCS) Conversion 13–15 4
    9–12 3
    6–8 2
    4–5 1
    3 0
    RTS = 0.9368 GCS + 0.7326 SBP + 0.2908 RR. The RTS correlates well with the probability of survival.
INJURY SEVERITY SCORE (ISS) (Table 2.3)
Table 2.3. Evaluation of multiple trauma patient injury severity score (ISS)
Abbreviated Injury Scale defined body areas (external structures)
  1. Soft tissue
  2. Head and neck
  3. Chest
  4. Abdomen
  5. Extremity and/or pelvis
  6. Face
Severity code
  1. Minor
  2. Moderate
  3. Severe (non-life-threatening)
  4. Severe (life-threatening)
  5. Critical (survival uncertain)
  6. Fatal (dead on arrival)
ISS = A2 + B2 + C2. A, B, and C represent individual body area severity code.
  • This anatomic scoring system provides an overall score for patients with multiple injuries.
  • It is based on the Abbreviated Injury Scale (AIS), a standardized system of classification for the severity individual injuries from 1 (mild) to 6 (fatal).
  • Each injury is assigned an AIS score and is allocated to one of six body regions (head, face, chest, abdomen, extremities including pelvis, and external structures).
  • The total ISS score is calculated from the sum of the squares of the three worst regional values. It is important to emphasize that only the worst injury in each body region is used.
  • The ISS ranges from 1 to 75, with any region scoring 6 automatically giving a score of 75.
  • The ISS limits the total number of contributing injuries to three only, one each from the three most injured regions, which may result in underscoring the degree of trauma sustained if a patient has more than one significant injury in more than three regions or multiple severe injuries in one region.
  • To address some of these limitations, Osler et al. proposed a modification to the system which they termed the New Injury Severity Score (NISS). This is defined as the sum of squares of the AIS scores of each of a patient’s three most severe injuries regardless of the body region in which they occur. Both systems
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    have been shown to be good predictors of outcome in multiple trauma patients.
EXPOSURE
  • It is important to undress the trauma patient completely and to examine the entire body for signs and symptoms of injury.
RADIOGRAPHIC EVALUATION
A radiographic trauma series consists of the following:
  • Lateral cervical spine: must see all seven vertebrae and the top of T1
    • Can perform swimmer’s view or CT scan if needed.
    • In the absence of adequate cervical spine views of all vertebrae, the cervical spine cannot be “cleared” from possible injury, and a rigid cervical collar must be maintained until adequate views or a CT scan can be obtained.
    • Clinical clearance cannot occur if the patient has a depressed level of consciousness for any reason (e.g., ethanol intoxication).
  • Anteroposterior (AP) chest
  • AP pelvis
  • Possibly a lateral thoracolumbar spine
  • Possibly a CT of the head, cervical spine (if not cleared by plain radiographs), thorax, abdomen, or pelvis with or without contrast as dictated by the injury pattern

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STABILIZATION
  • The stabilization phase occurs immediately following initial resuscitation and may encompass hours to days, during which medical optimization is sought. It consists of:
    • Restoration of stable hemodynamics.
    • Restoration of adequate oxygenation and organ perfusion.
    • Restoration of adequate kidney function.
    • Treatment of bleeding disorders.
  • Risk of deep venous thrombosis is highest in this period and may be as high as 58% in multiply injured patients. Highest-risk injuries include spinal cord injuries, femur fractures, tibia fractures, and pelvic fractures. A high index of suspicion must be followed by duplex ultrasonography.
  • Low-molecular-weight heparin, or low-dose warfarin has been shown to be more effective than sequential compression devices in preventing thromboses, but it is contraindicated in patients at risk for hemorrhage, especially following head trauma. Prophylaxis should be continued until adequate mobilization of the patient out of bed is achieved.
  • Vena caval filters may be placed at time of angiography and are effective in patients with proximal venous thrombosis.
  • Pulmonary injuries (e.g., contusion), sepsis, multiorgan failure (e.g., because of prolonged shock), massive blood replacement, and pelvic or long bone fractures may result in the adult respiratory distress syndrome (ARDS).
DECISION TO OPERATE
  • Most patients are safely stabilized from a cardiopulmonary perspective within 4 to 6 hours of presentation.
  • Early operative intervention is indicated for:
    • Femur or pelvic fractures, which carry high risk of pulmonary complications (e.g., fat embolus syndrome, ARDS).
    • Active or impending compartment syndrome, most commonly associated with tibia or forearm fractures.
    • Open fractures.
    • Vascular disruption.
    • Unstable cervical or thoracolumbar spine injuries.
    • Patients with fractures of the femoral neck, talar neck, or other bones in which fracture has a high risk of osteonecrosis.
  • Determination of patient medical stability
    • Adequacy of resuscitation
      • Vital signs of resuscitation are deceptive.
      • Laboratory parameters include base deficit and lactic acidosis.
    • No evidence of coagulopathy
    • As long as homeostasis is maintained, no evidence exists that the duration of the operative procedure results in pulmonary or other organ dysfunction or worsens the prognosis of the patient.
    • Must be ready to change plan as patient status dictates.
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    • Patients who are hemodynamically stable without immediate indication for surgery should receive medical optimization (i.e., cardiac risk stratification and clearance) before operative intervention.
  • Decision making
    • Determined by general surgery, anesthesia, and orthopaedics.
    • Magnitude of the procedure can be tailored to the patient’s condition.
    • Timing and extent of operative intervention based on physiologic criteria.
    • May require damage control surgery as a temporizing and stabilizing measure.
  • Incomplete resuscitation
    • Based on physiologic assessment.
    • Intensive care includes monitoring, resuscitation, rewarming, and correction of coagulopathy and base deficit.
    • Once the patient is warm and oxygen delivery is normalized, reconsider further operative procedures.
CONCOMITANT INJURIES
Head Injuries
  • The diagnosis and initial management of head injuries take priority in the earliest phase of treatment.
  • Mortality rates in trauma patients are associated with severe head injury more than any other organ system.
  • Neurologic assessment is accomplished by use of the Glasgow Coma Scale (see earlier).
  • Intracranial pressure monitoring may be necessary.
Evaluation
Emergency computed tomography (CT) scan with or without intravenous contrast is indicated to characterize the injury radiographically after initial neurologic assessment.
  • Cerebral contusion
    • Diagnosis: history of prolonged unconsciousness with focal neurologic signs
    • Treatment: close observation
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  • Epidural hemorrhage (tear of middle meningeal artery)
    • Diagnosis: loss of consciousness with intervening lucid interval, followed by severe loss of consciousness
    • Treatment: surgical decompression
  • Subdural hemorrhage (tear of subdural veins)
    • Diagnosis: neurologic signs may be slow to appear. Lucid intervals may be accompanied by progressive depressed level of consciousness.
    • Treatment: surgical decompression
  • Subarachnoid hemorrhage (continuous with cerebrospinal fluid)
    • Diagnosis: signs of meningeal irritation
    • Treatment: close observation
Thoracic Injuries
  • These may result from blunt (e.g., crush), penetrating (e.g., gunshot), or deceleration (e.g., motor vehicle accident) mechanisms.
  • Injuries may include disruption of great vessels, aortic dissection, sternal fracture, and cardiac or pulmonary contusions, among others.
  • A high index of suspicion for thoracic injuries must accompany scapular fractures.
  • Emergency thoracotomy may be indicated for severe hemodynamic instability.
  • Chest tube placement may be indicated for hemothorax or pneumothorax.
Evaluation
  • AP chest radiograph may reveal mediastinal widening, hemothorax, pneumothorax, or musculoskeletal injuries.
  • CT with intravenous contrast is indicated with suspected thoracic injuries and may demonstrate thoracic vertebral injuries.
Abdominal Injuries
These may accompany blunt or penetrating trauma.
Evaluation
  • CT scan with oral and intravenous contrast may be used to diagnose intraabdominal or intrapelvic injury. Pelvic fractures, lumbosacral fractures, or hip disorders may be observed.
  • Diagnostic peritoneal lavage remains the gold standard for immediate diagnosis of operable intraabdominal injury.
  • Ultrasound has been increasingly utilized to evaluate fluid present in the abdominal and chest cavities.
  • Positive peritoneal lavage
    • Gross blood, bile, or fecal material
    • >100,000 red blood cells/mL
    • >500 white blood cells/mL
Genitourinary Injuries
Fifteen percent of abdominal trauma results in genitourinary injury.
Evaluation
  • If genitourinary injury is suspected (e.g., blood seen at the urethral meatus), a retrograde urethrogram should be performed before indwelling bladder catheter insertion. Urethral injury may necessitate placement of a suprapubic catheter.
  • If hematuria is present, a voiding urethrogram, cystogram, and intravenous pyelogram are indicated
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