TraumaHead Injury

1
Trauma/Head Injury
2
Trauma

• Trauma is the leading cause of death in young
  people
• A well organized trauma team can reduce mortality
  by recognizing and responding to trauma more
  appropriately
• Airway obstruction is more rapidly fatal than
  inadequate ventilation
• Inadequate ventilation is more serious than loss
  of circulation
• The next most serious problem is an expanding
  intracranial mass lesion

3
Trauma

• Primary survey
• Airway and cervical spine control
• Put every trauma victim on oxygen!
• Immobilize the spine
• Make sure the airway is patentintubate if the
  airway is at risk
• Breathing
• Tx life-threatening injuries, like a pneumo
• Ventilate if necessary
• Prophylactic mechanical ventilation used with
  head trauma to decrease ICP

4
Trauma

• Primary Survey
• Circulation
• Control major hemorrhage
• Establish IV access
• Check clinical signs for evidence of blood loss
• Give fluids
• Neurological
• Check pupil response to light
• Check reflexes
• Glascow Coma Score
• General management
• Remove clothing
• Put in a catheter
• Insert NG/OG tube

5
Trauma

• Secondary
• Head/face
• Inspect for lacerations/hematomas/fx/eye injury
• Chest
• Inspect for tracheobronchial injuries,
  chest/pulmonary contusions, aortic rupture,
  esophageal rupture, diaphragm rupture
• Abdomen
• Suspect concealed bleeding if fluid resuscitation
  doesnt reverse shock
• Inspect for lacerations, bruising, tenderness,
  and distension

6
Trauma

• Spinal injuries
• Most common area is the cervical spine
• Check motor and sensory function to determine
  level of cord lesion
• X-rays help pinpoint spinal fx/displacement
• MRIs can show ligament and spinal cord damage

7
Trauma

• Management of cord injuries
• Early steroids may reduce swelling and improve
  outcome
• Stabilize the spine
• Ventilate the patient above C4 cuts off
  innervation to the diaphragmintercostals are
  innervated by T2-T12 so lesions above this region
  limit the Vt and cough
• Circulation
• Cord injury causes huge sympathetic system
  outflow causing severe hypertension
• Subsequent loss of sympathetic tone causes
  massive vasodilation and hypotension (neurogenic
  shock)
• Lesions above T1 prevent sympathetic reflex
  tachycardia which limits the CV response to
  stress (like suctioning) so profound bradycardias
  can occur with vagal stimulation
• Neurology
• Muscles will be flaccid and reflexes will be
  diminished/absentthis can last from 2-70 days
• Muscle contractures and spasms may follow
  resolution
• General
• Hypothermia may occur from massive vasodilation
• Paralytic ileus and bladder atony are problems
• Pressure sores can occur if not turned regularly

8
Head Injury

• Head injuries account for 33 of all trauma
  deaths
• Two mechanisms cause neural tissue damage
• Primary injury
• Happens during the trauma
• Includes brain lacerations, contusions, and
  diffuse injury from shear forces during
  acceleration or deceleration
• These are irreversible
• Secondary injury
• Due to increased ICP after the accident and
  inadequate cerebral perfusion
• This accounts for 50 of head injury deaths but
  intervention can increase the survival
• Causes are intracranial (edema, hemorrhage,
  ischemia) and systemic (hypotension,hypoxia,
  anemia)

9
Head Injury

• Pathophysiology
• The skull has a fixed size, so it cant swell
  with injury
• Initially, cerebral edema displaces blood and CSF
  with little effect on the ICP
• Further swelling, however, increases the ICP
• After trauma the ICP peaks at about 72 hours
• Normal ICP is 5-10 mm Hg
• Cerebral perfusion pressure (CPP) is more
  important as it indicates cerebral blood flow
• CPP MAP ICPto maximize the CPP, keep the MAP
  up and the ICP down
• CPP lt40 neural dysfunctionCPPlt20 neuronal
  death
• Normally, cerebral blood flow is independent of
  BP (its autoregulated) but its sensitive to
  PaCO2 and PaO2injured brains lose the ability to
  autoregulate and perfusion parallels the CPP

10
Head Injury

• Pathophysiology
• Hypoxia and/or hypercapnia dilate normal vessels
  which diverts blood flow away from damaged
  cerebral vessels
• The increase in cerebral blood volume from
  vasodilation increases the ICP, decreases the
  CPP, and increases the ischemia in the damaged
  tissue
• Hypocapnia constricts normal vessels decreasing
  cerebral blood volume and ICPthis increases CPP
  and cerebral blood flowvasoconstriction of
  normal vessels and failure of autoregulation in
  injured tissue help divert blood flow to the
  injured tissue so theres less ischemiaexcess
  vasoconstriction can cause too much blood flow to
  the injured tissue and ischemia in the normal
  tissuecurrent recommendations are to keep the
  PaCO2 in the low end of the normal range

11
Head Injury

• Immediate management
• Prompt resuscitation
• Oxygen/ventilation
• Fluids/antiarrhythmics
• Maintain BP and hemodynamic stability
• Spinal immobilization
• Protect the airway
• Detect other injuries (lethal thoracic/abdominal
  injuries)
• Sedate/paralyze the patient to prevent ICP
  elevation and further spinal injuries

12
Head Injury

• Assessment
• Glascow coma score
• Severe head injury is a score lt8
• The more severe the higher the mortality
• Physical exam
• Detects wounds, lacerations, fractures
• Should include tests of neurological reflexes
• CT scan or X-ray of skull essential

13
Head Injury

• Monitoring
• ICP
• With more severe injury
• Catheter inserted into extradural, subarachnoid
  space, or directly into brain tissue
• Cerebral oxygen saturation
• Measured using a jugular venous bulb fiberoptic
  catheter
• lt55 suggests inadequate cerebral blood flow

14
Head Injury

• Management
• General measures
• Optimize cerebral blood flow by keeping MAP gt70
• Maintain oxygenation
• Reduce ICP
• Hyperventilation rapidly reduces ICP
• Not recommended as vasoconstriction can reduce
  cerebral blood flow to the normal brain tissue
• Loop diuretics (Lasix) and osmotic diuretics
  (Mannitol) can reduce ICP but results dont last
  too long (8 hr)
• Improve venous drainage by keeping the head
  midline and elevated 15-30 degreesminimize PEEP
  and suctioning as these impede venous drainage
• Ventriculostomy drainage can drain CSF from the
  ventricles of the brain and reduce ICP
• Decompressive surgery removes a part of the skull
  so swelling and edema cause less damage
• Steroids dont seem to help

15
Head Injury

• Management
• Reduce cerebral metabolism
• Tight glycemic control by keeping BS in the
  normal rangethis reduces cerebral lactate
  production
• Prophylactic anticonvulsants to prevent seizures
• Sedation and/or paralysis decreases metabolism
  and agitationPropofol may be neuroprotective
• Barbiturates reduce cerebral metabolic demand but
  may cause hemodynamic instabilitybenzodiazepines
  (eg-Valium) are better alternatives
• Prevent hyperthermia with antipyretics and
  coolingmild hypothermia (33-34C) may be
  neuroprotective
• Correct any associated complications