CDR JOHN P WEI, USN MC MD
4th Medical Batallion, 4th MLG
BSRF-12
CRANIO-CEREBRAL AND SPINAL CORD INJURIES
INTRODUCTION
• Current military actions with high risk for neurologic trauma to head and spinal cord
• Isolated blunt force trauma• Penetrating trauma• Combination of blunt and penetrating injuries
TRAUMATIC BRAIN INJURY
• Closed head injury: an object or an external force has sufficient energy to damage brain tissue
• Open head injury: an object pierces the skull and enters the brain or when blunt force fractures the bony skull with soft tissue disruption
TYPES OF BRAIN INJURIES
• Closed head injury• Contusion / concussion• Coup / Contre-Coup• Cerebral edema• Diffuse axonal injury
• Open head injury • Gunshot wound• Stab wound• Compound skull fracture
COMPLEX HEAD TRAUMA
MANAGEMENT IN FIELD
• Airway• Breathing• Circulation• Disposition
• Cervical spine immobilization• Stop on going bleeding• Splint or bandage extremity injuries
EPIDURAL HEMATOMA
Guidelines for Prehospital Management of TBI
• Aggressive airway management, hyperventilation (but not mannitol) only if signs of ICP or herniation
• Fluid resuscitation / glucose to achieve euvolemia / glycemia
MANAGEMENT OF SEVERE BRAIN INJURY
• Maintain MAP>90.• Hyperventilate only if neurologic
deterioration • Mannitol (0.25-1gm/kg) if neurologic
deterioration• No glucocorticoids
• While awaiting surgery, Propofol vs LA NMB depending on MAP
CONTUSION AND IPARENCHYMAL HEMMORHAGE
TRANSCRANIAL GUNSHOT WOUND
INCREASED INTRACRANIAL PRESSURE
The volume of the skull is a constant and contains:• Brain• Blood• CSF
An increase in the volume of any of these will raise intracranial pressue.
INCREASED INTRACRANIAL PRESSURE
• Initial ICP rises as volume is added (CSF and then blood exits the skull)
• As volume increases, compliance worsens and ICP rises rapidly:• Arterial blood flow is impaired, producing
ischemia• Focal increases in volume also cause
herniation from high pressure compartments to lower pressure ones
HERNIATION
INCREASED INTRACRANIAL PRESSURE
• Management• Correct the underlying pathology with
surgery if possible• Airway control and prevention of
hypercapnea• When intubating patients with elevated ICP
use thiopental, etomidate, or intravenous lidocaine to blunt the increase in ICP associated with laryngoscopy and tube passage
• ICP monitoring needed to guide therapy
INCREASED INTRACRANIAL PRESSURE
•Avoid jugular vein compression
•Head should be in neutral position
•Cervical collars should not be too tight
•Elevate head and trunk to improve jugular venous return
•Zero the arterial pressure transducer at the ear to measure the true cerebral perfusion pressure when the head is above the heart
INCREASED INTRACRANIAL PRESSURE
• Hyperventilation (PaCO2 < 35 mmHg) works by decreasing blood flow and reserved for emergency treatment and for brief periods
• The major determinant of arteriolar caliber is the extracellular pH not measured PaCO2
INCREASED INTRACRANIAL PRESSURE
• Pharmacologic options• Mannitol 0.25 gm/kg q4h (may need to
increase dose over time)• Hypertonic saline (requires central line)
• 3%• 7.5%• 23.4% (30 mL over 10 min)
• Steroids not for use in trauma
INCREASED INTRACRANIAL PRESSURE
Sedation to decrease cerebral metabolic rate• Benzodiazepines• Propofol
Requires autoregulation, which often fails in patients with elevated ICP
Often causes drop in MAP, impairing cerebral perfusion and thus requiring vasopressors (e.g., norepinephrine)
INCREASED INTRACRANIAL PRESSURE
• Neuromuscular junction blockade• titrate with train-of-four stimulator to 1 or 2
twitches• High-dose barbiturates
• pentobarbital 5 – 12 mg/kg load followed by infusion to control ICP
INCREASED INTRACRANIAL PRESSURE
• Surgical options• Evacuate hematoma• Ventriculostomy to drain CSF• Resection of brain tissue, i.e. temporal lobectomy• Craniectomy
• - Lateral for focal lesions• - Bifrontal for diffuse swelling
CRANIOTOMY
Secondary Injury in Head Trauma
• Hypoxia and hypotension are the 2 major causes of secondary CNS injury following head trauma
• Even in intensive care these complications occur frequently
• Preventing hypoxia and hypotension could have the greatest effect of any available treatment for head trauma
DIFFUSE AXONAL SHEAR
• Process triggered by the injury that takes about 24 hours to develop
• May occur without any radiographic abnormality
• Seen in areas of radiographically apparent “shear injury”, usually occurs at the grey-white junction
• Often with negative CAT scan, and will require MRI
DIFFUSE AXONAL SHEAR
TREATMENT OF BRAIN INJURY
• Antiseizure drugs• phenytoin 20 mg/kg • Keppra 1000 mg/day
• Nutrition and GI bleeding prophylaxis
• Thromboembolism prophylaxis
SPINAL CORD INJURIES
• ABCs• If intubation needed, use in-line stabilization• Maintain blood pressure with volume, packed
RBCs, vasopressors as needed
• Prevent secondary injury• C-spine immobilization with C-collar• Log-rolling
• Consider concomitant head injury
SPINAL CORD INJURIES
SPINAL CORD INJURIES
COMPLETE SPINAL CORD INJURY
• Loss of all function
below level of the lesion
• Typically associated
with spinal shock
INCOMPLETE SPINAL CORD INJURY
• Central cord syndrome
• Anterior cord syndrome
• Brown-Sequard syndrome
• Spinal cord injury without radiologic abnormality (SCIWORA)
SECONDARY INJURY TO SPINAL CORD
• After the initial macroscopic injury, secondary injuries are an important cause of disability:• Movement of unstable
spine• Vascular insufficiency
SPINAL CORD INJURIES AND THE CARDIOVASCULAR SYSTEM
• “Spinal” shock• Acute loss of tendon reflexes and muscle
tone below the level of spinal cord lesion• Neurogenic hypotension is very common
and can be profound with spinal cord lesions above T1
• Hypotension in spinal shock accompanied by bradycardia
SPINAL CORD INJURIES AND THE CARDIOVASCULAR SYSTEM
• Treat hypotension with volume expansion
• If conscious, making urine, and lactate is decreasing, MAP is adequate
• Neurogenic pulmonary edema common in cervical spinal cord injuries
• May develop pulmonary vascular redistribution and interstitial edema
SPINAL CORD INJURIES AND THE CARDIOVASCULAR SYSTEM
• Suspect associated injuries:• symptoms and physical findings absent due
to the spinal cord injury
• Resuscitation cannot be guided by physical findings:• Hypotension and bradycardia persist
regardless of the volume of administered
• Replace the missing adrenergic tone with -agonists (phenylephrine or norepinephrine depending on heart rate)
SUMMARY
Trauma to head and spinal structures Trauma to head and spinal structures common in current military actionscommon in current military actions
Combination of blunt and penetrating Combination of blunt and penetrating injuriesinjuries
Consideration for early medical Consideration for early medical intervention from field to definitive intervention from field to definitive treatment centertreatment center
Surgical intervention at earliest timeSurgical intervention at earliest time