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