Anesthesia for Patients with Spinal Cord Injury

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Anesthesia for Patients with Spinal Cord Injury

• Dr. Ashish
• Moderator Dr.R.Tope

www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
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Blood supply

• Two posterior spinal arteries
• Anterior spinal artery formed by the confluence
  of two vertebral arteries
• The lower cervical cord is a region of
  relative ischemia and is vulnerable for ischemic
  injury should the anterior spinal artery be
  compromised between the foramen magnum and C8,
  the cervical watershed.

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Spinal Cord Paralysis Levels

• C1-C3
• All daily functions must be totally assisted
• Breathing is dependant on a ventilator
• Motorised wheelchair controlled by sip and puff
  or chin movements is required
• C4
• Same as C1-C3 except breathing can be done
  without a ventilator
• C5
• Good head, neck, shoulder movements, as well as
  elbow flexion
• Electric wheelchair, or manual for short
  distances

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• C6
• Wrist extension movements are good
• Assistance needed for dressing, and transitions
  from bed to chair and car may also need
  assistance
• C7-C8
• All hand movements
• Ability to dress, eat, drive, do transfers, and
  do upper body washes
• T1-T4 (paraplegia)
• Normal communication skills
• Help may only be needed for heavy household work
  or loading wheelchair into car

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• T5-T9
• Manual wheelchair for everyday living
• Independent for personal care
• T10-L1
• Partial paralysis of lower body
• L2-S5
• Some knee, hip and foot movements with possible
  slow difficult walking with assistance or aids
• Only heavy home maintenance and hard cleaning
  will need assistance

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Treatment of Spinal Injuries

• No Current Effective Treatment
• Prevention is Key
• all current medical and surgical treatments aimed
  to prevent further injury to the spinal cord.

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Spinal Cord Injuries

• May occur with neck or back trauma
• Associated with blunt head trauma, especially
  when casualty is unconscious
• Can occur with penetrating trauma of vertebral
  column
• Improper handling may cause further injury

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Mechanisms of Spinal Injury

• Hyperextension
• Hyperflexion
• Compression
• Rotation
• Lateral Stress
• Distraction

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Pathophysiology

• Damage Begins centrally in grey matter and
  spreads centrifugally.
• Primary insult B/W Time of injury and initial
  care
• Secondary insult Delayed swelling
• Continued
  mechanical trauma
• Low perfusion
• Endogenous factors
  
• Initial segmental loss can be withstood because
  only small portion of grey matter neuronal pool
  is involved.

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• ASIA A Complete no motor or sensory function is
  preserved in the sacral segments S4-S5
• ASIA B Incomplete sensory but NOT motor
  function is preserved below the neurological
  level and includes the sacral segments
• ASIA C Incomplete motor function is preserved
  below the neurological level and more than half
  of key muscles below the neurological level have
  a muscle grade lt3
• ASIA D Incomplete motor function is preserved
  w/ muscle grade gt 3
• ASIA E Normal

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Diagnosis and management of acute spinal cord
injury

• Initial assessment and immobilization
• Resuscitation and medical management
• Radiological diagnostics
• Anaesthesia management
• Surgical therapy
• Post op critical care management

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Initial assessment and immobilization
History Pain/paresthesias Transient or
persistent motor or sensory symptoms Physical
Examination Abrasions/hematoma Tenderness Interspi
nous process widening
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• Immobilize the casualtys head and neck manually
• Apply a cervical collar, if available, or
  improvise one
• Secure patient to short spine board if extracting
  from a vehicle
• Secure head and neck to spine board for
  extraction

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• Transfer patient to long spine board as soon as
  feasible
• Logroll in unison
• Stabilize head and neck with sandbags or rolled
  blankets

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• Secure casualty to long spine board with straps
  across forehead, chest, hips, thighs, and lower
  legs

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Resuscitation and medical management ATLS
principles

• Airway
• Breathing
• Circulatory
• Neurologic Classification
• Spinal Imaging
• GastroIntestinal System
• Genitourinary System
• Skin

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Airway

• Risk Associated with Level of Injury
• Decision to Intubate
• Airway Intervention

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Risk Associated with Level of Injury contd

• Ventilatory Function
• C1 - C7 accessory muscles
• C3 - C5 diaphragm
• C3-4-5 keeps the diaphragm alive!
• T1 - T11 intercostals
• T6 - L1 abdominals

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Decision to Intubate

• Need for Artificial Airway is Usually Related to
  Resp Compromise e.g.
• Loss of innervation of the diaphragm
• (C 3-4-5 keep the diaphragm alive)
• Fatigue of innervated resp muscles
• Hypoventilation SaO2 lt60, PaCO2 gt45
• V/Q mismatch PaO2/FiO2 lt250
• Secretion retention
• Atelectasis

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Decision to Intubate Related to Neurological
Level

• Occiput - C3 Injuries (ASIA A B)
• Require immediate intubation and ventilation due
  to loss of innervation of diaphragm

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Decision to Intubate Related to Neurological
Levelcontd

• C4-C6 Injuries (ASIA A B)
• Serious consideration for prophylactic intubation
  and ventilation if
• Ascending injury (requires serial M/S assessment
  by a trained clinician)
• Fatigue of unassisted diaphragm
• Inability to clear secretions

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Airway Intervention

• Maintaining Spinal Precautions
• Supine position
• Maintain neutral C-spine
• Remove rigid collar and sandbags
• Manually stabilize C-spine
• 2 person technique
• 1st person to provide manual in-line
  stabilization (not traction) of C-spine
• 2nd person intubates

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Complications of cervical spine immobilization

• Airwaydelayed tracheostomy-poor oral hygeine
• Breathing prolonged mechanical ventillation-VAP
• Circulationdifficult central line insertion and
  access, increased thromboembolism
• Neurological increased ICP
• Gut gastrostasis,reflux and aspirationdelayed
  enteral nutrition
• Skin pressure sores around collar
• Staffing minimum 4 for log rolling cross
  infection

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Breathing

• Cough Function
• C1-C3 absent
• C4 non-functional
• C5-T1 non-functional
• T2-T4 weak
• T5-T10 poor
• T11 below normal

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Breathing contd

• Vital Capacity (acute phase)
• C1-C3 0 - 5 of normal
• C4 10-15 of normal
• C5-T1 30-40 of normal
• T2-T4 40-50 of normal
• T5-T10 75-100 of normal
• T11 and below normal

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Breathing contd

• SCI Respiratory Sequale
• Atelectasis
• Ventilatory failure
• (PaCO2 gt 50mmHg and pH lt 7.30)
• Increased secretions
• Pneumonia
• Pulmonary emboli
• Pulmonary edema (Autonomic)

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Breathing contd

• Intervention
• O2 therapy
• Assisted ventilation
• Medications (bronchodilators)

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Circulatory

• Spinal Shock
• Temporary suppression of all reflex activity
  below the level of injury
• Occurs immediately after injury
• Intensity duration vary with the level degree
  of injury

• Neurogenic Shock
• The bodys response to the sudden loss of
  sympathetic control
• Distributive shock
• Occurs in people who have SCI above T6 (gt 50
  loss of sympathetic innervation)

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Hemodynamic Instability Intervention

• First Line Volume Resuscitation (1-2 L)
• Second line Vasopressors- (dopamine/norepinephri
  ne) to counter loss of sympathetic tone and
  provide chronotropic support to the heart

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Hemodynamics and Cord Perfusion

• Options
• Avoid hypotension
• Maintain MAP 85-90mmHg for first 7 days if
  possible

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Bradycardia Intervention

• Prevention
• Avoid vagal stimulation
• Hyperventilate and hyperoxygenate prior to
  suctioning
• Pre-medicate patients with known hypersensitivity
  to vagal stimuli
• Treatment of Symptomatic Bradycardia
• Atropine 0.5 - 1.0 mg IV

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Neurological Classification

• Motor and sensory assessment
• ASIA Impairment Scale (A-E)
• Clinical Syndromes (patterns of incomplete
  injury)

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Spinal Shock

• An immediate loss of reflex function, called
  areflexia, below the level of injury
• Signs
• Slow heart rate
• Low blood pressure
• Flaccid paralysis of skeletal muscles
• Loss of somatic sensations
• Urinary bladder dysfunction
• Spinal shock may begin within an hour after
  injury and last from several minutes to several
  months, after which reflex activity gradually
  returns

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Central Cord Syndrome

• Usually involves a cervical lesion
• May result from cervical hyperextension causing
  ischemic injury to the central part of the cord
• Motor weakness is more present in the upper limbs
  then the lower limbs
• Patient is more likely to lose pain and
  temperature sensation than proprioception
• Patient may complain of a burning feeling in the
  upper limbs
• More commonly seen in older patients with
  cervical arthritis or narrowing of the spinal cord

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Brown-Sequard Syndrome

• Results from an injury to only half of the spinal
  cord and is most noticed in the cervical region
• Often caused by spinal cord tumours, trauma, or
  inflammation
• Motor loss is evident on the same side as the
  injury to the spinal cord
• Sensory loss is evident on the opposite side of
  the injury location (pain and temperature loss)
• Bowel and bladder functions are usually normal
• Person is normally able to walk although some
  bracing or stability devices may be required

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Anterior Spinal Cord Syndrome

• Usually results from compression of the artery
  that runs along the front of the spinal cord
• Compression of SC may be from bone fragments or a
  large disc herniation
• Patients with anterior spinal cord syndrome have
  a variable amount of motor function below the
  level of injury
• Sensation to pain and temperature are lost while
  sensitivity to vibration and proprioception are
  preserved

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Cauda Equina Syndrome

• Injury to the lumbosacral nerve roots w/ in the
  neurocanal resulting in areflexive bladder, bowel
  and lower limbs

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Spine Imaging

• the Asymptomatic Patient
• Option - Xray not needed in alert, sober,
  compliant patient without neck pain and
  tenderness or major distracting injuries
• Symptomatic Patient
• Standard Ap lat and odontoid view
• Option discontinue protection after.
• normal and adequate dynamic radiography, or
• normal MRI within 48hrs of injury, or
• at the discretion of treating MD

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• CT myelogram Bony detail of fracture site, and
  anatomic relation of segment to spinal cord.
• MRI anterior discs, ligamentum flava cord
  contusion.

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GI System

• Risk of aspiration is high d/t
• cervical immobilization
• local cervical soft tissue swelling
• delayed gastric emptying
• Parasympathetic reflex activity is altered,
  resulting in
• decreased gut motility and
• often prolonged paralytic ileus

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• GI Intervention- Nasogastric tubeIV H2 blockers
• GU Intervention Catheterisation
• Skin Intervention
• Remove spine board
• Turn or reposition individuals with SCI
  initially every 2 hours in the acute phase if the
  medical condition allows.

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Pharmacologic Therapy

• Methylprednisolone-controversial
• 30mg/kg IV loading dose 5.4 mg/kg/hr (over
  23hrs) effective if administered within 8 hours
  of injury
• If initiated lt 3hrs continue for 24 hrs, if 3-8
  hrs after injury, continue for 48hrs (morbidity
  higher - increased sepsis and pneumonia)
• Thromboprophylaxis - LMWH, discontinued at
  3months

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Secondary Interventions

• Without mechanical compression on CT myelogram
  External stabilisation
• Mean arterial pressures are kept b/w 80-90 mmHg
  and CO kept ( N/ high N )
• Dopamine infusion may be necessary

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Anaesthesia Management

• Pre op assessment
• Medical history
• Premedication and pt. Education
• Airway management
• Positioning
• Fluid requirements
• Special intraop requirements(wake up test)
• Post op pain and pulmonary toilet

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• Airway evaluation
• MP classification and range of neck mobility and
  elicitation of pain/ neurological symptom
• Pulmonary evaluation
• During spinal shock (3 days 6 wks)
• ABG- assess adequacy of ventilation, intubation
  if hypoxemia or hypercapnia (on O2 mask)
• Chronic stage
• PFT and Chest X ray Restrictive pattern
  (FEV1FVC)

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• Severity of functional impairment related to
  Angle of scoliosis, No of vertebrae, cephalad
  location of curve and loss of normal kyphosis.
• Respiratory function should be optimised
• Treating infection
• Bronchodilation
• Chest physiotherapy

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• Cardiac evaluation
• ECG myocardial ischemia
• Cardiovascular instability evidenced by
  hypotension, hypertension, brady arry.
  assessment of cardiac reserve and to optimise
  circulatory volume according to cardiac function
  and peri. Vas. Tone.
• Pacemaker persistently bardycardic.
• High spinal cord injury initially spinal
  shock,autonomic dys,impaired LVF and later
  autonomic dysreflexia.

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• Neurological evaluation
• Document preexisting deficits
• Neurological dys may dictate intubation
  tech,monitoring and choice of agents.
• Pharmacology
• Altered P/K because of muscle wasting,inc volume
  of distribution,dec serum albumin

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• Preop preparation
• Hb, Hct, WBC and urinalysis
• Other tests indicated by history
• SE, BUN, Creatinine, PT,aPTT, Platelet count,
  ECG, Chest radiograph, ABG and PFT.
• Echo to assess LV function pulmonary artery
  pressures and stress echo in sedentary patients

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• Premedication
• If anxious IV midazolam Under supervision
• Atropine if HR lt 70 Dose 0.04mg/kg
• H2 receptor blocker/ PPI
• Induction
• Unnecessary/ contraindicated for unconscious,
  recently injured patients with spinal cord trauma
  / those with severe shock.

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• Technique of intubation
• Elective - fiberoptic intubation
• Emergency MILS with rapid sequence
• Maintenance
• Nitrous oxide, inhalation agent

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Positioning

• Goals
• Adequate surgical exposure
• Anatomic position of extremities head
• Avoid abdominal pressure
• Adequate padding
• Various positions
• a) Prone
• b) Supine
• c) Sitting (obsolete

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PRONE POSITION MOST COMMONLY USED

• EYES
• Corneal abrasion
• Optic neuropathy
• Retinal artery occlusion
• HEAD NECK
• Venous and lymphatic obstuction
• ABDOMEN
• Impaired ventilation
• Decreased CO

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Monitoring
Physiological Pulse oximetry Continuous ECG
monitoring EtCo2 CVP Temperature Urine
output Invasive BP Swan Ganz catheter?

• Neurological
• Wake up test
• SSEP
• Transcutaneus MEP

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Post operative pain relief

• NSAIDS (IM,IV,P/R)
• IV opiods (Intermitent / continuous infusion )
• PCA

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Post op critical care management

• Indications for post op ventilation
• Preexisting NM disorder
• Severe restrictive VC lt35
• Obesity / RVF
• Prolonged surgery
• Surgical invasion of thoracic cavity
• Blood loss gt 30ml/kg

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post op contd Prepare for weaning

• Adequate nutrition and metabolic state
• Infection May be masked(Poikilothermia)
• Optimal fluid management
• Treat mechanical impairment to breathing like abd
  distention, tight halo cast, position
• Psychological preperation

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Post op contd

• Chest Physiotherapy Postural drainage, chest
  wall percussion and vibration, tracheal
  suctioning and breathing exercises.
• Cough Glossopharyngeal breathing and huffing.
• Breathing exercises

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Perioperative complications of spine surgery

• Airway obstruction edema, hematoma,recurrent
  laryngeal nerve palsy.
• Respiratory motor paralysis and infection
  (pneumonia).
• Cardiovascular hypotension, bradycardia,
  arrhythmias, hypertension ( spinal cord injury,
  carotid sinus stimulation).
• Neurological
• Injury to nerve roots as a result of direct
  surgical
• manipulation
• Injury to lower cranial nerves VII, IX, X, XII
• Injury to peripheral nerves - as a result of
  positioning
• Injury to spinal cord .

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• e) Vessel injury vertebral and carotid artery
  during
• dissection
• f) Tracheal and oesophageal injury
• g) CSF leaks - due to tear of dural and
  arachnoid
• membranes can lead to meningitis,
  pseudomeningocoele, permanent CSF fistula
• h) DVT seen in 30 of neurosurgical
  patients, especially those who had been
  paraplegic. Pulmonary embolism may occur

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Outcome

• Acute spinal injury who survive gt24hrs,85alive
  at 10years
• Most common causes of death-pneumonia,
  non-ischemic heart disease (occult autonomic
  dysfn), suicide (lifelong impact of injury)
  
  
  

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