Case 49 - Jevoha witness and scoliosis

Question 1

Define scoilosis and how is the curvature assessed in patients with scoliosis?

Answer 1

Scoliosis

• lateral curvature of the spine
• lateral curvature are associated with rotation of vertebrae and can result in deformity of rib cage

Cobb Angle

• measures curvature of scoliosis
• perpendicular lines drawn at uppermost border of curvature and lowermost border of curvature
• angle made by intersecting perpendicular lines = degree of curvature

Question 2

What will a jehovah’s witness refuse and accept in terms of blood transfusion?

Answer 2

• JWs believe that blood removed from body must be discarded
• many refuse whole blood transfusion and its components (FFP, PLT, Cryo, WBC, plasma)
• need to discuss with JW about nonblood alternative such as albumin, factor concentrate, cell savage with a continuous circut.

Question 3

What conditions are associated with scoliosis?

Answer 3

• idiopathic scoliosis is most common form

Associated conditions include:

• Marfan syndrome
• Ehlers-Danlos syndrome
• RA
• osteogensis imperfecta

Question 4

What is you pre-op evaluation for a scoliotic patient?

Answer 4

History and Physical

• etiology (marfan, ehlers-danlos)
  
  • coexisting diseases present
• Cobb angle
  
  • degree may indicates cardiopulmonary involvement
  • 50 to 60 degree - lung function abnormalities
• cardiovascular impairment

Labs

• Coags: PT/INR, PTT
• CBC (hgb + plt)
• Blood type and crossmatching (large blood loss expected)
• ABG
  
  • in presence of severe pulmonary disease

Question 5

what tests would you want to consider pre-operatively in a scoliotic patient?

Answer 5

Tests

• PFT
  
  • restrictive lung disease most common
  • if obstructive disease present, is there response to bronchodilators
  • Spirometry (FVC, FEV1, V1/VC)
  • lung volumes
    
    • poor VC may indicate postop ventilation
• Echo
  
  • severe restrictive lung disease –> pulm HTN (cor pulmonale) –> RVH and R CHF
    
    • R chf = jvd, hepatomegaly, peripheral edema
• CXR

Question 6

What are intraop anesthetic considerations for posterior spinal fusion surgery?

Answer 6

1) Talk to surgeon

• wake up test or no wake up test
• SSEP, MEPs

2) pre meds
* if patient has significant resp dysfunction, avoid preop sedation as hypoxemia, hypercarbia, and acidosis worsens pulmonary pressures
3) Induction

• peds - inhalation induction; mature - iv induction
• SSEPS
  
  • inhaled anes < 0.5 MAC, propofol, remifentanil
  • consider muscle relaxants if MEPs not used
• MEPs
  
  • avoid muscle relaxants
  • inhaled anes < 0.5 MAC, propofol, remifentanil

4) Monitors

• standard montiors
• arterial line
  
  • beat to beat BP monitoring
  • blood sampling
• CVC
  
  • depends on IV access, pressor therapy, cardiac function
• TEE
  
  • if severe cardiopulmonary disease

5) normothermia
* avoid hypothermia, forced air warming blankets, IV fluid warming systems

Question 7

How would you position this patient undergoing poseterior spinal surgery?

Answer 7

• avoid pressure on eye, ears, nose
• proper alignment of head and neck
• chest, abdomen, pelvis should be free of compression (avoid pressure on axilla, breasts, and genitalia)
• arms at sides with elbows flexed and shoulders abducted no greater than 90 degrees (avoid stretching of brachial plexus)

Question 8

What are strategies to minimize blood loss and need for homologous blood transfusion during posterior spine surgery?

Answer 8

1) Pre op erythropoietin
2) acute normovolemic hemodilution
3) intraop cell salavage with retransfusion
4) surgical technique
5) antifibrinolytics (amicar, transexamic acid)
6) anesthesia induced hypotension

• MAP 50-60 is ideal
  
  • maintains adequate spinal cord perfusion and CBF
• deepen anesthetic (volatile, remifentail)
• vasodilators (NTG, SNP)
• CCB (nicardipine)
• BB - Labetalol

Question 9

What is the wake-up test?

Answer 9

• patients are awakened intraoperatively to test motor tracts
• assess anterior spinal cord (motor) pathways after spinal instrumentation
  
  • does not assess sensory (posterior spinal cord)
• patient asked to squeeze the hand followed by moving the feet
  
  • if patient unable to move feet, spinal distraction must be decreased
• after test, return to general anesthesia

Question 10

what are the cons of wake up test

Answer 10

Cons

• evaluates patient’s motor function at only one point in time
  
  • after the test, the possiblity of spinal cord injury still exists
• not appropriate for young children or cognitvely impaired patients
• excessive patient movement –> self extubation, bleeding, air embolus, disruption of surgical instrumentation

Question 11

what are post-op anesthetic considerations after scoliosis repair?

Answer 11

• goal at end of sx = awake and extubate
• may need to delay extubation for underlying pulmonary dysfunction, persistent muscle weakness, issues reated to coexisting diseases
• monitor in ICU post-operatively

complications

• bleding
• atelectasis / resp distres
• neurologic deficits

Pain

• epidural placed by sx
• IV PCA
• continuous opioid infusion