Anesthetic Considerations for Anterior Mediastinal Masses

1
Anesthetic Considerations for Anterior
Mediastinal Masses

• Raeford E Brown, Jr., MD
• Professor of Anesthesiology and Pediatrics
• University of Kentucky Medical Center

2
Case Presentation

• 9 yo male, healthy until 6 wks ago flu
• increasing SOB 10 days PTA, decreased exercise
  tolerance
• cyanosis LOC straining with a BM
• CXR anterior mediastinal mass

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Case Presentation Physical

• tachypneic (24/min), mild retractions, increased
  dyspnea when supine
• BBS, coarse rhonchi, prolonged exhalation on
  left side
• normal CV exam, no JVD
• CXR widened mediastinum, no definitive evidence
  of airway obstruction

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Case Presentation Anesthetic

• sitting position, mask O2 halothane
• cyanosis despite spont. ventilation
• supine for intubation, halothane off
• HR decreased to 60 with intubation
• CPR unsuccessful, despite resuscitation drugs
  and apparently adequate ventilation
• Anes 55471-2, 1981

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Anterior Mediastinal Tumors

• The Four Ts
• T-cell lymphoma (40)
• Teratoma
• Thymoma
• Thyroid tumors
• Others vascular, esophageal, cystic

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Pathophysiology

• Airway compression
• Compression of pulmonary artery
• Superior vena cava syndrome

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History Physical

• Airway compromise
• cyanosis
• cough
• wheezing
• dyspnea
• upright position
• decreased breath sounds
• retractions

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History Physical

• Cardiac compromise
• syncope / dizziness
• sudden pallor
• exacerbation with Valsalva
• JVD / head neck swelling
• postural BP changes
• increased pulsus paradoxus

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High Risk Patients

• HP dyspneic / orthopneic, exacerbated with
  Valsalva, SVC syndrome
• PFTs decr. expiratory flow supine
• CT gt50 tracheobronchial compression
• Echo compression of atria or great vessels

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Flow Volume Loops

• Identify flows and obstruction in upright and
  supine positions
• Intrathoracic lesions show expiratory flow
  decrease, possible inspiratory flow decrease

Exp flow
Insp flow
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Anesthetic Effects

• Premeds
• may cause respiratory depression
• benzodiazepines may smooth induction
• Position
• supine position decreases thoracic volume
• decreases rib cage dimensions
• diaphragm displaced cephalad
• supine position increases blood flow to mass

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Anesthetic Effects

• Inhalational agents
• decreases muscle tone and lung volume
• reduces expiratory flow rate
• cardiac depression and venodilation
• Muscle relaxants
• relaxed diaphragm moves cephalad
• loss of negative intrapleural pressure and
  tenting effect

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Anesthetic Management

• Local is best, if tolerated
• Consider radiotherapy if symptomatic
• may confuse pathologic diagnosis
• which patients are really at risk?
• General anesthesia if necessary
• discuss plans with surgeon preop
• have backup equipment available

14
General Anesthesia

• Plan for smooth induction premed?
• IV access and resuscitation drugs
• Sitting or Semi-Fowler position
• Maintain spontaneous ventilation
• attempt assisted ventilation
• routinely avoid muscle relaxants
• Deep intubation no coughing!

15
Problem Management

• Positioning decubitus or even prone
• Airway rigid bronchoscope available
• Lower extremity IV in SVC syndrome
• May plan for fem-fem bypass as last resort

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References

• Keon TP. Death on induction of anesthesia for
  cervical node biopsy. ANES 55471-2, 1981.
• Neuman GG, et al. The anesthetic management of
  the patient with an anterior mediastinal mass.
  ANES 60144-7, 1984.
• Sibert KS, et al. Spontaneous respiration during
  thoracotomy in a patient with mediastinal mass.
  AA 66904-7, 1987.
• Ferrari LR, Bedford RF. General anesthesia prior
  to treatment of anterior mediastinal masses in
  pediatric cancer patients. ANES 72991-5, 1990.