A CASE OF AIR EMBOLISM DURING CRANIOTOMY

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A CASE OF AIR EMBOLISM DURING CRANIOTOMY

• Dr Dennis Reid

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Patient data

• 67 year old female
• Craniotomy for ventricular cyst, on
  18/12/06.Patient position semi-sitting
• Presented with headache and drowsiness
• Other issues GERD, smoker

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Intra-operative events
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Initial Management

• Supine position, flood wound,100 oxygen,
  ephedrine, crash cart to room.
• Apply pre-cordial Doppler battery dead.
• Diagnosis venous air embolism
• Surgery deemed technically impossible in present
  circumstances

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Brief notes on venous air embolism

• Pathophysiology.
• Volume of entrained air
• Rate of accumulation.
• Position of the patient
• Height of the vein above the right heart

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Critical volume of air

• 200-300 ml or 3-5 ml/kg
• The closer the vein of entrainment to the right
  heart the lower the critical volume

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How big a hole ?

• A pressure decrease of 5 cm. H2O across a 14G
  cannula(1.8 internal diameter) can entrain 100ml
  of air/second.

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Clinical presentation in anesthetized patients

• Tachyarrythmias
• Cardiovascular collapse

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High risk procedures

• Sitting position craniotomy
• Posterior fossa/neck surgery.
• Laparoscopic procedures
• Total hip arthroplasty.
• Cesarean section
• Central venous access

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Detection

• Trans-oesophageal echocardiography can detect
  0.02ml/kg
• Pre-cordial Doppler can detect 0.05ml/kg.Confirm
  position with Bubble test.
• End-tidal nitrogen-0.04 is significantly faster
  than E-tidal C02 by 30-90 seconds
• End-tidal C02 decrease by 2mm Hg significant?
• Vigilance

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Prevention

• Patient positioning, e.g. park bench versus
  sitting for posterior fossa craniotomy
• High index of suspicion in any surgery where
  there is a negative gradient between surgical
  field and heart.
• Reverse Trendelenberg of 5 degrees in Cesarean
  section 44 vs. 1 in one study
• Avoid nitrous oxide

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Treatment

• Prevent further air entrainment
• 100 oxygen
• Trendelenberg position/Durant position
• CPR/ inotropes.
• Aspiration of air.
• -Swan Ganz Catheter 6-16
• - Multi-orifice Cooke catheter 30-60

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Bibliography

• Mirski, M A. et al, Diagnosis and Treatment of
  Vascular Air Embolism
• Anesthesiology 2007 106164-77

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