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Sudden circulatory collaps
Venous decanullation, protamine test
Stable patient, uneventful anaesthesia, surgery, ECC, and weaning to 1 L/min
LMS lesion, in-hospital case CABG
43 year old male
Case
Bubbles are lead to the venous side, and bubbles are evacuated via vent before the arterial
cannula – large amounts of air!
Perfusionist notices bubbles near the clamp on the arterial line
Re-priming of the HLM
Re-cannulation of right atrium
Mechanical evacuation of air via red canullae
Internal cardiac massage. Air in the left ventricle and the arterial cannula / ”foaming”
• Perfusion starts, left ventricle de-aired, stable haemodynamics.
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Case
SSAI-CTVA Helsinki 2019
Jannie Bisgaard Stæhr
Massive Air Embolism
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Prevention
Management
Mechanisms
Pathophysiology
Major categories
Outline
• Surgical air
• Pump air
• Anaesthetic air
Categories
Pulmonary hypertension
RVOT obstruction
• Venous air embolism
Pathophysiology
Reactive hyperaemia
Vasodilatation
Blood stasis
Progeny bubbles
Decreased blood flow
Vasoconstriction
• Arterial air embolism
Pathophysiology
• Rate of entry
• Volume
• Gas composition
Emboli to cerebral arteries
Emboli to coronary arteries
• Arterial gas embolism
Pathophysiology
• Effects persists after resolution
Protein denaturation
WBC activation
• Bubbles = foreign surface
• Blood-bubble interaction: Platelet aggregation
Pathophysiology
Tissue oedema
Protein leakage
Increased vascular permeability
• Damage to the blood brain barrier
• Endothelial effects:
Pathophysiology
Semin Thorac Cardiovasc Surg 1990;2:400
Mechanisms (1990)
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Cardiotomy suction containing air
Surgical air during cannulation of LA, aorta, RA or VC
Venous air from loose pursestring sutures
Physical damage to membrane material
Mini-bypass systems
Vacuum-assisted venous drainage
Mechanisms
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Re-prime HLM – resume CPB
Cooling
De-air arterial cannulae and pump line
Remove arterial filter
Remove aortic cannulae
Clamping venous line
Stop CPB immediately
Management – Surgeon/perfusionist
• Retrograde cardioplegia cannula in SVC
• RCP with cold blood from the cardioplegia circuit
Consider retrograde cerebral perfusion (RCP):
Management – Surgeon/perfusionist
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Consider barbiturate, lidocaine, cooling of head, mannitol/hypertone NaCl,
hyperventilation, steroids…
Steep trendelenburg
Induce hypertension
FiO2 100%
Management - Anaesthesiologist
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Effective communication
Thorough cardiac de-airing, TEE
Techniques, protocols
Safety devices
Prevention
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Membrane oxygenators
Cetrifugal pump
One-way valves
Vented arterial line filter
Air bubble detectors
Level alarm
Safety devices
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Use pre-bypass checklist
Test vents before use
Notify perfusionist of placement/removal of vents
Venous cannulation site air-free and leak-free
Shunt between CPB arerial and venous tubing
Bubble free arterial cannula
CO2 flooding of surgical field
Closure of LA under blood
Safety - techniques
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Manual carotid compression
Trendelenburg position during de-clamping
Lung expansion to clear pulmonary venous blood
Ballottement, shaking, fill and empty the heart
Prepare for de-clamping
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Perfusion 2000; 15: 51–61
• Consider hyperbaric oxygen therapy
• Prevent!
• Evacuate air, prevent embolism
• Increase oxygen delivery, reduce oxygen consumption
• Rare condition, but very high mortality
Take home messages
Questions?