Gas embolism

Question 1

What is vascular air/gas embolism?

Answer 1

Life-threatening condition.

The entrainment of air or gas into the venous or arterial system, producing systemic effects.

Question 2

What is an arterial gas embolism?

Answer 2

Entrainment or injection of gas into the arterial circulation with embolism to distal capillaries.
This usually has the clinical complications of ischaemia.
Most significant effects are seen when in the coronary or cerebral circulation.

Question 3

What is a venous gas embolus?

Answer 3

Gas entering the venous system, passing into the right atrium and into the lungs where some or all can be filtered.
Large amounts of gas entrained in a short period of time can lead to catastrophic right-sided heart failure and potential for cardiac arrest.

Potentially arterial complications if there is a intracardiac shunt

Question 4

What are the complications of venous gas embolus?

Answer 4

Entrainment into the right heart and pulmonary circulation.
Right heart failure
Reduced preload
Cardiac arrest
Arrhythmias

Question 5

What are the complications of arterial gas embolus?

Answer 5

Widespread potentially or local depending on the location of the entrainment.

If peripheral such as radial arterial line - local ischaemia and platelet activation and clotting risk.
If central (e.g. CPB, angio) - stroke, limb ischaemia, coronary ischaemia and arrhythmias, visceral ischaemia.

Question 6

What situations can cause arterial gas embolus?

Answer 6

CVS procedures:

• cardiac cath/imaging
• CPB/surgery
• VA ECMO

Pulmonary veins:

• Barotrauma during mechanical ventilation
• chest trauma

Paradoxical embolus:

• intracardiac shunt
• AVM in lungs

Question 7

What can cause a venous gas embolus?

Answer 7

• Central line insertion, management removal

- Laparoscopic procedures with open venous channels

Question 8

How may a gas embolus present?

Answer 8

Respiratory:
- dyspnoea

CVS:

• chest pain
• palpitations/arrhythmias
• hypotension
• Right heart strain/failure

Neuro:
- Seizures, hemiparesis, coma

Others:

• Fundoscopy shows retinal vessel gas
• Marble rash skin

Question 9

How would you manage a patient with suspected venous gas embolism?

Answer 9

Resuscitate in an ABCDE approach, correcting abnormalities as you find them.

Supportive:

• Stop further entrainment
• 100% O2
• Stabilise/support blood pressure
• Consider Durant position if not in cardiac arrest - to prevent further air entering right heart
• Assess neurology and cardiac function

Further options:

• attempt aspiration of air via in situ device.
• Echocardiogram
• Rule out other causes
• Consider hyperbaric oxygen therapy

Question 10

How might you prevent venous gas embolus on insertion of a CVC?

Answer 10

Preparation and insertion:

• head level or down
• US to ensure filled vessel and not collapsing, may need fluid resuscitation
• ensure all lumens are flushed
• aspirate from all lumens prior to flushing once inserted
• Attach needle free device caps

Usage:

• ensure all giving sets are primed and flushed before attaching.
• pumps with air-in-line sensors
• extracorporeal circuits and warmers should have air traps
• infuse via needle free attachments
• direct injection with air expelled and syringe pointing downwards

Removal:
- head down position - exit site below heart