Treating Massive Air Embolism

What to do in case of Air embolism

Initiate Temporary Hypothermic RCP

Step 1 of Temporary Hypothermic RCP

Stop CPB & clamp arterial & venous lines

Step 2 of Temporary Hypothermic RCP

• Place pt in steep Trendelenburg position

  • Anesthesia Ice bags on the head

  • At the field, fill the chest w/ normal saline to a level at about the aorta in steep trendelenburg

Why do we place pt in steep trendelenburg?

• Head down, feet up

• Air will rise towards the lower part of the body away from the head

Why do we fill the field w/ normal saline?

• Less room for air to enter into the chest

• displaces air from the surgical field making it easier to remove

• better visualization

Step 3 of Temporary Hypothermic RCP

• Remove Arterial Cannula, de-air the circuit & arterial cannula

• This creates an open aortotomy

• Surgeon will place finger over hole and remove intermittently to allow air to come out

Step 4 of Temporary Hypothermic RCP

• Establish RCP by connecting an arterial line to a snared cannula placed in the SVC

• Can be the same arterial cannula that was used for the arterial line

• Return blood & air exiting arterial cannulation site to circuit from Root Vent

Step 4 if you are using Bi-caval cannulation

• Use the existing SVC cannula for RCP

• clamp IVC cannula

Step 4 if you are using a 2 stage venous cannulation

• For single vena cava / atrial cannulation

• Place aortic cannula in the SVC for RCP

Step 5 of Temporary Hypothermic RCP for Adults

• Maintain RCP at 20°C & shoot for a CVP pressure of 20-25 mmHg or 300-1500 mL/min for 1-2 mins

  • Max of 5 mins

• Until no air is observed exiting the aortotomy w/in the saline-filled chest

Step 5 of Temporary Hypothermic RCP for infants & peds

• Maintain RCP at 20°C & shoot for 15 mL/kg/min for 1-2 mins

  • max of 5 mins

• Until no air is observed exiting the aortotomy w/in the saline-filled chest

Step 6 of Temporary Hypothermic RCP

• Intermittent carotid compression by anesthesia allows pressurization enhancing retrograde purging of air from the vertebral arteries

• Intermittent so you do not completely block flow to brain

Temporary Hypothermic RCP steps

1. Stop CPB & clamp arterial & venous lines

2. Place pt in steep Trendelenburg position

   • Ice on head & fill chest w/ normal saline

3. Remove arterial cannula creating an aortotomy

4. Establish RCP by connecting an arterial line to a snared cannula placed in the SVC

5. Maintain RCP @ 20°C for 1-2 min

   • CVP = 20-25 OR 300-1500 mL/min OR 15 mL/kg/min for infants & peds

6. Intermittent carotid compression

What should you do after temporary Hypothermic RCP?

Resume Antegrade CPB

Steps for Resuming Antegrade RCP

1. Maintain 20°C for 40-45 min

2. Induce HTN MAP of ~80mmHg

3. Maintain pCO2 of 45-55mmHg

4. Set FiO2 at 100% for 6 hrs (including post op which is passed onto anesthesia)

5. Warm pt slowly maintaining a temp gradient of < 6-8°C

Why do we maintain 20°C for 40-45 min?

• Keeping the body temp cold will keep more air/bubbles in soln

• ↓ Temp = ↑ solubility

Why do we Induce HTN MAP of ~80mmHg?

• Pressurize bubbles into smaller bubbles

• Keeps bubbles out of arterial system which can lead to narrowed blood vessels

• Instead they go to capillaries

Why is it bad for big air bubbles to be in the arterial system?

• Bigger air bubbles will block/narrow vessels much quicker

• This can lead to a whole section of capillaries going ischemic

• If the bubbles are small, maybe only 1 or 2 capillaries will go ischemic (i.e. 20 vs 2)

Why do we Maintain pCO2 of 45-55mmHg?

• Cerebral vasodilation

• Get better flows to the carotids that lead to the brain

• Permissive hypercapnia

Why do we Set FiO2 at 100% for 6 hrs?

• So that only O2 is in the blood/vessels

• It keeps nitrogen out of the mix

  • Hardest gas to get back into soln

What should be done immediately following the case

Have circulating nurse call radiology for CT of head w/out contrast

What should we terminate CPB at after treating MAE

• Terminate CPB w/ a systolic BP >100 mmHg for Adults

• 20-25mmHg above normal for infants & peds

• Low filling pressures

What is very important post op after MAE

Ventilate w/ 100% O2 for at least 6 hrs