Test Your Knowledge of Dealing With Air Embolism

A 56-year-old male is undergoing an aortic valve replacement through a full sternotomy with standard aortic and right atrial cannulation at a temperature of 34 degrees. You are preparing to place your last annulus suture when you notice a large bolus of air travel through your arterial line, into the arterial perfuser and into the patient’s aorta.

Directed questions:

1. What organ is at greatest risk for damage due to massive air embolism?

2. What is the first instruction you should give to your perfusionist when you first note an air embolism?

3. What is the first instruction you should give to your anesthesiologist?

4. What strategy can be used to "de-air" the cerebral circulation?

5. What neuroprotective strategies can be employed intraoperatively?

6. What therapeutic adjuncts can be employed postoperatively to minimize neurologic sequelae?

7. What is most common source of air emboli?

8. What routine strategies can be employed to minimize the risk of massive air embolism?

Key Points and Answers to Questions:

1. The greatest concern from massive air embolism is a stroke. Massive air embolism is rare with an estimated frequency of less than 0.01% but carries a significant morbidity and mortality.

2. Upon detection of air embolism, the cardiopulmonary bypass machine should be stopped to avoid further injection of air into the arterial circulation. An expeditious search for the source of the air should take place and steps taken to de-air the circuit to be able to resume cardiopulmonary bypass.

3. The patient should be placed in steep trendelenberg position to minimize further travel of air into the cerebral circulation. Hopefully, air will return into the proximal aorta and can be aspirated or drained via the aortotomy.

4. Retrograde cerebral perfusion can be performed to flush the air from the cerebral circulation. A cannula can be inserted into the superior vena cava and perfused with cold blood (< 20 degrees) in a retrograde fashion. The aorta may need to be opened to allow egress of air from the cerebral circulation.

5. In addition to retrograde cerebral perfusion, deep hypothermia and corticosteroids might be beneficial. Hypothermia decreases brain oxygen consumption and allows for more time for retrograde perfusion under circulatory arrest.

6. Postoperatively, continued use of steroids and moderate hypothermia might be beneficial and some have recommended barbiturate coma to minimize brain metabolism. Reports suggest a benefit of hyperbaric oxygen therapy in the immediate postoperative period. The benefit of hyperbaric oxygen therapy appears greatest when instituted within about 5 hours of surgery and seems less efficacious if there is a delay in the initiation of therapy.

7. The most common source of air emboli is unremoved air from the cardiac chambers.

8. Important strategies include careful inspection of the arterial circuit for air prior to initiation of bypass, stringent use of cardiopulmonary bypass safety alarms which monitor the reservoir level and bubble monitors to detect air in the cardiopulmonary bypass circuit, compulsive de-airing maneuvers at conclusion of surgery, and careful examination for residual intracardiac air with transesophageal echo.

Select References and Additional Resources

PIHammon JW. (2008). Extracorporeal Circulation: Perfusion System. In Cohn LH (Ed), Cardiac Surgery in the Adult. (3^rd edition, 350-370). New York: McGraw-Hill.

PIKern JA, Arnold S. Massive Cerebral Embolization: Successful Treatment with Retrograde Perfusion. Annals of Thoracic Surgery. 69: 1266, 2000.

PIMills NL, Ochsner JL. Massive air embolism during cardiopulmonary bypass: causes, prevention and management. Journal of Thoracic and Cardiovascular Surgery. 80:708–717, 1980.

PIUtley JR. Techniques for avoiding neurologic injury during adult cardiac surgery. Journal of Cardiothoracic and Vascular Anesthesia. 10(1): 38-44, 1996.

PIZiser A, Adir Y, et al. Hyperbaric oxygen therapy for massive arterial air embolism during cardiac operations. Journal of Thoracic and Cardiovascular Surgery. 117(4): 818, 1999.

This Challenge was provided by Resident Medical Editor, Dr. Christian Peyre.

A 56-year-old male is undergoing an aortic valve replacement through a full sternotomy with standard aortic and right atrial cannulation at a temperature of 34 degrees. You are preparing to place your last annulus suture when you notice a large bolus of air travel through your arterial line, into the arterial perfuser and into the patient’s aorta.

Directed questions:

1. What organ is at greatest risk for damage due to massive air embolism?

2. What is the first instruction you should give to your perfusionist when you first note an air embolism?

3. What is the first instruction you should give to your anesthesiologist?

4. What strategy can be used to "de-air" the cerebral circulation?

5. What neuroprotective strategies can be employed intraoperatively?

6. What therapeutic adjuncts can be employed postoperatively to minimize neurologic sequelae?

7. What is most common source of air emboli?

8. What routine strategies can be employed to minimize the risk of massive air embolism?

Key Points and Answers to Questions:

1. The greatest concern from massive air embolism is a stroke. Massive air embolism is rare with an estimated frequency of less than 0.01% but carries a significant morbidity and mortality.

2. Upon detection of air embolism, the cardiopulmonary bypass machine should be stopped to avoid further injection of air into the arterial circulation. An expeditious search for the source of the air should take place and steps taken to de-air the circuit to be able to resume cardiopulmonary bypass.

3. The patient should be placed in steep trendelenberg position to minimize further travel of air into the cerebral circulation. Hopefully, air will return into the proximal aorta and can be aspirated or drained via the aortotomy.

4. Retrograde cerebral perfusion can be performed to flush the air from the cerebral circulation. A cannula can be inserted into the superior vena cava and perfused with cold blood (< 20 degrees) in a retrograde fashion. The aorta may need to be opened to allow egress of air from the cerebral circulation.

5. In addition to retrograde cerebral perfusion, deep hypothermia and corticosteroids might be beneficial. Hypothermia decreases brain oxygen consumption and allows for more time for retrograde perfusion under circulatory arrest.

6. Postoperatively, continued use of steroids and moderate hypothermia might be beneficial and some have recommended barbiturate coma to minimize brain metabolism. Reports suggest a benefit of hyperbaric oxygen therapy in the immediate postoperative period. The benefit of hyperbaric oxygen therapy appears greatest when instituted within about 5 hours of surgery and seems less efficacious if there is a delay in the initiation of therapy.

7. The most common source of air emboli is unremoved air from the cardiac chambers.

8. Important strategies include careful inspection of the arterial circuit for air prior to initiation of bypass, stringent use of cardiopulmonary bypass safety alarms which monitor the reservoir level and bubble monitors to detect air in the cardiopulmonary bypass circuit, compulsive de-airing maneuvers at conclusion of surgery, and careful examination for residual intracardiac air with transesophageal echo.

Select References and Additional Resources

PIHammon JW. (2008). Extracorporeal Circulation: Perfusion System. In Cohn LH (Ed), Cardiac Surgery in the Adult. (3^rd edition, 350-370). New York: McGraw-Hill.

PIKern JA, Arnold S. Massive Cerebral Embolization: Successful Treatment with Retrograde Perfusion. Annals of Thoracic Surgery. 69: 1266, 2000.

PIMills NL, Ochsner JL. Massive air embolism during cardiopulmonary bypass: causes, prevention and management. Journal of Thoracic and Cardiovascular Surgery. 80:708–717, 1980.

PIUtley JR. Techniques for avoiding neurologic injury during adult cardiac surgery. Journal of Cardiothoracic and Vascular Anesthesia. 10(1): 38-44, 1996.

PIZiser A, Adir Y, et al. Hyperbaric oxygen therapy for massive arterial air embolism during cardiac operations. Journal of Thoracic and Cardiovascular Surgery. 117(4): 818, 1999.

This Challenge was provided by Resident Medical Editor, Dr. Christian Peyre.

A 56-year-old male is undergoing an aortic valve replacement through a full sternotomy with standard aortic and right atrial cannulation at a temperature of 34 degrees. You are preparing to place your last annulus suture when you notice a large bolus of air travel through your arterial line, into the arterial perfuser and into the patient’s aorta.

Directed questions:

1. What organ is at greatest risk for damage due to massive air embolism?

2. What is the first instruction you should give to your perfusionist when you first note an air embolism?

3. What is the first instruction you should give to your anesthesiologist?

4. What strategy can be used to "de-air" the cerebral circulation?

5. What neuroprotective strategies can be employed intraoperatively?

6. What therapeutic adjuncts can be employed postoperatively to minimize neurologic sequelae?

7. What is most common source of air emboli?

8. What routine strategies can be employed to minimize the risk of massive air embolism?

Key Points and Answers to Questions:

1. The greatest concern from massive air embolism is a stroke. Massive air embolism is rare with an estimated frequency of less than 0.01% but carries a significant morbidity and mortality.

2. Upon detection of air embolism, the cardiopulmonary bypass machine should be stopped to avoid further injection of air into the arterial circulation. An expeditious search for the source of the air should take place and steps taken to de-air the circuit to be able to resume cardiopulmonary bypass.

3. The patient should be placed in steep trendelenberg position to minimize further travel of air into the cerebral circulation. Hopefully, air will return into the proximal aorta and can be aspirated or drained via the aortotomy.

4. Retrograde cerebral perfusion can be performed to flush the air from the cerebral circulation. A cannula can be inserted into the superior vena cava and perfused with cold blood (< 20 degrees) in a retrograde fashion. The aorta may need to be opened to allow egress of air from the cerebral circulation.

5. In addition to retrograde cerebral perfusion, deep hypothermia and corticosteroids might be beneficial. Hypothermia decreases brain oxygen consumption and allows for more time for retrograde perfusion under circulatory arrest.

6. Postoperatively, continued use of steroids and moderate hypothermia might be beneficial and some have recommended barbiturate coma to minimize brain metabolism. Reports suggest a benefit of hyperbaric oxygen therapy in the immediate postoperative period. The benefit of hyperbaric oxygen therapy appears greatest when instituted within about 5 hours of surgery and seems less efficacious if there is a delay in the initiation of therapy.

7. The most common source of air emboli is unremoved air from the cardiac chambers.

8. Important strategies include careful inspection of the arterial circuit for air prior to initiation of bypass, stringent use of cardiopulmonary bypass safety alarms which monitor the reservoir level and bubble monitors to detect air in the cardiopulmonary bypass circuit, compulsive de-airing maneuvers at conclusion of surgery, and careful examination for residual intracardiac air with transesophageal echo.

Select References and Additional Resources

PIHammon JW. (2008). Extracorporeal Circulation: Perfusion System. In Cohn LH (Ed), Cardiac Surgery in the Adult. (3^rd edition, 350-370). New York: McGraw-Hill.

PIKern JA, Arnold S. Massive Cerebral Embolization: Successful Treatment with Retrograde Perfusion. Annals of Thoracic Surgery. 69: 1266, 2000.

PIMills NL, Ochsner JL. Massive air embolism during cardiopulmonary bypass: causes, prevention and management. Journal of Thoracic and Cardiovascular Surgery. 80:708–717, 1980.

PIUtley JR. Techniques for avoiding neurologic injury during adult cardiac surgery. Journal of Cardiothoracic and Vascular Anesthesia. 10(1): 38-44, 1996.

PIZiser A, Adir Y, et al. Hyperbaric oxygen therapy for massive arterial air embolism during cardiac operations. Journal of Thoracic and Cardiovascular Surgery. 117(4): 818, 1999.

This Challenge was provided by Resident Medical Editor, Dr. Christian Peyre.