Page 10 - CASA Bulletin of Anesthesiology 2022; 9(3)-1 (1)

CASA Bulletin of Anesthesiology

When our patient had a sudden onset of hemodynamic instability and EKG changes
progressing rapidly to pulseless rhythm, we immediately started cardiopulmonary resuscitation
and notified the surgeon who started to compress the hepatic veins, pull up Pringle Maneuver to
stop all hepatic blood inflow, and identified and repaired the holes in middle hepatic veins. We
then aspirated air bubbles from the patient’s central line and surgeons withdrew a large amount
of air from the right ventricle under ultrasound guidance. In spite of heroic measures including
chest compression, IV vasopressors, and blood products transfusion, the patient did not respond
and failed to have return of spontaneous circulation throughout the period of resuscitation. The
resuscitation was ceased and death attributed to a large VAE and air lock in the right heart.

In general, VAE can be detected by several monitoring modalities. The common methods for
detecting VAE are trans-esophageal echocardiography detecting as little as 0.02 ml/kg of air
administered by bolus injection; precordial Doppler capable of detecting as little as 0.25 ml of air
(0.05 ml/kg); ECO2 was reported a sudden reduction of 2-5mmHg can be an indicator of VAE,
especially in high-risk procedures; other monitoring parameter such as esophageal stethoscope
and EKG change have been shown low sensitivity 3, 13, 15 . Clinical symptoms/signs of VAE and
monitoring both lack specificity and often occur late after a significant volume of air has been
entrained.

As an anesthesia provider, the most efficient management for intraoperative VAE is paying
meticulous attention to classify the patient’s risk of VAE preoperatively, monitor and prevent air
entry and alert any vital signs changes during the liver surgery.

1. Intraoperative communication between the surgical and anesthesia team for surgical process
is paramount, especially with regards to the early suspicion and detection of VAE
2. Anesthesiologists should keep in mind that nitrous oxide can quickly expand the volume of
air embolism in a circulation, if VAE is suspected, nitrous oxide use should be discontinued
20 . Anesthesia provider must have a high vigilant to monitor and explain any intraoperative
clinical symptoms and signs possibly relevant to VAE
3. For patients with high risk liver surgery, anesthesiologists should well secure the central
catheter to prevent accidently fell out or air entrained, and should promptly aspirate air if
VAE was suspected
4. Ideally, increase CVP with IV fluid and use Positive end-expiratory pressure (PEEP), the
pressure in the lungs above atmospheric pressure could reduce the air pressure gradient
between venous circulation and site of air entrainment. These managements need weigh
benefit and risk for liver surgery
5. The effect of patient positioning on the VAE occurrence and management have been reported
controversial and used less frequently 3, 19 . Moreover, repositioning of patients might be
difficult due to resuscitation and open surgical field.

If there is suspicion of intraoperative VAE with or without cardiovascular compromised,
supportive management is the mainstay. The goal of treatment in VAE is to prevent further air
entry, reduce the volume of air entrained, and provide hemodynamic support. The surgeon
should be notified and additional anesthesia help should be requested.

1. Anesthesia team members should be assigned to each specific role, work together as a whole
code blue team and if needed, start immediate cardiopulmonary resuscitation with 100% O2.
IV fluid resuscitation, blood products transfusion, IV inotropic and vasopressor
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