Neuro: Posterior Fossa Crani
Sitting position for tumor resection. Manage VAE risk and brain relaxation logic.
"A 45 y.o. female is scheduled for resection of a posterior fossa tumor in the sitting position. During the procedure, the ETCO2 suddenly drops from 35 to 18 mmHg..."
Venous Air Embolism (VAE) detection, sitting position risks, and ICP management.
Commonly tests management of sudden intraoperative hemodynamic and respiratory shifts.
How a Board-Certified Consultant answers this scenario.
A sudden drop in ETCO2 from 35 to 18 mmHg in the sitting position is a classic sign of Venous Air Embolism (VAE). My immediate actions are to notify the surgical team to flood the field with saline and pack the wound to prevent further air entry.
I will simultaneously increase FiO2 to 100%, lower the head of the bed if possible, and aspirate from the pre-positioned multi-orifice central venous catheter. I will support hemodynamics with fluid boluses and pressors. I will also listen for a 'mill-wheel murmur' and use precordial Doppler for confirmation. If hemodynamics do not stabilize, I will request the surgeons to immediately close the wound and move the patient to the left lateral decubitus position (Durant's maneuver) to trap the air in the right ventricle apex, away from the pulmonary artery.