Anaes · Neuroanaesthesia
Venous air embolism in the sitting position: detection, prevention, and management
Also known as VAE sitting craniotomy · Venous air embolism anaesthesia · Mill-wheel murmur
Sitting-position neurosurgery risks, VAE pathophysiology, detection hierarchy from TOE to EtCO2, PFO and paradoxical embolism, Durant manoeuvre management, multi-orifice CVP aspiration, and prevention for fellowship exams.
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Target exams
Red flags
- Sudden EtCO2 drop in sitting craniotomy is VAE until proven otherwise.
- PFO raises concern for paradoxical embolism — screen and counsel high-risk sitting cases.
- TOE is most sensitive; precordial Doppler is the practical continuous monitor.
- Stop N2O immediately — it expands air emboli.
- Massive VAE can cause right ventricular outflow obstruction and arrest.
Meet the patient
A 54-year-old is in the sitting position for a posterior fossa meningioma. The precordial Doppler confirms clear heart tones and the EtCO2 trace is tight. As the surgeon works the bone edge, the EtCO2 suddenly falls from 34 to 18 mmHg, the Doppler turns to a high-pitched roar, and the blood pressure drops to 70 over 40. One sentence decides the next minute: this is venous air embolism until proven otherwise. Field control comes first, gas expansion stops, the right heart gets support, and the field is resealed before any drug is reached for.[1]
References2ShowHide
- [1]Günther F, Frank P, Nakamura M, Hermann EJ, Palmaers T Venous air embolism in the sitting position in cranial neurosurgery: incidence and severity according to the used monitoring Acta Neurochir (Wien), 2017.PMID 27896454
- [2]Hurth H, Ebner FH, Clement E, Naros G, Rosenberger P, et al. The risk of intraoperative venous air embolism from neurosurgical procedures performed in the lounging position: an in-depth analysis of detection, management, and outcomes of 1000 consecutive cases J Neurosurg, 2025.PMID 39303312