Venous air embolism

Incidence

As high as 76% (by TEE) or 40% by precordial Doppler (less sensitive than TEE) in patients undergoing posterior fossa procedures in the sitting position. Incidence is lower in p-fossa procedures not in the sitting position. Even lower but still possible in cervical laminectomy. Most commonly in tumors near the posterior saggital sinus. Can occur in peds craniosynostosis procedures, as well as during Caesarean sections during uterine exteriorization (at least one fatality has been reported)

Diagnosis

Standard of care is precordial doppler (left or right parasternal, between 2nd and 3rd ribs) + ETCO₂ monitoring although this is not the most sensitive test – TEE is most sensitive. Pulmonary artery pressure will rise and CO₂ will fall w/ VAE. If Post-fossa crani in sitting position should consider placing R-atrial multiorifice j-tipped central line place in the arm and threaded into heart. Use catheter as EKG lead, bi-phasic (pos/neg) P-wave indicates mid-RA placement

Sensitivity of modalities for VAE Detection (most to least sensitive, see Miller Figure 63-11)

• TEE (most sensitive)
• Doppler (left or right parasternal, between 2nd and 3rd rib, mill wheel murmur)
• ETCO₂ and/or PA pressure
• Cardiac output and/or CVP
• Blood pressure, EKG (RV strain pattern, ST depression), stethoscope (least sensitive)

Treatment

Notify surgeon to flood/pack surgical field, jugular compression, lower head, aspirate RA-cath, 100% FiO₂, pressors.