Venous air embolisms and sitting position in Helsinki pineal region surgery

Nowadays, the sitting position has lost favor among neurosurgeons partly due to assumptions of increased complications, such as venous air embolisms (VAEs) and hemodynamic disturbances. The aim of our study is to describe the importance of some anesthetic considerations and the utility of antigravity trousers as well, together with a skillful neurosurgery and an imperative proper teamwork, in order to prevent the risk of severe VAE during pineal region surgery. We routinely use them for the variant of the sitting position we developed, the "praying position."

A retrospective review of 51 pineal lesions operated on in the "praying position" using antigravity trousers was carried out. In the "praying position" the legs of the patient are kept parallel to the floor. Hence, antigravity trousers are used to generate an adequate cardiac preload.

VAE associated to persistent hemodinamic changes was nonexistent in our series. The rate of VAE was 35.3%. VAEs were diagnosed mainly by monitoring of the end-tidal CO₂ (83.33%). A venous system lesion was the cause in most of the cases. When VAE was suspected, an inmediate reaction based on a good teamwork was imperative. No cervical spine cord injury nor peripheral nerve damage were reported. The average microsurgical time was 48 ± 33 min.

The risks of severe VAE during pineal region surgery in the "praying-sitting position" may be effectively prevented by some essential anesthetic considerations and the use of antigravity trousers together with a skillful neurosurgery, and an imperative proper teamwork.