Does standing or sitting position of the anesthesiologist in the operating theatre influence sevoflurane exposure during craniotomies?

BACKGROUND: Exposure of the OR staff to inhalational anesthetics has been proven by numerous investigators, but its potential adverse effect under the present technical circumstances is a debated issue. The aim of the present work was to test whether using a laminar flow air conditioning system exposure of the team to anesthetic gases is different if the anesthetist works in the sitting as compared to the standing position.

METHODS: Sample collectors were placed at the side of the patient and were fixed at two different heights: at 100 cm (modelling sitting position) and 175 cm (modelling standing position), whereas the third collector was placed at the independent corner of the OR. Collected amount of sevoflurane was determined by an independent chemist using gas chromatography.

RESULTS: At the height of the sitting position the captured amount of sevoflurane was somewhat higher (median and IQR: 0.55; 0.29-1.73 ppm) than that at the height of standing (0.37; 0.15-0.79 ppm), but this difference did not reach the level of statistical significance. A significantly lower sevoflurane concentration was measured at the indifferent corner of the OR (0.14; 0.058-0.36 ppm, p < 0.001).

CONCLUSIONS: Open isolation along with the air flow due to the laminar system does not result in higher anesthetic exposure for the sitting anesthetist positioned to the side of the patient. Evaporated amount of sevoflurane is below the accepted threshold limits in both positions.