Cerebral hypotension and desaturation can occur during shoulder surgery in the seated position. We evaluated the correlation of cerebral oxygen saturation (rSO₂) using near infra-red spectroscopy (NIRS) and mean arterial pressures (MAP) (at the levels of the brain and heart).

Fifty patients, scheduled for the arthroscopic shoulder surgery in the seated position, were enrolled to monitor the rSO₂, bispectral Index (BIS), and MAPs at the levels of the brain and heart. The values of each parameter were collected at 5 min after intubation, immediately after placing the patient in the sitting position, 5 min after the patient was seated, immediately after the surgical incision, and every 30 min after incision.

A correlation between the cerebral rSO₂ and the MAP at the level of brain were statistically significant. Cerebral rSO₂ and MAP after a change of posture from supine to sitting position were significantly decreased, compared to the baseline value.

Monitoring cerebral rSO₂ and MAP at the level of brain can be helpful to detect the possibility of cerebral deoxygenation earlier.