Technical considerations in continuous jugular venous oxygen saturation measurement.

Fibreoptic reflection oximetry allows continuous in-vivo estimation of jugular venous oxygen saturation. In combination with pulse oximetry the oxygen extraction ratio SaO2-SjO2/SaO2 can be derived enabling identification of states of global luxury perfusion, normal coupling of global cerebral blood flow with global cerebral metabolism, global cerebral hypoperfusion and global cerebral ischemia. Several technical difficulties may arise affecting the accuracy of SjO2 recordings which must be recognised by the clinician before medical intervention is contemplated.