Jugular venous oxygen saturation (SjO2)

🔹 Assess  the balance between global cerebral oxygen delivery and utilization.

🔹 Normal SjO2 is 55–75%

🔹 Low SjO2 (<50%)  /↓CBF or ↑CMRO 2/

CAUSES

➖↓BP

➖↓PaCO2 

➖Seizures 

➖Fever 

➖↑ICP or ↓CPP

➖Vasospasm 

➖Arterial hypoxia 

🔹 High SjO2 (>80%) /↑CBF or ↓CMRO2/

CAUSES

➖Hyperemia 

➖Failure of oxygen utilization (mitochondrial failure) Hypothermia 

➖Sedation

➖Arteriovenous shunting 

➖Brainstem death

🔹 When the catheter tip lies level with the mastoid process above the lower border of the first cervical vertebra on a lateral cervical spine radiograph contamination from the extracranial circulation, will be minimal. 

🔹 Accuracy is ensured, only if the dominant jugular bulb is cannulated, but in practice the right side is usually selected

🔹 A stat sample provides a stat measure of the brain’s oxygenation and metabolic status

🔹 SjO2 can be used to guide intraoperative blood pressure and ventilatory management. SjO2 monitoring is also widely used after TBI

🔹 Relatively insensitive to regional ischemia

🔹 The complications and contraindications of SjO 2 monitoring are same as for the insertion of an internal jugular central venous line

Reference: Key Monitoring in Neuroanesthesia: Principles, Techniques, and Indications by Martin Smith, Essentials of Neurosurgical Anesthesia & Critical Care 2012 Strategies for Prevention, Early Detection, and Successful Management of Perioperative Complications