Surgery>>>>>Physiologic Monitoring of the Surgical Patient
Question 17#

Regarding jugular venous oximetry in patients with TBI:

A. It requires placement of a catheter in the jugular bulb
B. Low jugular venous oxygen saturation (Sjo₂) has not been show to predict poor clinical outcomes
C. It is less invasive than placing an intraventricular monitor, but does not allow for continuous monitoring
D. It can replace ICP monitoring in patients without evidence of regional variation in cerebral blood flow

Correct Answer is A

Comment:

When the arterial oxygen content, hemoglobin concentration, and the oxyhemoglobin dissociation curve are constant, changes in jugular venous oxygen saturation (Sjo₂) reflect changes in the difference between cerebral oxygen delivery and demand. Generally, a decrease in Sjo₂ reflects cerebral hypoperfusion, whereas an increase in Sjo₂ indicates the presence of hyperemia. Sjo₂ monitoring cannot detect decreases in regional cerebral blood flow if overall perfusion is normal or above normal. This technique requires the placement of a catheter in the jugular bulb, usually via the internal jugular vein. Catheters that permit intermittent aspiration of jugular venous blood for analysis or continuous oximetry catheters are available. Low Sjo₂ is associated with poor outcomes after TBI. Nevertheless, the value of monitoring Sjo₂ remains unproven. If it is employed, it should not be the sole monitoring technique, but rather should be used in conjunction with ICP and CPP monitoring. By monitoring ICP, CPP, and Sjo₂, early intervention with volume, vasopressors, and hyperventilation has been shown to prevent ischemic events in patients with TBI.