Jugular venous O2 tension

[drlee]

My question pertains to the 1995 ABA ITE Question stem 54. Does anybody know the normal values for jugular venous oxygen tension?

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[Planktonmd]

My question pertains to the 1995 ABA ITE Question stem 54. Does anybody know the normal values for jugular venous oxygen tension?

It would be helpful if you list the whole question if you want an answer.

 

[pgg]

My question pertains to the 1995 ABA ITE Question stem 54. Does anybody know the normal values for jugular venous oxygen tension?

I don't think many people will claim that SjvO2 is a very good monitor of cerebral perfusion & O2 uptake, but Miller says anything less than 50% suggests cerebral ischemia (p 1542). The "normal" number I had memorized was something in the 60s but I can't find that reference.

This chart is from Chieregato et al, Normal jugular bulb oxygen saturation, Journal of Neurology Neurosurgery and Psychiatry 2003;74:784-786. The findings in this study were a mean of 57% with a 95% CI between 44% and 65%, which is substantially lower than previous studies, and would suggest that even the <50% figure Miller cites isn't all that useful.

 

[pgg]

It would be helpful if you list the whole question if you want an answer.

Which of the following best reflects findings of inadequate cerebral perfusion during carotid cross clamping?
(A) Decreased frequency on EEG
(B) Increased latency, of brain stem auditory evoked potentials
(C) Increased spectral edge frequency
(D) Jugular bulb oxygen tension of 27 mmHg
(E) Stump pressure of 50 mmHg

Key says the answer is A.

Even by Miller's criteria a PO2 of 27 in the jugular vein isn't suggestive of ischemia.