What is the normal range for brain tissue oxygen tension (PbtO2) to maintain cerebral oxygen supply and demand?

What is the normal range for brain tissue oxygen tension (PbtO2) to maintain cerebral oxygen supply and demand?

• A. 55% to 75%
• B. 20 to 40 mm Hg
• C. 70 to 150 mm Hg
• D. 80 to 100 mm Hg

Answer: (B)

PbtO2 tells you how much oxygen is actually available in brain tissue and is used to gauge whether delivery meets metabolic demand. The normal range to maintain cerebral oxygen supply and demand is about 20 to 40 mm Hg. Keeping PbtO2 above roughly 20 mm Hg helps prevent cerebral hypoxia and secondary injury, and many clinicians aim for a target in the mid-20s to 30s or within the 20–40 mm Hg window depending on the protocol. Values well above this range are not typical targets and prolonged higher oxygen tension can carry risks of oxidative stress. Note that PbtO2 is measured in mm Hg, not percent, so ranges expressed as percentages aren’t applicable, and tissue values in the 70–150 or 80–100 mm Hg range would not reflect normal brain tissue oxygen tension.

PbtO2 tells you how much oxygen is actually available in brain tissue and is used to gauge whether delivery meets metabolic demand. The normal range to maintain cerebral oxygen supply and demand is about 20 to 40 mm Hg. Keeping PbtO2 above roughly 20 mm Hg helps prevent cerebral hypoxia and secondary injury, and many clinicians aim for a target in the mid-20s to 30s or within the 20–40 mm Hg window depending on the protocol. Values well above this range are not typical targets and prolonged higher oxygen tension can carry risks of oxidative stress. Note that PbtO2 is measured in mm Hg, not percent, so ranges expressed as percentages aren’t applicable, and tissue values in the 70–150 or 80–100 mm Hg range would not reflect normal brain tissue oxygen tension.