A cerebral autoregulation index from arterial pressure and cerebral oxygenation¶

A moving correlation between mean arterial pressure and INVOS cerebral oxygenation, and how lag between the two devices changes it.


Side	time
Status	planned
Variables	Invos regional oxygen saturation, Arterial pressure (SNUADC)
Studies	Drug effects as a clock check

The question¶

Does cerebral oxygenation follow arterial pressure passively (impaired autoregulation)?

Inputs¶

Each input links to its measurement page: how it is timed, how its value was recorded, and how uncertain both are.

Input	Unit	What it is
Invos regional oxygen saturation	%	Cerebral oximetry; no signal shared with the reference.
Arterial pressure (SNUADC)	mmHg	Invasive arterial pressure, sampled by SNUADC at 500 Hz from the monitor's analogue output.

Why the atlas changes the answer¶

The index is a correlation over minutes; a lag between the two signals lowers it. INVOS keeps its own clock, which the atlas so far bounds only to well within a minute of the recorder (Drug effects as a clock check).

Takeaways¶

Planned, small: INVOS and an arterial waveform together in about 0.5% of recordings (4 of 846 sampled, about 30 cases in the release).

Studies it relies on¶

Study	Date	Status	Summary
Drug effects as a clock check	2026-10-13	current	Infusion pumps, the rapid infuser and the cerebral oximeter share no waveform with the reference. Drug effects that follow infusions at plausible delays (propofol to BIS in about 2 minutes, fluid to CVP in about 30 s) bound their clocks to well within a minute of the recorder.