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Solar8000 ART and CVP numerics

Arterial and central venous pressure values from the Solar8000 monitor.

Stub

Imported from the time-source table; the full page is still to be written.
Name in the dataset Solar8000/ART_MBP
Type numeric
Device Solar8000 monitor
Stamped by Recorder PC clock
Unit mmHg

Measurement space

Time side (after the per-case delay label): the true time lies between -8.4 s and -0.055 s from the stamp: the delay range plus the interval one value describes.

Time

From UTC to the stored time stamp

Derived from this signal's timing table; a written chain is still to come.

The clock path first (UTC to the clock that stamps or spaces the samples), then the signal's own path to its stored time. Each bar: the time shift or error the step introduces (pale) and what is left after the atlas's correction (solid), on a log scale; dashed when estimated or assumed.
UTC
The reference every chain starts from.
Recorder PC clock
sync assumed 3 ms – 900 ms · clock link, parameter
Windows time synchronisation to the hospital's time server every 8–24 h (assumed), drifting a few ppm in between. Not observable in the release: dates are shifted to 2100. No step of 0.5 s or more was found.
Recorder PC clock
clock measured 300 ms – 4.7 s → 55 ms – 400 ms after correction
Delay or clock offset to the stamp; removed by the per-case delay label.
Stored time stamp
window measured 3 s – 8 s
The width of the interval one value or sample stands for.

Timing

Against the working reference. Delay: from the end of the interval a value describes to its stamp. Interval: how wide that interval is.

Form Delay Interval Clock domain Status Evidence
after the per-case delay label (default) 55 ms – 400 ms 3 s – 8 s Solar8000 numerics measured numeric_delay label SE p10-p90: ART 0.06-0.35 s, CVP 0.11-0.40 s (fixed within a case)
as stamped 300 ms – 4.7 s 3 s – 8 s Solar8000 numerics measured delay from window end: ART 0.3-2.5 s, CVP 3.1-4.7 s; windows 3-6 s + 2 s poll

Combine it with other signals in the synchronisation planner.

Delays

Value

Its value side is still to be described.

Parameters

Parameter Value Status From
Solar8000 ART mean delay 1.7 s (p10–p90 1.0 to 2.5) measured Numeric delays are fixed within a case, different between cases
Solar8000 CVP delay 3.8 s (p10–p90 3.1 to 4.7) measured Numeric delays are fixed within a case, different between cases

Observations

Observation Status Summary
Monitor numerics describe the past, never the future established Every monitor numeric describes a window of 3–30 s or more that ended 1–9 s before its stamp. None is stamped before its data exist, so the stamps already respect the availability rule.
Numeric delays are fixed within a case but differ between cases established A numeric's delay does not drift through a recording, but 40–70% of its variance lies between cases. One delay per case describes it; one delay for the whole dataset is wrong by up to about 2 s.

Studies

Study Date Status Summary
The SNUADC clock through the Solar8000 numerics, whole release 2026-10-19 current On the SNUADC's own sample count, the delay from the waveform to the PC-stamped Solar8000 heart rate and mean arterial pressure ramps at the SNUADC's drift against the PC, measured without its stamps or resets. In recordings with whole reset intervals it agrees with them (−63 ppm; median difference +1.5 ppm, 581 recordings). It is too noisy per recording, and in recordings under about 4 h its rate is biased toward zero, so it cannot yet speak for recordings without resets.
Value resolution of every signal 2026-10-19 draft How finely every waveform and numeric track in the release records its values. The SNUADC waveforms are 10-bit codes, though VitalRecorder's documentation describes the SNUADC as 12-bit; Primus waveforms use about 10 bits of 12; BIS EEG is a 16-bit grid of 0.05 µV. Numerics are 32-bit floats on decimal grids of 1, 0.1, 0.01 or 0.001, one per track; settings sit on coarser grids of 10 or 100.
Numeric delays are fixed within a case, different between cases 2026-10-12 current With each numeric's algorithm held fixed, delays were fitted for every case and every 30-minute block. They do not drift within a case, but 40–70% of their variance lies between cases, so a single population delay is wrong by up to 2 s for HR and 1 s for the others. Each case gets its own delay label.
How the monitors compute their numbers 2026-10-12 current Recomputing each monitor numeric from its own waveform finds a short, simple algorithm for every one (a median, an exponential average or a time mean over 3–30 s) and a delay of 2–9 s behind the newest data it uses. No value is stamped before its data exist.

Worked examples

Example Side Status Summary
Cuff pressure against the arterial line both draft 12,238 cuff readings against the arterial line at the cuff's own moment, in 2,283 patients: no bias over the cohort at any pressure, but each patient's cuff reads a constant 10 mmHg (SD) above or below their line, and half the arterial readings below 65 mmHg are not below 65 by cuff.
Minutes of hypotension per patient, from the monitor and from the waveform both draft Minutes with MAP below 65 mmHg in 3,476 recordings, from the monitor's numeric and from the arterial waveform's beats: the two routes to one pressure differ by several mmHg per patient, which moves half of all patients' minutes by 5 or more and a fifth of their labels, and the numeric's averaging hides short dips in every patient.
Post-induction hypotension, from the charted start and from the devices time draft The charted anaesthesia start comes a median 14 minutes before the patient is induced; measured from it, "hypotension within 20 minutes of induction" is found in 27% of 2,913 patients, against 51% from the devices' induction, and the label changes for a quarter of patients.
Pulse arrival time against blood pressure, before and after synchronisation time draft In 3,270 recordings, PAT tracks systolic pressure only once each pulse is paired with its own beat: the hourly correlation moves from a mean of −0.04 to −0.21 (88% of recordings negative), reproducing Ruffolo et al. 2025 in a second dataset; paired naively, PAT is a heart-rate signal.

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