Parameters¶
One number the atlas relies on, with its uncertainty and where it came from.
| Parameter | Value | Status | From |
|---|---|---|---|
| Adopted mean pulse arrival time | 270 ms (plausible range 250–290 ms) | assumed | The PPG hardware delay and the adopted pulse arrival time |
| Arterial line access rate | 1.1 per hour (8,245 in 7,507 h); occlusions 0.4 per hour | measured | Arterial line accesses in the pressure waveform |
| BIS correction interval | 8,192 s (2 h 16.5 min), ± 20 s in 95% of intervals | measured | When each device's clock is corrected, in every recording |
| BIS correction size | 0.17 s median | measured | When each device's clock is corrected, in every recording |
| BIS drift against SNUADC | −72 ppm (IQR −82 to −54) | measured | Shared bursts between the ECG and the EEG |
| BIS drift against the recorder PC | 25 ppm (p10–p90 12 to 50; 5th–95th 7.3–51.1 ppm; census fit of 4,728 recordings median 21.1 ppm) | measured | The stamp sawtooth model for SNUADC and BIS |
| BIS index averaging window | 16 s in 48% of good fits (the 15 s setting); 32–61 s in 40%; half the weight older than 30 s | measured | How the BIS index trails its EEG |
| BIS index delay | 3 s (p10–p90 3 to 4) | measured | How the BIS index trails its EEG |
| Blood gas timestamp after the draw | 7.2 min (p10–p90 3.2 to 12.2; two modes, 2–6 and 8–12 min) | measured | What the lab timestamp marks |
| CardioQ re-anchoring interval | at most about 300 s; about 40 re-anchors per case | measured | — |
| CardioQ stamps behind SNUADC | 0.4–4.4 s (p5–p95); matched-beat MAD 0.24 s (24 cases) | measured | Rare devices against SNUADC |
| Central lab timestamp after the draw | about 8–24 min (median about 14; weak, mostly chance matches) | estimated | What the lab timestamp marks |
| Drift of Solar8000 numeric delays within a case | 0 s/h median (p10–p90 about ±0.5 s/h) | measured | Numeric delays are fixed within a case, different between cases |
| EEG–ECG constant after the stamp model | −804 ms in step mode (1,526 recordings); −660 ms in frequent-correction mode (78) | measured | The stamp sawtooth model for SNUADC and BIS |
| EEG–ECG timing error after the stamp model | 42 ms median, p90 150 ms (17 ms and 79 ms with the recording's own bursts) | measured | The stamp sawtooth model for SNUADC and BIS |
| EMR 5-minute entries, rounding | (t − 300 s, t]; estimate t − 150 s (SD 87 s); observed shift against minute entries −89 to −293 s | measured | Anaesthesia record times are rounded up |
| Largest recorder PC clock step | no step of 0.5 s or more in 6,388 files (19,006 h) | measured | Recorder PC clock steps and recording pauses |
| Monitor 240 Hz line against SNUADC | −25.4 to −28.7 ppm (6 cases) | measured | Monitor clocks in the waveforms' spectral lines |
| Oximeter frame clock against SNUADC | +7 to +92 ppm by setup (medians over 42 PC keys); within 3 ppm of its setup's median in 89% of recordings | measured | The PPG's 30 Hz frame clock |
| PPG hardware delay | 385 ms, one global value (stored R-to-foot delay 655 ms minus an adopted 270 ms); setups differ by under ±15 ms | measured | One device delay for the PLETH across the release |
| PPG sawtooth rate | 18–52 ppm by setup | measured | The PPG sawtooth and its correction |
| PPG slip size | 32.3 ms (IQR 30.4 to 34.8) | measured | The PPG sawtooth and its correction |
| Pacing interval agreement between stretches | 0.05–0.1 ms | measured | Paced ECG as an independent clock |
| Primus ETCO₂ delay | 1.55 s (p10–p90 0.75 to 3.4) | measured | Numeric delays are fixed within a case, different between cases |
| Primus PIP delay | 4.6 s (p10–p90 3.65 to 6.5) | measured | Numeric delays are fixed within a case, different between cases |
| Primus RR delay | 4.3 s (p10–p90 1.6 to 7.6) | measured | Numeric delays are fixed within a case, different between cases |
| Primus correction interval | about 7,230 s (2.0 h; p90 twice that) | measured | When each device's clock is corrected, in every recording |
| Primus correction size | whole 16 ms samples either way; median −16 ms (one sample back), p10–p90 −144 to +144 ms | measured | When each device's clock is corrected, in every recording |
| Primus drift against the recorder PC, from breath matching | 104 ppm (p10–p90 28 to 184; 178 recordings; whole-recording lines give +87 ppm median in 1,060 (p10–p90 −49 to +229)) | measured | The Primus ventilator against SNUADC, by breaths |
| Primus drift implied by its corrections | about 1–11 ppm | derived | How often each device is corrected |
| Primus drift used in the delay fits | 115 ppm | assumed | — |
| Recorder PC drift against UTC | 0.1–10 ppm (assumed) | assumed | — |
| Recorder PC offset from UTC | 3 ms to 0.9 s (assumed) | assumed | — |
| Recorder PC synchronisation interval | 8–24 h (assumed) | assumed | — |
| Recording pause | 19.6 s (p10–p90 15.7 to 29.8; 2,025 pauses in 1,846 files (29%)) | measured | Recorder PC clock steps and recording pauses |
| SNUADC frequent-correction steps | +5 to +15 ms (median +10), about one an hour (median 1.1 per hour per recording) | measured | Clock corrections in every file |
| SNUADC stamp arithmetic | −0.954 ppm (n = 6321; census of 6,321 files (17 October): median −0.9535 ppm; 89.5% of recording hours within 0.05 ppm of −0.954; 747 files (12%) between −0.90 and −0.55 ppm) | measured | SNUADC stamp arithmetic |
| SNUADC start after the file's first record | 1.56 s (5–95%: 0.44–4.5 s; 99th percentile 12 s; maximum 10,879 s) | measured | The vitaldb package's loading conventions |
| SNUADC step-mode correction interval | 2.08 h (5th–95th 1.65–3.57 h between resets; per-recording means p10–p90 1.68–3.07 h) | measured | The stamp sawtooth model for SNUADC and BIS |
| SNUADC step-mode correction size | about 0.498 s true (paced: 0.4981–0.4988 s); −0.480 s on the stamps | measured | Paced ECG as an independent clock |
| SNUADC step-mode drift | −63 ppm (p10–p90 −79 to −44; 5th–95th −80.3 to −36.9 ppm; medians of −46 to −74 ppm by serial port) | measured | The stamp sawtooth model for SNUADC and BIS |
| Signal lost at a SNUADC step-mode correction | 17.7 ms (range 17.2 to 18.2; n = 3; 3 corrections in 2 paced cases; ECG–EEG bursts give 13.0 ± 1.7 ms) | measured | Paced ECG as an independent clock |
| 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 |
| Solar8000 HR delay, early group | 1.92 s (± 0.51 SD; 36% of classified cases) | measured | Two heart-rate delay groups, one poll apart |
| Solar8000 HR delay, late group | 4.2 s (± 0.65 SD; 64% of classified cases) | measured | Two heart-rate delay groups, one poll apart |
| Solar8000 HR window | about 6 s (best 6–8 s in both delay groups) | measured | How the monitors compute their numbers |
| SpO₂ onset latency | about 4 s to the start of the dip, 8 s to its deepest; window 10–20 s (estimated) | measured | SpO₂ and pulse rate latency from step events |
| Stamp shift across a recording gap | 127–149 ms early (4 gaps, 2 cases; modulo one pacing period) | measured | Paced ECG as an independent clock |