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MIT-LCP / mimic-website

Website for the MIMIC Critical Care Database (currently version MIMIC-III)
https://mimic.mit.edu
MIT License
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Details on "numerics" and "waveforms" #65

Closed Dubrzr closed 5 years ago

Dubrzr commented 7 years ago

Hi,

1) I'm working on mimic3 waveforms and I would like to know if there is a description somewhere of the process done to derive numerics values from waveform data? For example, how did you derived Heart Rate from waveforms? Do you have details about algorithms used? (Pan-Tompkins?) It would be interesting to know that before exploiting them as it might influence my algorithms. Moreover, would it be possible to make it available to us so that we can choose the frequency of numerics? (maybe it will be better for me to have 3 measurement/second instead of one for the heart rate).

I saw that in some cases the kind of signal available from waveform data is changing for example here it is changing from V to III then to II and MCL1... but you succeeded in computing the heart rate from those different signals, how?

timeline-example

2) You are saying here https://mimic.physionet.org/mimicdata/waveforms/ that the "numerics" are derived second by second from waveform data, but I see that there is "%" signal in numerics, I guess it's % of O2? There is also Respiration that is available in numerics while not present in waveforms, how could it be derived??

3) There are many unknown signals "???", "?", "[0]" and one signal for which I couldn't find the meaning: "P1", could you give some information about them?

nb_entry_by_signame_numerics nb_entry_by_signame_waveforms

4) For anyone interested, I've created a dictionary containing descriptions of each signal here: https://github.com/MIT-LCP/mimic-website/issues/59#issuecomment-287394857, if anyone could confirm the descriptions it would be awesome! Can I find them somewhere?

I posted my questions here as I thought it might be helpful to add those information on the website.

Many thanks!

alistairewj commented 7 years ago

Speaking from limited knowledge here - but I'll do my best!

  1. We don't calculate the numerics. They are directly extracted from the monitors. The algorithm used is proprietary and we don't have access to it. I know that a single channel can switch leads - but this may be due to the archiving agent, and not necessarily the monitor.
  2. Correct, it's SpO2. That's calculated by the PPG. The respiration rate is usually derived from impedence pneumography using the ECG leads.
  3. No idea what they are, and not sure we have an easy method of finding out.
  4. @cx1111 do you know where on PhysioNet we have the index which maps all the signals into categories? I recall it being used by the PhysioNet waveform search tool but I forgot the exact link to it.
Dubrzr commented 7 years ago

Thank you very much for your answers.

cx1111 commented 7 years ago

https://physionet.org/physiobank/database/sigtypes This maps signal names into categories.

PO-MIN commented 5 years ago

Hi there, I would like to figure out of what PLETH, PLETH L, PLETH R, PLETH l, PLETH r represent? What methods does PPG use? Is the PPG using the reflective method or others?

alistairewj commented 5 years ago

Left, right, left, right.

Reflectance isn't used. It doesn't work.