ROSC time & TTM

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Jul 4, 2023, 10:48:33 PM7/4/23
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Dear Challenge Organizers,

I would like to inquire about the method for determining whether we have recordings exceeding 72 hours after ROSC for a particular patient. Upon reviewing the PhysioNet website (, I noticed that the start and end times in the EEG header files are indicated as the time after cardiac arrest rather than ROSC. This has left me somewhat confused. Does this imply that the "ROSC time" is equivalent to the "time of cardiac arrest"? If not, I would be grateful if you could clarify how we should ascertain which files extend beyond the 72 hours following ROSC.

Also, how should we interpret "NaN" values in relation to targeted temperature management (TTM)? Do these indicate missing values, signifying the absence of available TTM data? Or do they suggest that no TTM procedure was performed?

Thank you again for all your efforts,

PhysioNet Challenge

Jul 4, 2023, 11:09:52 PM7/4/23
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Dear Morteza,

Thank you again for your kind words.

Our clinical partners have described these times as the time after cardiac arrest. However, practices vary from institution to institution, and the times are often estimates. We may have described these times somewhat interchangeably at times because, for most patients, the time between the onset of cardiac arrest and the return of spontaneous circulation is a matter of minutes, so the difference between the two time points is usually relatively small compared to the hours of monitoring. Our clinical partners may respond to clarify, but I would not be concerned about the difference.

Regardless, when we are describing the times of 12, 24, 48, or 72 hours after cardiac arrest or ROSC, we are describing the start and end times in the WFDB header files. We have split the recordings into segments so that each recording segment ends at the hour, or at the end of the recording, whichever happens first, which should make it relatively to identify recordings that extend beyond 72 hours.

The NaN values for targeted temperature management (TTM) indicate either that no TTM procedure was performed or that we don't know if a TTM procedure was performed. Unfortunately, we do not have additional information that allows us to distinguish between the absence of TTM or the absence of information about TTM.

(On behalf of the Challenge team.)

P.S.: I mistakenly posted this response to another thread, so apologies if you receive this response twice.

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