MIMIC-III Matched: how to match numeric to waveform data

[PatriciaBota]

I am only considering files with PPG data in .dat file (e.g. p00/p000333/3092245_0040.hea), how can I match the PPG with the numeric SpO2 in e.g. 3092245n.dat?

The PPG and SPO2 have different lengths, even when accounting for sampling rate differences.

Is there any time reference I can take into account to know the file 3092245_0040 PPG time collection to match the SpO2 data in the numeric file 3092245n.dat?

Thank you very much.