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S9 Data Format

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ResMed Data Format (excluding S8 models)

This page was originally written by Mark Watkins, during the initial build of the SleepyHead program. It needs change in approach, or should be taken as "history".

Data format analysis

Grade: C (extra points awarded for being open)

Negatives

  • Only keeps basic summary data when the card is left out. NO graphs.
  • Unnecessarily deletes high-res flow waveform data after 7 days, all other graphs after 30 days.
  • Summary does not contain settings info for each session, only once per day, according to ResMed split, which is not suitable for night-owls.
  • Evil SDcard "drift" problem, which causes Events to NOT sync well over flow waveform. Needs a regular card format to work around this.
  • Bloaty data format.

Positives

  • Manufacturer chose to use an industry-standard data format.
  • Reasonable assortment of data available, and at a decent resolution.

Data Format

ResMed chose an intelligent and sensible approach when designing their machines, they used an industry standard. (Thankyou ResMed for showing common sense!)

EDF+ Format
ResMed uses the European Data Format Plus format. This format is documented here. It is rather verbose, but sensibly designed.. The Event Annotations are a little tricky.

ResMed SDCard Folder Structure

[DATALOG]            Folder containing all the session data
[SETTINGS}           Folder with machine settings
Identification.crc   Checksum info
Identification.tgt   Machine identification data
Journal.dat          tbd
STR.crc              Checksum info
STR.edf              All overall summary information

Analysis of folders and files

Identification.tgt

This file holds an extensive number of data and parameters of the machine. These are shown here in the same fixed order as in the file.

Code Remark Explanation Example
#IMF All later models TBD #IMF 0001
#VIR All later models TBD #VIR 0064
#RIR All later models TBD #RIR 0064
#PVR All later models TBD #PVR 0064
#PVD All later models TBD #PVD 000F
#CID All later models TBD #CID CX040-044-018-015-100-100-100
#RID All later models TBD #RID 0012
#VRN Only S9 Models TBD #VRN 20142455118
#VPC Only S9 Models TBD #VPC 3688P
#NID Only S9 Models TBD #NID 0001
#VID All Models TBD #VID 002C
#SRN All Models Serial number #SRN 22182060837
#SID All Models Serial ID? #SID SX584-0201
#RID Only S9 Models TBD #RID 0064
#PNA All Models Part Name #PNA Lumis_VPAP_150_ST
#PCD All Models TBD #PCD 28328
#PCB All Models Printed Circuit Board number? #PCB (90)R280-776(91)T3(21)89180702
#MID All Models TBD #MID 0028
#FGT All Models TBD #FGT 28_M40_V44
#BID All Models TBD #BID SX585-0100

DATALOG Folder

The main data is stored in 4 EDF files per session, with each file name consisting of a date, time, and type, followed by .edf

There is also a .crc (checksum) file for each of the above, but they are not needed to parse the data.

Example

20110601_021922_EVE.edf
(date)_(time)_(type).edf

The 4 File Types

Type  Details
EVE    Event annotation data
BRP    High resolution graph data 
SAD    Pulse oximetry data
PLD    Low resolution graph data

File Type Notes

Note: Some foreign language machines use a different set of signal codes in the EDF data.

EVE Event Annotation Data

The S9 series flags the following events:

  • Hypopnea
  • Apnea
  • Obstructive Apnea
  • Central Apnea

BRP High resolution graph data

Code            Details                        Units                            Notes
"Flow"          Flow Rate                      ?
"Mask Pres"     High-res Mask Pressure         cmH2O
"Resp Event"    Respiratory Event              ?                                VPAP

SAD Pulse Oximetry data

Code            Details                        Units                            Notes
"Pulse"         Pulse Rate                     Beats per minute
"SpO2"          SpO2 (Oxygen Saturation)       % Saturation

The oximetry device that records this information is hideously expensive, notoriously unreliable, and ResMed should be ashamed for releasing it.

PLD Low resolution graph data

Signal List

Code            Details                        Units                            Notes
"Snore Index"   Snore Index                    ??
"Therapy Pres"  Therapy Pressure               cmH2O
"Insp Pres"     IPAP / Inspiratory Pressure    cmH2O
"MV"            Minute Ventilation             ?
"RR"            Respiratory Rate               Breaths per Minute
"Vt"            Tidal Volume                   ?
"Leak"          Leak Rate                      L/Second (I convert to L/Min)
"FFL Index"     Flow Limitation Index          ?
"Mask Pres"     Low-res Mask Pressure          cmH2O
"Exp Pres"      EPAP / Expiratory Pressure     cmH2O
"I:E"           Inspiratory : Expiratory Ratio ?                                VPAP
"Ti"            Ti??                           ?                                VPAP
"Te"            Te??                           ?                                VPAP
"TgMV"          Target Minute Ventialation     ?                                ASV Machines
""              Unknown Empty                  ?
""              Unknown Empty                  ?

most ? fields are known, I just have to look them up again..?? fields really are unknown (to me).

The two empty signals always appear at the end. not entirely sure of their purpose.

SETTINGS Folder

The Settings folder holds a number of log (.log) files and settings (.tgt) files, each with its own .crc (checksum) file.

STR.edf File

This file contains a summary database in EDF format. It contains things like AHI indexes, 95% values, etc...

There is only one copy, in the root directory of the SD-card, and it is updated at the end of a session.


Most records contain one entry per day.

SleepyHead doesn't need much of it, as it provides it's own indexing..

It does contain some data not available elsewhere, most notably EPR data.

ResMed S9 Storage Gotchas

The S9 continuously erases older data to keep the card from overflowing:

  • BRP data older than 7 days.
  • PLD data older than 30 days.
  • Everything older than 365 days.

Regularly backup copies of your SD card to work around this!

SleepyHeads Implementation

SleepyHeads EDF parser and S9 importer has been written from scratch

It consists of two parts

  • A generic EDF parser class named EDFParser
  • and the custom S9 importer class named ResMedLoader

It is implemented in SleepLib/loader_plugins/resmed_loader.cpp / .h

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