Phoenix Ambulatory Blood Pressure Monitor Project
6/26/2005 Meeting Notes



To introduce the Phoenix Project to our new members, El summarized the overall project goal, Dave summarized the hardware projects and Chris summarized the systems engineering requirements and software projects.
Chris discussed the subsystems, especially the diary.
- Germaine added that user baseline information that is collected needs to include: gender, age, medication,
SOAP: subjective (diary), objective (initial information about the patient), Assessment, Plan.
History: history of present illness, daily progress notes include the phenomenon and other. Then, the analysis program needs to be able to deal with multiple profiles, each of which is a contiguous measurement sequence that begins at one time and ends at another time. The reference values from one profile can be used or updated to other profiles for the same person. Or reference data may be updated for the entire system.

Chris noted that patient medical history is outside the project scope, but we need basic patient identification information.
Gerry noted that much of health informatics lately has been organized around Health Level 7, HL7. We would like to learn more about HL7 so that we can determine which of the interface specifications are relevant to us, to which we need to comply, and how it will help us determine how to organize our information.

Chris will identify what of HL7 we need to know and report back to us.

Chris noted that new reference data may be available and the clinician determines when to update.

John asked if we could interface a generic analysis program so that we don't have to develop it. Germaine said that A&D produces their own which must be installed and de-installed after every use. So we concluded that we must develop the analysis program. Much of the analysis the Halberg Chronobiology Center performs is done within their own DOS-based program that was originally written in Fortran and is available to us. Post-analysis is done on Excel. We'll need to perform the same analysis within the data analysis portion of Phoenix.
Chris asked what Phoenix must do and what it does not need to do.

Then, we discussed what is the minimal information Phonenix could produce that would be useful. Establish that as Phase 1, then add another phase that extends it. It needs to identify the patient, and identify the values (Patient ID, HR, BP, x3, x4, diary value, time). Furthermore, it must be comparable to the Sphygmometer measurements for BP, therefore it should have been calibrated before and after.

Chris identified six applications needed in the local (wearable) subsystem:
1. Clock
2. Diary
3. Device status
4. Biometrics (display)
5. Data acquisition
6. Data transfer

The sampling interval may vary during the measurement.
In more detail:
1. Clock: for diary recording, time, not date but not display, time stamp format is: yr, mo,day,hr,min.
Bob said we don't want to confuse: accuracy, resolution and interval. The interval is one minute. Currently, the A&D ABPM takes around two minutes from the time it begins to take a measurement and the time it displays the result. The intervals are in increments of minute.
Bob notes that non-sphygmometer devices typically provide measurments every heart beat, approximately every second. Therefore, we think that the sample rate would occur everry 10-20 msecs, or precision = 1.
Gerry noted that sampling Beat-to-beat may occur at 300 beats per minute during tachycardia or arrhythmia. Or 300 beats per minute x 25 samples per cycle = 7500 samples per minute. Timestamps will include data, timestamps in UCT, localized display, time, date and timezone are set a initialization, 10 v per meter (FDA guidelines for EMC). We discussed where there are requirements to endure an MRI measurement and Chris noted that there are MRI requirements for pacemakers. Bob said that meant that the pacemaker would not be pulled out of the chest by a 1.5 Tesla field. Chris noted that we should consider these requirements and document how we made the decision.

We will meet next at 7/10, but not the 7/24 Sunday. Similarly we will meet 8/14, but not 8/28.



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