Phoenix Ambulatory Blood Pressure Monitor Project
10/14/2007 Meeting Notes



Requirements Layer-by-Layer by Chris Adams

Component Model
- Review

Data Analysis
Software Subsystem
The requirements have changed based on the information form last week's presentation on the Piezo-electric film project.

Architectural Onion
* Body
* Data Acquisition
* Measurement (new)
* Data Transport Layer
* Measurement Chain: (renamed from Session Management)
collection of data acquired from the device, the make up of a time series, plus the ability to recombine a time series.
* Analysis
* Tool Integration: a way of exchanging data between different tools, like multiple analyses
* Plotting and Charting: (graphical representation of the time series)
* Reporting: assemblage of the charts and text into a report.
* Session: basis u=on which we store reports, plots and measurement chains; an encapsulation of a set of work. Session starts when patient walks into the office, and ends when the patient walks out of the office. The session encompasses the period when analysis occurs.


Data Acquisition (DAQ)
(some of the data access layer has movement to the measurement layer).

* More digital signal processing
* Convert signals/events to measurements.
- One sensor may produce multiple measurements
- One measurement may require multiple sensors
* Stamp each measurement with:
- Time
- Trustworthiness
-- Good vs. bad
-- Extend to which the measure reflects reality

-- Same as accuracy?
Subject to calibration
* Flexible framework for sensor configuration that varies by
-- Sensor technology
- Biophysics
- Target measurements

Acquired Data Alarms
* Sensor analysis of acquired data
- Compare measurement to limit
- Limited by user-specific
* Respond to limit violation
- Categorize violation
-- Caution
-- Warning
-- Alarm
- Tag measurement
-- Alert user or other subsystems.
(Requirements for acquired data alarms are expected but not yet identified)

We separated Data Acquisition from Measurement because it isn't clear how much we can put into the wearable subsystem. We've decoupled data acquisition from measurement and therefore decoupled measurement from device design. Now we can s tore waveforms.

A key question is whether the measurement layer is in firmware or software. The implications are in how large the software kernel, specifically the memory size. It could affect the requirements for the data transport layer.

Data Transport
* Communications with device
* Framework for multiple transports
- RTF, Bluetooth, serial, USB
* Open protocol.
* Integrity assured.
* Source authenticated.

We have not made the decision to retain the wave form, making that decision based on the five parameters of classic project management: (cost, schedule, quality, staffing, functions).

What does the open protocol standard carry, blood pressure measurements or waveforms. DAQ XML. listed on an MIT website, of XML standards.

Measurement Chain
* Data Chain
- a forward and backward linked list of data items each associated with a pointer to the next and sometimes also too the previous one.
* Measurement Chain
- Data Chaining Representing A Time Series
-- Measurements, not signals.
- Corresponds to a data uploaded.
-- From a device to an analysis workstation
-- During a single connection session.
* Need
- Handle sequences of data independently of capacity of data acquisition device.
- Current requirement = 7 days of data
- Longer cycles are in play

Measurement Chain
User can align overlapping chains.
- Duplicate data items, uploaded multiple times.
* User can link chains into super-chains.
* User can split chains into sub chains.
* System analyzes any data sequence.
- Super-chain
- Sub-chain.

(which layer cares about HIPPA?)
Do the elements of a chair

Open Source Work Group for the American Informatics Association.

Once someone collects data on you, then publishes it on a website, who owns it?

HIPAA only deals with covered entities. Specifically those covered by medical insurance. Transmission of information between health providers and insurance firms. A third category are clearing hoses which are not covered by either. Would you trust Microsoft (or Google) with your health data.

In the context of HealthVault and similar PHR systems, which are not governed by law.

Will my data be off shored and therefore subject to no US law?
* Will my data be merged with other non-health related information Microsoft collects about me?
* If read/write authority is granted can the grantee give read/write authority to my data?

From Liam Gray on 10/09/07
My medical information, protected by HIPAA ,w as stolen by my physician's staff, yet nobody was prosecuted and no charges were even filed, even though the detective complemented me for cracking the case myself. In fact, hardly anyone, perhaps nobody at all, has been prosecuted under HIPAA, to d ate.

Gmail isn't protected by HIPAA, either. However, Google has kept my Gmail private. In fact, Google even resisted a federal subpoena. Thus I'd rather store my health records in Gmail, Hotmail than in my physician's office. Thus if Google or Microsoft builds a health records database, even if no more secure than Gmail or Hotmail, I will regard technical security as more meaningful than the legal fiction of security.

Gerry noted that many physicians don't use the patient record because it is outdated so easily, so they collect new data instead that they trust. So, if we are putting so many requirements around an entity of questionable value, perhaps the practical response is to not use it.




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