Phoenix Ambulatory Blood Pressure Monitor Project
10/28/2007 Meeting Notes


Attendees

Discussion

* Chris: considering Lean Design
* Larry Beaty, next step, implement Daily Sphygmochron's and put them on a website for Germaine's colleagues to use.
* Dwayne: Made a quick plot for Germaine.

 

Requirements Layer-by-Layer by Chris Adams

Component Model - shifting from an "onion model" to a "block model".

Component Model]
Added
* Person Identification System

Architectural Onion
*Changes: Introduced Time as its own layer. It is important and crosses over many different layers. Such as clocks, time zones, timestamps, session times and dates, data is acquired at specific times, analysis, and people times.
* Layers
- Body
- Signal Acquisition
-- 1)
--- Measurement
--- Time Series
--- Analysis
--- Plot/Chart
--- Report
--- Session
-- 2)
--- Data Transport
--- Tool
- Time
- Outside
-- Desktop
-- Person Identity
-- Clinical Health Record/ Personal Health Record.
-- Networking
-- Change Management

Signal Acquisition
* No longer assumes that we've converted signals into measurements.
* Frameworks where one sensor might produce multiple measurements. Or multiple readings from sensors may be needed to gain a single measurement.

Data Transport
* No change here. A framework that supports multiple transports.

Measurement
* Changes:
See: Analysis Patterns, by Martin Fowler. Specifically, his model of measurement, observations, protocols, dual time records, measurement protocols.
* Good vs. Bad
- Signal vs. noise. Or accuracy vs. dispersion.

Acquired Data Alarms
* Changes: added
-- Able to incorporate 3red party alarm subsystem
-- Deactivate-able

Time Series
* - Concept: a seque3nce of data points
-- Measured typically at successive times
-- Spaced at (often uniform) time intervals
* Measurements,
* Acquired Series
- Concept: Time Series corresponding to data uploaded
-- From a device to an analysis workstation
-- During a single connection session.

Time Series
* System analyses any data sequence
- Super-series
- Sub-series

Individual Analysis
- SBP-DBP-HR-Blood Flow
- MESOR
-- Circadian amplitude
- Circadian Acrophase
- 2430hour cosine curve by least squares (cosinar analysis))
Special sampling period requirements.
- Marking of:
-- Overswing
(circadian ampl. > upper limit of 90% of reference set)
-- Underswing
(circadian ampl. < lower limit of 90% of reference set)
-- Dipping
* SBP|DBP
-- Hyperbaric index
* Arterial compliance (future?)

We discussed Jim Holte's comment that SBP and DBP are artifacts of the cuff and sound (Korotkoff) process. This may change and we need to allow for that. Perhaps we should capture the entire plethysmograph.

Requirements:
1. Measure blood pressure
2. The user can determine it.

Population Analysis

Plotting/Charting
* Types of plots
* Multilayered
* Varied resolution
* Annotations

Being able to detect no signal is different that being able to detect no data. Our process requires that there be signal in order to detect.

Reporting
* Form-like reports
* Flexible
* Incorporate
- Charts & graphs
- Tables
- Free-form text.

We discussed whether we wanted to enable saving the entire waveform. Two outcomes emerged: No - we want minimal memory requirement, so we want to save only the peak (SBP) and valley (DPB). Yes - we need to save enable saving both, because the test system will need it to validate that we are calculated it properly, so it should be an adjustable parameter that the typical user doesn't use, but can be used by an advanced user. The question is whether we can dump the 40 samples per second (or doubled to test impact of resolution) to extended memory quickly enough.

 

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