andrew king, sam procter, dan andersen, john hatcliff, steve warren (kansas state univerty) william...

An Open Test Bed for Medical Device Integration and Coordination

Rohit Nampelli00913835

Andrew King, Sam Procter, Dan Andersen, John Hatcliff, Steve Warren (Kansas State

Univerty)

William Spees, Raoul Jetley, Paul Jones, Sandy Weininger (US FDA)

Old Dominion University

Old Dominion University 2

Introduction

Lack of Medical Device Integration V & V Techniques for Single Systems Developers More Focused on Firmware

Dev—Not “formal” QA Techniques Most Devices Have Connectivity, But Not

Well Integrated Many Commercial Companies Are

Producing Integrated Products—Somewhat Dangerous


Challenges

Choosing Middleware & Integration Architectures to Support Integration

Choosing Programming Models for V&V, Certification, RAD, etc.

Appropriate V & V Techniques Can Existing Regulatory Guidelines be

Extended Innovation of New

Technology—Safe/Effective Interoperability & Security


Medical Device Coordination Framework (MDCF)

Three Contexts› Clinical (Room-Oriented)› Alarm Integration and Forwarding› Critical Care

Flexible Pub/Sub middleware architecture using JMS

Model-Based Programming

5

Context 1: Room Oriented Device Information Presentation

Intensive Care Ward› Several Stand Alone Devices, Each Having it’s

Own Logging/Monitoring Tools (EHR, Billing, etc.)

› Inefficiencies: different interfaces (confusion) physically separated different roles/views separate logs

Old Dominion UniversityContext 1: Room Oriented Device Information

Presentation

6

Context 1 – Integration Solution

EHR DB is Single Consumer –aggregates device data into one place

Heads Up Display—info from multiple devices displayed on Monitor(s) near patient bed

Eg: CareAware uses IBM’s Eclipse Framework› Define “view(s)” based on device



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Context 1– Integration Solution



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Context 1 – Implementation

Requirements› Support different data amounts/rates

Pulse oximeter—updated every 10 seconds Electronic stethoscope—8 kilosamples/second

› Integration of “Data Transformations” Filters, aggregations, etc.

› Allow definition of producers, consumers, transformers

› Provide facilities for validation and auditing› Single Server or Server/Room?



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Context 1 – V&V and Regulatory

Performance› Unacceptable Latencies and Jitter?› Impact of Heightened Activity in Another Room

Security› Private data, unobservable, unalterable

Safety› Redisplay must be faithful to the precision &

presentation of original



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Context 2: Alarm Integration & Forwarding

Devices Produce Alarms › IEC 60601-1-8 Standard—distributed alarm

system Problem of False Positives

› “Smart Alarms” – Fuzzy Logic (reasoning)› Consider: patient body type, weight, history

Eg: pulse oximeter and respiratory monitor Solution:

› Priority/source of alarm › Information signals from monitoring devices› Programmable support to correlate data from many

sourcesOld Dominion University Alarm integration and forwarding

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Context 3: Critical Care Device Coordination

Not just unidirectional flow Automated Agent Control to Communicate

Between Devices Eg: X-ray/Ventilator

› Acquiring chest x-rays from patients on ventilators

› Doctors must turn off Ventilator – Human Error› Automatically Coordinate

Ventilator can identify full inhalation/exhalation Capture x-ray at optimal point

Eg: “Smart Pumps” (fluid infusion)Old Dominion University Alarm integration and forwarding

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Context 3

Integration Solution› Network capable devices (MAC based ID)› DB for scripts written by experts› Allow clinician to choose appropriate script› Script “selects” necessary devices › Script may run uninterrupted or stop for input

Issues› Coordination components as simple automata› Support rigorous validation for regulatory

oversight› Server per Room (too critical)

Old Dominion UniversityAlarm integration and forwarding

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Context 3

Old Dominion UniversityAlarm integration and forwarding


Goals of MDCF

Provide middleware to enable integration of devices from different vendors with minimal effort

Support for common data formats Enable transformation of data streams Support “realistic” device integration contexts Performance/programmability scales Options for guaranteed delivery, logs/audits,

message persistence Script programming from building blocks Infra should be freely available and open source


Goals of MDCF

Standards-based Framework for enterprise-level Support real and simulated devices


MOM Foundation

Messaging-Oriented-Middleware› Based on JMS

Meets the Goals of MDCF› Flexible messaging, open source, enterprise-level, etc.


JMS Primary Objects

Client uses JNDI to get Connection Factory Create “Active” Connection Exception Listener monitors problems If Conn is good, client creates a JMS

Session Session is Single Threaded (serial

delivery)


JMS Primary Objects


JMS Destinations

Dest is “abstract” entity (to/from, pub/sub)

Session creates MessageProducers/Consumers

Client requests a Message, updates it, and sends it using MessageProducer

Clients can add filter expressions Supports diff message formats: text (eg.

HL7) and objects (eg. DICOM images)


JMS Destinations


JMS Message FormatKey-value pairs


MDFC Modules

Device Connection Manager› Listens on JMS channel for desired connections› Assumes every device has JVM› JVM-capable adapter available for non-JVM device

HHSQL (stores device, driver info) Consoles

› Maintenance (allow installation/updates)› Monitoring (flow of events)› Clinician (data visuals, invocation of scripts)

Scenario Manager (manages life-cycle of objects within a script, teardown of objects)


Programming Model

Component-Based Programming› Abstract details of lower-level system› Rapid assembly of integration scenarios

Supports “typed” input/output event ports

Supports multiple categories of comps› Data producers, data transformers, data

consumers


Cadena Framework

IDE Component-based meta-modeling Cadena generates

› Component interface editor … define comp types

› System scenario editor … allocate/connect comps

› Builds executable system “Active Typing”: checks for type

correctness


ICU Scenario Components


OR Scenario Components


CORBA Component Model

Generates Java Skeleton/Container Has all logic required for framework Code “Business Logic” Only Analyzes scenario model; gen xml spec

file› details of the scenario model› location of class files

Reduces Programming errors


Experiments

Baseline› Simple producer/consumer; measure raw perf

Clinical› Asses ability to support typical usage modes

Categories of Data› Device data› Alarm events› Medial informatics (patient, images, drug, etc.)

Parameter settings (rates set to worst-case)


Baseline Configurations

Simple Event Notifications› No payload (10 bytes)

HL7› 313-byte (vaccine)› 2227-byte (adverse reactions to vaccine)› 4312-byte (additional vaccine events)

DICOM› Chest (379 kb), knee (130 kb), shoulder (70 kb)

Connection Topologies› Likely “real world’ setup


Baseline Experimental Results

Th

roughput

(mess

ages)

Producers to Consumers


Baseline Experimental Results

Message Size + Topology Affect TP Larger Message reduces TP rate

(marshalling) Greatly affected by Topology Increasing Producers; limited impact Increasing Consumers; high impact Possibly due to Queue sharing Messages

› Many producers: msgs arrive in Q at once› Many consumers: msg removed from Q and

copy to many worker threads


Critical Care Device Coordination

OR equipped with› Anesthesia machine with integrated ventilator,

ECG, and blood pressure cuff› Large “heads-up” displays (render data)› Transformer (software) preprocessor for ECG› Results (latency) –shows the framework can

support coordinated activitiesWhy so high?


Integrated Displays and Alarms

Large ICU ward with multiple rooms› Equipped with blood pressure cuff, cardiac

monitor, intravenous medicator, pulse oximeter, and ventilator.

› device produces data/alarm› room has monitor to render data› room has a nurse’s station display (subs to

alarms)


Integrated Results

Scales to 20 rooms

Max latency 4

sec

Max latency 3

sec


Conclusions

The Good› Provides scalability› Enterprise-Level architecture› “Solid” performance with open source› Loosely coupled component-model programming

The Bad› Unacceptable performance with persistence

More Work› Expand list of devices› Include wearable, ambulatory sensor-based

devices

andrew king, sam procter, dan andersen, john hatcliff, steve warren (kansas state univerty) william...

Documents

device old dominion

integration of devices

key value pairs slide

multiple devices

necessary devices script

room security private

common data formats

appropriate script script