Liberating medical device data

for clinical research

An architecture for

semantic and temporal harmonization

Assistant Professor Anesthesiology & Critical Care Medicine The Johns Hopkins Medical Institutions Baltimore, MD 2224-2760

IEEE Senior Member & CTO & VP Clinical Applications Nuvon, Inc. 3624 Market St., Philadelphia, PA 19104

Application Development Engineer Nuvon, Inc. 3624 Market St., Philadelphia, PA 19104

Rafael Richards, MS, MD John R Zaleski, PhD Sameer Peesapati, MS

Introduction: The State of Device Data

2

Medical Device Data: The Problem

3

Medical device data are trapped in silos

Unique Protocols

Unique Physical Connectivity

Unique Clock Times

Unique Time frequency of output

Unique Terminology

Differences must be harmonized before data can be

used

Introduction

4

We present a tool that:

Liberates device data

Integrates data from multiple devices

Semantically and temporally harmonizes data from as

many as eight medical devices connected to a given

patient

Data are delivered to the clinical investigator in

multiple formats

CSV (spreadsheet) or HL7

Architecture

5

Data collection appliance (DCA) Each DCA can be connected to as many as eight patient physiologic

monitoring or therapeutic medical devices. DCA can be remotely accessed via hospital network to select

parameters and frequency of collection from devices connected to the patient.

Data aggregation gateway (DAG) DAG orchestrates integration of data of from multiple patients Filters and synchronizes data such that it can be easily stored in a

data warehouse (DW) or EMR.

Management Server (MS) Orchestrates coordination of data between each bedside and DAG. Functions include time synchronization of all devices at all bedsides

to a single universal clock, and use of a standard dictionary to harmonize terminology.

Nuvon VEGA Server

IDM-MG 3000

IDM-MG 4000

Enterprise Clinical Information Systems /Electronic Medical Record Systems

IDC

NativeData

NativeData

NativeData

NativeData

IDM-SpecificHL7 Data

HL7 Data

Infusion Pumps

Physiological Monitors

Ad-Hoc Vitals Monitors

Mechanical Ventilators

Nuvon VEGA Server

IDM-MG 3000

IDM-MG 4000

Enterprise Clinical Information Systems /Electronic Medical Record Systems

IDC

NativeData

NativeData

NativeData

NativeData

IDM-SpecificHL7 Data

HL7 Data

Infusion Pumps

Physiological Monitors

Ad-Hoc Vitals Monitors

Mechanical Ventilators

DAG & MS DCA

Nuvon VEGA Server

IDM-MG 3000

IDM-MG 4000

Enterprise Clinical Information Systems /Electronic Medical Record Systems

IDC

NativeData

NativeData

NativeData

NativeData

IDM-SpecificHL7 Data

HL7 Data

Infusion Pumps

Physiological Monitors

Ad-Hoc Vitals Monitors

Mechanical Ventilators

.

.

.

Physical Architecture

Devices

DCA Device DAG

MS

Clinical

Information

System

CSV or TXT

HL7

Device

Drivers`

Network Time

Server

Logical Architecture

monitoring

Data file

push polled

Configuration

8

DCA is accessible via its web page through laptop of DAG

Through this web page, parameters may be included or excluded from offered set (or completely replaced relative to the offered set).

Note that parameter description, its code, and units of measure are defined at this level with respect to specifications of manufacturer.

At DAG it is possible to alter parameters

Common codebook allows parameter semantic synchronization so that user can receive these parameters in unified codes that are desired by user

Parameters are synchronized in time for output so all data from single patient aligned with one UTC time increment

Time Synchronization

9

Each device collects data in accord with its own time clock. Data are aggregated and are written out synchronized to

a single clock at DAG.

Each medical device has a separate clock—not synchronized with any universal clock or with each other.

Each medical device is polled at a separate frequency.

As data are collected on each DCA, these clocks are aggregated locally: that is, data are packaged for transmission to DAG along with DCA time stamp—UTC.

Finally, on DAG, times of individual devices are synchronized according to a universal, UTC-based clock.

Medical Device-1

Medical Device-2

Medical Device-

M

.

.

.

…

DCA DAG

Network Time

Service

UTC UTC

Text

EMR

10

Obtain Device

Measurements

RkRkRk ttt

RRk tt RRRk ttt and

kkk ttt

PCD k = 1 Output Auto poll

DCA DAG

(end of flow) (start of

data query)

)( kk tx )( RR tx

RRR ttt

0ttk )( kk tx

Rkk tt RkRkk ttt and

Output PCD

Measurements such that

Output PCD

Data such that

)( Rkk tx

Aggregator Manual frequency

Obtain Device

Measurements

RkRkRk ttt kkk ttt

Auto

(start of

data query)

)( kk tx0ttk

)( kk tx

Rkk tt RkRkk ttt and

Output PCD

Measurements such that

Manual PCD k = 2

.

.

.

Obtain Device

Measurements

RkRkRk ttt kkk ttt

Auto

(start of

data query)

)( kk tx0ttk

)( kk tx

Rkk tt RkRkk ttt and

Output PCD

Measurements such that

Manual PCD k = M

Time Sync Process

11

Device 1 Reporting Time

Device 2 Reporting Time

Device M Reporting Time

.

.

.

Common Reporting Time

tR

tR1

tR2

tRk

Selecting Common Reporting Time

12

Device 1 Reporting Time

Device 2 Reporting Time

Device M Reporting Time

.

.

.

Common Reporting Time t0 t1

tR

NULL

Reporting When No Data Exist

13

Terminology Synchronization

14

Master codebook is stored on DAG. Updated by driver specifications of each device and is modified

and maintained within DAG in data file format. It is modified by user to user-defined specifications. Dictionary is linked to individual device dictionary through

codebooks that map the device-specific parameters to a common codebook.

Devices have their data vectors mapped to common unified codes representing specific data elements within master codebook. Parameters from each device may be mapped to common unified

codes within codebook. Therefore, this codebook establishes a common dictionary of

terms that are then written out to file or as HL7 messages to end user clinical information systems.

Medical Device-1

Medical Device-2

Medical Device-

M

.

.

.

…

DCA DAG

Network Time

Service

UTC UTC

Text

EMR

Parameters:

Device-1:

A1, A2, A3, …

Device-1:

B1, B2, B3, …

Device-1M

M1, M2, M3, …

Master Dictionary:

A

B

C

D

E

F

.

.

.

A1

A2

A3

…

B1

B2

B3

…

…

M1

M2

M3

…

15

HR

SpO2

NBPs

NBPd

NBPm

ARTs

ARTd

ARTm

CO

PVC

etCO2

…

HR

SpO2

fR

Mve

Tve

fRe

PIP

etCO2

…

HR-ECG

NBPs

NBPd

NBPm

RR

MVe

TVe

Device 1

Device 2

User-Selected Mapped Output

SpO2-1

SpO2-2

HR-SPO2

User-defined Mapping

16

Terminology Sync

17

cbcb xxx

Rx

Y

cbx~

nullxcb

cbcbcb xxx

U

cbcbcb xxx~~

U cbx~

N

User defined Auto defined` Input

Output Union

Data Output

18

Output data are written to a comma-delimited

format file in a local directory on the DAG laptop.

Data between the DCA and DAG are constructed

using three separate elements

(1) Patient Info Table;

(2) Param Header Table;

(3) Param Values Table.

Device 1

Device 2

Patient Name(32)+0x2c Patient ID(32)+0x2c Bed Location(32)+0x2c Device Name(32) +0x2c 0x0d 0x0a

Parameter Header:

DCA_TS + 0x2c Chosen Device Parameter Codes and separated by comma (n*paramlen+(n-1) 0x2c(commas)) 0x0d 0x0a

Param Values: This is the protocol for each MSH Segment—

DCA_TS_value+0x2c Chosen Device Parameter Values (n*value_len+(n-1) 0x2c (commas)) 0x0d 0x0a

…N Parameters

Patient

information

from ADT

(optional)

Parameter

selection and

periodicity of

measurements

DCA DAG

CSV FILE +

HL7

19

CSV Output

20

Time measured from start of data collection (seconds)

CSV Data Plot

21

Time synchronized

Conclusions

22

A tool has been developed that acquires all data from up to eight patient care devices connected to a patient

Tool semantically and temporally harmonizes and generates a readily useable spreadsheet of time synchronized data that can be imported to any statistical analysis software.

This tool should greatly enhance the capabilities of clinical investigators to do physiologic research.

Nomenclature

23

PoC Point of Care: physical location at bedside proximity of patient.

DCA Data Collection Appliance: physical device containing 8 serial ports that

communicates with the medical devices at the point of care.

DW Data Warehouse: repository for locating, storing, and retrieving data.

EMR Electronic Medical Record: ―a longitudinal collection of health information

in electronic format for and about persons‖ – derived from the 2003 IOM

Patient Safety Report.

DAG Data Aggregation Gateway: the system component that receives

disaggregated patient care data from DCAs and aggregates, formats,

synchronizes and harmonizes these data for communication to an EMR or

for writing to a DW or a file.

Nomenclature

24

MS Management Server: software that maintains a repository of device

drivers used by the DCA to communicate with medical devices; maintains

a web server that enables viewing individual DCAs and DAG through Web

pages; manages a database server and receives health and status of

DCAs and DAG for presentation in a web dashboard to facilitate general

management and oversight of the system.

HL7 Health Level Seven: a non-profit organization that maintains a collection

of interoperability standards associated primarily with data communication

and interoperability of healthcare systems.

ORU^R01 Observation Request-Unsolicited Results Transaction: one of

several HL7 formatted transactions used in standard practice to

communicate observations such as measurement data obtained from

medical devices.

WiFi Term used to describe wireless communication.

RJ45 A registered jack connector and wiring pattern normally used for

connecting computers and similar appliances over high-speed networks.

Nomenclature

25

O/S Operating System: based set of programs that operate the hardware of

a computer hardware resources.

PACU Post Anesthesia Care Unit: an area within a hospital that typically

adjoins the surgical area in which patients are moved to recover from

the effects of anesthesia.

MB MegaByte: 220 Bytes or 1048576 bytes.

DB-xx Designation of port connectors for attaching devices serially to

computers. Common connectors are DB-9 (9 pin serial connector, either

male or female), DB-15 (15 pin connector), etc. These connectors are

used to interface RS-232 connections with said computers.

UTC Coordinated Universal Time: is a time standard based on international

Atomic Time.

XML Extensible Markup Language: a standardized and flexible mechanism

for sharing information formats following a format standard designed for

Web-based documents.

Vector An array of scalar values with each value representing a different

attribute of a unique object, with device and UTC time stamp appended.

Medical

Device

Software

functions

DCA

Proprietary

(RS232)

Text

(TCP/IP)

Database

DAG,

MS

NTS

Symbols

26

control

(TCP/IP)