IHE PCD – Use Cases

Patient Care Device Controls – Frequency Response "Spectrum"

Rev1 14Dec05 JW

• Based on ISO/IEEE 1073 .0 (P.1.1 RF Wireless Guide) .1 (.1.1 Nomenclature, .2.1 DIM) .2 ( P.3.1 Remote Control Pkg) for representative variety of control types

• Adapted relational DB from IEEE 1073 “Demo” project• Used for VS Monitor/Infusor/Ventilator “Demo” project (2002-3)

• Adapted for ORF harmonization (2004-5)

• Adapted for CAN harmonization (2005) based on recently developed “Injector” application/standard

• Generated Ctls Freq-Response graphics from spreadsheet tool, sorting on decreasing latency then increasing frequency [inter-Control period] based on single PoC use context

• latency estimates may need to be empirical based on accuracy rqmts• other data types, scalability, network type, fault-tolerance, etc., may need to be modeled

Methodology

Figure 1. Variations in Effective Throughput

In this model, various classical data types are modeled message sequences from transactions that occur stochastically. In this model, for example, a “Near RT” Wave” transaction is a continuous, periodic process, typically generating several-to-tens of packets per second (Pps), while a “Chart” transaction is an intermittent, aperiodic process, typically generating a burst of graphical, tabular data as the user opens or scrolls through the patient flowsheet. Fault-tolerance is modeled by including nominal bit error and packet retry rates, characteristic of RF wireless networks.

Source: IEEE P1073.0.1.1 “RF Wireless Guide” project “UseMatrix.xls”.

Figure 2. Variations in Control Freq Response

Low-latency variations

Effect of scaling up is higher effective

frequency of LAN-based “remote”

controlsRelatively hi-

freq, low-latency

machine-machine controls

Table 1. Related attributes for Controls messaging

Retries tend to increase latency constraints and complexity, esp.

on WLAN

Various medical device-sourced or –destined [remote]

controls

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