Many medical devices are restricted to RS-232 communication, and will remain so for some time to come. That doesn't preclude them from being networked.
Some newer medical devices have Ethernet ports that provide communication through either fixed or dynamic host configuration protocol (DHCP) settings. Therefore, they can be attached to an enterprise LAN.
Ethernet communications can work well for the newer medical because they connect to hospital LAN or over a virtual LAN (VLAN) and are thus Internet-ready. Using a VLAN ensures data privacy and security between the medical device and an electronic medical health-record system.
In my first book, one of the topics I covered -- still relevant today -- is the network-enablement of medical devices. Figure 1 illustrates one of those devices: a Moxa Nport serial-to-Ethernet converter. I illustrate ad-absurdum that some devices that should be easy to connect to the enterprise could require extraordinary measures using off-the-shelf hardware.
Figure 1 MOXA NPort Serial-to-Ethernet Device (Reference: Integrating Device Data into the Electronic Medical Record, Page 43)
Figure 2 is one such attempt. A consumer glucometer, often used for home management of diabetes mellitus, is attached through its proprietary serial cable to a serial-to-Ethernet converter. Many of the devices on the market for accomplishing this task, however, were not specifically designed for medical applications. While they can accomplish the task in terms of raw data translation, other mandated requirements exist for appliances placed in the proximity of patients. Not all medical devices automatically satisfy these requirements.
Figure 2 MOXA Nport configured to communicate to a consumer glucometer (LifeScan) via NPort appliance.
For example, IEC 60601 is a series of standards specifying safety requirements of medical equipment. Over the years, a number of manufacturers have evolved (including the author's own company) that manufacture devices for translating data from serial to Ethernet. They transmit data on the enterprise network and make those data accessible. Figure 3 illustrates one such unit that meets IEC 60601-1 and UL requirements on placement at the bedside for use in medical device data collection.
Figure 3 Nuvon Device Manager connected to a GE Dash 5000 monitor within a post-anesthesia care unit (PACU).
The unit shown here contains eight serial ports that receive serial input through RJ45 serial adapters communicating over standard Ethernet cables to the appliance. Data are translated into a format suitable for communication over either wired or wireless LAN. This approach lets medical devices otherwise constrained by the physics of their design or by limitations in the environment to communicate to an existing healthcare enterprise.
What sorts of network connectivity issues have you had to deal with?
Editor's note: This blog was originally posted to EDN.