Introduction to Computerized Medical Instrumentation

Module M50c

About this Document | Audience and Objectives

Contents

What Are Computerized Medical Instruments?

Computerized medical instruments are:

Two Types Of Computerized Medical Instruments

There are two primary types of computerized medical instrumentation:

Standalone: Computerized instruments designed to operate on their own, without being connected into a larger computer network.

Networked: Computerized instruments designed to operate as part of a network, feeding information to other locations and/or receiving information and commands through the network.

Standalone Computerized Instruments

There are many types of standalone computerized instruments. Most evolved from simpler, non-computerized devices which are still available - for example, the simple thermometer and sphygmomanometer. Some of these devices, like the two just mentioned, were first electrified and then computerized; others started out as electronic devices without "brains" and evolved into computerized devices. The electrocardiograph is one example. Still other types could not have existed before computerized processing; the ultrasound is such a device: practically speaking, only a computerized device could interpret the sound waves and produce an image as a result.

Here are a few examples; but note that many more are not listed, and new ones are continually being developed.

What Are They?

Here are some examples of standalone computerized medial devices: So how do you recognize a computerized standalone instrument?

Why Instruments Are Computerized

You may wonder why so many instruments are being computerized now. There are a variety of reasons, including:
 

Improved accuracy

Microprocessors provide greater control over the measurements and dosages than mechanical or even electrical circuitry. A simple example is the infusion pump, which can be set to deliver any desired rate of flow, and maintain it accurately. With a simple IV mechanism, on the other hand, flow must be estimated by counting drops-per-minute and calculating using a chart to arrive at the correct rate of delivery; once the flow rate is set, a movement of the patient's arm or a twist in the tubing may change the flow rate, all of which lead to inaccurate delivery of the medication.

Greater flexibility

Even when the tasks the instruments perform don't require the "intelligence" of computers, the fact that they can be controlled by programs makes it possible to have the same microprocessor chip do many different tasks. For example, one chip can be programmed to record and monitor temperature, pulse, respiration, blood pressure, blood oxygen saturation level, and many other measurements. Before microprocessors, electronic devices to record these diverse measurements were far more complicated to build and maintain.

Added "intelligence"

Machines that are "smart" can save lives, even compared with earlier electronic equipment. Computerized cardiac monitors can detect the difference between genuine cardiac anomalies and artifacts caused by patient movements; between cardiac arrest and a patient whose leads have come loose. With earlier electronic monitors, these conditions would all set off the same alarm, so that staff would tend to ignore the alarm - not conducive to patient safety!

Lower cost

Although you might think computers would be more expensive than basic electronic equipment, the reverse is acutally true. Microprosessors capable to controlling most standalone medical devices are available for under one dollar each (wholesale). These microprocessors can replace large amounts of complex wiring, saving not only money but space. The result is equipment which is less expensive, smarter, and more compact.

How They Are Used In Caregiving

Standalone computerized equipment is used primarily in two kinds of situation:
  1. Where portability is needed. Infusion pumps and defibrilators are prime examples of these.
  2. Where there is no centralized monitoring system. In hospitals or wards which don't have networking for patient equipment, standalone devices provide many benefits over non-computerized devices, without the added demands of standardization that would have to be met to network the instruments.
Because networking requires that equipment "talk the same language," some standalone equipment may be used even when there is centralized networking. There are also some kinds of equipment that have less of a need for networking, such as an OR anesthesia machine.

The disavantage of standalone equipment is that hospital staff must be in the physical presence of the machine to deal with problems. This may cause a delay in making a needed adjustment.

Networked Instrument Systems

Networking is when computer devices are connected so they can "talk" to each other. An important trend in the computer world is connecting standalone computers so they can share resources and information. This trend is well devloped in hospital systems, and extends to computerized medical instruments as well as computer workstations.

Advantages Of Networking

There are several reasons why it's useful to network instruments...
  1. It enables many patients to be monitored from a central location - typically from a ward's nursing station.
  2. Some equipment can be controlled from a central location. This makes it possible to adjust the devices much more quickly and efficiently.
  3. It enables "smarter" interaction between devices - for example, between a cardiac monitor and a medication delivery device.
  4. When combined with a hospital-wide computer network, it allows staff in all parts of the hospital campus to access critical information about a patient as an event unfolds. For example, a cardiac specialist in his or her office could monitor a cardiac arrest in the emergency room and consult with residents there without having to run to the ER. With the proper connections, this can be expanded to enable:
    1. The specialist at home using a modem to log in to the hospital network; and
    2. Data sent using mobile telemetery from instruments in ambulances.

Uses Of Networked Instruments

Networks of computerized instruments are most common in the "high-tech" areas of hospitals: These are the areas where acutely ill patients are sent, and where response-time to patient events can be critical. In the case of the clinical lab, computerized medical instruments and testing devices are present in large numbers, and speedy communication of test results to other areas of the hospital is important.

As the cost of networked equipment goes down, and experiece with networked systems grows, they tend to be installed in more and more areas of the hospital.

General Organization

The usual organization plan for computerized medical instruments is to install a local area network server, often specialized for networking instruments, in a central location of a small administrative area. Typically, this is the nursing station of a ward, ER, OR, RR, CCU, or ICU. (It may be a computer room or administrative office for a clinical laboratory.) Networking cables are installed to each patient bed or instrument location, with wall plugs for the instruments.

(Figure 1)

Most commonly, the bedside equipment is all supplied by the same manufacturer to ensure compatibility. One master bedside control unit plugs into the network, also providing on-site connections and control for individual instruments (such as cardiac monitor, vital signs monitors, and possibly infusion pumps). These bedside units are sometimes modularized, allowing various types of monitors to be added or removed as needed.

At the central station are one or more control and display units. The central station often has a printer for producing reports and a strip-chart recorder to provide hard copy of patient events. It also has the capability of issuing audible alarms and initiating strip-chart recordings for various types of events, under the control of programs that analyze data from the instruments. The staff can set alarm levels for various measurements, such as pulse rate, oxygen saturation level, temperature, and many others. In addition, patient data (including name and registration number) can be entered at the central station for accurate identification of displays and printouts.

Some instrument networks are separate from hospital local area networks, but the more sophisticated are connected hospital-wide.

How Networked Instruments Are Used In Caregiving

  1. Inservice training in the operation of computerized medical equipment is generally provided at the hospital, using training materials developed by the hospital staff and the medical equipment manufacturers.
  2. On a patient's arrival at the unit, a physician will assess his/her need for monitoring and/or controlled infusion of medication. Orders will be communicated to the staff.
  3. Nursing staff is responsible for proper attachment of the devices to the patient and starting the intravenous infusion. The bedside control and display unit is started, and its connections both to the patient and to the network are checked.
  4. Patient data is entered, usually at the central station. This includes name, registration number, bed location, height, weight, gender, etc. Parameters for events monitored are usually left at default values: normal range of acceptable pulse rate, blood pressure, and so on. But if physician orders or nursing experience indicate a need for different parameters, they are usually entered at the central nursing station as well.
  5. During the patient's stay on the unit, monitoring is carried out by the nursing staff, either at the central station or at the bedside unit. The computerized equipment continuously monitors for values outside of normal parameters, and sounds an alarm at the central station if the values are outside the set limits. Incoming data is analyzed, for example, to discriminate between disconnected leads and real patient events.
  6. Nursing staff are charged with responding to alarms: they need to understand their meaning and know how to set or reset the equipment, as well as care for the patient.

Learning to Use Computerized Instrumentation

Computerized instrumentation often makes your life easier and your work more accurate, but they often require some investment on your part to learn how to use them properly. Here are some pointers about learning to use them...

Your Responsibilities

Like learning to drive an automobile, learning to use computerized instruments promises you speed and convenience. Also like learning to drive, these instruments give you additional power - and with power comes responsibility. Just as you can kill by poor driving, you can kill by poor use of medical devices, whether they are computerized or not.

Here's what you need to do:

  1. When you are first asked to operate an instrument, take the responsibility of finding out how to use it correctly:
    1. Ask a fellow staff member to show you how it works
    2. If you don't feel 100% confident of using it, ask for inservice training
    3. If formal inservice is not available, ask to see a training video
    4. Practice: try it on yourself or on a willing fellow staff member before using the instrument on a patient
  2. When the instrument is upgraded or receives new software or attached devices, again take the responsibility to find out how it works.
  3. If you're not sure how to do something, ask. Don't guess!
  4. Use care in operating the equipment, and be sure to follow instructions carefully.

What to Look for, What to Learn

Every instrument is a bit different from every other. However, with all computerized medical devices, you should look for certain features and learn how to do certain things:

Parts and Components

Every instrument has parts which it's useful to identify. In particular, learn to find:

Things to Learn

Of coure, what you need to learn depends on what the instrument is for. But there is a common set of things you need to know about most instruments before using them:

Summary

There are many varieties of computerized medical instruments, both networked and standalone. They can make your work easier and more effective, but you must first learn how to use them properly.

Audience:

You will get the greatest benefit from this module if you have a general idea of how computers are used in hospital settings; module M01c "Computers in Medicine" is intended to provide this background. It is also helpful to have a general idea what computers are and what they do; modules G01c, G02c, G03c, G04c, G05c, and G06c are designed to give you that background.

Objectives:

When you successfully complete this lesson, you will be able to...

About this document...

Module M50c: Introduction to Computerized Medical Instrumentation

Review:  M50cr
Author:
Laurence J. Krieg
Institution:
Department of Computer Information Systems, Washtenaw Community College
Date:
Original 31 March 1996; this version Tuesday, 17-Feb-2004 12:39:10 EST.
Copyright:
Copyright © 1999, Laurence J. Krieg.
Instructors: You may point to this file in your Web-based materials.
Students: you may make a copy for your personal use.
All other uses: contact the author, Laurence J. Krieg for permission. Email krieg@ieee.org