Monthly Archives: July 2014

Preventive Maintenance (Scheduled Maintenance)

Purpose and Methodology. Scheduled maintenance ensures that equipment previously acquired continues to function

Figure 10. Preventive maintenance cell saver. Depending on the medical instrument, preventive maintenance can be more involved than just a functional and safety test. Problems that are uncovered must be rectified, and some instrumentation requires that compo­nents be replaced due to wear or number of hours of use. This, as well as observed spills, may necessitate opening the unit. The cell saver shown is used to salvage blood shed during an operation allowing its return to the same patient.

properly, has not deteriorated (due to usage and aging), and is safe for use. An attempt is made to uncover and correct problems that have not been reported or of which the user is unaware. Problem correction at an early stage can prevent incidents from occurring.

Testing done during PM tends to be more functionally ori­ented and is not as inclusive as that done during acceptance testing. Equipment that is mechanical in nature is tested to ensure that moving parts are structurally sound. If electri­cally operated, ac safety tests are performed (Fig. 10).

Some equipment requires replacement of parts normally expected to deteriorate with use, such as O-rings, gaskets, and brushes. In fact, some PM (i. e., for dialysis machines and some ventilators) is scheduled not by period (yearly, etc.), but by number of hours of equipment operation. PM kits are ob­tainable from the manufacturer. Other sensitive medical equipment (audiometer) requires extensive calibration dur­ing PM.

PM procedures specifically geared toward each instrument are used, except when the instrument is simple enough that a generic PM procedure can be used. Procedures can either be written in-house or purchased commercially. A PM worksheet keyed to the instrument’s unique identification number is filled out and filed in the equipment’s history folder.

Most equipment is maintained on-site in the user facility or clinical area, while others must be done in the clinical engi­neering laboratories. Precautions should be taken to ensure that the equipment has been properly cleaned and/or steri­lized before work on it is attempted. The infection control de­partment has guidelines on cleaning prior to repair. Notation must be made in the computerized maintenance management system (CMMS) of equipment that is temporarily taken out of service, its storage location, and whether PM must be done while it is stored. The unit should be tagged indicating that clinical engineering staff must inspect it prior to its being put back into service. Clinical engineering’s test equipment used to maintain and calibrate the medical instrumentation must also be periodically checked and calibrated. Certification against standards traceable to the National Bureau of Stan­dards may be required.

A recent trend is to use laptop computers to collect test data on-site which are then imported into the CMMS. Com­puter-compatible test equipment can also be used to some­what automate the test process. Such systems are available from Bio-Tek and DNI Nevada Inc.

PM Risk Management. Risk factors are used to determine if equipment requires scheduled PM, and if so, how often. This allows health-care organizations to concentrate their re­sources on equipment presenting the greatest risk. All pa – tient-care equipment is evaluated, independent of the manner in which the institution acquired it.

During risk analysis, consideration is given to equipment function, physical risk associated with clinical application, and equipment maintenance requirements. A weighted num­bering system is used and an appropriate threshold is set. Clinical engineering experience (incident history and fre­quency of use) is used to modify the initial assessment as re­quired (22). Some low-risk devices with no PM requirements only require acceptance testing when first acquired, and a zero PM frequency assigned. The following is one example of assigning risk levels.

Equipment Function. This assessment considers how a de­vice and its data are used and the possible consequences of its failure. It is important whether a device is used for life support, routine treatment, diagnosis, monitoring, or for mi­nor functions.

Patient related and other

A device malfunction could result in—

Patient death 5

Patient or operator injury 4

Inappropriate therapy or misdiagnosis 3

Patient’s discomfort 2

No significant risk 1

Maintenance Requirements.

This assessment considers whether the device requires periodic parts replacement, recal­ibration, lubrication, and clinical engineering tasks necessary to supplement user maintenance.

Maintenance is weighted as follows:



Above average




Below average




Cannot Locate. Equipment that cannot be located (CNL) is an ongoing problem that most clinical engineering depart­ments face when attempting to do PM. Movable equipment often winds up in locations other than those indicated in the inventory records. The equipment may even have left the in­stitution with the patient upon transport. This requires ex­tensive search time, entails hospital sweeps, and if unsuccess­ful, notification to the user and the Safety Committee. Should the device not turn up in a reasonable time period set by the institution (i. e., within three PM periods, two years), the clini­cal owner and property control personnel should be notified and the device removed from the active equipment inventory list.

Reduction of PM Requirements. From 1974, when the JCAHO first required that all electrically powered equipment be tested four times a year, through 1988, when the JCAHO introduced risk-based equipment management, which encour­aged health-care facilities to develop more realistic equipment management programs, there has been a decline in the re­quirement to do PM (39).

Today (1998), as competition between health-care institu­tions intensifies and resources dwindle, further PM reduction is being discussed. At issue is the extent that PM contributes to patient care, patient and user safety or quality. PM is la­bor-intensive and uses personnel resources that are in short supply. Advances in the manufacture of medical devices (in­cluding the use of solid-state integrated circuits) produce in­struments with longer mean times to failure rates and better electrical isolation. It is questioned if PM further improves these failure rates and whether clinical engineering resources would be better spent in providing additional training to equipment operators to improve their skills, thus reducing patient incidents and enhancing patient care (39). It remains to be seen if this approach will be adopted. For now, time spent on PM should be limited to what is required by law or as determined by prudent practice (17).


An institution must manage its medical equipment well in order to provide high-quality medical care at competitive prices. For this reason, the clinical engineering department should avail itself of the many methods of providing service to its institution. A clinical engineering director must be flex­ible and fully aware of the skills of the clinical engineering staff and the budgetary constraints of the department in or­der to select the proper cost-effective mix of services. The in­tent is always to provide quality service while striving to re­duce overall costs. When outside services are selected to supplement in-house capabilities, they must be monitored to ensure quality, correctness of charges, and receipt of appro­priate documentation for entry into the equipment history files and computerized system (30). Several service options are discussed below.

In-House Service

Advantages. In-house service is cost-effective, provides very short response times (measured in minutes rather than in hours (20), and allows for single-point (one phone call) ser­vice. Informal (not always chargeable) service requests can sometimes be accommodated. Specialized service such as sup­port for a cardiothoracic surgery program is also feasible (Fig. 9). Providing in-house service for complex state-of-the-art equipment requires an adequate number of well-trained staff. If staffing levels permit, in-house service should be substi­tuted for service contracts whenever possible.

Considerations. Maintaining equipment in-house requires consideration of the critical importance and downtime that can be tolerated for each device. Consideration must also be given to the availability of backup equipment, tools, spare parts, test equipment, diagnostic software, and manuals, as well as how the equipment will be repaired should it fail off- hours (30). Some equipment such as ECG machines lend themselves to in-house repair as they are not one of a kind, parts are easily obtained, and backup units are readily available.

Original Equipment Manufacturer (OEM) Service

Advantages. Manufacturer’s service has the advantage of parts availability, servicer familiarity with the equipment, possibility of equipment upgrade as part of the service, and possibly remote diagnostic capability (37).

Figure 9. Cardiothoracic support, bedside monitor setup. Clinical engineering support for cardiothoracic surgery assures a specially trained engineer is available in the operating room throughout the surgical procedure to check the physiological monitoring equipment prior to patient connection as well as to troubleshoot equipment prob­lems should they develop. The engineer is shown checking the patient bedside monitoring setup in the Cardiothoracic Surgical Intensive Care Unit (CTICU) to assure its functionality. He also verifies that all patient cables are available for quick connection upon patient ar­rival to the CTICU following surgery.

Service Contracts and Clinical Engineering Screening. Service contracts are available that include parts, materials, and la­bor. Yearly cost can be roughly estimated by taking 10% of the equipment acquisition cost (the closer to 5% the better the deal). Original equipment manufacturers often bundle PM and upgrades with repair service as an enticement to select them as a service provider. Decisions must be made as to whether these items should be unbundled, and their value and need for determined separately (17). Clinical engineering screening lowers service contract cost. Screening requires that the clinical engineering department verifies that the equipment malfunctioned and the problem was not due to user error, prior to a service call being requested. For easily rectified problems the service provider may opt to supply the parts for clinical engineering to install. Screening keeps the clinical engineering staff familiar with a wider variety of in­strumentation, allowing them to better assist during emer­gency situations. Screening may not be feasible for equipment that must be up continuously and requires the service con­tractor to be called in immediately to reduce downtime and minimize revenue lost to the institution. Equipment lends it­self to a service contract if it is relied on heavily, only limited downtime is acceptable, and backup equipment is not readily available. Intra-aortic balloon pumps could fall into this cat­egory.

Fee-for-Service. OEM service is also available on an as – needed basis (fee-for-service). Fees include travel time (to or from the institution), labor, parts and materials, or, using printers as an example, a flat fee may be specified. Repair and/or PM service can be provided. Service may be provided either on-site (infusion pump) or at a remote depot or facility (glucometer). A vendor-supplied repair estimate assists in de­termining if the repair is cost-effective. Fee-for-service may be chosen for sophisticated repairs of equipment or when clinical engineering staff cannot find the cause of a problem after a reasonable troubleshooting time period has elapsed.

Third-Party Service Providers

Independent service organizations (ISO) tend to be less ex­pensive than OEM. Service vendors should be selected based on the quality and timeliness of past service. Service con­tracts and fee-for-service are available. Repair and/or PM ser­vice can be provided. It should be determined if parts other than OEM will be used and whether the manufacturer might void the warranty or negate product liability if a nonfactory authorized service provider is used. The equipment has less chance of getting factory upgrades and product recall ret­rofits.

Shared-Service Providers

Services can also be obtained from shared-service providers, which can be for-profit or nonprofit. These organizations are formed by health-care institutions usually located close to­gether that do not have the resources necessary to maintain an equipment management program on their own. Instead they pool their resources and have a common entity provide service to all of them. They share in the capital cost of setting up such an entity and then pay for services in proportion to their use (20). The logistical problems of providing such ser­vices must be overcome.

Some clinical engineering programs after becoming suc­cessful within their own institution expand and provide shared services to neighboring institutions as well. As an ex­ample, Thomas Jefferson University Hospital in Philadelphia, Pennsylvania, has a full-service in-house program as well as a shared-service component.

Maintenance Insurance

This insurance protects against catastrophic failures by smoothing out service cost. Service is done on an as-needed, fee-for-service basis. The insurance company either pays the vendor directly or reimburses the institution for the service. Some programs pay clinical engineering personnel to handle those repairs it wishes to in-house. Proper clinical engi­neering screening of service calls and good equipment man­agement decisions can result in year-end rebates. However, the paperwork in managing an insurance program often re­quires dedicating at least one full-time employee (FTE) to this task. Maintenance insurance backup provides a reasonable way for clinical engineering to start assuming equipment maintenance duties in areas in which they may not as yet be involved, such as radiology and clinical laboratories.


Medical equipment is tested for electrical safety throughout its lifetime. Baseline tests are run during acceptance testing. Tests are also run during PM, following equipment repair, upgrade, or patient incident. The measurements are recorded and compared to previous readings. Changes indicate possible electrical degredation that must be investigated to eliminate electrical hazards before an incident can occur. Training of equipment users in electrical safety concepts is also im­portant.

Electrical Safety Analyzers. Electrical safety analyzers are used to determine that electrical devices, ac receptacles, and conductive surfaces meet required safety standards and are safe for use. These solid-state instruments incorporate true rms measurement capability. They allow testing of portable medical equipment and fixed (hard-wired) installations. In­ternal circuitry [AAMI test load (14)] simulates the human body’s impedance to current flow. The measurements made are representative of the leakage currents (if present), which could flow through the body. Normal and reverse polarity tests, as well as current source tests, are run (32).

Micro – and Macroshock

Electrical safety as related to medical instrumentation con­cerns itself with limiting the amount of electric current al­lowed to pass through the body to a few microamps. This lim­its the current density (current per unit area) to values below a threshold that could affect or damage tissue and vital or­gans such as the heart and brain (33).

In a health-care setting patients are compromised when their skin is punctured and catheters are inserted, or when their skin is prepped (rubbed and cleaned with alcohol) prior to the placement of electrodes, and where moist environments exist. The electrical resistance of patient’s bodies to current flow is reduced from its normal range of 10,000 П to 100,000 П, to a range of 1000 П to 10,000 П. Under normal conditions 110 V ac applied to the skin results in currents of 1 mA to 10 mA. Under these compromised conditions larger currents of 10 mA to 100 mA result.

Macroshock (current above 1 mA) can be hazardous when delivered at the body’s surface. For example, 100 mA applied at the skin could cause ventricular fibrillation. Microshock (current below 1 mA) can be hazardous when delivered di­rectly or close to heart tissue. For example, current in the order of 0.1 mA may cause ventricular fibrillation. Currents such as these that can injure the patient are usually too low to affect the uncompromised equipment operator.

Ac Leakage Current

Ac leakage currents are found in electrical instruments other than battery-operated direct-current (dc) devices. Leakage currents are produced as a result of the ac signal coupling to the chassis of the instrument due to capacitance effects. Such currents flow from chassis to ground when a low-resistance path is made available.

The ground wire within the equipment’s three-wire line cord provides a safe low-resistance path for the leakage cur­rent. It is for this very reason that two-wire line cords are prohibited for hospital use. The ground wire is connected to the chassis of the instrument on one end and to the ground pin of the ac plug on the other. While this connection is intact the leakage current is safely conducted away from the pa­tient, as it flows from the chassis through the ground wire to ground via the ac wall outlet. Should this path open or pres­ent a high resistance from chassis to ground due to a loose wire connection in the plug, or an improperly grounded ac outlet, the leakage current seeking other pathways could flow through the compromised patient. Leakage currents can also flow between patient leads and ground due to poor lead isola­tion. The large number of medical devices that surround and could route electrical current to the patient compounds the problem.

Manufacturers limit leakage current by (34):

Incorporating patient isolation circuitry utilizing isolation amplifiers, optical coupling, and infrared transmission techniques

Doubly insulating some devices with an outer nonconduc – tive plastic housing so that even if touched, they cannot conduct electricity

Using specially constructed low-leakage ac line cords

Incorporating isolation transformers into systems, which have components whose total leakage current exceeds safety standards

Hospital Grade Plugs and Outlets

Safety is also provided by use of heavy-duty hospital grade ac plugs (with a green dot). These plugs are mechanically keyed to prevent polarity reversal. Explosion-proof plugs previously used due to the explosive nature of some anesthetic gases are no longer prevalent. Prior to opening new clinical areas, in addition to having the clinical gases certified, all ac outlets should be tested with a tension tester to verify that the ac outlets will tightly grip equipment plugs when inserted and with an ac polarity checker to ensure that the wiring has been properly done.

PROCUREMENT OF MEDICAL DEVICES Reasons for Equipment Acquisition

Equipment is acquired by a health-care facility for a multi­tude of reasons, including the following:

Replacement of obsolete equipment that cannot be re­paired as parts are no longer available or that is not cost-effective to repair as a new unit would be compara­ble in price to the repair cost. Included is equipment that breaks down frequently, resulting in lost patient revenue to the institution. Such equipment replacement increases the hospital’s cost-effectiveness and reduces its risk exposure.

Replacement of technologically obsolete equipment that is not as precise as newer microprocessor equipment, to improve diagnostic and therapeutic efficiency.

Introduction of new types of technologies, such as magnetic resonance imaging (MRI) and Catscan to provide en­hanced services.

Requirement of additional units of a type already being used in the facility to reduce equipment downtime and patient waiting.

Attracting highly qualified physicians including new de­partment chairmen.

Provided free of charge to the institution as part of a dis­posable contract.

Brought into the facility by clinicians for specific practice purposes.

Loaned to, or rented by, the institution.

Clinical Capital Equipment Committee

Equipment acquisition usually starts with a perceived need expressed by a clinician, a hospital administrator, or clinical engineer and a request is forwarded to the institution’s Clini­cal Capital Equipment Committee. However, equipment is sometimes purchased on an emergency basis based upon med­ical contingencies or for political reasons without committee input.

The Clinical Capital Equipment Committee is made up of clinical department chairpersons, physicians, hospital admin­istrators, as well as representatives from nursing, clinical en­gineering, finance, and purchasing. The committee reviews the equipment requests. Clinical engineering staff provides equipment inventory lists, instrumentation repair trends, and other equipment management information requested to expe­dite the decision-making process. Priorities are determined, a purchase list is generated, and requesting departments are notified. They prepare appropriate purchase requisitions, and necessary hospital administration signatures are obtained. The purchase requisitions are then submitted to clinical engi­neering for technical review.

"Turn-Key" Installations

Large ‘‘turn-key’’ installations require a request for quotation (RFQ) to be prepared for a bid process. Turn-key installations require the vendor to provide all equipment, materials (ca­bles, mounting devices, etc.), and labor to install the system completely, and, when ready, to turn it over to the institu­tion for acceptance testing. The RFQ document includes equipment specifications, environmental specifications, and legal requirements that address issues of noncompliance and penalties. During installation, such systems may require ex­tensive vendor-clinical engineering interaction and problem­solving, as fully detailed documentation is not always possible. They also require extensive acceptance testing. Sub­sequent to the bid award, a detailed purchase requisition is generated.

Purchase Requisition Review

Assists the clinician in obtaining needed equipment, ensuring that everything required (peripheral items, supplies, etc.) is being ordered and that all items are compatible with each other and with existing equipment. It also ensures that the physical plant is ready (e. g., water, gas, special electrical re­quirements) so that equipment installation and use will not be delayed.

Requisitions are first reviewed to determine the following:

If equipment falls within clinical engineering jurisdiction (i. e., items used in the health-care facility for which clinical engineering is responsible).

If the FDA has approved the equipment for clinical use. If approved only for investigational purposes (i. e., a re­search phase requiring clinical trial to prove its effi­cacy), clinical engineering staff could assist the clinician in obtaining IRB clearance for clinical trials.

If the equipment utilizes a new technology requiring an engineering evaluation and clinical trial period prior to purchase. Evaluation may also be required if several vendors have viable products that should be compared. Visits to other health-care institutions are sometimes required to view the equipment in use. Larger systems such as replacement of all of an institution’s obsolete physiological monitoring equipment necessitates input from future users including physicians and nurses.

If the equipment requires special physical plant utilities or has physical attributes (size, weight) that the facilities engineering department must be made aware of. If so, the facilities engineering manager’s purchase approval is required.

If equipment or accessories require special treatment to not pose an infection threat to patient or user (i. e., spu­tum chamber certification). If so, the infection control department should be notified so that appropriate hos­pital policies will be generated.

If equipment is year 2000 (Y2K) compliant. If not, the im­pact of this equipment on patient care must be deter­mined.

If sole-source justification (exemption from advertisement) is required. Sole-source acquisition is justifiable if the unit must be compatible with an existing item, a vendor holds a service contract and must supply parts, the unit has unique features needed by the requester, or no com­petition by manufacturer or vendor exists.

Purchase requisitions are next checked to ensure the fol­lowing (35):

All needed accessories have been specified and are compat­ible.

Vendor or manufacturer will uncrate, assemble, or cali­brate the unit (if required).

Vendor will assist with acceptance testing (if required).

Vendor will install the equipment (if required, i. e., mount to walls, etc.).

Vendor will provide (or loan) test kits or fixtures (i. e., phantom for diagnostic imaging) or simulators specifi­cally geared to the unit.

Vendor will provide user in-service training.

Vendor will provide sufficient number of operator and ser­vice manuals.

Vendor will provide VCR training tapes.

Vendor will provide acceptance testing and PM protocols.

Vendor will provide clinical engineering service training.

Vendor will provide an equipment loaner in the event of delayed delivery.

Vendor will provide system isolation transformers (if re­quired).

Specification of the correct delivery location (clinical engi­neering). This is true even for large items so that the clinical engineering department will be aware of deliv­ery, at which time the receiving department could be notified to route the unit to the intended user site.

Contact person has been specified should the vendor have to make arrangements with the clinical engineering de­partment or for training purposes.

Sufficient start-up materials are specified both for accep­tance testing and for start of clinical use.

Warranty period is specified and service contract specified (if required).

Although clinical engineers must concentrate on the tech­nical issues, they might also verify quotations, specify dis­counts if appropriate, ensure that buying service pricing is adhered to, determine if special promotions are offered, see if trade-in of obsolete equipment is feasible, and check on avail­ability and delivery dates.

The requisition is next submitted to the purchasing de­partment. A copy of the entire paperwork package, including all technical information gathered, is stored in clinical engi­neering’s open purchase requisition file awaiting equipment delivery. After delivery and acceptance, it will be stored in the equipment’s history file.

Bid Review

This review assists the clinician and purchasing department in determining if a low bidder offering an “equivalent” unit to what has been specified meets clinical requirements.

Depending upon the institution, equipment cost, and if a sole source is not justifiable a bid process may be required. Following bid opening a purchasing department bid analysis is sent to the clinical engineering staff and to the clinical re­quester. Working together, they determine if the ‘‘equivalent’’ device proposed by the low bidder is a viable alternative that meets clinical needs and the important specifications of the desired unit. If not, the more expensive unit may be justifi­able. This process requires comparison of the low bidder’s equipment to the unit originally specified and bid comparison to ensure that items have not been excluded that could artifi­cially lower the price. The low bidder may have to supply a loaner unit for engineering test and clinical trial. Subse­quently, a letter of justification is written, the award is made, and the equipment delivered.

Equipment Acceptance Testing

Equipment acceptance testing, also know as initial checkout or incoming inspection, ensures that all items ordered have been received and are undamaged, the equipment functions as per the manufacturer’s performance specifications, and the equipment is safe for both the clinical user and the patient.

Acceptance testing uncovers equipment defects including those not readily apparent, prior to the equipment being used on or for patients so as to reduce liability to the institution. Such testing is usually more in-depth than PM testing and is

Figure 8. Acceptance testing, endoscopic system. Acceptance testing assures that medical equipment functions properly, meets manufac­turers’ specifications, and is safe for use. It also verifies that all items ordered have been received, and appropriate in-service education is provided to the clinical and engineering staff. Shown here, an endo­scopic video system is undergoing an acceptance test. Such devices allow intra-body images to be displayed on monitors for ease of view­ing and allow their documentation via video recording or printout.

much more than just electrical safety testing (leakage current and grounding resistance). All medical equipment (whether purchased, leased, rented, loaned, physician owned, used as a demonstration model, or donated) should undergo acceptance testing. Short-term items are given a ‘‘loaner tag,’’ while long­term items are assigned an inventory number.

Acceptance testing should be thorough (36). A visual in­spection externally, as well as internally (when justified), en­sures that the instrument was not damaged in transit and has no loose or extraneous components. The visual inspection also verifies that the device is new, of the latest model, and has not been previously used (occasionally factory refurbished demonstration units may be purchased). Devices are checked for electrical safety, mechanical safety, and functionality and to assure that they meet the manufacturer’s own performance specifications (an important concept). Built-in diagnostics are run to provide future confidence in them (Fig. 8).

A report is generated documenting test results, conversa­tions with the manufacturer, and information learned about the device, such as electromagnetic compatibility. These data serve as a baseline for future repair and PM testing and to help answer questions posed by the clinical staff. Acceptance testing also provides a practical training ground for the clini­cal engineering staff, keeping them current should emergency clinical situations develop or a patient incident occur involv­ing this equipment. All defects uncovered and the steps taken to resolve them should be documented in a defect log, which becomes part of the equipment history file. Until the defects are resolved, the equipment should not be released for clinical use. There is typically a 60-day period starting with equip­ment delivery in which acceptance testing is expected to be concluded. Should there be a defect (or should only a partial shipment of equipment be received) expenditures processing must be notified immediately so that they can inform the ven­dor that the payment clock has been stopped to avoid the in­stitution paying a penalty. Also, equipment warranty must not start until acceptance testing is successfully concluded. The documentation showing that the hospital did thorough testing is invaluable to the institution during a lawsuit.

Patient Monitoring

Medical instrumentation used for patient monitoring has be­come quite sophisticated. This microprocessor-controlled equipment provides multiphysiological parameter monitoring with alarm generation and recording capability. It incorpo­rates telemetry, S—T segment analysis, and full physiological parameter disclosure capability (which stores selected wave­forms for recall), allowing clinical study of abnormalities. It also includes automatic arrhythmia detection at the bedside, which until a few years ago required a large stand-alone com­puter housed in a specially cooled room. Using individual per­sonal computers, patient data can also be collected and ar­chived for additional statistical studies.

The patient’s physiological parameters are viewed on bed­side monitors as well as on remote slave displays. Parameters monitored include ECG, heart rate, respiration rate, cardiac output, noninvasive blood pressure, invasive blood pressures (arterial, pulmonary artery, central venous, etc.), oxygen sat­uration (SAO2), pulse rate, end-tidal carbon dioxide (ET CO2), and temperature.

In critical care areas, the bedside monitors are hard-wire connected to central nursing stations allowing centralized

Figure 7. Central nursing station. Physiologi­cal monitoring has grown quite sophisticated. Patient information gathered at the bedside is routed to a central nursing station providing clinical staff with a comprehensive viewing area. Each central station monitor typically shows waveforms and parameters for four dif­ferent patients and has the ability to zoom in on a specific patient to show all monitored pa­rameters. Recorders provide documented printouts of alarm conditions including de­tected arrythmias. Closed circuit TVs visually monitor patient isolation rooms as well. Clini­cal engineering is involved with the entire life cycle of such equipment from prepurchase se­lection through acceptance testing, PM, repair, and eventual obsolescence retirement.

viewing at one location (Fig. 7). Nursing stations may be con­nected together via local area ethernet-type networks, allowing remote patient viewing between nursing stations and sharing of full disclosure equipment. Telemetry informa­tion is likewise routed to a nursing station for centralized viewing of ambulatory patients. In this case, the telemetry transmitter takes the place of the bedside monitor, transmit­ting a signal to an antenna system that routes it to a receiver and display unit.

Equipment Classification; Nomenclatures

Equipment classification nomenclature systems bring order to the vast array of medical equipment presently in use. These systems simplify the gathering and distribution of data relat­ing to medical devices. Complete nomenclature listings are found in ECRI’s Health Devices Sourcebook (28), and the Med­ical Device Register (29). Another nomenclature system was developed by the U. S. Food and Drug Administration (FDA) as part of its regulatory responsibilities for medical devices. ECRI and the FDA are presently attempting to standardize their two systems.

In the sample nomenclature listing below, note the two ways of listing an ECG monitor.

Cart, resuscitation Pacemaker, cardiac Heart rate monitor, ECG ECG monitor Diathermy unit

Equipment Inventory List

To be effective an equipment management program requires maintenance of an up-to-date, complete inventory of medical equipment used in the health-care institution. This equip­ment inventory list helps identify equipment for product re­call and hazard alerts, as well as to locate equipment due for

PM. As much information as possible should be included for each piece of equipment in the list (30), such as the following:

Unique identification number, which could be a property control asset number, but is usually assigned by clinical engineering and is generally not the serial number Equipment manufacturer, model, serial number, and de­scription (nomenclature)

Equipment location Purchase order number Departmental owner

Service organization responsible for the equipment (in­house, contract, etc.)

Acceptance date, when approved for clinical usage Warranty expiration date Equipment acquisition cost

PM frequency and PM procedure number to be used Additional information the organization believes useful for proper equipment management

Equipment Records

Equipment history files are maintained to provide informa­tion for equipment management and technology assessment purposes, as well as to satisfy regulatory requirements. When equipment is taken out of service and is disposed of, its his­tory file should be maintained for a minimum of three addi­tional years (31), or longer if an institution’s legal council or risk manager deems it necessary. This will offer the institu­tion some protection in the event that a patient incident law­suit is initiated at the time of equipment disposal, of which clinical engineering or risk management is unaware. Records for equipment involved in patient incidents are usually se­questered by the risk manager so as to avoid possible tam­pering.

MEDICAL EQUIPMENT Patient-Care Equipment

Equipment used ‘‘on’’ patients or ‘‘for’’ patient care in health­care facilities is both varied and numerous. It runs the gamut from simple thermometers to sophisticated MRI machines. Equipment used ‘‘on’’ the patient, such as an electrocardio­gram (ECG) monitor, is readily visible in the patient’s imme­diate physical vicinity. Equipment used ‘‘for’’ patient care, such as a clinical chemistry analyzer, may be housed in a laboratory at a location remote from the patient. Both types are important when considering the environment of patient care.

Medical equipment falls mainly into three different catego­ries. These categories are diagnostic, therapeutic, or assistive. Diagnostic equipment such as a monitor acquires data and uses transducers to enhance and supplement human senses. Therapeutic instruments such as high-voltage X rays, pace­makers, and defibrillators arrest or control physiological pro­cesses affected by disease or trauma. Assistive devices supple­ment diminished or lost functions, and include life-support (ventilator) and life-sustaining (dialysis unit) devices (27).

The equipment that a typical university hospital clinical engineering department such as the Scientific and Medical Instrumentation Center is responsible for (excluding x-ray or ionizing radiation devices) runs to 10,000 active items. These include capital and noncapital devices. Capital devices are classified as costing greater than or equal to $500 per item. Noncapital devices cost less than $500. To describe this equip­ment approximately 500 different equipment nomenclatures are used. This alone shows the diversity of knowledge that a clinical engineering staff must have.