wireless patient monitors bp consult 01.07

8/7/2019 Wireless Patient Monitors BP Consult 01.07

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Wireless Patient Monitors:

Considerations

prior tospecifying, acquiring and implementing

by

Bryanne Patail, BS, MLS, FACCE

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Wireless Patient Monitors

Items to Consider when specifying, acquiring and

implementing

Outline

I Introduction

II Patient populationa) Intermediate Care Units (step-down units)b) Rehabilitation Units (cardiac rehab units)c) Ambulatory/transport monitoring

III Logisticsa) Number of beds to be monitoredb) Location of patients (same floor or multiple floors)

c) Do you want to monitor patients (and watch the waveforms and manage alarmsfrom a remote station) during transport to and from OR, Cath. Lab, X-ray, etc?

IV Transmitters vs. Transceivers (bi-directional)a) Frequency (WMTS, ISM, others)b) Parameters monitored (ECG, Heart Rate, Arrhythmia, Pulse Oximeter, NIBP,

etc.)c) Battery considerations

V Antenna Systema) Local vs. house-wide

b) Existing infrastructure

VI Central Stationa) At nurse deskb) Centralized (remote off the floor)c) Bothd) Displays in the patients room

VII Monitor Watchersa) 24 X 7 coverageb) Work habits and schedules of watchersc) Cost

VIII Alarm Notificationa) Primary vs. Secondaryb) Bi-directional

IX Conclusions

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I Introduction

When wireless (telemetry) patient monitoring systems were first introduced, over 25years ago, the reimbursement mechanisms were different and healthcare facilities hadadequate nursing staff; hence, telemetry monitoring systems were designed to providewaveform visualization and alarm notification at the nurses desk. Now, in the era ofnursing shortages and trying to do more with less (patient to nurse ratio in a typical

step-down unit exceeds 6:1) nurses can no longer monitor telemetry waveforms andalarms at the nurses desk. What has happened is that the old telemetry monitoringsystems have set the nurses up for failure (systems approach in patient safety always

asks the question: Did the system support the person?).Nurses are now busy in thepatients room and logistically it is impossible to be at the nurses desk and visualizethe waveforms to verify arrhythmias and hear the monitor alarms. A very dishearteningscenario is, to walk by a telemetry monitoring units nurses desk, and hear the alarmsbinging, beeping, bonging and the alarm event recorder is spitting and spewing reams ofpaper, with no one paying attention to these alarms. Therefore, in order to design,specify, evaluate, acquire and effectively implement a wireless patient monitoring systemin a healthcare facility and assure that the system will be used properly, safely and

effectively, it is recommended that the following items be considered.

II Patient Population

a) Intermediate Care Units (step-down units)As the acuity of admitted inpatients increase (growing trend in private sectorfacilities), it is conceivable that all non-intensive care units will eventuallybecome monitored beds (intermediate care beds) and therefore, it is desirable toflex up from an acute care bed to an intermediate care bed. Typically, these bedsare to care for post angioplasty, post stenting, other post minimally invasiveprocedure treated patients and 24 hour observation units. The parameters

monitored are limited; therefore, these units are not for intensive care patients. Acarefully, well thought out admit and discharge criteria must be in place and thepatient to nurse ratios must be piloted and the logistics understood and worked outbefore hand. Certain nursing skill sets such as the ability to apply electrodes,operate the transmitters and receivers, read, understand arrhythmias and takeclinical action as needed are prerequisites for the nursing staff. Strict admit anddischarge criteria and protocols must be established and adhered to.

b) Rehabilitation Units (cardiac rehab units)Wireless patient monitoring systems are also used in cardiac rehab units. It is lesscumbersome to monitor patients ECG, heart rate and arrhythmias with wirelessdevices while they are on tread mills, ergo meters and other exercise equipment.Here the patient population is defined by the fact that they are assigned to thecardiac rehab unit. However, patients should be evaluated on an individual basisfor indications and contraindications before they are wirelessly monitored.

c) Ambulatory/transport monitoringAt one point in time, monitored patients were not allowed to leave thebed/room/floor, unaccompanied by staff, to get their diagnostic tests andtherapeutic procedures such as CT, MRI, PET, Nuclear Medicine scans, PT,hydro therapy, etc, because the technology did not exist to support their mobility(e.g. .the monitors were too cumbersome). Now, with wireless monitoring

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systems, if the infrastructure (antenna system) is well thought out and planned,patients can be monitored anywhere in the facility, from a remote site, providedantennas exist throughout the facility.

III Logistics

a) Number of beds to be monitored

It is always good to start the implementation of the system with a manageablenumber of beds to be monitored, and most wireless monitoring systems in themarket come in multiples of 8 to 10 beds per central display unit. Considerationshould be given for future expansion and other applications identified above.

b) Location of patientsA typical telemetry monitoring unit is on the same floor as the patients that areindicated for monitoring and certain beds close to the nurses desk are theassigned beds. Some facilities would deploy the antenna system throughout thefloor to allow ambulation of the monitored patients and also allow for flexibilityof the monitored beds (e.g. on a nursing floor where there are 30 beds and amonitoring system that has capability to monitor/visualize 10 patients at a time,

any one of those beds can become a monitored bed but only 10 patients can bemonitored all at once).c) Monitor patients from a remote site

There are systems out there where the monitoring station is remote (on anotherfloor or on another part of the facility completely away from any of the inpatientbeds). Usually, the capacity to monitor remotely exceeds 48 patients all at once,and monitor watchers are assigned to those tasks, instead of RNs, in an effort tobe cost effective. This is a highly political and emotionally charged conceptbecause the RNs are paid for their monitoring skill sets and they do not want togive up their skill sets. The remote monitoring station will be able to monitorambulatory/transport patients also if the antenna system is deployed along the

routes the patients are being transported.

IV Transmitters vs. Transceivers (bi-directional)

Historically, wireless patient monitoring systems allow for one-waycommunication, where the transmitter (with no display) worn by the patient,sends a signal to the receiver (in the central station) at the nurses desk, displaysthe waveforms and provides alarms when certain set parameters are violated.With Federal Communication Commissions (FCCs) newly allocated frequenciesof the radio spectrum for wireless medical telemetry, transceivers can be used,where bi-directional (two way) communication is possible. (see ISM band) Thereare systems in the market today with this capability.

a) FrequencyAll TV broadcasters were required to operate their Digital TV (DTV) transmittersat their maximum licensed power by July 2006. This means that all medicaltelemetry still operating in TV channels 7 13 (174 216 MHz), 14 36 (470 608 MHz) and 38 46 (614 668 MHz) are vulnerable to interference; therefore,medical telemetry systems should migrate to the part of the radio spectrum knownas the Wireless Medical Telemetry System (WMTS) designated by the FCC in

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2000. I believe all medical telemetry transmitters currently sold in the UnitedStates have migrated to the WMTS. FCC designated a total of 16 MHz in threedistinct frequency ranges previously assigned for other use. They are: 608 614MHz, 1395 -1400 MHz, and 1427 1429.5 MHz. Each frequency range has itsown sets of issues that need to be understood, and potential risks should beassessed prior to specifying, acquiring and implementing a wireless patientmonitoring system.

608 614 MHz: Since this is still in a TV band (channel 37) any DTV orLow Power TV (LPTV) transmission within the range of the facility cancompletely override a medical telemetry signal. In addition, this band offrequencies is the home for 13 Radio Astronomy sites. Therefore thefacility must coordinate with local authorized users of this band to preventinterference.

1395 1400 MHz: Since this band of frequencies was assigned to 17government radar sites, facilities within the range of these incumbent radarsites must coordinate with the local authorized users of this band toprevent interference.

1427 1429.5 MHz: Currently there are approximately 40 incumbent

mobile Utility Telemetry Operators in seven areas of the United States,which use these frequencies.These areas are:

1) Pittsburgh, Pennsylvania2) Washington, DC3) Richmond Norfolk, Virginia4) Austin Georgetown, Texas5) Battle Creek, Michigan6) Detroit, Michigan7) Spokane, Washington

Facilities within the range of these incumbent sites must coordinate with

the authorized users of these bands to prevent interference. Industrial, Scientific and Medical (ISM) Bands: 904 928 MHz, 2.4 2.4835 GHz and 5.725 5.850 GHz. These arefrequencies of the radio spectrum that can be used by the general publicwithout a license in many countries. Commonly used applications in theISM Bands are: Spread Spectrum, microwave ovens, industrial heaters,military radars and Bluetooth. Spread Spectrum techniques provide addedadvantages such as secure communications, prevention of detection,increased resistance to natural interference, prevention of jamming, andthey allow for two-way communication(another patient safety issueregarding alarm broadcasting and acknowledging receipt of alarms)

and sharing of the antenna infrastructure for multiple applications. Seriousconsideration should be given to the deployment of the wireless network,fiber optic back-bone, and the antenna/access point in the strategicinfrastructure planning at each healthcare facility to assure security of thetransmitted information, efficacy of the system, safety to the patients/staffand economies of scale.

The new FCC ruling does not require WMTS users to hold FCC license (whichwas past practice for the old TV channels) for operations in these new bands of

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frequencies. However, WMTS users are held to license by rule. This means thateach new WMTS installation is required by the FCC to register its deploymentbefore the equipment is used. FCC has designated the American Society forHealthcare Engineering (ASHE) as the exclusive WMTS coordinator. Althoughreputable manufacturers and vendors of medical telemetry systems have beenhelpful in assisting healthcare facilities for all the pre-installation preparationssuch as spectrum analysis and FCC license applications, it is the responsibility of

each healthcare facility to assure that all coordination activities have beencompleted prior to installation of the wireless, medical telemetry patientmonitoring system.

b) Parameters monitoredWith the advent of digital transmitters and transceivers, telemetry monitoring isno longer limited to just ECG, heart rate and arrhythmia. Newer devices can nowadd Non-Invasive Blood Pressure (NIBP), pulse oximetry and improvedarrhythmia algorithms to minimize false alarms.

c) BatteriesStudies have shown that a typical telemetry patient is monitored forapproximately 72 hours. However, as new parameters are added, and bi-

directional communication is deployed, trade offs with battery life occurs. NCPSis aware of a few reports of battery depletion issues with telemetry patientmonitoring systems. Although there are audio and visual alarms to alert the

caregivers of impending battery depletion, at the central station, the

complaints were that the system did not give enough warning (15 minutes)

and the audio and visual alarms were not strong enough. When the battery is

depleted, all monitoring functions cease. There are systems that are available inthe market place that use a standard 9 volt battery (not medical grade or industrialgrade) and provide a battery management system, which includes displaying thebattery voltage. The transmitter continues to transmit until the battery reaches 7.4volts. A telemetry monitoring station implemented a protocol where all the battery

voltages at 7.5 volts (typically after 72 hours of continuous monitoring) arereplaced during morning rounds.

V Antenna Systems

There are many ways, options and configurations a facility can deploy the antennasystem. Consideration should be given to sharing the existing wirelessinfrastructure (if any), sectoring to assure that a single point failure will notimpact the whole system, provide redundancy, and future expansion in addition tocost issues.

a) Local vs. house-wideAs discussed in a few sections above, careful consideration should be given to theobjectives of investing in a wireless telemetry monitoring system, the patientpopulation it is intended to serve and the availability of staff along with costissues. As the antenna system gets larger, careful signal strength analysis andamplification at each leg of the antenna will need to be adjusted and tweaked(sometimes it takes a few days to accomplish this) before any patients areadmitted to the unit. Signal strength analysis and amplification adjustments mustbe repeated as additional legs of the antenna are installed or added.

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b) Existing infrastructureAs Wireless Personal Area Networks (WPANs) are deployed in healthcarefacilities, IEEE standards such as the 802.11 and technologies such as Bluetoothwill become common utilities available for other applications such as the wireless,telemetry patient physiologic monitoring systems. Therefore, it is extremelyimportant to contact departments (typically IRM) that have deployed thesetechnologies when considering acquisition of wireless patient monitoring systems.

VI Central Station

a) At the nurses desk If the number of patients that needs to be monitored, at any moment in time, isless than 10, then by placing the central station at the nurses desk and limitingthe monitored rooms to those that are directly across and/or contiguous to thenurses desk might be the best alternative.

b) Centralized (remote potentially off the floor)If the number of monitored beds exceeds 48 and multiple floors are beingmonitored, then designing and implementing a centralized telemetry monitoring

station with staff dedicated to watch the monitors might be a good alternative.c) BothIt is not unusual to have a centralized telemetry monitoring station off the floorsaway from inpatient rooms and still have a central station on each of the floorswhere the monitored beds are.

d) Displays in the patients roomNew digital telemetry transmitters and transceivers now have a small displayscreen (much like the screen on a cell phone) directly on the patient worntransmitter/transceiver. (This idea/concept attempts to solve the problem of thecaregiver not being able to view the wave forms or hear the alarms in the

patients room system supporting the person). Other concepts are: a

dedicated, larger size display unit, the size of a tablet, which is wirelesslyinterfaced to the transmitter/transceiver and the central station to display all theparameters monitored, at a remote site and the patients room and broadcast thealarms at the same time.

VII Monitor Watchers

Another patient safety related solution is to provide an adequately trained,

dedicated staff to watch the telemetry monitoring stations and notify the

nursing staff of validated alarms.

a) 24 X 7 coverageCoverage must be twenty four (24) hours a day, seven (7) days a week as long asthere are patients that needs to be monitored.

b) Work habits and schedules of the watchersIt is important to realize and understand that the watchers should not be at themonitoring station, actually watching the monitors, for longer than 2 hours at atime. When they are not watching, other duties such as charting, attachingelectrodes to the patients, replacing telemetry batteries or disconnectingtransmitters/transceivers (on patients where the monitoring has been discontinued)(DCd), can be assigned. The value of the monitor watchers attaching the ECG

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electrodes, following a sound technique, assures that the patients are monitoredwith fewer artifacts, interference and unintentional disconnects.

c) In order to support a 48 bed centralized, remote, telemetry monitoring station thatmonitors 24 X 7, approximately 8.5 Full Time Equivalents (FTEs) are neededplus supervisory staff. Therefore, the cost associated with screening, hiring,training (to properly attach electrodes, identify arrhythmias and operate themonitoring system), scheduling, staffing and managing a crew might be

prohibitive. However, after investing $15,000 to $20,000 per bed, in telemetryequipment and not utilizing it safely, appropriately and effectively is worse. Thefacilitys administrative, medical and nursing staff must be fully aware of theramifications associated on deploying such a system.

VIII Alarm Notification

NCPS issued a Patient Safety Alert in July 2, 2004 titled: Failure of medical

alarm systems using paging technology to notify clinical staff. This alertidentified unacceptable practices that depend on paging technology as the primarymethod of alarm notification.

a) Primary vs. secondaryAssure that the wireless, telemetry system is provided with a robust alarmnotification system that not only has audio and visual alarms but also have theability to document and print alarm events. This is considered the primary alarmand must be within the caregivers vicinity either at the nurses desk, in themonitored patients room, or in both areas. The notification from a monitorwatcher would then be considered a secondary alarm.

b) There are alarm notification systems that can notify the caregiver concurrently totheir Personal Digital Assistance (PDA) device, such as a palm pilot, cell phone,black berry, with the nurses desk, in the patient room display unit and/or theremote monitor watcher. The important thing to remember is that a feedback loop

must be established so that the caregiver can acknowledge receipt of the alarm.This is where the transceiver becomes an important link to provide the bi-directional communication.

IX Conclusions

Wireless patient physiologic monitoring is a complex system and must beapproached from a systems perspective when specifying, evaluating, acquiringand implementing such a system to assure efficacy, safe and optimized use of theinvestment.In any patient care system the patient is part of the system. Therefore, patientselection and the population of patients chosen to be monitored with thistechnology must be carefully considered and understood.Patient interface in the second block of the system should be considered next.Then the device itself (e.g. the transmitter/transceiver and the central station)needs to be taken into consideration. Also to be considered are environmentalaspects including the infrastructure such as the antenna system; qualifications andproper staffing of the care givers and their support team (e.g. the monitorwatchers) and finally the communications protocols and policies and proceduresthat govern the unit. Wireless systems are always vulnerable to Electro Magnetic

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Interference (EMI); allocation of dedicated frequencies is one way to minimizeinterference from external sources such as TV and radio transmitters. However,internal sources such as arc welding, walkie talkies and energy saving

fluorescent ballast have been found, proven and documented as causing EMI

in healthcare telemetry systems. Therefore, it is important to make sure thatimplementation of devices and systems that might be the internal source of EMIbe carefully screened and monitored.

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