Health Devices IPM System

INSPECTION AND PREVENTIVE MAINTENANCE

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Procedure No. 454-20010301 (Acceptance)

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Blood Pressure Monitors, Electronic Indirect

Used For:
Sphygmomanometers, Electronic [16-157]
Sphygmomanometers, Electronic, Automatic [16-173]
Sphygmomanometers, Electronic, Manual [16-174]

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Also Called: Noninvasive blood pressure (NIBP) units

Commonly Used In: All patient care areas

Scope: Applies to electronic noninvasive blood pressure monitors with either automatic or manual
inflation; does not include manual sphygmomanometers (see Procedure 424) or invasive blood pressure
monitors or transducers (see Procedure 434 or 435, respectively); can be used on physiologic
monitoring systems and vital signs monitors that include NIBP measurement

Risk Level: Medium

Type Interval Time Required

Major 12 months _____ hours

Minor Not Applicable
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Overview
Electronic sphygmomanometers noninvasively Arterial blood pressure measurement is an
measure and display a patient's arterial blood essential indicator of physiologic condition. As one
pressure. The use of these units may help to of the most frequently used diagnostic tests, it is
overcome some of the problems associated with critical to the ongoing management of patients
manual sphygmomanometry, such as variations in under anesthesia or undergoing drug and other
user techniques and hearing acuity and the therapies to determine the need for blood, a
difficulty of obtaining measurements on volume substitute (e.g., plasma expander), or a
hypotensive patients. In addition, many automatic change in medication. Although invasive
blood pressure units can be programmed for techniques for measuring blood pressure may
readings at regular intervals and will sound an provide greater accuracy and permit continuous
alarm if a patient's blood pressure exceeds preset measurement during cardiac and respiratory
limits. Some units can display heart rates based on cycles, noninvasive techniques are most often
the blood pressure waveform. used because of their low risk and simplicity, and

Health Devices Inspection and Preventive Maintenance System 2001 ECRI. All Rights Reserved.
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 Procedure No. 454-20010301 Blood Pressure Monitors, Electronic Indirect (Acceptance)

they have proven sufficiently accurate for many setting and average them; this average, over
clinical applications. time, should remain constant for each individual
NIBP monitor.
Two primary methods of determining blood
pressure are used with noninvasive electronic Although NIBP simulators provide added
blood pressure monitors. The auscultatory method convenience in performing several tasks of the
uses a transducer under the occluding cuff to procedure, they are expensive and not required.
detect arterial sounds (Korotkoff sounds) as cuff
pressure is gradually lowered from above the
systolic pressure. This enables the system to
Citations
(from Health Devices if not otherwise noted)
directly determine both systolic and diastolic
values but not mean arterial pressure (MAP).
Automatic sphygmomanometers [Evaluation],
Some of these units display a MAP that is
1986 Jul;15:187-208. (See also 1986 Aug; 15:247
calculated from the systolic and diastolic values
and 1986 Nov;15:317.)
using an empirically derived algorithm.
Physiologic monitoring and the standard of care,
Hypotensive patients and patients about to go into
1991 Mar-Apr;20:79-80.
shock can be very difficult to monitor with this
Physiologic patient monitors [Evaluation], 1991
method because the Korotkoff sounds are difficult
Mar-Apr;20:81-136.
to detect at low pressures.
Physiologic patient monitors [Evaluation], 1999
Jan-Feb;28:77.
The oscillometric method of determining arterial
blood pressure does not require a transducer
under the occluding cuff and is the most common Test Apparatus, Supplies,
method used. This method detects volume
displacements that originate within the artery (as
Parts
cuff pressure is reduced) and that are sensed as
pressure oscillations in the occluding cuff. The  Leakage current meter or electrical safety
point of maximal oscillation corresponds to the analyzer
MAP. Systolic and diastolic pressures may be
determined by special measurement techniques or  Ground resistance ohmmeter
clinically tested algorithms. This method may be
more reliable than auscultation on hypotensive  Calibrated pressure gauge or meter (0 to 300
patients and patients who are likely to become mm Hg)
hypotensive.
 Stopwatch or watch with a second hand
There are several oscillometric NIBP simulators on
the market, costing approximately $4,000 to  NIBP simulator (optional)
$5,000. The units have a test mode that can
provide an easier means of performing the static  Y-connector compatible with cuff tubing
pressure accuracy task, leak task, and connectors
overpressure task. If the simulator does not use
the NIBP monitor's patient cuff (i.e., the simulator  Cylindrical object to simulate an arm (e.g., can
has an internal bladder), then the leak task will or pipe) with a 3 in to 4 in outer diameter
need to be repeated with the patient cuff in place.
 Adult pressure cuff with squeeze bulb
These simulators also provide a means of
evaluating the dynamic performance of the NIBP
monitor by simulating the dynamic signals that the Procedure
occlusive cuff would sense if placed on a patient's
arm. However, while they are useful in looking at Before beginning an inspection, carefully read this
long-term trends of unit performance, they are not procedure and the manufacturer's instruction and
necessarily useful in evaluating device accuracy. service manuals; be sure that you understand how
Since NIBP monitors calculate their readings based to operate the equipment, the significance of each
on an algorithm, and the simulators use a similar control and indicator, and the alarm capabilities.
algorithm to generate their signals, if the two Also review special inspection and preventive
algorithms are not exactly matched, then what the maintenance procedures or frequencies
simulator states the pressure should be may differ recommended by the manufacturer.
from the pressure that the monitor indicates. It is
also necessary to take several readings at each

Health Devices Inspection and Preventive Maintenance System 2001 ECRI. All Rights Reserved.
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 Procedure No. 454-20010301 Blood Pressure Monitors, Electronic Indirect (Acceptance)

Qualitative Tasks The cord should be of suitable quality and current-

carrying capacity. Hard Service (SO, ST, or STO),
Chassis/Housing. Check for shipping Junior Hard Service (SJO, SJT, or SJTO), or an
damage; report any damage to the manufacturer, equivalent-quality cord should be used. Also check
shipper, or service organization, and arrange for line cords of battery chargers.
repair or replacement.
Verify that the unit has adequate protection
Check that the unit is suitably constructed to against power loss (e.g., from accidental
withstand normal hospital use and abuse. (Any disconnection of a detachable power cord,
design deficiencies should usually be recognized disconnection of the power cord from the wall, or
during prepurchase evaluation. However, if any are depleted battery if a battery-powered device is not
evident, discuss corrective action with the plugged in). Equipment having a detachable power
manufacturer. If not correctable, warn users or cord should also have adequate capture devices,
take other preventive measures.) cleats, or channels to hold the cord in place. If
these are absent, request that the supplier provide
Examine the exterior of the unit for cleanliness and suitable means of securing the cord. Verify that
general physical condition. Ensure that plastic the unit has adequate alarms or indicators for line-
housings are intact, that all hardware is present power loss and battery depletion and an adequate
and tight. battery-charging indicator.

Mount/Fasteners. If the unit is mounted on Strain Reliefs. Examine the strain reliefs at
a stand or cart, examine the condition of the both ends of the line cord. Be sure that they hold
mount. If it is attached to a wall or rests on a the cord securely.
shelf, check the security of this attachment.
Circuit Breaker/Fuse. If the unit has a
Casters/Brakes. If the unit is mounted on a switch-type circuit breaker, check that it moves
cart or stand, verify that the correct casters have freely. If the unit is protected by an external fuse,
been supplied with the unit (e.g., size, correct verify that the fuse type is labeled and that all
swivel). (ECRI recommends 5 in [12.7 cm] fuses and spares are the proper current rating and
diameter casters for mobile units to reduce shock type. If the value and type are not labeled, check
to the unit and to minimize the effort required to the manual for the proper current rating and type
roll the unit across elevator thresholds and other and permanently mark this information on the unit
uneven surfaces.) Verify caster and brake housing near the fuse holder.
operation, if the unit is so equipped.
Tubes/Hoses/Bulbs. Check the condition
AC Plug. A solidly constructed, good quality of all tubing, all hoses, the cuff, and the bulb (if
plug with adequate strain relief is acceptable, but present). Be sure that they are not cracked or
the use of a Hospital Grade plug (identifiable by a kinked.
green dot and/or labeling) will eliminate
guesswork and ensure a plug of acceptable Fittings/Connectors. Examine all fittings
construction quality. Right-angle plugs are
and connectors for general condition. Fittings
unacceptable for devices that are moved
should be tight (or within manufacturer's
frequently. A good quality two-prong plug is
specifications) and should not leak. If keyed
acceptable for double-insulated devices. Replace
connectors are used, make sure that the keying is
the plug or have the supplier replace it if it is not
correct.
Hospital Grade or otherwise suitable. Hospital
Grade molded plugs are acceptable.
Transducers (non-oscillometric
Examine the AC power plug for damage. Attempt units). Ensure that any necessary transducers
to wiggle the blades to determine if they are are on hand and check their physical condition.
secure. Shake nonmolded plugs and listen for
rattles that could indicate loose screws. Controls/Switches. Examine all controls
and switches for physical condition, secure
Line Cord. Ensure that the line cord is long mounting, and correct motion. If a control has
enough for the unit's intended application; an fixed-limit stops, check for proper alignment, as
extension cord should not be required. (A length of well as positive stopping. Ensure to check that
10 ft [3 m] is suitable for most applications.) each control and switch performs its proper

Health Devices Inspection and Preventive Maintenance System 2001 ECRI. All Rights Reserved.
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 Procedure No. 454-20010301 Blood Pressure Monitors, Electronic Indirect (Acceptance)

function, including the control that enables manual

deflation. Verify that alarms are loud, distinctive, and/or
bright enough to be noticed in the environment in
Battery/Charger. Determine the which the unit will normally be used. If a remote
replacement interval for all batteries and alarm-indicator is required, verify that it is
document the interval(s) in an equipment control available and functioning. Audible alarm-volume
system or a hard copy file for the unit. It may be controls should not allow the alarm to be turned
desirable to disconnect the battery and determine off or lowered to an indiscernible volume.
if the unit still operates on line power.
Induce alarm conditions to activate audible and
Operate the unit on battery power for several visual alarms. Check that all associated interlocks
minutes to verify that the battery is charged and (e.g., auto deflate) function. If the unit has an
can hold a charge. Activate the battery test alarm-silence feature, check the method of reset
function, if so equipped. Check the condition of the (i.e., manual or automatic) against the
battery charger, and verify that battery charge manufacturer's specifications.
indicators function. Provide users with instructions
and/or checklist procedure to ensure adequate Audible Signals. Operate the unit to activate
battery charging and performance. any audible signals. Confirm appropriate volume,
as well as the operation of a volume control, if so
Battery. Inspect the physical condition of equipped.
batteries and battery connectors, if readily
accessible. Check operation of battery-operated Labeling. Check that all necessary placards,
power-loss alarms, if so equipped. Operate the labels, conversion charts, and instruction cards are
unit on battery power for several minutes to check present and legible.
that the battery is charged and can hold a charge.
(The inspection can be carried out on battery Accessories. Verify that all necessary features
power to help confirm adequate battery capacity.) and accessories (e.g., appropriately sized cuffs)
Check battery condition by activating the battery have been supplied and stored with the unit.
test function or measuring the output voltage. Check that Velcro closures hold firmly. At least one
Confirm the operation of a charging indicator. Be copy each (two are generally preferred) of the
sure that the battery is recharged or charging instruction and service manuals, including
when the inspection is complete. If it is necessary schematics, should be shipped with the unit and
to replace a battery, label it with the date. filed in the central equipment file. A copy of the
instruction manual should be kept with the unit
Indicators/Displays. Confirm the operation and read by all operators before the unit is put in
of all lights, indicators, meters, gauges, and visual use.
displays on the unit. Be sure that all segments of a
digital display function. If the unit has a printer/recorder, check to see that
it operates when it is supposed to, that the paper
User Calibration. Verify that the calibration folds smoothly, and that the printout is accurate
function operates. and legible.

Alarms. Verify that configurable alarm features

are appropriately set and consistent among all Quantitative Tasks
units. It should not be possible for critical alarms
to be turned off, silenced, or defeated without Grounding Resistance. Using an
adequate warning to the operator or automatic ohmmeter, electrical safety analyzer, or
alarm reactivation after a short delay. Such multimeter with good resolution of fractional
deficiencies should usually be recognized during ohms, measure and record the resistance between
prepurchase evaluation. However, if any are found, the grounding pin of the power cord and exposed
review the justification for purchasing this unit and (unpainted and not anodized) metal on the
discuss corrective action with the manufacturer. chassis. Grounding resistance should not exceed
(Alarm features may be optional or 0.5 . If the system is modular or composed of
programmable.) If no remedy is available, a user separate components, verify grounding of the
training program should be instituted to reduce mainframe and each module or component. If the
the risk of incorrect use. A warning label on the unit is double insulated, grounding resistance need
unit or a poster in the area of use may be
appropriate.

Health Devices Inspection and Preventive Maintenance System 2001 ECRI. All Rights Reserved.
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 Procedure No. 454-20010301 Blood Pressure Monitors, Electronic Indirect (Acceptance)

not be measured; indicate "DI" instead of the (use the calibration function) to about the
ground resistance value. maximum scale indication. Read the indicator after
1 min to determine the rate of pressure loss in mm
Chassis Leakage Current. With the Hg/min. This rate should not exceed 15 mm
polarity of the power line normal and the Hg/min. If it does, recheck all fittings and repeat
equipment ground wire disconnected, measure the task.
chassis leakage current with the unit operating in
all normal modes, including on, standby, and off.
Record the maximum leakage current; it should
not exceed 300 A for patient-care equipment
used in a patient-care vicinity [NFPA 99 7-
5.1.3.5(a)]. ECRI does not recommend chassis
leakage current tests of double-insulated devices.

Leakage current must be measured with the unit

powered by a conventional (grounded) power
system, even if it is normally used in an area with
isolated power. If the unit has a special plug (e.g.,
explosion proof), a corresponding adapter is
required.

Though confirmation of grounding integrity

provides reasonable assurance of safety for
devices with permanent redundant grounding,
NFPA 99 calls for measurement of chassis leakage Figure 1. Test setup.
current with the redundant ground intact [NFPA 99
7-5.1.3.5]. Where practical, verify that these units If a unit does not allow testing this way, wrap the
meet appropriate chassis leakage current cuff around a simulated limb. Connect the blood
requirements before installation or connection to pressure set to a calibrated gauge or meter as
ground during acceptance testing. shown in Figure 1.

Be alert for leakage current of the unit in the off Heart Rate. Use an NIBP simulator or connect
mode that is greater than about 30 A and is the cuff to yourself or a volunteer. Displayed heart
greater than or equal to the leakage current in the rate should correspond to manually palpated rate
on mode. Although this may be normal and proper within 10%.
for the unit, it may indicate that the on/off switch
is incorrectly wired in the neutral (instead of the
Static Pressure Accuracy. Use an NIBP
hot) line. Incorrect switch wiring poses a risk to
simulator or connect the blood pressure set to a
service personnel who believe that the power is
pressure gauge or meter as shown in Figure 1.
disconnected when the switch is off. Check the
Inflate the system to around 200 mm Hg with
wiring, or contact the manufacturer.
either the squeeze bulb or the unit's calibration
mode. The readings on the unit and the test device
Inspect AC adapters used to power (or recharge)
should not differ by more than 3 mm Hg. Repeat
certain units for CE mark or UL (or other testing
the task for a pressure around 120 mm Hg and 80
laboratory) listing and to verify that it is labeled to
mm Hg.
identify the unit with which it is to be used. ECRI
recommends testing of adapters, particularly those
that are not listed, by measuring the leakage Accuracy on Volunteer. Apply the cuff to
current from each secondary (low voltage) yourself or a volunteer, activate the unit, and
connection to ground. The leakage current should verify that it cycles through the measurement
not exceed the limits for the device chassis correctly. Compare measurement by a nurse to a
leakage current to ground (300 A in patient-care blood pressure reading with the unit. The nurse's
areas). (See Electrical Safety for further details reading and the unit's reading should not differ by
and a discussion of the use of these devices in more than 10 mm Hg. Differences in readings may
hospitals.) be due to technique, cuff location (i.e., right or left
arm), and time (if not taken simultaneously). If
significant differences are obtained on repetitive
Air Leakage. Use an NIBP simulator or wrap
tries, consider having another qualified person
the cuff around a simulated limb. Inflate the cuff
obtain the manual reading before contacting the

Health Devices Inspection and Preventive Maintenance System 2001 ECRI. All Rights Reserved.
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 Procedure No. 454-20010301 Blood Pressure Monitors, Electronic Indirect (Acceptance)

manufacturer. The deflation rate should be 2 to 6

mm Hg/sec, unless the unit has an algorithm that
interpolates the reading between pulses. If the
rate is faster, check all fittings and repeat the
task.

Maximum Pressure. Using the simulated

limb setup in Figure 1, inflate the cuff to determine
maximum pressure. Adult units should not exceed
330 mm Hg; units with neonatal and/or pediatric
modes should have lower maximum pressure when
operating in these modes.

Before Returning to Use

Make sure that all controls are set properly. Set
alarms loud enough to alert personnel in the area
in which the unit will be used. Other controls
should be in their normal pre-use positions.

Recharge battery-powered units or equip with

fresh batteries if needed.

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