Blood Pressure Packet V2.pdf


1. Introduction*to*Blood*Pressure*Monitors!(PowerPoint)!


1. Introduction*to*Blood*Pressure*Monitors!
• Blood!Pressure!Monitor:!Brief!Overview!(p.!3)!
• Introduction!to!Blood!Pressure!(p.!4O16)!
• Introduction!to!the!Pulse!(p.!17O20)!
• Operation!and!Use!of!Blood!Pressure!Monitors!(p.!21O25)!
• Sphygmomanometer!Introduction!(p.!26)!
• Stethoscope!Introduction!(p.!27)!

2. Schematics*and*Diagrams!!
• Figure!1:!Equipment!Used!to!Manually!Measure!Blood!Pressure!(p.!29)!
• Figure!2:!The!Human!Circulatory!System!(p.!30)!
• Figure!3:!Pressure!Valves!of!the!Circulatory!System!(p.!31)!
• Figure!4:!Setup!of!a!Pressure!Measuring!System!&!Circuit!Diagram!(p.!32)!
• Figure!5:!Fundamental!parts!of!NIBP!Measuring!System!(p.!33)!
• Figure!6:!How!to!Take!Blood!Pressure!(p.!34O35)!

3. Preventative*Maintenance!!
• Blood!Pressure!Machine!(Automatic)!Preventative!Maintenance!(p.!37)!
• Blood!Pressure!Machine!(Manual)!Preventative!Maintenance!(p.!38O39)!
• Sphygmomanometer!Preventative!Maintenance!Checklist!(p.!40)!
• Stethoscope!Preventative!Maintenance!Checklist!(p.!41)!

4. Troubleshooting*and*Repair!!
• Blood!Pressure!Machine!(Automatic)!Troubleshooting!Flowchart!(p.!43O46)!
• Blood!Pressure!Machine!(Manual)!Troubleshooting!Flowchart!(p.!47O51)!
• Sphygmomanometer!Troubleshooting!Checklist!(p.!52)!
• Stethoscope!Troubleshooting!Checklist!(p.!53)!

5. Resources*for*More*Information!(p.!55)!
6. Bibliography:*(p.!56O57)!

1. Operation*and*Use**







* !
© Copyright ECRI Institute 2011 (not including the GMDN code and device name).

Reproduced with Permission from ECRI Institute’s Healthcare Product Comparison System.

© Copyright GMDN Agency 2011. GMDN codes and device names are reproduced with permission from the GMDN Agency.











Health problem addressed
NIBP is an essential indicator of physiologic condition. As one of
the most frequently used diagnostic tests, it indicates changes
in blood volume, the pumping effi ciency of the heart, and the
resistance of the peripheral vasculature. Vital signs monitors are
used to measure basic physiologic parameters so that clinicians
can be informed of changes in a patient’s condition. Depending
on their confi guration, these units can measure and display
numerical data for NIBP, oxygen saturation, and temperature.

Product description
Automatic electronic sphygmomanometers noninvasively
measure and display a patient’s arterial blood pressure. The main
unit includes controls and a display; it also includes appropriate
attached cuffs, probes, and sensors that make possible sequential
and/or simultaneous measurements of the parameters. Some of
the NIBP monitors can be used as vital sign monitors with the
real-time measuring and display of two or more of the vital signs.
These monitors typically consist of portable or mobile electronic
units. The monitor may be connected to the line and/or powered
by internal batteries. Many devices may also perform continuous
monitoring during transportation or at the bedside. Vital signs
physiologic monitors are intended mainly for periodic automated
measuring of the parameters of one or more patients.

Principles of operation
Automatic electronic sphygmomanometers (NIBP monitors)
measure by the use of sound and detection of blood sound
turbulence (Korotkoff sounds). A microphone positioned against an
artery compressed by the device cuff detects the Korotkoff sounds,
enabling the unit to directly determine systolic and diastolic values
blood pressure values. NIBP is usually measured using cuffs and
either auscultatory or oscillometric techniques. The measurement
of temperature is typically accomplished using an intraoral sensor,
and SpO2 is determined using pulse oximetry sensors. These
monitors typically consist of portable or mobile electronic units
that facilitate movement from one location to other; the monitor
may be connected to the line and/or powered by internal batteries.

Operating steps
The cuffs, probes, and sensors are attached to the patient, and
then the monitor will begin taking intermittent or continuous
measurements as selected by the clinician. The devices may
remain at a patient’s bedside or can be transported by a caregiver
for vital signs spot checking throughout a care area. Alarms (e.g.,
for high blood pressure or low oxygen saturation) can typically
be set by caregivers and can be manually temporarily silenced.

Reported problems
Problems associated with monitors are often user-related.
Poor cuff placement or sensor preparation and attachment
are most commonly reported. Cables and lead wires should
be periodically inspected for breaks and cracks. Automatic

electronic sphygmomanometry and pulse
oximeters may have the inability to effectively
monitor patients with certain conditions (e.g.,
tremors, convulsions, abnormal heart rhythms,
low blood pressure)

Use and maintenance
User(s): Physicians, nurses, other medical staff

Maintenance: Biomedical or clinical engineer/
technician, medical staff, manufacturer/

Training: Initial training by manufacturer,
operator’s manuals, user’s guide

Environment of use
Settings of use: Hospital (all areas),
ambulatory surgery centers

Requirements: Battery, uninterruptible power
source, appropriate cuffs/sensors

Product specifi cations
Approx. dimensions (mm): 100 x 150 x 200

Approx. weight (kg): 3

Consumables: Batteries, cables, sensors/
electrodes, cuffs

Price range (USD): 580 - 4,500

Typical product life time (years): 10

Shelf life (consumables): NA

Types and variations
Roll stand, portable, pole or bed mounts

Blood pressure monitor

Sphygmomanometers, Electronic, Automatic,
Sphygmomanometers, Electronic, Automatic,
Monitors, Physiologic, Vital Signs

16173 Automatic-infl ation electronic
sphygmomanometer, non-portable

Other common names:
Vital signs monitoring units; noninvasive blood pressure (NIBP) monitors; auscultatory sphygmomanometers;
oscillometric sphygmomanometers; oscillotonometers, spot check monitors; spot checking; Recorder,
sphygmomanometer, automatic

WHO. “Blood Pressure Monitor,” From the publication: C re Medical Equipment. Geneva,
Switzerland, 2011.

Blood Pressure Monitor Brief Overview

Blood pressure 1

Blood pressure
See Hypertension for more information about high blood pressure.

A sphygmomanometer, a device used for
measuring arterial pressure.

Blood pressure (BP) is a force exerted by circulating blood on the
walls of blood vessels, and is one of the principal vital signs. During
each heartbeat, BP varies between a maximum (systolic) and a
minimum (diastolic) pressure. The mean BP, due to pumping by the
heart and resistance in blood vessels, decreases as the circulating blood
moves away from the heart through arteries. It has its greatest decrease
in the small arteries and arterioles, and continues to decrease as the
blood moves through the capillaries and back to the heart through
veins.[1] Gravity, valves in veins, and pumping from contraction of
skeletal muscles, are some other influences on BP at various places in
the body.

The term blood pressure usually refers to the pressure measured at a person's upper arm. It is measured on the inside
of an elbow at the brachial artery, which is the upper arm's major blood vessel that carries blood away from the heart.
A person's BP is usually expressed in terms of the systolic pressure and diastolic pressure, for example 120/80.


A medical student checking blood pressure using
a sphygmomanometer and stethoscope.

Arterial pressure is most commonly measured via a
sphygmomanometer, which historically used the height of a column of
mercury to reflect the circulating pressure.[2] Today BP values are still
reported in millimetres of mercury (mmHg), though aneroid and
electronic devices do not use mercury.

For each heartbeat, BP varies between systolic and diastolic pressures.
Systolic pressure is peak pressure in the arteries, which occurs near the
end of the cardiac cycle when the ventricles are contracting. Diastolic
pressure is minimum pressure in the arteries, which occurs near the
beginning of the cardiac cycle when the ventricles are filled with
blood. An example of normal measured values for a resting, healthy
adult human is 120 mmHg systolic and 80 mmHg diastolic (written as 120/80 mmHg, and spoken [in the US] as
"one-twenty over eighty").

Systolic and diastolic arterial BPs are not static but undergo natural variations from one heartbeat to another and
throughout the day (in a circadian rhythm). They also change in response to stress, nutritional factors, drugs, disease,
exercise, and momentarily from standing up. Sometimes the variations are large. Hypertension refers to arterial
pressure being abnormally high, as opposed to hypotension, when it is abnormally low. Along with body
temperature, respiratory rate, and pulse rate, BP is one of the four main vital signs routinely monitored by medical
professionals and healthcare providers.[3]

Arterial pressures are usually measured non-invasively, without penetrating skin or artery. Measuring pressure
invasively, by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a
hospital setting.

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Introduction to Blood Pressure

Blood pressure 2

Noninvasive measurement
The non invasive auscultatory and oscillometric measurements are simpler and quicker than invasive measurements,
require less expertise in fitting, have virtually no complications, and are less unpleasant and painful for the person.
However, noninvasive methods may yield somewhat lower accuracy and small systematic differences in numerical
results. Non-invasive measurement methods are more commonly used for routine examinations and monitoring.

Palpation method

A minimum systolic value can be roughly estimated without any equipment by palpation, most often used in
emergency situations. Historically, students have been taught that palpation of a radial pulse indicates a minimum
BP of 80 mmHg, a femoral pulse indicates at least 70 mmHg, and a carotid pulse indicates a minimum of 60 mmHg.
However, at least one study indicated that this method often overestimates patients' systolic BP.[4] A more accurate
value of systolic BP can be obtained with a sphygmomanometer and palpating for when a radial pulse returns.[5] The
diastolic blood pressure can not be estimated by this method.[6] Sometimes palpation is used to get an estimate
before using the auscultatory method.

Auscultatory method

Auscultatory method aneroid sphygmomanometer
with stethoscope

Mercury manometer

The auscultatory method (from the Latin word for listening) uses a
stethoscope and a sphygmomanometer. This comprises an inflatable
(Riva-Rocci) cuff placed around the upper arm at roughly the same
vertical height as the heart, attached to a mercury or aneroid
manometer. The mercury manometer,considered the gold standard,
measures the height of a column of mercury, giving an absolute result
without need for calibration, and consequently not subject to the errors
and drift of calibration which affect other methods. The use of mercury
manometers is often required in clinical trials and for the clinical
measurement of hypertension in high risk patients, such as pregnant

A cuff of appropriate size is fitted smoothly and snugly, then inflated
manually by repeatedly squeezing a rubber bulb until the artery is
completely occluded. Listening with the stethoscope to the brachial
artery at the elbow, the examiner slowly releases the pressure in the
cuff. When blood just starts to flow in the artery, the turbulent flow
creates a "whooshing" or pounding (first Korotkoff sound). The
pressure at which this sound is first heard is the systolic BP. The cuff
pressure is further released until no sound can be heard (fifth Korotkoff
sound), at the diastolic arterial pressure.

The auscultatory method has been predominant since the beginning of
BP measurements but in other cases it's being replaced by other
noninvasive techniques.[7]

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 3

Oscillometric method

The Oscillometric method was first demonstrated in 1876 and involves the observation of oscillations in the
sphygmomanometer cuff pressure[8] which are caused by the oscillations of blood flow, i.e. the pulse.[9] The
electronic version of this method is sometimes used in long-term measurements and general practice. It uses a
sphygmomanometer cuff like the auscultatory method, but with an electronic pressure sensor (transducer) to observe
cuff pressure oscillations, electronics to automatically interpret them, and automatic inflation and deflation of the
cuff. The pressure sensor should be calibrated periodically to maintain accuracy.
Oscillometric measurement requires less skill than the auscultatory technique, and may be suitable for use by
untrained staff and for automated patient home monitoring.
The cuff is inflated to a pressure initially in excess of the systolic arterial pressure, and then reduces to below
diastolic pressure over a period of about 30 seconds. When blood flow is nil (cuff pressure exceeding systolic
pressure) or unimpeded (cuff pressure below diastolic pressure), cuff pressure will be essentially constant. It is
essential that the cuff size is correct: undersized cuffs may yield too high a pressure, whereas oversized cuffs yield
too low a pressure. When blood flow is present, but restricted, the cuff pressure, which is monitored by the pressure
sensor, will vary periodically in synchrony with the cyclic expansion and contraction of the brachial artery, i.e., it
will oscillate. The values of systolic and diastolic pressure are computed, not actually measured from the raw data,
using an algorithm; the computed results are displayed.
Oscillometric monitors may produce inaccurate readings in patients with heart and circulation problems, that include
arterial sclerosis, arrhythmia, preeclampsia, pulsus alternans, and pulsus paradoxus.
In practice the different methods do not give identical results; an algorithm and experimentally obtained coefficients
are used to adjust the oscillometric results to give readings which match the auscultatory results as well as possible.
Some equipment uses computer-aided analysis of the instantaneous arterial pressure waveform to determine the
systolic, mean, and diastolic points. Since many oscillometric devices have not been validated, caution must be given
as most are not suitable in clinical and acute care settings.
The term NIBP, for Non-Invasive Blood Pressure, is often used to describe oscillometric monitoring equipment.

White-coat hypertension

For some patients, BP measurements taken in a doctor's office may not correctly characterize their typical BP.[10] In
up to 25% of patients, the office measurement is higher than their typical BP. This type of error is called white-coat
hypertension (WCH) and can result from anxiety related to an examination by a health care professional.[11] The
misdiagnosis of hypertension for these patients can result in needless and possibly harmful medication. WCH can be
reduced (but not eliminated) with automated BP measurements over 15 to 20 minutes in a quiet part of the office or

Debate continues regarding the significance of this effect. Some reactive patients will also react to many other
stimuli throughout their daily lives, and require treatment. In some cases a lower BP reading occurs at the doctor's

Home monitoring

Ambulatory blood pressure devices that take readings every half hour throughout the day and night have been used
for identifying and mitigating measurement problems like white-coat hypertension. Except for periods during sleep,
home monitoring could be used for these purposes instead of ambulatory blood pressure monitoring.[14] Home
monitoring may also be used to improve hypertension management and to monitor the effects of lifestyle changes
and medication related to BP.[15] Compared to ambulatory blood pressure measurements, home monitoring has been
found to be an effective and lower cost alternative.[14] [16] [17]

Aside from the white coat effect, BP readings outside of a clinical setting are usually slightly lower in the majority of
people. The studies that looked into the risks from hypertension and the benefits of lowering BP in affected patients

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 4

were based on readings in a clinical environment.
When measuring BP, an accurate reading requires that one not drink coffee, smoke cigarettes, or engage in strenuous
exercise for 30 minutes before taking the reading. A full bladder may have a small effect on BP readings, so if the
urge to urinate exists, one should do so before the reading. For 5 minutes before the reading, one should sit upright in
a chair with one's feet flat on the floor and with limbs uncrossed. The BP cuff should always be against bare skin, as
readings taken over a shirt sleeve are less accurate. During the reading, the arm that is used should be relaxed and
kept at heart level, for example by resting it on a table.[18]

Since BP varies throughout the day, measurements intended to monitor changes over longer time frames should be
taken at the same time of day to ensure that the readings are comparable. Suitable times are:
• immediately after awakening (before washing/dressing and taking breakfast/drink), while the body is still resting,
• immediately after finishing work.
Automatic self-contained BP monitors are available at reasonable prices, some of which are capable of Korotkoff's
measurement in addition to oscillometric methods, enabling irregular heartbeat patients to accurately measure their
blood pressure at home.

Invasive measurement
Arterial blood pressure (BP) is most accurately measured invasively through an arterial line. Invasive arterial
pressure measurement with intravascular cannulae involves direct measurement of arterial pressure by placing a
cannula needle in an artery (usually radial, femoral, dorsalis pedis or brachial). This procedure can be done by any
licensed medical doctor, nurse, or a Respiratory Therapist.
The cannula must be connected to a sterile, fluid-filled system, which is connected to an electronic pressure
transducer. The advantage of this system is that pressure is constantly monitored beat-by-beat, and a waveform (a
graph of pressure against time) can be displayed. This invasive technique is regularly employed in human and
veterinary intensive care medicine, anesthesiology, and for research purposes.
Cannulation for invasive vascular pressure monitoring is infrequently associated with complications such as
thrombosis, infection, and bleeding. Patients with invasive arterial monitoring require very close supervision, as
there is a danger of severe bleeding if the line becomes disconnected. It is generally reserved for patients where rapid
variations in arterial pressure are anticipated.
Invasive vascular pressure monitors are pressure monitoring systems designed to acquire pressure information for
display and processing. There are a variety of invasive vascular pressure monitors for trauma, critical care, and
operating room applications. These include single pressure, dual pressure, and multi-parameter (i.e. pressure /
temperature). The monitors can be used for measurement and follow-up of arterial, central venous, pulmonary
arterial, left atrial, right atrial, femoral arterial, umbilical venous, umbilical arterial, and intracranial pressures.

The following classification of blood pressure applies to adults aged 18 and older. It is based on the average of
seated BP readings that were properly measured during 2 or more office visits.[15] [19]

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 5

Classification of blood pressure for adults

Category systolic, mmHg diastolic, mmHg

Hypotension < 90 < 60

Normal 90 – 120 and 60 – 80

Prehypertension 121 – 139 or 81 – 89

Stage 1 Hypertension 140 – 159 or 90 – 99

Stage 2 Hypertension ≥ 160 or ≥ 100

Normal values
While average values for arterial pressure could be computed for any given population, there is often a large
variation from person to person; arterial pressure also varies in individuals from moment to moment. Additionally,
the average of any given population may have a questionable correlation with its general health, thus the relevance of
such average values is equally questionable. However, in a study of 100 subjects with no known history of
hypertension, an average blood pressure of 112/64 mmHg was found,[20] which is in the normal range.
Various factors influence a person's average BP and variations. Factors such as age and gender[21] influence average
values. In children, the normal ranges are lower than for adults and depend on height.[22] As adults age, systolic
pressure tends to rise and diastolic tends to fall.[23] In the elderly, BP tends to be above the normal adult range,[24]

largely because of reduced flexibility of the arteries. Also, an individual's BP varies with exercise, emotional
reactions, sleep, digestion and time of day.
Differences between left and right arm BP measurements tend to be random and average to nearly zero if enough
measurements are taken. However, in a small percentage of cases there is a consistently present difference greater
than 10 mmHg which may need further investigation, e.g. for obstructive arterial disease.[25] [26]

The risk of cardiovascular disease increases progressively above 115/75 mmHg.[27] In the past, hypertension was
only diagnosed if secondary signs of high arterial pressure were present, along with a prolonged high systolic
pressure reading over several visits. In the UK, patients’ readings are considered normal up to 140/90 mmHg.[28]

Clinical trials demonstrate that people who maintain arterial pressures at the low end of these pressure ranges have
much better long term cardiovascular health. The principal medical debate concerns the aggressiveness and relative
value of methods used to lower pressures into this range for those who do not maintain such pressure on their own.
Elevations, more commonly seen in older people, though often considered normal, are associated with increased
morbidity and mortality.

There are many physical factors that influence arterial pressure. Each of these may in turn be influenced by
physiological factors, such as diet, exercise, disease, drugs or alcohol, stress, obesity, and so-forth. [29]

Some physical factors are:
• Rate of pumping. In the circulatory system, this rate is called heart rate, the rate at which blood (the fluid) is

pumped by the heart. The volume of blood flow from the heart is called the cardiac output which is the heart rate
(the rate of contraction) multiplied by the stroke volume (the amount of blood pumped out from the heart with
each contraction). The higher the heart rate, the higher the arterial pressure, assuming no reduction in stroke

• Volume of fluid or blood volume, the amount of blood that is present in the body. The more blood present in the
body, the higher the rate of blood return to the heart and the resulting cardiac output. There is some relationship
between dietary salt intake and increased blood volume, potentially resulting in higher arterial pressure, though

Blood pressure 6

this varies with the individual and is highly dependent on autonomic nervous system response and the
renin-angiotensin system.

• Resistance. In the circulatory system, this is the resistance of the blood vessels. The higher the resistance, the
higher the arterial pressure upstream from the resistance to blood flow. Resistance is related to vessel radius (the
larger the radius, the lower the resistance), vessel length (the longer the vessel, the higher the resistance), as well
as the smoothness of the blood vessel walls. Smoothness is reduced by the build up of fatty deposits on the
arterial walls. Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing BP.
Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure.
Resistance, and its relation to volumetric flow rate (Q) and pressure difference between the two ends of a vessel
are described by Poiseuille's Law.

• Viscosity, or thickness of the fluid. If the blood gets thicker, the result is an increase in arterial pressure. Certain
medical conditions can change the viscosity of the blood. For instance, low red blood cell concentration, anemia,
reduces viscosity, whereas increased red blood cell concentration increases viscosity. Viscosity also increases
with blood sugar concentration—visualize pumping syrup. It had been thought that aspirin and related "blood
thinner" drugs decreased the viscosity of blood, but studies found[30] that they act by reducing the tendency of the
blood to clot instead.

In practice, each individual's autonomic nervous system responds to and regulates all these interacting factors so that,
although the above issues are important, the actual arterial pressure response of a given individual varies widely
because of both split-second and slow-moving responses of the nervous system and end organs. These responses are
very effective in changing the variables and resulting BP from moment to moment.

Mean arterial pressure
The mean arterial pressure (MAP) is the average over a cardiac cycle and is determined by the cardiac output (CO),
systemic vascular resistance (SVR), and central venous pressure (CVP),[31]

MAP can be approximately determined from measurements of the systolic pressure   and the diastolic pressure
  while there is a normal resting heart rate,[31]

Pulse pressure
The up and down fluctuation of the arterial pressure results from the pulsatile nature of the cardiac output, i.e. the
heartbeat. The pulse pressure is determined by the interaction of the stroke volume of the heart, compliance (ability
to expand) of the aorta, and the resistance to flow in the arterial tree. By expanding under pressure, the aorta absorbs
some of the force of the blood surge from the heart during a heartbeat. In this way the pulse pressure is reduced from
what it would be if the aorta wasn't compliant.[32]

The pulse pressure can be simply calculated from the difference of the measured systolic and diastolic pressures,[32]

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 7

Vascular resistance
The larger arteries, including all large enough to see without magnification, are low resistance conduits (assuming no
advanced atherosclerotic changes) with high flow rates that generate only small drops in pressure.

Vascular pressure wave
Modern physiology developed the concept of the vascular pressure wave (VPW). This wave is created by the heart
during the systole and originates in the ascending aorta. Much faster than the stream of blood itself, it is then
transported through the vessel walls to the peripheral arteries. There the pressure wave can be palpated as the
peripheral pulse. As the wave is reflected at the peripheral veins it runs back in a centripetal fashion. Where the
crests of the reflected and the original wave meet, the pressure inside the vessel is higher than the true pressure in the
aorta. This concept explains why the arterial pressure inside the peripheral arteries of the legs and arms is higher than
the arterial pressure in the aorta,[33] [34] [35] and in turn for the higher pressures seen at the ankle compared to the arm
with normal ankle brachial pressure index values.

The endogenous regulation of arterial pressure is not completely understood. Currently, three mechanisms of
regulating arterial pressure have been well-characterized:
• Baroreceptor reflex: Baroreceptors detect changes in arterial pressure and send signals ultimately to the medulla

of the brain stem. The medulla, by way of the autonomic nervous system, adjusts the mean arterial pressure by
altering both the force and speed of the heart's contractions, as well as the total peripheral resistance. The most
important arterial baroreceptors are located in the left and right carotid sinuses and in the aortic arch.[36]

• Renin-angiotensin system (RAS): This system is generally known for its long-term adjustment of arterial
pressure. This system allows the kidney to compensate for loss in blood volume or drops in arterial pressure by
activating an endogenous vasoconstrictor known as angiotensin II.

• Aldosterone release: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high
serum potassium levels. Aldosterone stimulates sodium retention and potassium excretion by the kidneys. Since
sodium is the main ion that determines the amount of fluid in the blood vessels by osmosis, aldosterone will
increase fluid retention, and indirectly, arterial pressure.

These different mechanisms are not necessarily independent of each other, as indicated by the link between the RAS
and aldosterone release. Currently, the RAS system is targeted pharmacologically by ACE inhibitors and angiotensin
II receptor antagonists. The aldosterone system is directly targeted by spironolactone, an aldosterone antagonist. The
fluid retention may be targeted by diuretics; the antihypertensive effect of diuretics is due to its effect on blood
volume. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer
from orthostatic hypotension and fainting.

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 8


High arterial pressure

Overview of main complications of persistent high
blood pressure.

Arterial hypertension can be an indicator of other problems and
may have long-term adverse effects. Sometimes it can be an acute
problem, for example hypertensive emergency.

All levels of arterial pressure put mechanical stress on the arterial
walls. Higher pressures increase heart workload and progression of
unhealthy tissue growth (atheroma) that develops within the walls
of arteries. The higher the pressure, the more stress that is present
and the more atheroma tend to progress and the heart muscle tends
to thicken, enlarge and become weaker over time.

Persistent hypertension is one of the risk factors for strokes, heart
attacks, heart failure and arterial aneurysms, and is the leading
cause of chronic renal failure. Even moderate elevation of arterial
pressure leads to shortened life expectancy. At severely high
pressures, mean arterial pressures 50% or more above average, a
person can expect to live no more than a few years unless appropriately treated.[37]

In the past, most attention was paid to diastolic pressure; but nowadays it is recognised that both high systolic
pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk
factors. In some cases, it appears that a decrease in excessive diastolic pressure can actually increase risk, due
probably to the increased difference between systolic and diastolic pressures (see the article on pulse pressure).

Low arterial pressure
Blood pressure that is too low is known as hypotension. The similarity in pronunciation with hypertension can cause
confusion. Hypotension is a medical concern only if it causes signs or symptoms, such as dizziness, fainting, or in
extreme cases, shock.[19]

When arterial pressure and blood flow decrease beyond a certain point, the perfusion of the brain becomes critically
decreased (i.e., the blood supply is not sufficient), causing lightheadedness, dizziness, weakness or fainting.
Sometimes the arterial pressure drops significantly when a patient stands up from sitting. This is known as
orthostatic hypotension (postural hypotension); gravity reduces the rate of blood return from the body veins below
the heart back to the heart, thus reducing stroke volume and cardiac output.
When people are healthy, the veins below their heart quickly constrict and the heart rate increases to minimize and
compensate for the gravity effect. This is carried out involuntarily by the autonomic nervous system. The system
usually requires a few seconds to fully adjust and if the compensations are too slow or inadequate, the individual will
suffer reduced blood flow to the brain, dizziness and potential blackout. Increases in G-loading, such as routinely
experienced by aerobatic or combat pilots 'pulling Gs', greatly increases this effect. Repositioning the body
perpendicular to gravity largely eliminates the problem.
Other causes of low arterial pressure include:
• Sepsis
• Hemorrhage - blood loss
• Toxins including toxic doses of BP medicine
• Hormonal abnormalities, such as Addison's disease

Blood pressure 9

Shock is a complex condition which leads to critically decreased perfusion. The usual mechanisms are loss of blood
volume, pooling of blood within the veins reducing adequate return to the heart and/or low effective heart pumping.
Low arterial pressure, especially low pulse pressure, is a sign of shock and contributes to and reflects decreased
If there is a significant difference in the pressure from one arm to the other, that may indicate a narrowing (for
example, due to aortic coarctation, aortic dissection, thrombosis or embolism) of an artery.

Other sites
Blood pressure generally refers to the arterial pressure in the systemic circulation. However, measurement of
pressures in the venous system and the pulmonary vessels plays an important role in intensive care medicine but
requires an invasive central venous catheter.

Venous pressure
Venous pressure is the vascular pressure in a vein or in the atria of the heart. It is much less than arterial pressure,
with common values of 5 mmHg in the right atrium and 8 mmHg in the left atrium.

Pulmonary pressure
Normally, the pressure in the pulmonary artery is about 15 mmHg at rest.[38]

Increased BP in the capillaries of the lung cause pulmonary hypertension, with interstitial edema if the pressure
increases to above 20 mmHg, and to frank pulmonary edema at pressures above 25 mmHg.[39]

Fetal blood pressure
In pregnancy, it is the fetal heart and not the mother's heart that builds up the fetal BP to drive its blood through the
fetal circulation.
The BP in the fetal aorta is approximately 30 mmHg at 20 weeks of gestation, and increases to ca 45 mmHg at 40
weeks of gestation.[40]

The average BP for full-term infants:
Systolic 65–95 mm Hg
Diastolic 30–60 mm Hg [41]

See also
• Ambulatory blood pressure
• Antihypertensive
• Auscultatory gap
• Central venous pressure
• Hypertension
• Hypotension
• Korotkoff sounds
• Lactotripeptides
• Mean arterial pressure
• Prehypertension
• Pulse pressure
• Pulse rate
• Resperate
• Sphygmomanometer

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Blood pressure 10

• Vital signs

1. Pickering, TG; Hall, JE; Appel, LJ et al. (2005). "Recommendations for blood pressure measurement in humans

and experimental animals: Part 1: blood pressure measurement in humans: a statement for professionals from the
Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood
Pressure Research" [42]. Hypertension 45 (5): 142–61. doi:10.1161/01.HYP.0000150859.47929.8e.
PMID 15611362. Retrieved 2009-10-01.

External links
• High Blood Pressure [43], The Institute for Good Medicine [44] at the Pennsylvania Medical Society [45]

• Blood Pressure Association (UK) [46]

• British Hypertension Society: list of validated blood pressure monitors [47]

• Blood pressure monitoring [48]

• Pulmonary Hypertension [49] Cleveland Clinic
• Blood Pressure Calculator for Diagnosis of High blood pressure in Children and Adolescents [50]

• dablEducational Trust: Blood pressure monitors - Validations, Papers, and Reviews [51]

• American Heart Association[52]

[1] Klabunde, Richard (2005). Cardiovascular Physiology Concepts. Lippincott Williams & Wilkins. pp. 93–4. ISBN 978-0781750301.
[2] Booth, J (1977). "A short history of blood pressure measurement" (http:/ / www. pubmedcentral. nih. gov/ articlerender. fcgi?artid=1543468).

Proceedings of the Royal Society of Medicine 70 (11): 793–9. PMID 341169. PMID 341169. PMC 1543468. . Retrieved 2009-10-06.
[3] "Vital Signs (Body Temperature, Pulse Rate, Respiration Rate, Blood Pressure)" (http:/ / www. ohsu. edu/ xd/ health/ health-information/

topic-by-id. cfm?ContentTypeId=85& ContentId=P00866). OHSU Health Information. Oregon Health & Science University. . Retrieved

[4] Deakin CD, Low JL (September 2000). "Accuracy of the advanced trauma life support guidelines for predicting systolic blood pressure using
carotid, femoral, and radial pulses: observational study" (http:/ / bmj. com/ cgi/ pmidlookup?view=long& pmid=10987771). BMJ 321 (7262):
673–4. doi:10.1136/bmj.321.7262.673. PMID 10987771. PMC 27481. .

[5] Interpretation - Blood Pressure - Vitals (http:/ / bcs. medinfo. ufl. edu/ sample/ page06. html), "University of Florida". Retrieved on

[6] G8 Secondary Survey (http:/ / www. gov. mb. ca/ health/ ems/ guidelines/ G8. pdf), "Manitoba". Retrieved on 2008-03-18.
[7] (Pickering et al. 2005, p. 146) See Blood Pressure Measurement Methods.
[8] (Pickering et al. 2005, p. 147) See The Oscillometric Technique.
[9] Laurent, P (2003-09-28). "Blood Pressure & Hypertension" (http:/ / www. blood-pressure-hypertension. com/ how-to-measure/

measure-blood-pressure-8. shtml). . Retrieved 2009-10-05.
[10] Elliot, Victoria Stagg (2007-06-11). "Blood pressure readings often unreliable" (http:/ / www. ama-assn. org/ amednews/ 2007/ 06/ 11/

hlsa0611. htm). American Medical News (American Medical Association). . Retrieved 2008-08-16.
[11] Jhalani, Juhee; Tanya Goyal, Lynn Clemow, et al (2005). "Anxiety and outcome expectations predict the white-coat effect" (http:/ / journals.

lww. com/ bpmonitoring/ pages/ articleviewer. aspx?year=2005& issue=12000& article=00006& type=abstract). Blood Pressure Monitoring
10 (6): 317–9. doi:10.1097/00126097-200512000-00006. PMID 16496447. PMID 16496447. . Retrieved 2009-10-03.

[12] (Pickering et al. 2005, p. 145) See White Coat Hypertension or Isolated Office Hypertension.
[13] (Pickering et al. 2005, p. 146) See Masked Hypertension or Isolated Ambulatory Hypertension.
[14] Mancia G, De Backer G, Dominiczak A, et al (June 2007). "2007 Guidelines for the management of arterial hypertension: The Task Force

for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology
(ESC)". Eur Heart J 28 (12): 1462–536. doi:10.1093/eurheartj/ehm236. PMID 17562668.

[15] Chobanian AV, Bakris GL, Black HR, et al (December 2003). "Seventh report of the Joint National Committee on Prevention, Detection,
Evaluation, and Treatment of High Blood Pressure" (http:/ / www. nhlbi. nih. gov/ guidelines/ hypertension/ ). Hypertension 42 (6): 1206–52.
doi:10.1161/01.HYP.0000107251.49515.c2. PMID 14656957. .

[16] Niiranen, TJ; Kantola IM, Vesalainen R, et al (2006). "A comparison of home measurement and ambulatory monitoring of blood pressure in
the adjustment of antihypertensive treatment". Am J Hypertens 19 (5): 468–74. doi:10.1016/j.amjhyper.2005.10.017. PMID 16647616.

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Blood pressure 11

[17] Shimbo, Daichi; Thomas G. Pickering, Tanya M. Spruill, et al (2007). "Relative utility of home, ambulatory, and office blood pressures in
the prediction of end-organ damage" (http:/ / www. nature. com/ ajh/ journal/ v20/ n5/ abs/ ajh200783a. html). Am J Hypertens 20 (5):
476–82. doi:10.1016/j.amjhyper.2006.12.011. PMID 17485006. PMC 1931502. .

[18] National Heart, Lung and Blood Institute. Tips for having your blood pressure taken (http:/ / www. nhlbi. nih. gov/ hbp/ detect/ tips. htm). .
[19] "Diseases and Conditions Index - Hypotension" (http:/ / www. nhlbi. nih. gov/ health/ dci/ Diseases/ hyp/ hyp_whatis. html). National Heart

Lung and Blood Institute. September 2008. . Retrieved 2008-09-16.
[20] Pesola GR, Pesola HR, Nelson MJ, Westfal RE (January 2001). "The normal difference in bilateral indirect BP recordings in normotensive

individuals" (http:/ / www. sciencedirect. com/ science?_ob=ArticleURL& _udi=B6W9K-45SRDHC-C& _user=10& _coverDate=01/ 31/
2001& _rdoc=1& _fmt=& _orig=search& _sort=d& view=c& _acct=C000050221& _version=1& _urlVersion=0& _userid=10&
md5=74f2b32e088d88986cd307f6c7219331). Am J Emerg Med 19 (1): 43–5. doi:10.1053/ajem.2001.20021. PMID 11146017. .

[21] Reckelhoff, Jane F. (1 May 2001). "Gender Differences in the Regulation of Blood Pressure" (http:/ / hyper. ahajournals. org/ cgi/ content/
abstract/ hypertensionaha;37/ 5/ 1199). Hypertension 37 (5): 1199–208. PMID 11358929. PMID 11358929. .

[22] National Heart, Lung and Blood Institute. Blood Pressure Tables for Children and Adolescents (http:/ / www. nhlbi. nih. gov/ guidelines/
hypertension/ child_tbl. htm). . (Note that the median BP is given by the 50th percentile and hypertension is defined by the 95th percentile for
a given age, height, and gender.)

[23] (Pickering et al. 2005, p. 145) See Isolated Systolic Hypertension.
[24] "...more than half of all Americans aged 65 or older have hypertension." (Pickering et al. 2005, p. 144)
[25] Eguchi K, Yacoub M, Jhalani J, Gerin W, Schwartz JE, Pickering TG (February 2007). "Consistency of blood pressure differences between

the left and right arms" (http:/ / archinte. ama-assn. org/ cgi/ content/ full/ 167/ 4/ 388). Arch Intern Med 167 (4): 388–93.
doi:10.1001/archinte.167.4.388. PMID 17325301. .

[26] Agarwal R, Bunaye Z, Bekele DM (March 2008). "Prognostic significance of between-arm blood pressure differences". Hypertension 51
(3): 657–62. doi:10.1161/HYPERTENSIONAHA.107.104943. PMID 18212263.

[27] Appel LJ, Brands MW, Daniels SR, Karanja N, Elmer PJ, Sacks FM (February 2006). "Dietary approaches to prevent and treat
hypertension: a scientific statement from the American Heart Association". Hypertension 47 (2): 296–308.
doi:10.1161/01.HYP.0000202568.01167.B6. PMID 16434724.

[28] "Hypertension: management of hypertension in adults in primary care" (http:/ / www. nice. org. uk/ nicemedia/ pdf/ CG034NICEguideline.
pdf). NICE Clinical Guideline 34. London, England: National Institute for Health and Clinical Excellence (NICE). June 2006. . Retrieved

[29] (http:/ / www. americanheart. org/ presenter. jhtml?identifier=4650)
[30] Rosenson RS, Wolff D, Green D, Boss AH, Kensey KR (February 2004). "Aspirin. Aspirin does not alter native blood viscosity". J.

Thromb. Haemost. 2 (2): 340–1. PMID 14996003.
[31] Klabunde, RE (2007). "Cardiovascular Physiology Concepts - Mean Arterial Pressure" (http:/ / www. cvphysiology. com/ Blood Pressure/

BP006. htm). . Retrieved 2008-09-29. Archived version 2009-10-03 (http:/ / www. webcitation. org/ 5kGLMdqnn)
[32] Klabunde, RE (2007). "Cardiovascular Physiology Concepts - Pulse Pressure" (http:/ / www. cvphysiology. com/ Blood Pressure/ BP003.

htm). . Retrieved 2008-10-02. Archived version 2009-10-03 (http:/ / www. webcitation. org/ 5kGLuC47S)
[33] Messerli FH, Williams B, Ritz E (2007). "Essential hypertension". Lancet 370 (9587): 591–603. doi:10.1016/S0140-6736(07)61299-9.

PMID 17707755.
[34] O'Rourke M (1 July 1995). "Mechanical principles in arterial disease" (http:/ / hyper. ahajournals. org/ cgi/ content/ full/ 26/ 1/ 2).

Hypertension 26 (1): 2–9. PMID 7607724. .
[35] Mitchell GF (2006). "Triangulating the peaks of arterial pressure" (http:/ / hyper. ahajournals. org/ cgi/ content/ full/ 48/ 4/ 543).

Hypertension 48 (4): 543–5. doi:10.1161/01.HYP.0000238325.41764.41. PMID 16940226. .
[36] Klabunde, RE (2007). "Cardiovascular Physiology Concepts - Arterial Baroreceptors" (http:/ / www. cvphysiology. com/ Blood Pressure/

BP012. htm). . Retrieved 2008-09-09.
[37] Textbook of Medical Physiology, 7th Ed., Guyton & Hall, Elsevier-Saunders, ISBN 0-7216-0240-1, page 220.
[38] What Is Pulmonary Hypertension? (http:/ / www. nhlbi. nih. gov/ health/ dci/ Diseases/ pah/ pah_what. html) From Diseases and Conditions

Index (DCI). National Heart, Lung, and Blood Institute. Last updated September 2008. Retrieved on 6 April, 2009.
[39] Chapter 41, page 210 in: Cardiology secrets (http:/ / books. google. com/ books?id=IYFAsxAUA_MC& printsec=frontcover#PPR3,M1) By

Olivia Vynn Adair Edition: 2, illustrated Published by Elsevier Health Sciences, 2001 ISBN 1560534206, 9781560534204
[40] Struijk PC, Mathews VJ, Loupas T, et al (October 2008). "Blood pressure estimation in the human fetal descending aorta". Ultrasound

Obstet Gynecol 32 (5): 673–81. doi:10.1002/uog.6137. PMID 18816497.
[41] Sharon, S. M. & Emily, S. M.(2006). Fundations of Maternal-Newborn Nursing. (4th ed p.476). Philadelphia:Elsevier.
[42] http:/ / hyper. ahajournals. org/ cgi/ content/ full/ 45/ 1/ 142
[43] http:/ / www. myfamilywellness. org/ MainMenuCategories/ FamilyHealthCenter/ Heart/ Hypertension. aspx
[44] http:/ / www. goodmedicine. org
[45] http:/ / www. pamedsoc. org
[46] http:/ / www. bpassoc. org. uk
[47] http:/ / www. davidgregory. org/ blood_pressure_monitors. htm
[48] http:/ / www. blood-pressure-monitoring. org
[49] http:/ / www. clevelandclinicmeded. com/ medicalpubs/ diseasemanagement/ nephrology/ arterial-hypertension/

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Blood pressure 12

[50] http:/ / www. etoolsage. com/ Calculator/ Blood_Pressure_Calculator. asp?toolsort=1500
[51] http:/ / www. dableducational. org/
[52] http:/ / www. americanheart. org/ presenter. jhtml?identifier=4650

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Article Sources and Contributors 13

Article Sources and Contributors
Blood pressure  Source:  Contributors: 4wajzkd02, 5-HT8, 5Q5, A8UDI, Abdmy011, Abeg92, Abrech, Aceofhearts1968, Adam Zivner,
Addshore, Aitias, Ajh16, Ale jrb, Alex.tan, Alexius08, Algumacoisaqq, Ali, Andre Engels, AndrewHowse, AndrewWTaylor, Anfieldroad, Angus Lepper, Anim8cme, Ann Stouter, Anna Lincoln,
Antonio Lopez, Arakunem, Arcadian, Arch dude, Arjun01, Ashishbhatnagar72, Assume5, AxelBoldt, B. Wolterding, Barek, Beano, Bear and Dragon, Beetstra, Bemoeial, Bencherlite,
Bensaccount, Bfesser, BillC, Biyer, BlaiseFEgan, Blood Pressure Association Publications Officer, Blue Tie, Bob K31416, BobKawanaka, Bobo192, Brandon, Brendan Moody, Brighterorange,
Bubba hotep, Buchskj, Burlywood, Butwhatdoiknow, Bücherwürmlein, CIreland, Can't sleep, clown will eat me, Canihaveacookie, CanuckViking, CapitalR, Cburnett, Ccacsmss, Celarnor,
Chamal N, Charles Gaudette, Chowbok, Chuckmoran7, Closedmouth, CoJaBo, Colenso, Cometstyles, Correogsk, Crystallina, Csdorman, DFS454, DMacks, DRosenbach, DVD R W, Da monster
under your bed, Dan Gluck, Daniel.Cardenas, Dank, Darth Panda, David Henderson, DavidSmith8888, Davidoff, Davidruben, DeadEyeArrow, December21st2012Freak, Defender of torch, Deli
nk, Delldot, Deor, DerHexer, Diberri, Dionysia, Djgregory, Djk3, Dlohcierekim, Docu, Dog Eat Dog World, Dominus, Doops, Dovid, DrMacrophage, Dreamyshade, Drum guy, Dwinner, E
Wing, E rulez, Edgar181, Eekerz, EhJJ, Eiler7, Ekko, ElKevbo, Eliazar, Emote, Emperorbma, Epbr123, Eric-Wester, Erik9, Fabrício Kury, Facts707, Faradayplank, FisherQueen, Flewis,
FlyingToaster, Fnielsen, Founders4, Fredrik, FreplySpang, Frmatt, Fulkkari, G0dsweed, Gabbe, Gene Nygaard, GermanX, Giftlite, Gilliam, Gizz, Gogo Dodo, GordonMarjory, Grubber, HTGuru,
Hadal, Haham hanuka, HappyInGeneral, Harej, Healy24, Heimoma, Heron, Hiberniantears, Holdspa, Hooperbloob, HorsePunchKid, Hu12, Hut 8.5, IW.HG, Ice Cold Beer, Iridescent, Isidore, J
Di, J.delanoy, J04n, JForget, JHP, Jack-A-Roe, Jackhynes, Jacqui M, James086, JamesAM, Jared Hunt, Jasonkodat, Jecowa, Jeff Silvers, Jeffq, Jeremygbyrne, Jfdwolff, JimmyAndRobert!, Jimp,
Jkgray, Jmarchn, Jmh649, Jmor7, John Kaduwanema, JohnCub, Johnduffell, Jojhutton, Jonathunder, Jonny-mt, Jorvik, Joyous!, Jprey, JuliaHavey, JulieADriver, Julo, Justinstroud, Kansas Sam,
Karlhahn, Kartano,, Kevino62, Kilbosh, King of Hearts, Kitty bean, Klausness, Knowledge Seeker, Kosebamse, Ksheka, Kukini, Kylet, Kyoko, LAX, Lactotripeptide,
LeadSongDog, LeaveSleaves, Lexicontra, Lheydon, LimpThis, LittleDan, Lkinkade, Lmuenchen, LordRae, Losmog, Luk, Lupinoid, M1ss1ontomars2k4, MAlvis, MER-C, MONGO,
Macaddct1984, Maderchoud334, Maderchoudsala44, Madhero88, Magioladitis, Marek69, MarkSutton, Martin451, Master Jay, Masterchiefthespartan117, Matt povey, Me, MeVsAll, Mentifisto,
Merube 89, Mfranck, Michael V Hayes, Mig174, Mikael Häggström, Mike Magowan, Mike Rosoft, Miranda, Mootros, Mr Goulash, Mrdocjb, Muchclag, Myadav, Mzcrazybitch, N-k, Naniwako,
Nastajus, Natkeeran, Nehrams2020, Neptune5000, Nfu-peng, Nick C, Nicnic m, Nikzbitz, Nmg20, Notepadpage, Nutcrakerr, Ocdcntx, Ohnoitsjamie, Okedem, Olorin28, Onevalefan,
Orangedwarf, OrgasGirl, Osbus, Oxymoron83, Paiamshadi, Pandaassassin7, Patrick, PatronSaintOfEntropy, Peruvianllama, PeteThePill, Phansen, Phgao, Phil Wardle, Philip Trueman, Piano non
troppo, Pilarian, Pinethicket, Piplicus, Pol098, Polacrilex, PreThinker, Prodego, Puffball, Quaint and curious, RDBrown, RNchoo, Rajah, Rdsmith4, Remi0o, Renato Caniatti, Res2216firestar,
RexNL, Rich Farmbrough, Rjwilmsi, Rob Hooft, Roberta F., Romanm, Ronz, RoyBoy, Rsduhamel, Ryancormack, Ryguasu, SJP, SMC, Sampi, Sango123, Scarian, Scohoust, Selket, Septine,
Seuwin, Shanes, Sho Uemura, Sinkker, Sjakkalle, Skarebo, Sljaxon, Snowmanradio, Someone else, Sonett72, Spiff666, Spongefrog, SportWagon, SqueakBox, SstrykerR, Stack, Statkit1, Stephen,
Steven Zhang, Stevenfruitsmaak, Supten, Surturz, Svadhisthana, TSoprano, Tarquin, TastyPoutine, Tempodivalse, TexasAndroid, The Rambling Man, The Thing That Should Not Be,
TheEgyptian, TheNewPhobia, Thumperward, Tide rolls, TigerShark, Tkessler, Todd Vierling, Tom Yates, Toreau, Tpaba, Tresiden, Troop350, TruthIsStrangerThanFiction, Tsujigiri, UISKuwait,
Uknowme imbehindu, Ulric1313, Uncle Bill, User38934, Uthbrian, Utopianheaven, V.narsikar, Van helsing, Vary, VasilievVV, WDM27, WadeSimMiser, Wap, Wayunga, Wayward,
Westendgirl, WhatamIdoing, Wikiperson0202, Wimt, Wisdom89, Wouterstomp, Wraithdart, Xlegiofalco, Yidisheryid, Yintan, Ymaziar, Yoweigh, Yuanchosaan, Zephalis, Zuff, Zzuuzz, محبوب
عال م, 983 anonymous edits

Image Sources, Licenses and Contributors
Image:Blutdruck.jpg  Source:  License: GNU Free Documentation License  Contributors: User:Peng
Image:MMSA Checking Blood Pressure.JPG  Source:  License: Creative Commons
Attribution-Sharealike 3.0  Contributors: Kilbosh
Image:Sphygmomanometer.jpg  Source:  License: Public Domain  Contributors: BrokenSphere, Edward,
EugeneZelenko, GreyCat, Ranveig, Saperaud
Image:Mercury manometer.jpg  Source:  License: GNU Free Documentation License  Contributors: Original uploader
was Michael V Hayes at en.wikipedia
File:Main complications of persistent high blood pressure.svg  Source: of persistent_high_blood_pressure.svg  License:
Public Domain  Contributors: Mikael Häggström

Creative Commons Attribution-Share Alike 3.0 Unported
http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/

Wikipedia, “Blood Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16,
2015. Retrieved from:

Pulse pressure 1

Pulse pressure
Pulse pressure is the difference between systolic and diastolic blood pressure, or the change in blood pressure seen
during a contraction of the heart.

Formally it is the systolic pressure minus the diastolic pressure.[1]
Theoretically, the systemic pulse pressure can be conceptualized as being proportional to stroke volume and
inversely proportional to the compliance of the aorta[2] .
• Systemic pulse pressure = Psystolic - Pdiastolic = 120mmHg - 80mmHg = 40mmHg
• Pulmonary pulse pressure = Psystolic - Pdiastolic = 25mmHg - 10mmHg = 15mmHg

Values and variation

Low values
In trauma a low or narrow pulse pressure suggests significant blood loss.[3] In an otherwise healthy person a
difference of less than 40 mmHg is usually an error of measurement. If the pulse pressure is genuinely low, e.g. 25
mmHg or less, the cause may be low stroke volume, as in Congestive Heart Failure and/or shock, a serious issue.
This interpretation is reinforced if the resting heart rate is relatively rapid, e.g. 100-120 (in sinus tachycardia),
reflecting increased sympathetic nervous system activity as the body's response to low stroke volume and low
cardiac output. A narrow pulse pressure can also be caused by aortic stenosis.
Examples: (these are examples of WIDENING pulse pressure causes)
• Atherosclerosis
• Chronic aortic regurgitation
• Thyrotoxicosis
• Fever
• Anaemia
• Pregnancy
• Anxiety
• Heart block
• Aortic dissection
• Endocarditis
• Raised intracranial pressure

High values during or shortly after exercise
Usually, the resting pulse pressure in healthy adults, sitting position, is about 40 mmHg. The pulse pressure increases
with exercise due to increased stroke volume[4] , healthy values being up to pulse pressures of about 100 mmHg,
simultaneously as total peripheral resistance drops during exercise. In healthy individuals the pulse pressure will
typically return to normal within about 10 minutes. For most individuals, during exercise, the systolic pressure
progressively increases while the diastolic remains about the same. In some very aerobically athletic individuals, for
example distance runners, the diastolic will progressively fall as the systolic increases. This behavior facilitates a
much greater increase in stroke volume and cardiac output at a lower mean arterial pressure and enables much
greater aerobic capacity and physical performance. The diastolic drop reflects a much greater fall in total peripheral
resistance of the muscle arterioles in response to the exercise (a greater proportion of red versus white muscle tissue).
Individuals with larger BMI's due to increased muscle mass (body builders) have also been shown to have lower

Introduction to the Pulse

Wikipedia, “Pulse Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16, 2015. Retrieved from: https://

Pulse pressure 2

diastolic pressures and larger pulse pressures.[5]

Consistently high values
If the usual resting pulse pressure is consistently greater than 40 mmHg, e.g. 60 or 80 mmHg, the most likely basis is
stiffness of the major arteries, aortic regurgitation (a leak in the aortic valve), arteriovenous malformation (an extra
path for blood to travel from a high pressure artery to a low pressure vein without the gradient of a capillary bed),
hyperthyroidism or some combination. (A chronically increased stroke volume is also a technical possibility, but
very rare in practice.) While some drugs for hypertension have the side effect of increasing resting pulse pressure
irreversibly, other hypertension drugs, such as ACE Inhibitors, have been shown to lower pulse pressure. A high
resting pulse pressure is harmful and tends to accelerate the normal aging of body organs, particularly the heart, the
brain and kidneys. A high pulse pressure combined with bradycardia is associated with increased intracranial
pressure and should be reported to a physician immediately.

Relationship to heart disease
Recent work suggests that a high pulse pressure is an important risk factor for heart disease. A meta-analysis in
2000, which combined the results of several studies of 8,000 elderly patients in all, found that a 10 mm Hg increase
in pulse pressure increased the risk of major cardiovascular complications and mortality by nearly 20%.[6]

Heightened pulse pressure is also a risk factor for the development of atrial fibrillation.[7] The authors of the
meta-analysis suggest that this helps to explain the apparent increase in risk sometimes associated with low diastolic
pressure, and warn that some medications for high blood pressure may actually increase the pulse pressure and the
risk of heart disease.

Self measurement
Pulse pressure readings can be taken on a home monitoring blood pressure device. Most home monitoring blood
pressure devices display systolic and diastolic blood pressure and pulse pressure readings. Monitoring at home will
measure true pulse and blood pressure and provide a doctor with a log of readings over time.

If the patient suffers from elevated pulse pressure, treatment should include medication that addresses this factor,
such as an angiotensin-converting enzyme inhibitor (ACE inhibitor).[8]

Effect of folic acid
A 2005 study found that 5 mg of folate daily over a three-week period reduced pulse pressure by 4.7 mm of Hg
compared with a placebo, and concluded that Folic acid is an effective supplement that targets large artery stiffness
and may prevent isolated systolic hypertension.[9]

See also
• Blood pressure
• Mean arterial pressure
• Cold pressor test
• Hypertension
• Prehypertension
• Antihypertensive
• Patent ductus arteriosus

Wikipedia, “Pulse Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16, 2015. Retrieved from: https://

Pulse pressure 3

[1] http:/ / wiki. answers. com/ Q/ Why_is_mean_arterial_pressure_not_equal_to_systolic_pressure_minus_diastolic_pressure_dived_by_2
[2] Arterial pulse pressure (http:/ / www. cvphysiology. com/ Blood Pressure/ BP003. htm)
[3] American College of Surgeons (2008). Atls, Advanced Trauma Life Support Program for Doctors. Amer College of Surgeons. pp. 58.

ISBN 1-880696-31-6.
[4] (http:/ / www. pps. org. pk/ PJP/ 3-2/ 07-Farida. pdf)
[5] (http:/ / hyper. ahajournals. org/ cgi/ content/ full/ 33/ 6/ 1385?maxtoshow=& HITS=10& hits=10& RESULTFORMAT=& fulltext=arterial&

searchid=1& FIRSTINDEX=60& resourcetype=HWFIG)
[6] Blacher J, Staessen JA, Girerd X, Gasowski J, Thijs L, Liu L, Wang JG, Fagard RH, Safar ME. Pulse pressure not mean pressure determines

cardiovascular risk in older hypertensive patients. Arch Intern Med 2000 Apr 24;160(8):1085-9. PMID 10789600
[7] Pulse Pressure Important Risk Factor for the Development of New-Onset AF CME http:/ / www. medscape. com/ viewarticle/ 552468
[8] Pulse Pressure Builds Steam as Mortality Predictor - Brief Article - Statistical Data Included http:/ / findarticles. com/ p/ articles/ mi_m0BJI/

is_1_30/ ai_59457655

hypertensive patients with high pulse pressures should include a drug that is effective at reducing pulse
pressure, and angiotensin-converting enzyme inhibitors are the best for this purpose.

[9] Carolyn Williams, Bronwyn A Kingwell, Kevin Burke, Jane McPherson and Anthony M Dart: Folic acid supplementation for 3 wk reduces
pulse pressure and large artery stiffness independent of MTHFR genotype. American Journal of Clinical Nutrition, Vol. 82, No. 1, 26-31, July
2005 http:/ / www. ajcn. org/ cgi/ content/ full/ 82/ 1/ 26

Wikipedia, “Pulse Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16, 2015. Retrieved from: https://

Article Sources and Contributors 4

Article Sources and Contributors
Pulse pressure  Source:  Contributors: 1ForTheMoney, Aesopos, Agentdenim, Anespa, Arcadian, Brummfuss, D6, Dpen2000,
Dreamyshade, Epbr123, Fibrosis, Fredrik, Frycow, Goodnightmush, Jfdwolff, Jmbigwood, Jmh649, John254, Ksheka, Ladida, Luna Santin, MAlvis, MastCell, Monitorer, Nodekeeper,
Notepadpage, Orlandoturner, Pol098, Prisonblues, Ptdecker, Ryanjc559, ShakingSpirit, Thorwald, Topgunner, Woohookitty, 55 anonymous edits

Creative Commons Attribution-Share Alike 3.0 Unported
http:/ / creativecommons. org/ licenses/ by-sa/ 3. 0/

Wikipedia, “Pulse Pressure.” Wikipedia, p. 1-12. Date retrieved: September, 16, 2015. Retrieved from: https://

Medical Instruments in the Developing World Malkin

Page 31

2.6 Blood Pressure Machines

2.6.1 Clinical Use and Principles of Operation

Blood pressure machines are one of the primary diagnostic tools used by health care workers.
Sphygmomanometers are used for determining the patient’s resting blood pressure, one of the
preliminary tests that health care workers may perform. A diagnosis of high or low blood
pressure can be indicative of other, more serious diseases. There are three main types of blood
pressure machines: mercury, aneroid, and electronic.

The measurement of blood pressure has been common for over a century and is often
misunderstood. The non-invasive measurement of blood pressure is accomplished by occluding
an artery in the upper arm with an inflatable cuff that is connected to a mercury manometer. A
stethoscope is used to listen for the Korotkoff’s sounds as the blood flows. The first sound is
heard as the pressure in the cuff passes the systolic pressure. The last sound is heard as the
pressure in the cuff passes the diastolic pressure.

The ideal pressure is 120 mmHg systolic and 80 mmHg diastolic. Systolic pressures above 150
mmHg or diastolic pressures above 100 mmHg are of clinical concern. The difference between
the systolic and diastolic pressures is called the pulse pressure. This generally runs between 40

A traditional blood pressure
measurement is made by occluding
the brachial artery with a cuff. As
the cuff is deflated, the technician
can hear, at first, nothing, as no
blood flows in the artery, then a
sound as the pressure in the cuff is
just below the systolic (maximum)
pressure. When the cuff pressure
just descends below the diastolic
(minimum) pressure, the sound
goes away because the flow
returns to laminar flow.

Malkin, R. “Blood Pressure Machines,” From the publication: Medical Instruments
in the Developing World. Engineering World Health, 2006.

Introduction to Blood Pressure

Operation and Use of Blood Pressure Monitors

Equipment found in the OR, ICU and ER

Page 32

and 50 mmHg. An estimated mean pressure can be obtained by adding one third of the pulse
pressure to the diastolic pressure. The mean pressure shouldn’t drop below about 80 mmHg.

To measure the pressure in the cuff, a mercury manometer is often used. A plastic or glass
column with graduations from 0 to 300 mm is connected to the cuff via latex or rubber tubing.
The tube is filled with mercury. The pressure reading is the height of the mercury column. To
get accurate readings the tube must be exactly vertical. At the top of the tube, under the cap is
a calf skin diaphragm that allows air to move in both directions. If this diaphragm is dirty the
mercury in the column will not move smoothly, either up or down. Mercury manometers are no
longer used in The United States. However, they are quite common in the developing world.

Another manometer used for blood pressure readings is the aneroid manometer. This is a
bellows based system that has a dial calibrated in the range of 0 to 300 mmHg. At the resting
point of the needle on the dial is a rectangular box. If the needle is in that box the manometer is
calibrated and can be used.

Non-invasive blood pressure machines (NIBP) are devices that automatically and electronically
measure blood pressure. In these system electronics replaces a human in the inflation/deflation
of the cuff. In most modern devices, the detection of the pulsation, not the listening for
Korotkoff sounds, drives the detection of the maximum and minimum pressure. The results are
displayed in digital format on separate displays or on a screen. The units can be programmed to
take blood pressures on a set cycle, 1, 5, 15, 30 minutes, trend the data and often sound alarms
if the results are outside of preset limits.

An aneroid manometer uses
a calibrated dial. Notice that
when the dial is at zero,
there is a small rectangle
where the needle should
rest. This manometer is also
calibrated in inches of water.

In this photo, the cover for
the mercury reservoir has
been removed (right). The
mercury has oxidized leaving
a fine powder that should be
removed before refilling the

Malkin, R. “Blood Pressure Machines,” From the publication: Medical Instruments
in the Developing World. Engineering World Health, 2006.

Medical Instruments in the Developing World Malkin

Page 33

Older NIBP’s may use two tubes to inflate the blood pressure cuff. Some devices have a
transducer in the cuff to detect the sounds.

A completely different approach to measuring blood pressure is to invasively introduce a catheter
into an artery. This is most common in surgery and intensive care units. The blood pressure
device is connected to the catheter via a rigid wall plastic tube filled with a saline solution. The
tube is connected to a transducer, which may be connected to bag of saline or “flush.” Figure
2.7.3 illustrates the set up. The transducer is hung at the level of the heart. The output from
the transducer is amplified and displayed as numbers, waveform or both. Since the skin has
been breached the patients first line of defense for both infection and electrical shock have been
bypassed. Extreme care must be taken to assure the safety of the

2.6.2 Common Problems

Non-invasive, manual blood pressure machines are extremely reliable. They are also
inexpensive. Even in the developing world, they are often replaced rather than repaired.
However, there are a few common problems.

Automatic non-invasive blood
pressure (NIBP) machines
typically measure the presence
of small oscillations in the
pressure to determine the
systolic and diastolic pressures.
Some older machines may use a
sensor to detect the Korotkoff

An invasive blood pressure measurement typically involves piercing the skin of the arm or leg. The
pressure transducer should always be at the level of the patient’s heart. The flush bag is held a foot
or more above the patient.

Malkin, R. “Blood Pressure Machines,” From the publication: Medical Instruments
in the Developing World. Engineering World Health, 2006.

Equipment found in the OR, ICU and ER

Page 34

Leaks in the tubing are common and can often be repaired with epoxy or silastic. To check for
leaks, inflate the cuff to 250 mmHg and allow it to stand. The pressure should slowly decrease
at a rate not exceeding 5 mmHg per minute. If there is a leak, you can find it by rubbing soapy
water over the tubing and looking for bubbles.

User errors related to calibration are somewhat common. The cuff must be at the level of the
heart and the manometer must read zero before the cuff is inflated. Check the cleanliness of the
mercury. After a time, mercuric oxide will form and is distinguishable by a black powder. The
mercury, the mercury reservoir, and tube will all need to be cleaned. Keep in mind that mercury
is toxic and care should be used to not release any into the ground or building. Check the
leather seal and washer located at the top of the upright tube. Pump the pumping bulb: as soon
as the pumping is stopped, the mercury should stop rising. If it continues to rise, the leather
seal and washer will have to be further investigated and perhaps replaced.

For automatic NIBP’s the most common problem is the use of the incorrect cuff. If the correct
cuff is being used, and if the transducer is located in the cuff itself, it may be possible to access
the transducer with some difficulty. However, repair often requires specialized knowledge, as the
manufacturer’s designs vary considerably.

For invasive blood pressure measurements, there are many possible problems. The most
common is reusing non-reusable transducers. The single use disposable transducers are now the
standard of care in the United States. While there are non-disposable alternatives, they are
rarely used. The transducer is commonly mounted on an IV pole next to the patient’s bed. It
should be at the same level as the patient. There is a 2.5 mmHg error for every inch that the
transducer is above or below the level correct level.

During the set-up process the invasive catheter transducer is vented to air, zeroed and all the air
removed from the line, usually using the flush solution. The technician may, or may not correctly
complete each of these steps, leaving air bubbles in the line or leaving the transducer improperly
zeroed. Also check that the transducer is at the level of the heart.

2.6.3 Suggested Minimal Testing

The most critical element to calibrate is the pressure measurement. A simple pressure standard
can be made by creating a column of water in a tube. Taping a tube to the wall and filling it with
water up to a height of 271 cm, for example, creates a pressure standard of 200 mmHg (the
density of mercury is 13.55 times that of water). Before releasing the blood pressure machine,
check several pressure levels (200 mmHg, 100 mmHg and 50 mmHg – or 271 cm H20, 136 cm
H20 and 68 cm H20, respectively). The manometer should be accurate to within 1-3 mmHg.

Malkin, R. “Blood Pressure Machines,” From the publication: Medical Instruments
in the Developing World. Engineering World Health, 2006.

Medical Instruments in the Developing World Malkin

Page 35

If the pressure is consistently too high or too low, you will need to adjust the zero by removing
or adding mercury or twisting the manometer face (if aneroid). Electronic blood pressure devices
will have a zero setting which should never need to be adjusted, if the device is properly zeroed
before each use. There is a gain setting for electronic devices that occasionally needs to be

If the blood pressure machine is intended for manual use, you should also check the device for
convenience of use. When inflated with the valve closed, the pressure should not drop
appreciably in ten seconds. When the valve is open, the pressure should drop slowly and
linearly. Consult with the physician or nurse about the leak and drop rates to be sure that the
device will be convenient for them to use.

If a mercury manometer has been used for many years, mercuric oxide may form in the tube and
will appear as a black powder. The mercury, tube, and reservoir will all have to be cleaned if the
nurse objects to its presence. Keep in mind that mercury is toxic and should not be touched or
the vapors excessively inhaled. To remove the mercuric oxide, take off the reservoir cap and
remove the mercury using a needle and syringe. Filter the mercury through filter paper into a
clean container. Repeat several times until all the solid oxide is removed. Take the tube and
reservoir outside and use an air line to blow out any particulate matter. Replace the clean
mercury into the reservoir and top off the reservoir with new mercury up to the ‘0’ mark.
Replace the reservoir cap.

Automatic, non-invasive blood pressure machines (NIBP’s) are more difficult to calibrate than the
others because the need to detect the Kortokoff sounds to function. If you do not have a
phantom arm, then the best approach is to use your own arm. Borrow a stethoscope and
measure your own BP. If you are not confident that you can use a sphygmomanometer
accurately, then ask someone else to measure your BP. Repeat the measurement five times.
Then connect yourself to the NIBP and measure your blood pressure five times. The average
diastolic and systolic pressures from the two systems should match to within 3 mmHg.

A manometer can be tested
against a known good manometer,
against a mercury manometer, or
against a simple column of water
in an IV tube (100 mmHg of
pressure is exerted by a column of
water 135 cm high).

Malkin, R. “Blood Pressure Machines,” From the publication: Medical Instruments
in the Developing World. Engineering World Health, 2006.

User Care of Medical Equipment – First line maintenance for end users


Chapter 4.17 Sphygmomanometers (B.P. sets)

Blood pressure is an indicator of several diseases as well as of general health. It is an easy screening test

using simple equipment. A sphygmomanometer can be used to measure the blood pressure at the high point
(systolic) and low point (diastolic) of the cardiac pressure cycle. Pressure is usually measured using a cuff on
the upper arm.

How it works
The cuff on the arm is inflated until blood flow in the artery is blocked. As the cuff pressure is
decreased slowly, the sounds of blood flow starting again can be detected. The cuff pressure at this point marks
the high (systolic) pressure of the cycle. When flow is unobstructed and returns to normal, the sounds of blood
flow disappear. The cuff pressure at this point marks the low (diastolic) pressure.
Pressure can be measured using a meter with dial (aneroid type), a mercury column or an electronic
display. The sounds are normally detected using a stethoscope, but some electronic equipment uses a different,
automatic technique with pressure sensors. The two methods do not always give the same results and the
stethoscope method is generally seen to be more accurate for all types of patient.



Inflation bulb and

Inflation bulb and

Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Sphygmomanometer Introduction

User Care of Medical Equipment – First line maintenance for end users


Chapter 4.18 Stethoscopes

A stethoscope is used to listen to sounds within the body. These might be sounds generated by
breathing, coughing, blood flow or the stomach. The sounds are picked up and transmitted to the ears of the
medical staff for diagnosis.

How it works
A membrane on the stethoscope chestpiece picks up the vibrations caused by internal sounds and

transmits them to the stethoscope tube. The sounds pass up the tube through the earpiece to the user. The
stethoscope chestpiece also contains an open bell which is used to pick up lower frequency sounds. The head
picks up the sound from a wide area so it sounds loud to the user. Care must therefore be taken not to hit or
shout into the stethoscope while in use.


Tube connector


Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Stethoscope Introduction












* *

NIH Senior Health. “High Blood Pressure: Symptoms and Diagnosis.” NIH. Last updated 2014. Retrieved

Figure 1: Equipment Used to Manually
Measure Blood Pressure

Figure 2: The Human Circulatory System

Wikipedia. “Circulatory System en. Svg.” Wikipedia Commons: May 2009. Retrieved From: https://

Cromwell, L. et. al. “Blood Pressure Measurement.” From the publication Biomedical
instrumentation and Measurements. Prentice Hall (1973), pgs. 208-232.

Figure 3: Pressure Valves of the
Circulatory System

Cromwell, L. et. al. “Blood Pressure Measurement.” From the publication Biomedical
instrumentation and Measurements. Prentice Hall (1973), pgs. 208-232.

Figure 4: Setup of a Pressure Measuring
System & Circuit Diagram

Cromwell, L. et. al. “Blood Pressure Measurement.” From the publication Biomedical
instrumentation and Measurements. Prentice Hall (1973), pgs. 208-232.

Figure 5: Fundamentals Parts of NIBP
(Non-Invasive Blood Pressure) Measuring


How$To:$Take$Blood$Pressure$ 1.&Prepare&the&patient.&o Sitting&down&
o Arm&unobstructed&
o Ask&about&blood&pressure&history& 2. Wrap&the&cuff&around&the&upper&arm&with&leads&facing&the&brachial&artery.&

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor (Manual)
Preventative Maintenance.” From the publication Medical Equipment Troubleshooting Flowchart

Handbook. Durham, NC: Engineering World Health (2013).

Figure 6: How To Take Blood Pressure

Should&be&about&level&with&&the&heart.&Be&sure&that&it&is&the&proper&cuff&size&for&the&patient’s&arm.&&&3. Put&on&stethoscope.&Listen&to&the&brachial&artery&very&close&to&the&cuff.&&&4. Ensure&that&the&knob&is&turned&completely&clockwise.&&&5. Pump&the&cuff&to&a&high&pressure&(for&adults:&160P180&mmHg,&for&children:&140&mmHg)&&&6. Carefully&turn&the&knob&counterclockwise&to&release&the&pressure&in&the&cuff&at&a&slow&rate.&&&7. Look&at&the&pressure&on&the&dial&while&listening&to&the&heartbeat&through&the&stethoscope.&&&8. Obtain&and&record&the&blood&pressure.&&&
o Systolic:&the&pressure&at&which&you&start&to&hear&the&heart&beat&o Diastolic:&the&pressure&at&which&you&stop&hearing&the&heart&beat& Examples&of&ranges&for&healthy&blood&pressures:&



Child,&<6&months& 90P105/70&
Child,&6&months&to&7&years& 105P117/70& Adult&


Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor (Manual)
Preventative Maintenance.” From the publication Medical Equipment Troubleshooting Flowchart

Handbook. Durham, NC: Engineering World Health (2013).










* *


• Check&power&supply.& If& the&machine&uses&batteries,& check& their&voltage&and&replace&when&output& is&low.&If&wall&input&is&utilized,&ensure&that&the&proper&power&is&being&used.&
• Inspect&power&cords&and&plugs.&Check&AC&plug&for& loose&or&damaged&parts.&Verify&proper&insulation&and&integrity&of&cords.&
• Assess& for& leaks,& cracks,& and& occlusions& in& the& cuff,& connections,& and& tubing& inside& and& outside&apparatus.&Inspect&all&fittings&and&connectors.&
• Inspect&inside&circuitry.&Verify&that&all&switches&operate&properly&as&well.&
• Check&that&any&alarms&go&off&when&the&measured&blood&pressure&is&outside&of&an&acceptably&healthy,&that& is& if& the&NIBP&has& this& capability.& The& clinical& staff& should& establish& this& range.& To& test& this& on&yourself,& set& the&parameters&such& that& they&should&go&off&when&you& take&your&own&blood&pressure.&Once&you&are&assured&that&the&alarms&are&functional,&be&sure&to&set&the&parameters&back!&
• Perform&a&selfEtest&on&the&BP&cuff&to&ensure&cuff&is&working&properly&and&within&reasonably&accuracy&(±5&mmHg).&Accuracy&can&be&determined&by&having&the&clinical&staff&take&your&blood&manually.&&

How(To:(Taking(Blood(Pressure(1. Prepare&the&patient.&
o Sitting&or&lying&down&
o Arm&unobstructed&
o Ask&about&blood&pressure&history&
o Ensure&that&it&is&a&quiet&space&and&that&the&patient&doesn’t&move&too&much&–&many&NIBPs&are&sensitive&to&noise&and&movement&2. Wrap&the&cuff&around&the&upper&arm&with&leads&facing&the&brachial&artery.&Be&sure&that&it&is&the&proper&cuff&size&for&the&patient’s&arm.&The&cuff&should&be&about&1E2&cm&above&the&elbow&and&about&level&with&the&patient’s&heart.&3. Turn&on&the&machine,&and&press&“start”&when&ready&to&measure&blood&pressure.&4. Have&the&patient&remain&still&and&quiet&until&a&blood&pressure&is&displayed.&Often&times&a&pulse&rate&will&also&be&measured&and&displayed.&5. If&the&patient&has&a&higher&than&usual&blood&pressure,&many&NIBPs&will&allow&the&user&to&hold&the&start&button&until&the&monitor&inflates&30E40&mmHg&higher&than&the&expected&blood&pressure.&6. If&the&cuff&needs&to&be&deflated&or&reset&during&inflation&for&any&reason,&press&the&off&button.&7. Record&the&blood&pressure.&

Examples of ranges for healthy blood pressures:

Age$ BP$(Systolic/$Diastolic)$Child,&<6&months& 90E105/70&Child,&6&months&to&7&years& 105E117/70&Adult& 120/80&
Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor (Automatic) Preventative

Maintenance.” From the publication Medical Equipment Troubleshooting Flowchart Handbook. Durham, NC: Engineering
World Health (2013).

AUTOMATIC Blood Pressure Monitor Preventative







• Remove&the&cuff&and&tubing&from&the&mercury&apparatus&
• Open&the&mercury&column&lever,&and&tilt&the&apparatus&back&to&allow&any&mercury&in&the&column&to& run&into&the&reservoir&
• Remove&the&tank&cover&(usually&using&a&screwdriver)&
• Remove&all&mercury&from&the&tank&using&a&syringe&
• Pour&mercury&into&a&clearly&labeled&container,&following&proper&protocol&
• Remove&cover&over&the&rise&tube&(usually&using&a&screwdriver)&
• Take&out&the&rise&tube& How$To:$Clean$Mercury$
• Roll&a&sheet&of&paper&into&a&funnel&
• The&pointed&end&should&have&a&tiny&hole&
• Put&the&funnel&in&a&bottle&
• Pour&the&mercury&into&the&funnel&and&let&pass&through&

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor (Manual)
Preventative Maintenance.” From the publication Medical Equipment Troubleshooting Flowchart

Handbook. Durham, NC: Engineering World Health (2013).

MANUAL Blood Pressure Monitor Preventative


• When&exposed&to&air,&mercury&vaporizes&and&is&extremely&poisonous&
• Always&handle&mercury&while&wearing&rubber&gloves&
• Work&with&mercury&outside&or&in&a&wellPventilated&area&
• Recover&mercury&with&a&large&syringe&
• When&storing&mercury,&add&some&water&to&prevent&evaporation&
• Always&have&an&airtight&cover&on&a&mercury&container&
• Wash&skin&thoroughly&if&it&comes&into&contact&with&mercury&

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor (Manual)
Preventative Maintenance.” From the publication Medical Equipment Troubleshooting Flowchart

Handbook. Durham, NC: Engineering World Health (2013).

User Care of Medical Equipment – First line maintenance for end users


User Care Checklist – Sphygmomanometers (B.P. sets)



9 If mercury is spilled, seal unit and send to technician

Visual checks

9 Ensure all parts are present and are tightly fitted

9 Check display is zero when cuff deflated


9 Before use, check pressure rises and returns to zero

9 Check equipment is safely packed



9 Remove all dust and dirt with damp cloth or by hand

Visual checks

9 Remove or replace any cracked rubber parts


9 Check correct operation of inflation bulb and valves

9 Remove any batteries if not in use for more than one month

9 Inflate to 200 mmHg and check leakage is not faster than

2 mmHg in 10 seconds

Every six months

9 Biomedical Technician check required

9 Check calibration of aneroid devices against mercury device

Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Sphygmomanometer Preventative Maintenance Checklist

User Care of Medical Equipment – First line maintenance for end users


User Care Checklist – Stethoscopes



9 Remove any dirt visible

Visual checks

9 Check all parts are present and tightly fitted


9 Tap chestpiece gently before use to check operation

9 Check equipment is safely packed



9 Remove all dirt with damp cloth or by hand

9 Remove earpieces and clean inside with warm water

Visual checks

9 Remove or replace any cracked rubber parts

9 Replace membrane if broken


9 Check tube connector rotates easily within chestpiece

9 Check sound can be heard from both sides of chestpiece

Every six months
Biomedical Technician check required

Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Stethoscope Preventive Maintenance Checklist










* *



* *

AUTOMATIC Blood Pressure Monitor Troubleshooting

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor
(Automatic) Troubleshooting Flowchart.” From the publication Medical Equipment

Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health (2013).


#! Text%Box! Comments!
1! Begin:!Automatic!Blood!Pressure!Cuff! Testing!and!maintenance!is!advised!when!the!automatic!blood!cuff!fails!to!give!out!a!complete!or!accurate!blood!pressure.!2! Does!machine!power!on?! Lights,!displays,!and!sounds!are!signs!that!the!device!is!powered!on.!
3! Troubleshoot!power!supply!(separate!flowchart).!

4! Change!battery!if!necessary.! If!batteries!are!required,!test!that!they!are!able!to!receive!and!hold!a!charge.!See!BTA!skills!on!Batteries.!
5! Wrap!cuff!around!arm.! Try!wrapping!cuff!around!your!arm!before!beginning!function!test.!NIBP!will!require!either!pulses!or!vibrations!brachial!artery,!so!it!is!important!that!the!cuff!is!on!correctly.!Follow!the!User%Guide!for!more!detailed!instructions.!
6! Press!"start.”! For!some!machines,!a!flashing!light!or!image!will!suggest!the!machine!is!ready!to!begin!the!blood!pressure!measurement.!!
7! Can!air!be!pumped!into!the!cuff?! Once!engaged,!the!machine’s!pump!will!begin!inflating!the!cuff.!Does!the!cuff!readily!inflate?!Is!a!reading!able!to!be!obtained?!
8! Test!for!leaks!and!cracks!in!tubing,!connections,!and!cuff!outside!machinery.! Use!BTA!skills!on!Connections,!Leaks!and!Blockages!to!assess!for!cracks,!leaks,!or!occlusions.!!
9! Open!up!apparatus!and!assess!inside!tubing!for!cracks,!leaks,!and!occlusions,!as!needed.!

10! Is!the!correct!amount!of!input!voltage!entering!the!pump?! Test!the!voltage!going!into!the!pump!using!a!multimeter.!Compare!the!measured!voltage!to!the!required!DC!input!voltage,!which!can!usually!be!found!as!a!marking!somewhere!on!the!pump.!
11! Troubleshoot!the!electrical!connections!around!pump.!Repair!or!replace!any!components!as!needed.!

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor

(Automatic) Troubleshooting Flowchart.” From the publication Medical Equipment
Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health (2013).

12! Troubleshoot!the!pump!and!pump!motor.!Replace!pump!as!needed.!

13! Go!to!step!6.! Restart!cuff!inflation!to!see!if!the!corrective!measures!have!repaired!the!machine.!
14! Do!any!alarms!go!off!to!indicate!blood!pressure!is!too!high!or!low?! Some!NIBP!machines!are!equipped!with!alarms!that!indicate!whether!or!not!a!blood!pressure!is!within!an!acceptable!healthy!range,!preset!by!the!machine’s!parameters.!
15! Change!parameters!as!needed!if!original!range!is!too!narrow.!

16! Is!BP!measurement!displayed?!! After!pressing!start,!is!a!numerical!value!for!blood!pressure!displayed?!NIBPs!will!usually!display!a!systolic,!diastolic,!and!pulse!rate!after!measurement.!
17! Ensure!proper!cuff!usage.! Is!the!cuff!the!proper!size!for!your!arm!or!the!patient’s!arm?!Are!the!leads!in!the!cuff!over!the!brachial!artery?!NIBPs!can!be!very!sensitive.!Check!the!User%Guide!to!ensure!proper!machine!usage.!
18! Is!a!service!manual!available?! Many!service!manuals!will!instruct!the!user!on!the!meaning!of!displayed!error!messages!for!the!specific!NIBP!system.!These!messages!can!also!point!to!general!areas!of!the!device!that!can!be!troubleshot!using!the!relevant!BTA!skills.!
19! Use!manual!to!interpret!the!meaning!of!display!and!respond!appropriately.! Most!of!the!time!these!messages!are!accompanied!by!a!proposed!set!of!actions.!
20! Go!to!Begin.! Restart!diagnostic!process!to!see!if!the!corrective!measures!have!repaired!the!machine.!
21! Open!up!apparatus!and!confirm!good!electrical!connections.!Especially!between!BP!module!and!display.!

22! Repair!and!replace!parts!as!needed.! If!there!is!any!obvious!damage,!repair!connections!and!replace!necessary!parts!using!the!appropriate!BTA!skills.!

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor
(Automatic) Troubleshooting Flowchart.” From the publication Medical Equipment

Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health (2013).

23! Ensure!cuff!accuracy!by!comparing!with!manual!method.!
After!obtaining!a!blood!pressure!measurement,!have!the!clinical!staff!take!a!blood!pressure!on!the!same!individual!using!a!working!manual!blood!pressure!cuff.!A!good!NIBP!will!be!within!5!mmHg,!but!ultimately!it!is!up!to!the!staff!whether!or!not!the!cuff!should!be!used!on!patients.!24! Cuff!is!working!properly.! Return!apparatus!to!appropriate!clinical!staff.!!

Cooper, Justin and Alex Dahinten for Engineering World Health. “Blood Pressure Monitor
(Automatic) Troubleshooting Flowchart.” From the publication Medical Equipment

Troubleshooting Flowchart Handbook. Durham, NC: Engineering World Health (2013).




ANUAL Blood Pressure M

onitor Troubleshooting

Cooper, Justin and Alex Dahinten for Engineering W
orld Health. “Blood Pressure M

onitor (M
anual) Troubleshooting

Flowchart.” From
the publication M

edical Equipm
ent Troubleshooting Flowchart Handbook. Durham

, NC: Engineering

orld Health (2013).




1!Begin:!Manual!Blood!Pressure!Cuff! Testing!and!maintenance!is!advised!when!the!manual!cuff!fails!to!give!

2! Does!the!cuff!have!a!mercury!


3! Is!mercury!leaking!from!the!



4! Disassemble!apparatus!and!check!




6! Disassemble!and!clean!specific!parts!


Cooper, Justin and Alex Dahinten for Engineering W
orld Health. “Blood Pressure M

onitor (M
anual) Troubleshooting

Flowchart.” From
the publication M

edical Equipm
ent Troubleshooting Flowchart Handbook. Durham

, NC: Engineering

orld Health (2013).

7! Is!the!mercury!level!at!zero!when!no!

8! Add/remove!mercury!to!column!as!




9! Begin!pumping!air!into!meter.!


10! Does!the!pressure!level!lower!over!

11! Check!for!any!leaks!in!meter!or!


12! Does!the!pressure!level!rise!over!

13! Investigate!leather!seal!and!washer.!


14! Do!bubbles!appear!in!mercury!





Cooper, Justin and Alex Dahinten for Engineering W
orld Health. “Blood Pressure M

onitor (M
anual) Troubleshooting

Flowchart.” From
the publication M

edical Equipm
ent Troubleshooting Flowchart Handbook. Durham

, NC: Engineering

orld Health (2013).

17! Before!applying!pressure!in!the!cuff,!

18! Open!meter!and!manually!twist!the!



20! Check!the!valve.!Ensure!that!the!

21! Clean!filter!between!the!bulb,!valve,!


22!Check!the!bulb.!Replace!if!necessary.! Is!the!bulb!able!to!pump!air?!Are!there!any!holes!or!leakage!in!the!

23! Pump!air!to!a!particular!pressure!

24! Does!the!pressure!drop!


25! Test!for!leaks!in!tubing!and!between!


27!Is!air!being!released!from!the!cuff?! You!will!hear!air!being!released!from!the!valve,!and!the!cuff!should!

Cooper, Justin and Alex Dahinten for Engineering W

orld Health. “Blood Pressure M
onitor (M

anual) Troubleshooting
Flowchart.” From

the publication M
edical Equipm

ent Troubleshooting Flowchart Handbook. Durham
, NC: Engineering

orld Health (2013).

28! Check!the!valve.!Ensure!that!the!

29! Clean!filter!between!the!bulb!and!


30! Test!for!accuracy!and!calibrate!if!


!Cooper, Justin and Alex Dahinten for Engineering W

orld Health. “Blood Pressure M
onitor (M

anual) Troubleshooting
Flowchart.” From

the publication M
edical Equipm

ent Troubleshooting Flowchart Handbook. Durham
, NC: Engineering

orld Health (2013).

User Care of Medical Equipment – First line maintenance for end users


Troubleshooting – Sphygmomanometers (B.P. sets)

Fault Possible Cause Solution


Mercury leakage
Mercury not at zero level

Mercury leakage or overfilling

Refer to technician for correction


Mercury is dirty

Oxidation of mercury

Refer to technician for cleaning


Pressure does not increase easily
Pressure increases after inflation

Valve or tube blockage

Remove and clean all valves and
tubes. Reassemble and test


Aneroid instrument does not
return to zero

Zero setting has moved

Rotate collar on base until zero
setting achieved and tighten.
If still malfunctioning, refer to


Pressure does not remain steady

Leakage of air

Isolate leak by closing off parts of
Replace leaking section and retest

Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Sphygmomanometer Troubleshooting Checklist

User Care of Medical Equipment – First line maintenance for end users


Troubleshooting – Stethoscopes

Fault Possible Cause Solution


Faint or no sound heard

Leakage or blockage

Remove all parts and check for
leakage and blockage. Water or
blowing air can be used to flush
tubes through.
Assemble and retest


Tube connector does not stay in

Broken locking mechanism

Refer to technician for repair


Parts damaged or faulty

Broken part

Replace with part taken from
other units

Strengthening Specialised Clinical Services in the Pacific. User Care of Medical
Equipment: A first line maintenance guide for end users. (2015).

Stethoscope Troubleshooting Checklist











1. Skeet,!Muriel!and!David!Fear.!“Blood!Pressure!Apparatus.”!Care%and%Safe%Use%of%Medical%

2. WHO.!“Blood!Pressure!Machines!(Sphygmomanometers).”!Maintenance%and%Repair%of%





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