Measuring blood pressure
&
pulse rate
All arteries carry blood away from the heart
All veins carry blood to the heart
Most arteries carry oxygenated blood
Most veins carry de-oxygenated blood

Veins have valves that prevent blood from flowing in the wrong direction

Veins are wider than arteries

Contraction of body muscles helps the blood flow through the veins

Arteries have more elastic tissue and a thick muscular layer to cope with the
high pressure of blood flow caused by the heart beat
 Capillaries transport blood
from the arterioles to
venules.
 They are microscopic
vessels which are in most
of our organs.
 They are one cell thick so they allow exchange of
gas (O2;CO2); salts and water to occur between the
capillaries and surrounding tissue.




The pulse may be palpated at any place that allows an artery to be
compressed against a bone.
Pressure waves generated by the heart in systole moves against the
arterial wall.
The pulse can be used as a tactile guide to determine the systolic
blood pressure (diastolic not palpable).
The pulse pattern can be clinically significant, so it is important to
note;
1. The rate in beats per minute.
2. The rhythm of pulse.
• Fast
• Slow
• irregular
3. The strength of the pulse.
1. Absent
2. Barely palpable
3. Easily palpable
4. Full
5. bounding
 Your pulse varies depending on your age, level of fitness and how
active you are being.
 A resting pulse is used in practice to record rate.
 The pulse rate needs to be taken over 1 full minute.
The normal heart beat
Terminology
 Slow pulse rate <60b/min = bradycardia
 Fast pulse rate >100b/min (resting) =
tachycardia
 Irregular pulse – related to palpitations
All these need to be referred to a healthcare professional
as they indicate an underlying problem – ask the patient
if they are aware of any problems
When you document the rate also document the rhythm
(e.g.regular or irregular)
What else can affect the heart rate?
 Caffeine & alcohol – increases the strength and
frequency of the heartbeat therefore increasing the rate
 Exercise increases the heart rate, but someone who
exercises regularly may have a low resting rate.
 Disease affect the heart rate. Thyroid disease can
either make the rate faster or slower depending type of
disease.
 Drugs (medical & recreational) e.g. digoxin & bets
blockers slow the HR. Recreational drugs tend to
increase HR.
• Count the heart beats for 60
seconds
• It needs to be a resting pulse
rate
• Remember to check rate,
rhythm & strength
1.
2.
3.
4.
5.
6.
7.
8.
9.
Temporal
External maxillary (facial)
Carotid
Brachial
Radial
Femoral
Popliteal
Posterior tibial
Dorsal pedis
Blood Pressure
What is blood pressure?
 Blood pressure refers to the force exerted by
circulating blood on the walls of blood vessels.
 The pressure of the circulating blood decreases
as blood moves through arteries, arterioles,
capillaries, and veins.
 Blood pressure values are reported in
millimetres of mercury (mmHg).
 Blood pressure is recorded as systolic over
diastolic e.g. 120/60.
What is blood pressure? (tap & hose)
How is blood pressure controlled
 Short term control – ANS –
barareceptors – vagus nerve.
 Intermediate control - Transcapillary shift – osmosis/plasma
proteins.
 Long term control –
Renin/angiotensin system;
aldosterone.
RAS System
 The systolic arterial pressure is defined as the
peak pressure in the arteries, which occurs near
the beginning of the cardiac cycle.
 The diastolic arterial pressure is the lowest
pressure (at the resting phase of the cardiac cycle
 Measures of arterial pressure are not static, but
undergo natural variations from one heartbeat to
another and throughout the day.
 Blood pressure also changes in response to
stress, nutritional factors, drugs, or disease.
Systole is the
contraction of heart
chambers, driving blood
out of the chambers.
The chamber valves are
closed.
Diastole is the period of
time when the heart fills
with blood after systole
(contraction).
The chamber valves are
open. The heart is at rest.
 High blood pressure (or hypertension) is
defined in an adult as a blood pressure greater
than or equal to 140 mm Hg systolic pressure
or greater than or equal to 90 mm Hg diastolic
pressure.
 High blood pressure directly increases the
risk of coronary heart disease (which leads to
heart attack) and stroke, especially when it's
present with other risk factors.
 High blood pressure is the most important
preventable cause of premature ill-health.
 Around 5.7 million people have
hypertension which is undiagnosed.
 There is no universally accepted
definition of hypotension (low blood
pressure).
 Chronic disease have a lower target
threshold e.g. diabetes; CKD.
Risk factors for developing hypertension
 Obesity
 Physical inactivity
 High consumption of alcohol
 High intake of dietary sodium
 Low intake of dietary potassium
 Stress
 Increasing age
 Cigarette smoking
 Increased blood cholesterol
 Patients with systemic diseases including: Diabetes
mellitus; renal disease; peripheral vascular disease
 Family history of hypertension, CHD or stroke
Measuring blood pressure
NICE clinical guideline 127; Quick reference guide; Aug 2011
 HCP need adequate training and should have their
performance reviewed periodically
 Devices for measuring BP must be properly validated,
maintained and regularly recalibrated according to
manufacturers instruction
 Ensure an appropriate cuff size for the patient’s arm is used
 Standardize the environment; relaxed temperate setting
with the person quiet and seated with arm outstretched and
supported
 Palpate the radial or brachial pulse before measuring BP
Blood Pressure Measurement
With Electronic Blood Pressure Monitors
Points to note;
 If checking an electronic device against a mercury or
aneroid sphygmomanometer the blood pressure may
differ slightly between devices.
 It is good practice to occasionally check the monitor
against a aneroid sphygmomanometer or another
validated device.
 It is important to have a monitor calibrated according to
manufacturer’s instruction.
 These devices should not be used for people with an
irregular heart beat (Atrial Fibrilation) or heart rate lower
than 50 beat/min
Blood pressure measurement
Estimation of blood pressure by auscultation
(NICE clinical Guideline 34 Partial update of CG 18)






Standardise the environment as much as possible: − relaxed temperate setting, with
the patient seated − arm out-stretched, in line with mid-sternum, and supported.
Correctly wrap a cuff containing an appropriately sized bladder around the upper
arm and connect to a manometer. Cuffs should be marked to indicate the range of
permissible arm circumferences; these marks should be easily seen when the cuff is
being applied to an arm.
Palpate the brachial pulse in the antecubital fossa of that arm.
Rapidly inflate the cuff to 20 mmHg above the point where the brachial pulse
disappears.
Deflate the cuff and note the pressure at which the pulse re-appears: the
approximate systolic pressure.
Re-inflate the cuff to 20 mmHg above the point at which the brachial pulse
disappears.
 Using one hand, place the stethoscope over the brachial artery ensuring
complete skin contact with no clothing in between.
 Slowly deflate the cuff at 2–3 mmHg per second listening for Korotkoff
sounds.
 Phase I: clear tapping sound (SBP)
 Phase II: Auscultatory gap: swishing sound or soft murmur
 Phase III: Loud slapping sound
 Phase IV: sudden muffling of sound
 Phase V: disappearance of sound (DBP)
 The first appearance of faint repetitive clear tapping sounds gradually
increasing in intensity and lasting for at least two consecutive beats: note the
systolic pressure.
 A brief period may follow when the sounds soften or ‘swish’. In some patients,
the sounds may disappear altogether.
 The return of sharper sounds becoming crisper for a short time.
 The distinct, abrupt muffling of sounds, becoming soft and blowing in quality.
 The point at which all sounds disappear completely: note the diastolic
pressure.
 When the sounds have disappeared, quickly deflate the cuff completely if
repeating the measurement.
 When possible, take readings at the beginning and end of consultations.
Terminology
 high blood pressure = hypertension
 low blood pressure = hypotension
 fast pulse rate = tachycardia
 slow pulse rate = bradycardia
Pediatrics. 2012 May;129(5):e1205-e1210. Epub 2012 Apr 16.
Comparison of Mercury and Aneroid Blood Pressure Measurements in Youth.
Shah AS, Dolan LM, D'Agostino RB Jr, Standiford D, Davis C, Testaverde L, Pihoker C, Daniels SR, Urbina EM; for the SEARCH for Diabetes in Youth Study
Group.
Source
Division of Endocrinology, ML 7012, Cincinnati Children's Hospital, 3333 Burnet Ave, Cincinnati, OH 45229. amy.shah@cchmc.org.
Abstract
OBJECTIVE:
Because of concerns about the safety and environmental impact of mercury, aneroid sphygmomanometers have replaced mercury-filled devices for blood
pressure (BP) measurements. Despite this change, few studies have compared BP measurements between the 2 devices.
METHODS:
The SEARCH for Diabetes in Youth Study conducted a comparison of aneroid and mercury devices among 193 youth with diabetes (48% boys, aged 12.9 ±
3.7 years; 89% type 1). Statistical analyses included estimating Pearson correlation coefficients, Bland-Altman plots, paired t tests, and fitting
regression models, both overall and stratified by age (<10 vs ≥10-18 years).
RESULTS:
Mean mercury and aneroid systolic and diastolic BPs were highly correlated. For the entire group, there was no significant difference in mean systolic BP
using the aneroid device, but there was a -1.53 ± 5.06 mm Hg difference in mean diastolic BP. When stratified by age, a lower diastolic BP (-1.78 ±
5.2 mm Hg) was seen in those ≥10 to 18 years using the aneroid device. No differences in systolic BP were observed, and there were no differences in
BP by device in individuals <10 years. Regression analyses did not identify any explanatory variables.
CONCLUSIONS:
Although a small discrepancy between diastolic BP measurements from aneroid versus mercury devices
exists, this variation is unlikely to be clinically significant, suggesting that either device could be used
in research or clinical settings.