BLOOD PRESSURE MEASUREMENT FOR MEDICAL STUDENTS

1. BP MEASUREMENT
DR PRANABANANDA PAL
DM PDT, DEPT OF CARDIOLOGY.
IPGMER & SSKM HOSPITAL KOLKATA, INDIA.
Date 06/05/2023

2. INTRODUCTION
• Blood pressure is defined as the lateral
force per unit area of vascular wall. It is
expressed as millimeter of mercury.
• Most important clinical tool in Medicine
and Cardiology.

3. BP COMPONENTS
• SBP & DBP: higher SBP and higher DBP are associated with increased CVD risk.
• PP: Pulse pressure (SBP−DBP) is a measure of pulsatile hemodynamic stress and a
marker of arterial stiffness.
• MAP:= DBP+1/3 PP: provide estimates of the overall arterial BP during a
complete cardiac cycle.
• Proportional Pulse Pressure: Pulse pressure/ SBP. Good systolic function =
lower PPP.

4. BP MEASUREMENT METHODS
• I. Office BP – Auscultatory method (mercury, aneroid)
• II. Office BP – Oscillometric method
• III. Automated Office BP (AOBP)
• IV. Home BP Monitoring (HBPM)
• V. Ambulatory BP Monitoring (ABPM)
• VI. Special Techniques
• VII. Invasive BP monitoring

5. OFFICE BP- “THE WEAK CORNERSTONE OF
HYPERTENSION DIAGNOSIS”
• I. Auscultatory method:
• The traditional method involves
auscultation of the brachial artery
with a stethoscope to detect the
appearance and muffling or
disappearance of the Korotkoff
sounds, which represent SBP and
DBP, respectively.
• II. Oscillometric method:
• software within a device evaluates
the oscillometric waveforms,
commonly during BP cuff deflation,
and uses algorithms to estimate BP.

6. 1. AUSCULTATORY METHOD

7. BP PHYSIOLOGY: KOROTKOFF SOUNDS
• Arterial oscillations resulting from
distension of arterial wall with each
cardiac impulse due to partial
occlusion of the artery.
• Heard with stethoscope placed
directly over brachial artery.
• Phase I= SBP, Phase V= DBP (Phase
IV in hyperdynamic states).

8. STEP 1: PROPER PREPARATION
• 1. Have the patient relax.
• 2. Avoid caffeine, exercise, and smoking
for at least 30 min before measurement.
• 3. Ensure that the patient has emptied
his/her bladder.
• 4. The patient should not talk during the
measurement.
• 5. Remove clothing covering the location
of cuff placement.

9. STEP 2: PROPER TECHNIQUES
• 1. Device that has been validated and
calibrated periodically.
• 2. Support the patient’s arm (eg, resting on a
desk).
• 3. Position the cuff at the level of the right
atrium.
• 4. Use the correct cuff size.
• 5. Correct tightness : One finger should easily
fit under the cuff.

10. STEP 3: PROPER MEASUREMENT
• 1. BP in both arms. Use the higher reading.
• 2. Separate 3 measurements and average
value to be taken.
• 3. Deflate the cuff pressure 2 mm Hg/s,
and listen for Korotkoff sounds.
• 4. Phase I and V Korotkoff sounds to
identify SBP and DBP.
• 5. Measure BP 1 min and 3 min after
standing to exclude orthostatic
hypotension.

11. COMPLETE EVALUATION
• 1. POSTURAL VARIATION:
• Measure BP 1 min and 3 min after standing
from a seated position in all patients at the
first measurement to exclude orthostatic
hypotension.
• In subsequent visits : older people, diabetic,
and people with autonomic dysfunctions.
• Supine hypertension: elderly, due to loss
of cerebral autoregulation.
• Supine hypotension: Pregnancy

12. COMPLETE EVALUATION
• 2. ARM VARIATION:
• Normal discrepancy <10mmHg
• Pathological differences:
• Subclavian artery occlusive disease
• CoA
• Aortic dissection
• Supravavular AS
• Higher arm BP value to be taken as
record.

13. COMPLETE EVALUATION..
• 3. LEG BP:
• The patient lies on the abdomen and
preferably, 8” wide cuff is applied with
compression over the posterior aspect
of the mid thigh.
• Auscultation is carried out in the
popliteal fossa.
• Higher than arm BP by 20 mmhg.
• >20mmHg in Severe AR (Hill’s Sign)

14. COMPLETE EVALUATION
• 4. ANKLE BP:
• Arm cuff is placed over the calf and
auscultation is done over the posterior
tibial artery (or over the dorsalis pedis).
• ANKLE BRACHIAL INDEX:

15. SPECIAL SITUATIONS
• 1. Atrial Fibrillation: Significant beat-to-beat variation in the arterial pressure,
which may result in underestimation of their BP. Hence, several recordings should
be taken (at least 3 recordings) and the average is noted in each limb.
• 2. Pulsus Paradoxus: Exaggeration of normal decline of SBP in inspiration.
Korotkoff sounds are heard only during expiration peak systolic pressure. Seen
in cardiac tamponade, COPD, severe CHF.
• 3. Pulsus Alternans: Diminution in the intensity of every other Korotkoff sounds
is noted at or near peak systolic pressure.
Careful and slow deflation of cuff is mandatory to detect these
abnormalities.

16. SPECIAL SITUATION
• 4. Isolated Systolic Hypertension: In elderly, mostly due to decreased
compliance, SBP in stage 1 hypertension range.
• 5. Pseudohypertension: When sphygmomanometric pressure is far higher than
the intra-arterial pressure, it is called pseudohypertension.
• In elderly, due to thickened calcified, noncompressible artery-- recognized by
Osler maneuver, where radial pulses are still palpable, with an occlusive pressure
(more than systolic) over the more proximal brachial artery.
• 6. Vascular stiffness: Augmentation index: indicator of central aortic stiffness.

17. AUGMENTATION INDEX
• Indicator of central aortic
stiffness-- measured by
peripheral tonometry.
• It is the index of how much
the percent increase of
systolic pressure due to early
return of reflection wave
during late systole.
• Major risk factor of CVD,
hypercholesterolemia.

18. SPECIAL POPULATION
• 1. CHILDREN: Oscillometry and auscultation are acceptable for screening. If
elevated BP is present when measured with an Oscillometric device, auscultation
should be performed to define BP categories.
• II. PREGNANT: Because of the hemodynamic and vascular changes that occur
during pregnancy, BP measurement devices need to be validated in pregnant
women.
• III. OLD: Sitting and standing BP measurements can be used to identify orthostatic
hypotension. Standing BP should be obtained immediately after rising and 1 and 3
min later.
• Orthostatic hypotension has been associated with risk for fractures, syncope, and
mortality.
• IV. OBESE: Tronco-conical-shaped BP cuffs may be useful for some obese adults. A
thigh cuff can be used.

19. AUSCULTATORY OBPM IS INACCURATE!
Routine auscultatory OBPMs are 9/6 mmHg higher than standardized research BPs.

20. II. OSCILLOMETRIC METHOD:
• Readings are based on the
amplitude of the oscillations
recorded in the lateral walls of the
upper arm.
• Mean arterial BP is estimated to be
the cuff pressure when the oscillation
amplitude is maximal, and then the
SBP and DBP are computed from a
proprietary algorithm that is known
only to the manufacturer.
• Validated devices :
www.stridebp.org

21. III. AUTOMATED OFFICE BP (AOBP)
• Record multiple automatic BP
readings after a rest period with a
single activation and then provide an
average of these readings.
• Unattended AOBP – no clear
advantage over attended AOBP.
[SPRINT Trial]
• BP measured with AOBP versus the
auscultatory method is closer to
awake out-of office BP levels
measured with ABPM. [CAMBO Trial].

22. BP PHENOTYPES
• A. WHITE COAT HYPERTENSION: untreated
condition in which BP is elevated in office
but normal when measured out-of-office.
• White coat effect mainly reflect pressor
response to alerting reaction elicited by BP
measurement
• B. MASKED HYPERTENSION: untreated
patients in whom BP is normal in office but
elevated when measured out-of-office.

23. BP PHENOTYPES
• C. NOCTURNAL HYPERTENSION:
• hypertensive BP during sleep.
• Prevalent in CKD and DM.
• High risk for CVD events independently of awake BP.
• D. NON DIPPING AND REVERSE DIPPING BP:
• Normally nocturnal BP falls by > 10%.
• Dipping absent in: obesity, OSA, autonomic neuropathy,
DM, CKD, orthostatic hypotension, old age.
• Non dipping or absent dipping and extreme dipping both
are associated with CV risk.

24. WHITE COAT HTN VS MASKED HTN
• Prevalence: upto 30-40%.
• More in old, women and non
smokers
• Low risk of CV events than SH
• Prevalence ~15% in normotensives.
• Young, men, smokers, alcoholics, job
stress.
• Higher risk of dyslipidemia,
dysglycemia, HMOD and CV events

25. SCREENING AND DIAGNOSIS

26. IV. HOME BP MONITORING
• Home BP is the average of all BP
readings performed with a
semiautomatic, validated BP monitor,
for at least 3 days and preferably for
6–7 consecutive days before each
clinic visit
• readings in the morning and the
evening, taken in a quiet room after 5
min of rest, with the patient seated
with their back and arm supported.
• Better predicts CV morbidity and
mortality than office BP.

27. V. AMBULATORY BP MONITORING
• ABPM is a noninvasive, fully automated
technique - BP is recorded over an
extended period of time (24 hr).
• Stronger association with HMOD and
clinical cardiovascular outcomes
compared with office-based BP
measurements
• Identify BP Phenotypes (ie, sustained,
white-coat, masked, and nocturnal
hypertension, and nondipping or reverse-
dipping BP)

28. ABPM TRACING

29. COMPARING ABPM AND HBPM

30. CLINICAL INDICATIONS FOR HBPM OR ABPM
Group Example
Suspected WCH 1. Grade 1 hypertension on office BP measurement
2. Marked office BP elevation without HMOD
Suspected MH 1. High normal office BP
2. Normal office BP in patients with HMOD
Special groups 1. Postural hypotension
2. Post prandial hypotension
3. Resistant hypertension
4. Exaggerated BP response to exercise
5. Highly variable office BP
ABPM SPECIFIC 1. Assessment of nocturnal BP values and dipping status.
2. Marked discrepancy between home and office BP.

31. VI. SPECIAL TECHNIQUES
• 1. FINGER CUFF
• 2. WRIST MONITOR
• 3. WEARABLE DEVICES

32. FINGER CUFF
• CareTaker: Wireless Continuous
Blood Pressure and Heart Rate
Monitor with Finger Cuff Technology.

33. WRIST MONITORS
• HEARTGUIDE
• The first comparison study of BPs
measured by a recently developed
wrist-worn watch-type oscillometric BP
monitoring (WBPM) device, the
“HeartGuide,” versus BPs measured by
an (ABPM) device.
• Difference between the WBPM and
ABPM device was acceptable both in
and out of the office.

34. WEARABLE DEVICES

35. VII. INVASIVE BP MONITORING
• Invasive arterial monitoring is a highly
useful tool, which allows close blood
pressure monitoring for patients
undergoing major surgery and the
critically ill.
• Insertion of a catheter in suitable artery
and displaying the pressure wave.
• More accurate specially in shock,
arrythmia, vascular stiffness.

36. NEED OF INVASIVE BP IN CRITICALLY ILL
• The poor performance of the
auscultatory method in patients with
circulatory shock is the result of
reduced systemic flow (from
hypotension and vasopressors), which
curtails the arterial counterpulsations
and reduces the intensity of the
Korotkoff sounds.
• Reliable blood pressure measurements
are essential in the management of
shock (e.g., to guide fluid resuscitation),
direct measurements of intraarterial
pressure is the consensus
recommendation.

37. INVASIVE BP WAVEFORM

38. PERIPHERAL AMPLIFICATION
• As BP measured further into
periphery:
• Anacrotic and dicrotic notches
disappear
• Waveform appears narrower.
• SBP and PP increase
• Diastolic and mean pressure
decrease.

39. QUALITY OF INVASIVE BP- DAMPING COEFFICIENT
• Determines the dynamic response
of the arterial catheter/tubing system
to the pressure impulses.
• Underdamping: stiff tubing/
defective transducer.
• Overdamping: low infusion bag
pressure, blood clot/ air bubble in
circuit

40. EXERCISE BP
• Isotonic (dynamic) exercise causes moderate increase
in BP (systolic greater than mean). Isometric exercise
causes an abrupt increase in all the systolic, diastolic as
well as mean pressure.
• Hypertensive Systolic Pressure Response: Rise in SBP
> 210 mmhg in men and > 190 mmhg in women.
Indicate future development of hypertension and MACE.
• Exercise Induced Systolic Hypotension: SBP falling
below resting systolic pressure or 20mmhg fall after
initial rise. Often related to multivessel CAD with LV
dysfunction.

41. GUIDELINES: SCREENING AND DIAGNOSIS OF
HYPERTENSION

42. HYPERTENSION CUT OFF

43. GRADING OF HYPERTENSION

44. REFERENCES
• 1. Measurement of Blood Pressure in Humans- A Scientific Statement From the American Heart
Association (Hypertension. 2019;73:e DOI:10.1161/HYP.0000000000000087.)
• 2. 2018 ESC/ESH Guidelines for the management of arterial hypertension. (doi:
10.1093/eurheartj/ehy339)
• 3. Management of Hypertension in the Digital Era: Small Wearable Monitoring Devices for
Remote Blood Pressure Monitoring (Hypertension. 2020;76:640-650. DOI:
10.1161/HYPERTENSIONAHA.120.14742.)
• 4. www.stridebp.org
• 5. Braunwald’s Heart Disease: A Textbook Of Cardiovascular Medicine, Twelfth Edition, Copyright
© 2022 by Elsevier Inc.

45. THANK YOU