Different Methods of Measuring Blood Pressure Based on AHA and JNC 7 guidelines on procedure for measuring blood pressure

1. DIFFERENT METHODS OF
MEASURING BLOOD
PRESSURE

2. Stephen Hales
• 1727- First Blood
Pressure measurements
by inserting glass tubes
inside arteries of a Mare
and recording pressure
from the column of
blood that rose

3. • Forssmann, Counard
and Richard
• Nobel Prize 1956
• Procedure of cardiac
catherisation

4. MEASURING BLOOD
PRESSURE

5. BP MEASUREMENT
DirectIndirect
TonometricUltrasonicOscillometricAuscultatory
HybridAneroidMercury
Palpatory

6. Palpatory Method
• Rough Estimation of Systolic Pressure
• Carotid Femoral radial >70 mm Hg
• Carotid and Femoral > 50 mm Hg
• Carotid >40 mm Hg
Deakin CD, Low JL (September 2000). Accuracy of advanced trauma life
support guidelines for predicting systolic blood pressure using carotid,
femoral and radial pulses: Observational ; BMJ 321 (7262): 673–4.

7. Direct Method
• Direct Intra arterial Measurement of
Pressure using a pressure transducer
• Systolic is recorded 5-10 mm Hg higher and
Diastolic is 5-10 mm lower than non- invasive
techniques
• Gold Standard
• Accurate beat-to-beat monitoring
Matthew Ward, Jeremy A Langton,
Disclosures Cont Edu Anaesth Crit Care and Pain. 2007;7(4):122-126.

8. Mercury Sphygmomanometer
• Samuel Siegfried Karl
Ritter von Basch
(1881)
• Riva Rocci (1896)
• Modern Version by
Harvey Cushing
(1901)
GOLD STANDARD IN CLINICAL PRACTICE

9. Aneroid Sphygmomanometer
• No Mercury
• Metal Bellow and
Lever system
• Inaccurate if not
calibrated
.
Mion D, Pierin AM. How accurate are sphygmomanometers? J Hum
Hypertens. 1998; 12: 245–248
Yarows SA, Qian K. Accuracy of aneroid sphygmomanometers in clinical
usage: University of Michigan experience. Blood Press Monit. 2001; 6:
101–106.

10. Hybrid BP monitors
• Combine features of mercury and aneroid
sphygmomanometers
• Mercury replaced by Electronic Pressure
Gauge
• Auscultatory method used

11. PHYSICS OF BP MEASUREMENT
• Reynolds number
Re = ρ D v
μ
ρ- Density of the fluid
D- Diameter of the vessel
V- Velocity of the fluid
μ- Viscosity of the fluid
Re < 2100 – Laminar flow
Re > 4000- Turbulent flow

13. Korotkoff Sounds
Phase 1 Phase 2 Phase 3 Phase 4 Phase 5
Silence Tapping Soft
Swishing
Crisp Blowing Silence
Cuff
pressure
SYSTOLIC DIASTOLIC

14. Oscillometric Sphygmomanometer
• Records Oscillations in BP
cuff
• Blood pressure determined
by an algorithm
• Calibration Must
• Ambulatory and Home BP

15. Auscultatory Vs Oscillatory

16. Other Techniques
• Ultrasonic probes under cuff
• Tonometry
• Doppler

17. HOW TO MEASURE
BLOOD PRESSURE IN
CLINICAL SETTING

18. Subject Position
• Quitely Seated atleast for 5 min in a chair
• Feet on the floor
• Arms at Level of Right Atrium (mid point of
sternum)
• Avoid Caffeine, Exercise and Smoking 30
min prior to recording

19. Body Position
• Back supported
• Legs Uncrossed
• Arm supported
• Cuff at level of Right
Atrium- Midpoint of
the Sternum

20. • Arm to be at level of
right atrium even
when patient is
supine (P=hρg)
• Support with pillow

21. Cuff Size
• Length: Width ratio
ideally 2:1
• Tubing at least 70 cm
long

22. Approx Size of Cuff
Length Width

23. Arm
Circumference
Cuff Cuff Size
Upto 10 cm Newborn 4X8 cm
11-15 cm Infant 6X12 cm
16-21 cm Child 9X18 cm
22-26 cm Small Adult 12 X22 cm
27-34 cm Adult 16X30 cm
35-44 cm Large Adult 16X36 cm
45-52 cm Adult Thigh 16X 42 cm

24. Cuff Placement
• Midline of bladder of
cuff over arterial
pulsation
• Lower end 2-3 cm
above cubital fossa
• Midthigh level in lower
limb

26. Instrument at Level of Cuff

27. Position of Eye of Observer
• Eye at level of
upper meniscus of
mercury column

28. Inflation and Deflation
• Initial Inflation atleast 30 mm above point
where radial pulse disappears
• Deflation at 2-3 mm per second
• First and Last sounds to be taken as
systolic and Diastolic Pressures
• Column to be read to nearest 2mm Hg

29. Number of Measurements
• Minimum of two readings at least
intervals of atleast one min
• Average of both readings to be taken
• If diff > 5 mm Hg, more readings to be
taken and averaged out

30. Both Arm Measurements
• Ideally, first visit should include
measurement of blood pressure in both
arms
• If Consistent difference in measurements
without identifiable cause, higher reading
should be used as baseline

31. Blood Pressure in Paediatric Age
Group
• BP in all four limbs to be checked on first
visit
• Auscultatory method satisfactory
• Doppler
• Oscillometric Most accurate
• Palpatory method for systolic pressure
• Flush method for infants – Systolic only

32. Self Monitoring at Home
• Useful in White Coat Hypertension
• Smokers

33. Continuous Ambulatory BP
• White Coat Hypertension
• Drug Resistance
• Hypotension with Anti hypertensive
therapy
• Episodic Hypertension
• Autonomic Dysfunction

34. TAKE HOME MESSAGE
• Comfortable Sitting position of Subject
• Appropriate Cuff Size
• Calibrated Instrument
• Proper Inflation and Deflation Procedure
• Average of Readings