THE ROAD TO A BETTER LIFE

by: Dr. Felma R. Dela Cruz

PROPER BLOOD PRESSURE MEASUREMENT

Proper measurement & interpretation of the BP is essential in the diagnosis & management of Hypertension (HPN). Incorrect technique of BP measurement results to false readings, unnecessary treatment, and inappropriate treatment follow-up.

Techniques of Blood Pressure Measurement:

1. Patient position:

* BP usually taken in sitting position; lying position increases SBP & decreases DBP by 2-3 mmHg.
*Lying, sitting & standing BP are to be taken to detect postural hypotension (lowering of BP in different position) seen the elderly & diabetics.
* Patients should sit quietly for 5 minutes before BP is taken: apprehension causes elevation in BP & 20-30 % of patients with clinic HPN are normotensive at home, called White Coat HPN.

2. Steps in Recording Blood Pressure:

•Sit patient in a quite room in a chair, with back supported, feet on the floor
( no cross legs) & arm resting with palm of the hand exposed upward & elbow flexed at heart level. Remove tight or restrictive clothing.
* Patient should not be talking while BP is measured
•Put him at ease ( 5 min before measurement)
•Place manometer at eye level- close enough to read the calibrations marking the gauge.
•Locate the brachial artery by palpation (inner upper arm)
•Wrap the cuff smoothly & snugly around the arm ( just enough for 2 fingers to fit in) and the center of the bladder over the brachial artery (find the center of the bladder by folding it into half).
•The lower margin of the bladder should be 1 inch or 2.5 cm above the elbow line (reduce noise from contact of stethoscope with cuff).
•Inflate cuff rapidly up to the level of maximal inflation, i.e. 30mm Hg above disappearance of the radial pulse. (to detect “Auscultatory Gap”)
•Place the bell lightly over the brachial artery & deflate slowly at a rate of 2-3 mmHg per heart beat or per second
•Record systolic & diastolic Blood Pressure to the nearest 2 mmHg mark.
•Record the first sound as the Systolic BP & the last sound as the Diastolic BP.
•Intensify the sounds by opening & closing the hand 10 X before inflation of the bladder.

3. Technique of Measurement:

* Measure BP initially on both arms & use arm w/ higher BP on next measurements.
•Take BP at least twice on each visit allowing 1- 2 min interval between measurements. May count Pulse Rate while waiting.
•Do additional measurements if a difference of more than 5 mmHg exist between 2 consecutive measurements
•Recorded BP should be the average of the last 2 measurements.
•The measurement can be repeated after 15 seconds without significantly affecting accuracy.(Let the mercury fall to zero level before inflating the cuff again).
•Pressing the stethoscope too firmly against the artery will give erroneously lower DBP
Record the pressure, patient position, the arm, & cuff size( for example 140/100 mmHg, seated, right arm, large adult cuff)

4. Instrumentation:

a) Sphygmomanometer:
* Mercury: Standard of all BP measurements; there should be no leaks,no break on the glass, & mercury level should be at zero mark. Will be phased out due to the concern of toxic spills.
* Anaeroid: No cracks on face, needle at zero mark, no stop pin at “O”, should be calibrated with a mercury manometer every 6 mos, less reliable & easily becomes inaccurate.
* Digital BP cuffs
* Electronic Devices: are non- mercurial manometers, the future BP measurement device.
* 21 % of mercurial & more than 50% of anaeroid manometers are inaccurate
b) BP Cuff : proper sizes for pediatric & adults (average or fatter arms )
c) Inflating-Deflating Device: Bulb
•Must achieve pressure of 200 mmHg after 3-5 secs of rapid inflation
•Must deflate smoothly at 2-3 mm/sec
•Deflation should not be jerky, not too rapid, nor too slow: 2 mm/ heart beat
d) The Stethoscope:
•Earpiece should face forward in the ear canal
•Must have thick tubing 12-15 inches in length

* Use the bell to detect low-frequency Korotkoff (K) sounds.

The following should be avoided 30 minutes before BP measurement:
1.food intake
2.exercise
3.intake of caffeine or smoking
4. full urinary bladder
5. cool environment ( 12 C or 54 F) –causes vasoconstriction/TE