Transcript General

Rasvahapot valtimotaudin vaaran arvioinnissa
Blood pressure measurement - EHES
September 21, 2010
Antti Jula
Developed Countries Deaths in 2000 Attributable to
Selected Leading Risk Factors
Blood pressure
Tobacco
Cholesterol
High Body Mass Index
Low fruit and vegetable intake
Physical inactivity
Alcohol
Urban air pollution
Lead exposure
Occupational carcinogens
Illicit drugs
Unsafe sex
Occupational particulates
Occupational risk factors for injury
Number of deaths (000s)
0
500
1000
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2000
2500
3000
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Hypertension as a cardiovascular risk
factor
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Systolic and diastolic blood pressure and
mean arterial pressure in different parts
of circulation
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What is blood pressure?
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Systolic blood pressure, higher of
the two values, represents the
pressure while the heart contracts to
pump blood to the body
– First appearance of a clear repetitive
sounds (Phase I)
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Diastolic blood pressure, lower of
the two values, represents the
pressure when the heart relaxes
between beats
– Disappearance of the repetitive
sounds (Phase V)
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Factors affecting the accuracy of BP measurement
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Measurement circumstances
Patient dependent factors
Observer dependent factors
Measurement technique
– Auscultatory technique
– Oscillometric technique
• Devices
– Accuracy of the measurement device
– Cuff size
3.4.2016
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Factors affecting BP variability
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Respiration – beat to beat oscillation
Emotions – sympathetic stimulation – white coat effect
Exercise
Meals
Tobacco
Caffeine
Alcohol
Temperature
Bladder distension
Pain
Diurnal variation
– Sleep, posture, BP-lowering medication
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Average effects on blood pressure of commonly
occuring activites relative to BP while relaxing
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Meetings
Work
Walking
Dressing
Telephone
Eating
Talking
Reading
Sleeping
+20.2/+15.0 mmHg
+16.0/+13.0 mmHg
+12.0/+9.2 mmHg
+11.5/+9.5 mmHg
+9.5/+7.2 mmHg
+8.8/+9.6 mmHg
+6.7/+6.7 mmHg
+1.9/+2.2 mmHg
-10.0/-7.6 mmHg
Clark LA et al. J Chronic Dis 1987;40:671-9
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Inter-room difference
with sphygmomanometer
8.7/3.5
mmHg
Kumpusalo et al. J Human Hypertens 2002;16:725-728
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Inter-room differences measured by
patients with Omron IC device
5.9/2.8
mmHg
2.9/1.1 mmHg
3.0/1.7 mmHg
Kumpusalo et al. J Human Hypertens
2002;16:725-728
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Paired BP readings without careful preceding
procedures and measurement techniques
Watson et al, J Hypertens 1987, 5:207–11
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Paired BP readings with careful preceding
procedures and measurement techniques
Jula et al, Hypertension 1999, 34:261–6
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Univariate correlates with the left
ventricle and albuminuria
Jula, Puukka, Karanko, Hypertension 1999;34:261-266
Systolic BP
LVM
LVMI
LUA
Clinic
0.38***
0.40***
0.34***
Home
0.45***
0.47***
0.32***
Ambulatory awake
0.41***
0.45***
0.32***
Ambulatory asleep
0.32***
0.35***
0.26***
Ambulatory 24-hour
0.40***
0.44***
0.32***
*** P <0.001. LVM = left ventricular mass, LUA=log urinary albumin
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Univariate correlates with the left
ventricle and albuminuria
Jula, Puukka, Karanko, Hypertension 1999;34:261-266
Diastolic BP
LVM
LVMI
LUA
Clinic
0.43***
0.37***
0.25***
Home
0.44***
0.44***
0.28***
Ambulatory awake
0.32***
0.35***
0.21**
Ambulatory asleep
0.31***
0.32***
0.17*
Ambulatory 24-hour
0.35***
0.37***
0.23**
*** P <0.001, ** P <0.01, * P <0.05. LVM = left ventricular mass,
LUA=log urinary albumin
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Interarm differences
• BP measured from the right arm is 2.3/0.5 mmHg
higher than that measured from the left arm
(unpublished findings from 493 subjects aged 25-74
years, The Finrisk 2007 study)
• If reproducible differences greater than 10 mmHg
are observed, the measurements should be done
from the arm with higher readings
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Three categories of observer error
Rose G et al. Lancet 1965; 1: 673-4.
1. Systematic error that leads to both intraobserver
and interobserver error
2. Terminal digit preference, which results in the
observer rounding of the pressure reading to a digit
of his or her choosing, most often to zero
3. Observer prejudice or bias, whereby the observer
adjust the pressure to meet his or her preconceived
notion of what the pressure should be
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Mismatching of bladder and arm
Maxwell ym. Lancet 1982;2:33-36
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Use appropriate cuff size
• A too small cuff overestimates and a too large cuff
underestimates BP
• Optimal size of the cuff: width >40% and length >80% of the
arm circumference
• Finnish guidelines:
– Cuff width 13 cm (arm circumference 26-32 cm)
– Cuff width 15 cm (arm circumference 33-41 cm)
– Cuff width 18 cm (arm circumference > 41 cm)
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Different BP measurement devices
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Oscillometric vs auscultatory measurement technique
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Regression Equation for Converting Auscultatory to
Automated Oscillometric (Omron M6) Systolic Blood
Pressure
Finriski 2007, unpublished findings, n=493
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Regression Equation for Converting Auscultatory to
Automated Oscillometric (Omron M6) Diastolic Blood
Pressure
Finriski 2007, unpublished findings, n=493
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Corresponding oscillometric BP of five
auscultory measured BP level
Auscultatory BP
Oscillometric BP
120/80
140/90
160/100
180/110
200/120
122.4/79.4
141.6/89.3
160.7/99.1
179.9/108.9
200.2/118.7
Finrisk 2007, junpublished findings, n=493
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Summary of the measurement I
• Participant conditions
– Posture: the participant should sit queitly for 5 min
with the cuff around the arm, arm baired and
supported at the level of the heart and the back
resting againts a chair
• Circumstances
– The participant should avoid a heavy meal, smoking,
heavy exercise and drinking caffeine containing
beverages at least within 30 minutes preceding the
reading
– A quiet, warm setting
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Summary of the measurement II
• Equipment
– Appropriate cuff size
– Either a mercury, a validated and recently calibrated aneroid or
validated electronic device
– The bell of the stetoscope should be used (avoid excess bell
pressure!)
• Technique
– At least two measurements (3) 1-2 minute apart of each other
– Avoid observer error by training observers in the proper
technique of auscultatory BP measurements (manuals, binaural
stethoscope, audio-tape training methods, video-films etc.)
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