blood pressure measurement by mercury sphygmomanometer - background information
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Blood pressure measurement by mercury sphygmomanometer - background information. EHES Training Material. Hypertension as a cardiovascular risk factor. What is blood pressure?. Systolic blood pressure (higher value), represents the pressure while the heart contracts to pump blood to the body - PowerPoint PPT PresentationTRANSCRIPT
Blood pressure measurement by
mercury sphygmomanometer
- background information
EHES Training Material
Hypertension as a cardiovascular risk factor
What is blood pressure?
• Systolic blood pressure (higher value), represents the pressure while the heart contracts to pump blood to the body• First appearance of a clear
repetitive sounds (Phase I)
• Diastolic blood pressure (lower value), represents the pressure when the heart relaxes between beats• Disappearance of the
repetitive sounds (Phase V)
Risk factors of elevated blood pressure
• Salt intake• Obesity• Alcohol use• Sedentary lifestyle• Smoking• Fat contents of the food
Factors affecting blood pressure levels
• Measurement environment• Noise, temperature
• Factors related to the participant• Factors related to the measurer• Measurement device
• Cuff size
Factors related to the participant
• Emotions – white coat hypertension• Exercise• Eating before measurement• Smoking• Use of caffeine containing drinks• Alcohol use• Full bladder• Pain• Daily variation• Medication
Average magnitude of the effects (1/3)
Effect Systolic bp (mmHg) Diastolic bp (mmHg)
Full bladder 10-15 mmHg, even up to 50 mmHg if bladder uncomfortably distended
10 mmHg, even up to 40 mmHg if bladder uncomfortably distended
Not resting 3 to 5 minutes before measurement
10-20 mmHg 14 mmHg
Back / feet unsupported
5-15 mmHg 6 mmHg
Supine posture instead of sitting posture
3-10 mmHg 1-5 mmHg
Average magnitude of the effects (2/3)
Effect Systolic bp (mmHg) Diastolic bp (mmHg)
Legs crossed 5-8 mmHg 3-5 mmHg
Participant talks during the measurement
10-15 mmHg 6-10 mmHg
Arm below heart level
10 mmHg 10 mmHg
Physical exercise before measurement
22 mmHg 7-8 mmHg
Left arm instead of right arm
1-3 mmHg 1 mmHg
Arm unsupported during the measurement
1-7 mmHg 5-11 mmHg
Average magnitude of the effects (3/3)
Effect Systolic bp (mmHg) Diastolic bp (mmHg)
Diaphragm of the stethoscope instead of bell
2 mmHg 0-2 mmHg
Cuff too small 3-12 mmHg 2-8 mmHg
Cuff too large 10-30 mmHg 10-30 mmHg
Cuff over clothing up to 5 mmHg
Three categories of observer error
1. Systematic error that leads to both intra-observer and inter-observer 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
Rose G et al. Lancet 1965; 1: 673-4
Acknowledgements
• Slides• Hanna Tolonen