5. Carrying out a measurement
5.1. Before the measurement
• Avoid eating, smoking as well as all forms of exertion directly before the measurement. All these
factors influence the measurement result. Try and find time to relax by sitting in an armchair in a
quite atmosphere for about 5 minutes before the measurement.
• Measure always on the same wrist (normally left).
• Attempt to carry out the measurements regularly at the same time of day, since the blood-
pressure changes during the course of the day.
5.2. Common sources of error
Note: Comparable blood-pressure measurements always require the same conditions! These are
normally always quiet conditions.
• All efforts by the patient to support the arm can increase the blood-pressure. Make sure you are
in a comfortable, relaxed position and do not activate any of the muscles in the measurement
arm during the measurement. Use a cushion for support if necessary.
• If the wrist artery lies considerably lower (higher) than the heart, an erroneously higher (lower)
blood-pressure will be measured! (Each 15cm difference in height results in a measurement error
of 10mmHg!)
• A loose cuff causes false measurement values.
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