Welch Allyn OSZ4 Series, Directions For Use Manual

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Directions For Use 9
Common sources of error
Note:
Comparable blood pressure measurements always require
the same conditions. These should be 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 arm
being measured during the procedure. Use a cushion for
support if necessary.
• If the arm artery lies considerably lower or higher than the
heart, an erroneous blood pressure will be measured. (Each
15 cm difference in height results in a measurement error of
10 mmHg.)
• Cuffs that are too narrow or too short result in false
measurement values. Selecting the correct cuff is very
important. The cuff size is dependent upon the
circumference of the arm (measured midway between the
armpit and elbow). The permissible range is printed on the
cuff. If this is not suitable for your use, contact your dealer.
Note : Only use clinically approved original cuffs.
• A loose cuff or a sideways protruding air pocket causes false
measurement values.
• With repeated measurements, blood accumulates in the
tested arm, which can lead to false results. Correctly
executed blood pressure measurements, therefore, should
be repeated at least 30 seconds after previous attempts.