Arm position is important for blood pressure measurement.
OBJECTIVE
To test the effect of positioning the arm on the arm-rest of a common chair, below the officially recommended right atrial level, on the blood pressure (BP) readings in a group of out-patients.


METHODS
A group of 69 patients (58 hypertensives; 39 males; mean +/- s.d. age 54.1 +/- 16.0 years) participated in the present study. BP and heart rate values obtained in each of the following two positions were compared: (1) sitting with the arms supported on the arm-rests of the chair and (2) sitting with the arms supported at the level of the mid-sternum (the approximation of the right atrial level). BP was measured simultaneously at both arms, with a mercury sphygmomanometer at the right arm and with an automatic oscillometric device at the left arm.


RESULTS
Both the systolic and diastolic BPs were significantly higher (P < 0.0001) when the arm was placed on the arm-rest of the chair than at the right atrial level. The same differences +/- s.d. in BP between the two positions were obtained with both measurement techniques: 9.7 +/- 9.4 mm Hg (systolic) and 10.8 +/- 5.8 mm Hg (diastolic) with the mercury sphygmomanometer and respectively 7.3 +/- 8.9 mm Hg and 8.3 +/- 6.0 mm Hg with the oscillometric device. No difference in the heart rate was found between the two positions.


CONCLUSIONS
Placing the patient's arms on the arm-rest of the chair instead of at the reference right atrial level, BP measurement will result in spuriously elevated BP values. This may be of great importance for the diagnosis and the subsequent treatment decisions for patients with hypertension.
Netea
R T
RT
Department of Internal Medicine, University Hospital Nijmegen, The Netherlands.
Lenders
J W
JW
Smits
P
P
Thien
T
T
D000328:Adult; D000368:Aged; D001132:Arm; D001795:Blood Pressure Determination / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D012680:Sensitivity and Specificity