[Blood pressure variations from clinostatism to orthostatism]

The reactivity of blood pressure (BP) and heart rate (HR) to change from supine to standing position was examined in 257 healthy adults, adolescents and children divided into equivalent group of both sexes. BP and HR were measured every minute during 14 minutes in a supine position then during 5 minutes in a standing position with an automatic device using the oscillometry method. A second measurement session was repeated two weeks later. On most patients an increase of diastolic BP (7.73 +/- 4.34 mmHg) and HR (16.40 +/- 7.47/mn) was observed after standing whereas systolic BP modifications were inconstant (2.19 +/- 5.55 mmHg). A comparison of variability indices according to postural state showed a significant higher variability index in a standing position only in female subjects. There was no difference according to age groups. Reproducibility of diastolic BP and HR increase is good two weeks later in respectively 65 p. 100 and 80 p. 100 subjects but it appears very poor for systolic BP. The results in healthy subjects would be compared to those observed in hypertensives to determinate if a postural change test may provide a clinical simple way to discriminate abnormalities in blood pressure regulation.