Changes in Peripheral Brachial Blood Pressure from Supine to Lateral Decubitus Position in Hypertensive and Normotensive Subjects.

Arterial blood pressure is crucial for supplying the nutritional demands of the all body tissues and is also under tight control for the same. The day to day stress impacts the blood pressure (BP), which is effectively corrected by the baroreceptors mechanism. The effect of lateral decubitus position on the blood pressure with respect to supine position needs to be evaluated as it impacts the haemodynamics. The peripheral brachial blood pressure changes are studied among the normotensives and hypertensives with its significance from change in supine to lateral decubitus position. Sixty (60) normotensives and 60 hypertensive subjects were evaluated for arterial blood pressure measurement using mercury sphygmomanometer by gold standard auscultatory method in the supine, right and left lateral decubitus position. The same observer measured the blood pressure at the similar point of time for all the participants. The Supine and lateral decubitus Systolic and diastolic blood pressure (Mean±SD) parameters were recorded and compared using the paired 't' test (Supine Normotensives SBP 112.5±16.9, DBP 70.1±17.7 mm of Hg; Hypertensives Stage I SBP 130.2±14.5, DBP 85.2±2.8 mm of Hg; Hypertensive Stage II SBP 152.6 ±17.5, DBP 98.4±9.5mm of Hg). The mean and percentage change in systolic and diastolic BP for Normotensives from supine to right lateral position- SBP 11.6 mm of Hg (10.3%), DBP 8.8 mm of Hg (12.5%) and supine to left lateral position SBP 12.5mm of Hg (11.1%), DBP 9.9 mm of Hg (14.1%) p<0.05, for Hypertensives Stage I supine to right lateral position SBP 13.8 mm of Hg (10.5%), DBP 14.8 mm of Hg (17.37%) and supine to left lateral position SBP 13.5 mm of Hg (10.3%), DBP 12.3 mm of Hg (14.13%) p<0.05 and for Hypertensive Stage II from supine to right lateral position SBP 22.6 mm of Hg (14.8%), DBP 16.6 mm of Hg (16.8%), form supine to left lateral position SBP 12.3mm of Hg (8%), DBP 14.7mm of Hg (14.9%) p<0.01) changed significantly among the all the groups with respect to change from supine to lateral decubitus position. The fall in diastolic BP was of greater magnitude than the systolic BP. The right lateral decubitus position was dominant among the hypertensives for producing the change as compared to left lateral decubitus position. However among the normotensives it was left lateral decubitus which produced greater reduction in blood pressure. The lateral decubitus position definitively reduces the blood pressure as compared to supine position and the changes produced can't be simply ascribed to the hydrostatic effect of gravity on blood column. Sleeping on lateral side could thus be advantageous in reducing the arterial blood pressure.