Affiliation:
1. From the Cattedra di Medicina Interna I (G.M.), Ospedale S. Gerardo, Monza; Istituto Scientifico Ospedale S. Luca (G.P.), IRCCS, Istituto Auxologico Italiano, Milano; and Divisione di Medicina d’Urgenza (G.B., P.M., R.C., G.T.) and Centro Fisiologia Clinica e Ipertensione (L.U., C.S., A.M.), Ospedale Maggiore, IRCCS, and University of Milano, Italy.
Abstract
Abstract
—Limited information is available for humans on whether blood viscosity affects total peripheral resistance and, hence, blood pressure. Our study was aimed at assessing the effects of acute changes in blood viscosity on both clinic and 24-hour ambulatory blood pressure (BP) values. In 22 normotensive and hypertensive patients with polycythemia, clinic and 24-hour ambulatory BPs were measured before and 7 to 10 days after isovolumic hemodilution; this was performed through the withdrawal of 400 to 700 mL of blood, with concomitant infusion of an equivalent volume of saline-albumin solution. Hematocrit, plasma renin activity, plasma endothelin-1, right atrial diameter (echocardiography), and blood viscosity were measured under both conditions. Plasma renin activity and right atrial diameter were used as indirect markers of blood volume changes. Plasma endothelin-1 was used to obtain information on a vasomotor substance possibly stimulated by our intervention, which could counteract vasomotor effects. Isovolumic hemodilution reduced hematocrit from 0.53±0.05 to 0.49±0.05 (
P
<.01). Plasma renin activity, plasma endothelin-1 and right atrial diameter were unchanged. Clinic blood pressure was reduced by hemodilution (systolic, 144.3±5.4 to 136.0±3.9 mm Hg[mean±SEM]; diastolic, 87.0±2.8 to 82.1±2.6 mm Hg,
P
<.05 for both) and a reduction was observed also for 24-hour average ABP (systolic, 133.6±2.9 to 129.5±2.7 mm Hg; diastolic, 80.0±2.0 to 77.3±1.7 mm Hg,
P
<.05 for both). The reduction was consistent in hypertensive patients (n=12), whereas in normotensive patients (n=10) it was small and not significant. Both clinic and 24-hour average heart rates were unaffected by the hemodilution. Thus, in polycythemia, reduction in blood viscosity without changing blood volume causes a significant fall in both clinic and 24-hour ambulatory BPs; this is particularly true when, as can often happen, blood pressure is elevated. This emphasizes the importance this variable may have in the determination of blood pressure and the potential therapeutic value of its correction when altered.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Cited by
34 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献