Normal and abnormal volume homeostasis

Item Type:	Book Section
Title:	Normal and abnormal volume homeostasis
Creators Name:	Luft, F.C. and Gallery, E.D.M. and Lindheimer, M.D.
Abstract:	This chapter describes changes in volume, renin–angiotensin–aldosterone, and other mineralocorticoids in abnormal pregnancies such as preeclampsia. Pregnancy is a physiologic process where repeated adjustments occur in the steady state marked by changes in both intracellular and extracellular volume. Each new steady state value is then held within relatively narrow limits, that is, these changes are sensed as normal and “defended” in face of variations in fluid and sodium intake. There is a 30–50% increase in extracellular fluid (ECF), plasma, and blood volume (associated with 30–50% increases in cardiac output, glomerular filtration rate (GFR) and renal blood flow. Women who develop preeclampsia seem to fall into two subgroups: those who experience an abnormal shift of ECF from the vascular to the extravascular compartment, and those with a total reduction of ECF volume. This dichotomy may possibly reflect different disturbances in the normal volume homeostatic mechanisms of pregnancy. Women with preeclampsia/eclampsia have significantly reduced plasma volumes. The degree of contraction appears to be an index of severity, and in this respect the greatest decreases have been reported in nulliparas with eclampsia, the convulsive phase of the disease associated with extreme severity.
Keywords:	Pregnancy, Preeclampsia, Total Body Water, Intravascular Volume, Interstitial Volume, Renin–Angiotensin–Aldosterone System, Natriuretic Hormones, Pressure Natriuresis, Na+K+-ATPase, Osmoregulation, Vasopressin
Source:	Chesley's Hypertensive Disorders in Pregnancy
Title of Book:	Chesley's Hypertensive Disorders in Pregnancy
ISBN:	978-0-12-374213-1
Publisher:	Elsevier
Page Range:	269-285
Date:	2009
Official Publication:	https://doi.org/10.1016/B978-0-12-374213-1.00015-X

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