Computational and Mathematical Methods in Medicine
Volume 2011 (2011), Article ID 965075, 4 pages
http://dx.doi.org/10.1155/2011/965075
Research Article

Plasma Volume Expansion Resulting from Intravenous Glucose Tolerance Test

1Section for Anaesthesia, Faculty of Health Sciences, Linköping University, 58185 Linköping, Sweden
2Research Unit, Södertälje Hospital, 152 86 Södertälje, Sweden
3Department of Clinical Science and Education, Karolinska Institutet, Södersjukhuset, 11883 Stockholm, Sweden

Received 4 May 2011; Accepted 6 July 2011

Academic Editor: Yoram Louzoun

Copyright © 2011 Robert G. Hahn and Thomas Nyström. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. To quantify the degree of plasma volume expansion that occurs during an intravenous glucose tolerance test (IVGTT). Methods. Twenty healthy volunteers (mean age, 28 years) underwent IVGTTs in which 0.3 g/kg of glucose 30% was injected as a bolus over 1 min. Twelve blood samples were collected over 75 min. The plasma glucose and blood hemoglobin concentrations were used to calculate the volume distribution ( 𝑉 𝑑 ) and the clearance ( 𝐶 𝐿 ) of both the exogenous glucose and the injected fluid volume. Results. The IVGTT caused a virtually instant plasma volume expansion of 10%. The half-life of the glucose averaged 15 min and the plasma volume expansion 16 min. Correction of the fluid kinetic model for osmotic effects after injection reduced 𝐶 𝐿 for the infused volume by 85%, which illustrates the strength of osmosis in allocating fluid back to the intracellular fluid space. Simulations indicated that plasma volume expansion can be reduced to 60% by increasing the injection time from 1 to 5 min and reducing the glucose load from 0.3 to 0.2 g/kg. Conclusion. A regular IVGTT induced an acute plasma volume expansion that peaked at 10% despite the fact that only 50–80 mL of fluid were administered.