This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Svensen, C. H. Articles by Hahn, R. G. Search for Related Content PubMed PubMed Citation Articles by Svensen, C. H. Articles by Hahn, R. G. Related Collections Physiology Clinical Pharmacology Pharmacology

---

ANESTHETIC PHARMACOLOGY

Arteriovenous Differences in Plasma Dilution and the Distribution Kinetics of Lactated Ringer's Solution

Christer H. Svensen, MD, PhD^*, Peter M. Rodhe, Joel Olsson, MD, PhD^*, Elisabet Børsheim, PhD^*, Asle Aarsland, MD, PhD^*, and Robert G. Hahn, MD, PhD

From the *Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas; Department of Clinical Science and Education, Karolinska institutet, Söder Hospital, Stockholm, Sweden; and Clinical Research Center, Södertälje, Sweden.

Address correspondence and reprint requests to Robert G. Hahn, MD, PhD, Clinical Research Center, Södertalje Hospital, SE-152 86 Södertalje, Sweden. Address e-mail to r.hahn{at}telia.com.

BACKGROUND: Conventional concept suggests that infused crystalloid fluid is first distributed in the plasma volume and then, since the capillary permeability for fluid is very high, almost instantly equilibrates with the extracellular fluid space. We challenge whether this view is consistent with findings based on volume kinetic analysis.

METHODS: Fifteen volunteers received an IV infusion of 15 mL/kg of lactated Ringer’s solution during 10 min. Simultaneous arterial and venous blood hemoglobin (Hgb) samples were obtained and Hgb concentrations measured. The arteriovenous (AV) difference in Hgb dilution in the forearm was determined and a volume kinetic model was fitted to the series of Hgb concentrations in arterial and venous blood.

RESULTS: The AV difference in plasma dilution was only positive during the infusion and for 2.5 min thereafter, which represents the period of net flow of fluid from plasma to tissue. Kinetic analysis showed that volume expansion of the peripheral fluid space began to decrease 14 min (arterial blood) and 20 min (venous blood) after the infusion ended. Distribution of lactated Ringer’s solution apparently occurs much faster in the forearm than in the body as a whole. Therefore, the AV difference in the arm does not accurately reflect the distribution of Ringer’s solutions or whole-body changes in plasma volume.

CONCLUSIONS: The relatively slow whole-body distribution of lactated Ringer’s solution, which boosts the plasma volume expansion during and for up to 30 min after an infusion, is probably governed by a joint effect of capillary permeability and differences in tissue perfusion between body regions.