Oral Rehydration Solutions

Abstract

SummaryViscosity‐enhancing agents such as carboxymethylcellulose (CMC) can alter absorption of solutes and fluid exchange in the small intestine. We investigated whether the standard World Health Organization oral rehydration solution (WHO‐ORS) with the addition of CMC would improve net water and sodium absorption in rats using an in vivo intestinal perfusion technique. Four WHO‐ORS, containing either 0, 2.5,5.0, or 10.0 g/L of CMC, were perfused in rats with a well‐tested model of cathartic‐induced chronic osmotic diarrhea (D) and in normal controls (C). In D rats, the ORSs with CMC improved sodium absorption at the three concentrations used (p < 0.01). The same effect was shown in C rats. Net water absorption was also enhanced in D rats given ORSs with CMC, although the changes in C animals were less marked. The improvement in sodium and water absorption in both C and D rats positively correlated with the log of relative ORS viscosity. Ultrastructural examination of tissues perfused with 10 g/L of CMC showed an extended brush border glycocalyx. This study indicates that CMC added to WHO‐ORS in the perfused rat jejunum improves the effectiveness of the solution by increasing sodium and water absorption.