Abstract
Providing optimum nutrition to the preterm infant will necessitate studying the postnatal development of absorptive processes. The thickness of the unstirred water layer, lying between the lumen of the gut and the microvillous membrane, affects the calculated kinetics in in vivo transport studies. We have previously measured transmucosal potential differences (P.D.) in preterm infants and have now used this technique to estimate the thickness of the unstirred water layer. Six preterm infants were studied on 8 occasions at a postnatal age of 8 to 57d (mean 30d). Gestational age ranged frcm 29 - 36w (mean 3l.5w) and birth weight was 970 - 2340g (mean 1520g). The distal duodenum was perfused with a solution containing 154 mM NaCl at 100ml/hr until a steady P.D. reading was obtained. A second solution containing 104mM NaCl and 100mM mannitol was then infused. Lowering the luminal NaCl created a diffusional pathway and change in P.D. The half time taken for development of this P.D. was measured and used to calculate the unstirred water layer by the method of Diamond (1).
Results: The unstirred water layer was 278 ± 31μm (mean ± S.E.M.) ranging from 181 to 435 μm.
Conclusion: The unstirred water layer can be estimated in the preterm infant by measuring diffusion potentials. The values obtained are less than estimated adult values - 632 ± 24μm (2).
(1) Diamond J.M., J.Physiol., 183:83-100(1966)
(2) Read N.W. et al., Gut 18:865-876 (1977)
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mayne, A., Durbin, G., Morgan, M. et al. ASSESSMENT OF THE UNSTIRRED WATER LAYER IN THE SMALL INITESTINE OF THE PRETERM INFANT. Pediatr Res 20, 701 (1986). https://doi.org/10.1203/00006450-198607000-00094
Issue Date:
DOI: https://doi.org/10.1203/00006450-198607000-00094