Glucose perturbation in experimental hyperviscosity.

Hyperviscosity was produced in one member of each of 7 sets of twin newborn lambs by an exchange transfusion with 500 ml maternal packed red blood cells. The remaining seven control twin lambs underwent an identical exchange with maternal whole blood. Postexchange hematocrits were 63 +/- 6 and 29.0 +/- 3% (mean +/- S.E.), respectively (P less than 0.01). Whole blood viscosity measured at 3 rpm increased from 3.2 +/- 0.4 centipoise (cps) to 14.4 +/- 6.1 cps in the lambs made hyperviscous (P less than 0.01) and remained unchanged in the control lambs (2.2 +/- 0.1 versus 2.8 +/- 0.3 cps). A 2-hr steady state glucose infusion was performed on each lamb before and after the packed cell or whole blood exchange transfusion. Mean steady state plasma glucose concentrations were significantly decreased from pre-exchange steady state glucose infusion levels in the same lambs made hyperviscous (P less than 0.05), whereas steady state glucose levels increased from preexchange levels in the twin lambs exchanges with maternal whole blood. Mean plasma insulin and glucagon values for the hyperviscous and control lambs remained unchanged during the glucose infusion.