  A very early start up time of the hydrodynamic evolution is needed in order
to reproduce observations from relativistic heavy-ion collisions experiments.
At such early times the systems is still not locally equilibrated. Another
source of deviations from local equilibrium is the viscosity of the fluid. We
study these effects at very early times to obtain a dynamical prescription for
the transition from an early 2-dimensional expansion to a nearly equilibrated
3-dimensional expansion at latter stages. The role of viscosity at latter
stages of the evolution is also illustrated.
