After setting all derivations to zero, there will be the big non-differential non-linear hybrid set of equations. Todays (2012) modern numerical environments have many problems to solve this huge set of equation for model HumMod Golem Edition. But there is an evidence, that the partial solutions exists.
If it should be possible to calculate the state variable values from this set of equation, then this initial state for original differential equation starts and continue with constant values of all variables.
Theoretically is possible to calculate the values of some depend parameters direct way in steady state (solve the set of steady-state equation for this parameters as unknown), if some variables are known(number of equations=number of unknowns).
Theoretically is possible to parametrize all unknowns by any chosen parameter. This could be called as sensitivity analysis of steady state and generate more usable informations us sensitivity analysis in dynamic situations.
Theoretically is possible to parametrize all unknowns by the one of then, if some equation are removed (e.g. starling: parametrization by filling arterial blood pressure. removed equation, that mean venous return arterial pressure = mean filling pressure of heart).