Define initial value for variable not integrated in ode45

How can I specify initial value for t=0s for a variable not solved via integration in ode45 solver?

[Jan]

The question is not clear yet. If a variable is not processed by an integrator, setting it to an initial value is meaningless. So please explain, what you want to achieve, e.g. show us the current code.

[Walter Roberson]

http://www.mathworks.com/help/matlab/math/parameterizing-functions.html