Getting the value from a column during a trigger
Triggers in SQL Server are fired once per set, not per row (like Oracle), so you need to build triggers that handle this.

In all triggers, you have two special tables called inserted and deleted, that contain  a virtual "mirror" of the entire table row(s) after and before the action that triggered it, respectively.

A word of warning: triggers should be small and very light-weight. In your case, running a cursor over your log rows and executing a stored procedure for each row can cause you locking mayhem and slow performance. (Triggers run synchronously, in the same transaction as the original DML statement.)

I would write your solution not in a trigger, but as a separate stored procedure and run it on-demand.