DBD::Pg using int2 / smallint

I need to have the perl DBI driver cast my queries to int2 / SMALLINT
for my queries to use the index in one of my tables. I don't think
the call:

$sth->bind_param(1, $smallint_value, SQL_SMALLINT);

seems to be doing it. How can I accomplish this? Or how can I verify
that the values are being passed as int2's?

Thanks,
Kyle