Pour information, j'ai trouvé comment faire :
$query="DECLARE @return_value int,
@p_RETURN_STATUS int
EXEC @return_value = [dbo].[TEST]
@p_ENL_I_ID = ?,
@p_RETURN_STATUS = @p_RETURN_STATUS OUTPUT
SELECT @p_RETURN_STATUS as 'p_RETURN_STATUS'";
$params = array(
$p_ENL_I_ID,
$p_RETURN_STATUS
);
$con = $this->entityManager->getConnection();
$result=$con->executeQuery($query, $params);