Problems with transactions codeigniter

my doubt is that I am executing the following code in codeigniter, it consists of executing the procedure in the SQLServer that returns a value (output), but in codeigniter I always get this error message:

$data = array(
            $this->input->post("CodcliRemitente"),
            $this->input->post("CodcliBeneficiario"),
            $this->input->post("slcSucursalEntrada"),
            $this->input->post("slcSucursal"),
            $this->input->post("idImporte"),
            $this->input->post("idComision"),
            "0.00",
            "0.00",
            "1",
            $this->input->post("txtSerie"),
            $this->input->post("txtCorrelativo"),
            $this->input->post("tipoComprobante"),
            $this->session->userdata("IDEmpleado"),
            $this->input->post("txtMensaje"),
            $this->input->post("txtEncargado"),
            $this->input->post("inter"),
            $this->input->post("lblNAT"),
            "-",
            "004",
            "-"
        );
    $this->db->trans_start();

    $this->db->query("SET NOCOUNT ON");
    $this->db->query("DECLARE @respuesta INT");
    $this->db->query("EXEC sp_regEnvioGiroRecepcionista_Recepcionista_1 ?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?, @respuesta = @respuesta OUTPUT",$data);
    $query = $this->db->query("SELECT @respuesta as N'@respuesta'");

    $this->db->trans_complete();


    var_dump($query->row_array());