Use function add_filter('gettext')

Hello,

I was trying to replace some text in a custom post type, but I could not.
In the code below, only the first case worked.
I believe that the second case does not work because:
1. Has no English letter in the word "médica" (médica) or
2. The text is in the relationship metabox of the post 2 post plugin.

add_filter('gettext', 'change_admin_cpt_text_filter', 20, 3);
function change_admin_cpt_text_filter( $translated_text, $untranslated_text, $domain ) {

global $typenow;

if( is_admin() && 'consulta' == $typenow ) {

//make the changes to the text
switch( $untranslated_text ) {

case 'Fichas Médicas Relacionado(a)':
$translated_text = __( 'Relacionado ao Paciente','text_domain' );
break;

case 'Enter title here':
$translated_text = __( 'para facilitar as buscas, informe data e o assunto (i.e 00/00/00 assunto consulta)','text_domain' );
break;

//add more items
}
}
return $translated_text;
}

Any suggestions to make it work?

How should I handle non-English characters? I'm trying to use UTF-8, but it seems that does not work.

Function there numbers 20,3 or 10,2, etc.. I did not find in the codex an explanation for these numbers. I just tried all that I found in other codes to work. Do you know where I find out what are these numbers?