Codeigniter HTML Caching with Dynamic Content

I have an application where I use ajax to update the comments & Like count.

I am using Codeigniter page caching http://ift.tt/1zxNZRP

and set following code to recreate caching every 60 minutes

$this->output->cache(60);

Problem is when somebody enter a new comment, DB operation is happening (Because of Ajax call), But the Newly inserted comment disappears after the page refresh, because of the cached HTML page. How to handle caching and also dynamic content to change?