In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Tranexamic acid ( TNA ) 1 g 8 - hourly was administered to her to control bleeding per vaginum .
### Output Text:
<span class="chemical">Tranexamic acid</span> ( <span class="chemical">TNA</span> ) 1 g 8 - hourly was administered to her to control bleeding per vaginum . 