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: These are increased with the presence of concomitant acute kidney injury ( AKI ) and intraoperative dialysis is sometimes required to allow the transplant to proceed .
### Output Text:
These are increased with the presence of concomitant acute kidney injury ( AKI ) and intraoperative dialysis is sometimes required to allow the transplant to proceed . 