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: RESULTS : Three patients ( 8 . 1 % ) in the unilateral group and 5 ( 13 . 5 % ) in the conventional group developed hypotension , P = 0 . 71 .
### Output Text:
RESULTS : Three patients ( 8 . 1 % ) in the unilateral group and 5 ( 13 . 5 % ) in the conventional group developed hypotension , P = 0 . 71 . 