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: Peri - operative hypotension ( 26 % , OR 3 . 80 , 95 % CI 1 . 91 - 7 . 54 , p = 0 . 0001 ) and bradycardia ( 17 % , OR 5 . 45 , 95 % CI 2 . 98 - 9 . 95 , p < 0 . 00001 ) were significantly increased .
### Output Text:
Peri - operative hypotension ( 26 % , OR 3 . 80 , 95 % CI 1 . 91 - 7 . 54 , p = 0 . 0001 ) and bradycardia ( 17 % , OR 5 . 45 , 95 % CI 2 . 98 - 9 . 95 , p < 0 . 00001 ) were significantly increased . 