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: Baseline blood pressures were higher in fluctuating patients ; a higher baseline blood pressure correlated with greater hypotensive effects .
### Output Text:
Baseline blood pressures were higher in fluctuating patients ; a higher baseline blood pressure correlated with greater hypotensive effects . 