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: Phenylephrine infusion increased arterial pressure , arteriolar diameter and clearance of fluorescent dextran by a similar magnitude in both groups .
### Output Text:
<span class="chemical">Phenylephrine</span> infusion increased arterial pressure , arteriolar diameter and clearance of fluorescent <span class="chemical">dextran</span> by a similar magnitude in both groups . 