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: In the five rats that developed somatic rigidity , ICP and CVP increased significantly above baseline ( delta ICP 7 . 5 + / - 1 . 0 mmHg , delta CVP 5 . 9 + / - 1 . 3 mmHg ) .
### Output Text:
In the five rats that developed somatic rigidity , ICP and CVP increased significantly above baseline ( delta ICP 7 . 5 + / - 1 . 0 mmHg , delta CVP 5 . 9 + / - 1 . 3 mmHg ) . 