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: The administration of ephedrine led to a similar increase in MAP ( 53 + / - 9 to 79 + / - 8 mmHg ; P < 0 . 001 ) , restored CO ( 3 . 2 + / - 1 . 2 to 5 . 0 + / - 1 . 3 l min ( - 1 ) ) , and preserved S ( c ) O ( 2 ) .
### Output Text:
The administration of <span class="chemical">ephedrine</span> led to a similar increase in MAP ( 53 + / - 9 to 79 + / - 8 mmHg ; P < 0 . 001 ) , restored CO ( 3 . 2 + / - 1 . 2 to 5 . 0 + / - 1 . 3 l min ( - 1 ) ) , and preserved S ( c ) O ( 2 ) . 