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: Left ventricular function ( assessed by echocardiography ) showed that PPA increased the stroke volume 30 % ( from 62 . 5 + / - 20 . 9 to 80 . 8 + / - 22 . 4 ml ) , the ejection fraction 9 % ( from 64 % + / - 10 % to 70 % + / - 7 % ) , and cardiac output 14 % ( from 3 . 6 + / - 0 . 6 to 4 . 1 + / - 1 . 0 L / min ) .
### Output Text:
Left ventricular function ( assessed by echocardiography ) showed that <span class="chemical">PPA</span> increased the stroke volume 30 % ( from 62 . 5 + / - 20 . 9 to 80 . 8 + / - 22 . 4 ml ) , the ejection fraction 9 % ( from 64 % + / - 10 % to 70 % + / - 7 % ) , and cardiac output 14 % ( from 3 . 6 + / - 0 . 6 to 4 . 1 + / - 1 . 0 L / min ) . 