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 end - diastolic pressure fell from 11 . 5 + / - 1 . 4 ( mean + / - SE ) to 5 . 6 + / - 0 . 9 mm Hg ( P less than 0 . 001 ) and left ventricular end - diastolic volume fell from 100 + / - 17 to 82 + / - 12 ml / m2 ( P less than 0 . 01 ) 1 h after ouabain infusion was completed .
### Output Text:
Left ventricular end - diastolic pressure fell from 11 . 5 + / - 1 . 4 ( mean + / - SE ) to 5 . 6 + / - 0 . 9 mm Hg ( P less than 0 . 001 ) and left ventricular end - diastolic volume fell from 100 + / - 17 to 82 + / - 12 ml / m2 ( P less than 0 . 01 ) 1 h after <span class="chemical">ouabain</span> infusion was completed . 