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 patient required massive transfusion support ( 55 units of red blood cells , 42 units of fresh - frozen plasma , 40 units of cryoprecipitate , 40 units of platelets , and three doses of recombinant Factor VIIa ) for severe intraoperative and postoperative bleeding .
### Output Text:
The patient required massive transfusion support ( 55 units of red blood cells , 42 units of fresh - frozen plasma , 40 units of cryoprecipitate , 40 units of platelets , and three doses of recombinant Factor VIIa ) for severe intraoperative and postoperative bleeding . 