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: It is concluded that intragastric pressure increases significantly during muscle fasciculations caused by suxamethonium in healthy children .
### Output Text:
It is concluded that intragastric pressure increases significantly during muscle fasciculations caused by <span class="chemical">suxamethonium</span> in healthy children . 