18767
CONCLUSIONS : The role of ketamine as a neuroprotective agent in humans remains inconclusive and adequately powered ; randomized controlled trials performed in patients undergoing surgery for traumatic brain injury are necessary .
 Chemical: ketamine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ketamine