2108
O2 and CO2 in the tracheostomy tube were continuously monitored by mass spectrometry using a special sample - hold phase - locked sampling technique .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities:  
Answer:
 None