2631
EA signs were observed in all 7 patients in association with propofol TIVA but did not recur in any of 123 subsequent anesthetics sessions during which low-dose ketamine was added to propofol.
 adverse event: observed 
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: adverse event, potential therapeutic event 
Text: {0} 
Answer:
 adverse event: observed 