Study: NCT03813875

Intervention type: OTHER
Intervention: Bispectral index (BIS) and analgesia nociception index (ANI)
Description: After giving routine anesthetic medications, the investigators assess the depth of anesthesia based on bispectral index (BIS) and modified observer's assessment/alertness scale (MOAA/S). BIS is maintained between 40 - 60 and MOAA/S less than 2. The vital signs, BIS, analgesia nociception index (ANI) are recorded automatically and continuously through computerized software. ANI is used to observational purposes only and do not guide anesthetic management in our protocol. Upon conclusion of the surgery or examination, the patient is observed until return of consciousness (MOAA/S = 5) before sending them to the recovery unit.

Intervention type: OTHER
Intervention: Bispectral index (BIS) and analgesia nociception index (ANI)
Description: After giving routine anesthetic medications, the investigators assess the depth of anesthesia based on bispectral index (BIS) and modified observer's assessment/alertness scale (MOAA/S). BIS is maintained between 40 - 60 and MOAA/S less than 2. The vital signs, BIS, analgesia nociception index (ANI) are recorded automatically and continuously through computerized software. ANI is used to observational purposes only and do not guide anesthetic management in our protocol. Upon conclusion of the surgery or examination, the patient is observed until return of consciousness (MOAA/S = 5) before sending them to the recovery unit.

Intervention type: DRUG
Intervention: alfentanil
Description: The investigators assess the depth of anesthesia based on bispectral index (BIS) and modified observer's assessment/alertness scale (MOAA/S) after routine drug regimen is given. BIS is maintained between 40 and 60 and MOAA/S less than 2. The drug doses are given as a part of routine anesthesia practice and is identical regardless of study participation. Typical alfentanil ranged from 0\~1000mcg according to patient condition. The timing and doses are recorded for backend analysis. At the conclusion of the examination, the patient is observed in the examination room until return of consciousness before sending them to the recovery unit.

Intervention type: DRUG
Intervention: Propofol
Description: The investigators assess the depth of anesthesia based on bispectral index (BIS) and modified observer's assessment/alertness scale (MOAA/S) after routine drug regimen is given. BIS is maintained between 40 and 60 and MOAA/S less than 2. The drug doses are given as a part of routine anesthesia practice and is identical regardless of study participation. Typical propofol ranged from 0\~200mg according to patient condition. The timing and doses are recorded for backend analysis. At the conclusion of the surgery or examination, the patient is observed in the surgery or examination room until return of consciousness before sending them to the recovery unit.

Intervention type: DRUG
Intervention: Propofol
Description: The investigators assess the depth of anesthesia based on bispectral index (BIS) and modified observer's assessment/alertness scale (MOAA/S) after routine drug regimen is given. BIS is maintained between 40 and 60 and MOAA/S less than 2. The drug doses are given as a part of routine anesthesia practice and is identical regardless of study participation. Typical propofol ranged from 0\~200mg according to patient condition. The timing and doses are recorded for backend analysis. At the conclusion of the surgery or examination, the patient is observed in the surgery or examination room until return of consciousness before sending them to the recovery unit.