An interventional study of PRST Monitoring and PRST + BIS Monitoring in Elective Surgeries, General Anesthesia and BIS, sponsored by Gadjah Mada University. Completed at 1 site in Indonesia. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-15.
Sponsored by Gadjah Mada University · Not applicable, Interventional, and Diagnostic
The goal of this randomized controlled trial is to evaluate whether the PRST (Evans) score is a valid method for monitoring the depth of general anesthesia in adult surgical patients. It will also assess whether combining the PRST score with Bispectral Index (BIS) monitoring improves anesthetic depth assessment compared with PRST-guided monitoring alone.
The main questions it aims to answer are:
Researchers will compare patients managed using PRST-guided monitoring alone with patients managed using PRST plus visible BIS-guided monitoring.
Participants will:
This single-center, parallel-group randomized controlled trial (RCT) aims to evaluate the validity of the PRST (Evans) score for monitoring the depth of general anesthesia and to assess its relationship with Bispectral Index (BIS) monitoring in adult surgical patients undergoing elective procedures under general anesthesia.
Intraoperative awareness remains a clinically important complication during general anesthesia. Traditional clinical assessment methods such as the PRST score evaluate autonomic responses including systolic blood pressure, heart rate, sweating, and lacrimation, whereas BIS provides an electroencephalography-based objective assessment of hypnotic depth. This study investigates whether combining PRST assessment with BIS monitoring may improve anesthetic depth evaluation compared with PRST-guided monitoring alone.
Eligible participants are randomized into either a PRST-guided monitoring group or a PRST plus visible BIS-guided monitoring group. Standard anesthetic induction and maintenance protocols are applied in both groups. In the intervention group, BIS monitoring is used as an adjunctive tool to guide anesthetic depth management, with a target BIS range of 40-60.
PRST score, BIS values, heart rate (HR), and mean arterial pressure (MAP) are recorded at predefined intraoperative timepoints including T0 (baseline before induction), T1 (after induction before laryngoscopy), T2 (1-3 minutes after airway instrumentation), T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase). Postoperative interviews are conducted to evaluate recall, dreaming, and anesthesia-related discomfort.
The primary objective is to determine the association between PRST score and BIS values during general anesthesia. Secondary objectives include evaluation of hemodynamic responses, anesthetic delivery variables, postoperative recall-related events, and the diagnostic performance of PRST score in identifying BIS-defined light anesthesia.
Gadjah Mada University is the lead sponsor of 62 studies on the registry; 20 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Participants in this group will undergo elective surgery under general anesthesia with anesthetic depth managed using standard clinical monitoring and PRST-guided assessment. PRST components, including systolic blood pressure response, heart rate response, sweating, and lacrimation, will be assessed at predefined intraoperative timepoints.
Device: PRST Monitoring
Participants in this group will undergo elective surgery under general anesthesia with anesthetic depth managed using standard clinical monitoring, PRST-guided assessment, and visible BIS monitoring. BIS monitoring will be initiated after induction and used as an adjunct to guide hypnotic depth titration, with a typical target BIS range of 40-60. PRST score, BIS values, and hemodynamic parameters will be recorded at predefined intraoperative timepoints.
Device: PRST + BIS Monitoring
Clinical anesthetic depth monitoring using PRST score assessment without visible BIS-guided titration.
Clinical anesthetic depth monitoring using PRST score combined with visible BIS-guided anesthetic titration targeting BIS 40-60.
PRST score
PRST components were assessed as follows: SBP response (increase from baseline \<15 mmHg = 0; 15-30 mmHg = 1; \>30 mmHg = 2), HR response (increase from baseline \<15 bpm = 0; 15-30 bpm = 1; \>30 bpm = 2), sweating (absent = 0; present = 1), and lacrimation (absent = 0; present = 1). The total PRST score ranged from 0 to 6 with higher scores indicating greater autonomic response to nociceptive stimuli.
Time frame: T0 (baseline before induction), T1 (after induction before laryngoscopy), T2 (1-3 minutes after airway instrumentation), T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
BIS Score
Bispectral Index (BIS) monitoring is an electroencephalography-based anesthetic depth monitoring system used to assess the hypnotic state during general anesthesia. In this study, BIS monitoring is initiated after anesthetic induction and used as an adjunctive tool to guide anesthetic depth management, with a target BIS range of 40-60 during maintenance of general anesthesia. Continuous BIS values are recorded throughout the intraoperative period to evaluate anesthetic depth and correlation with PRST score measurements.
Time frame: T0 (baseline before induction), T1 (after induction before laryngoscopy), T2 (1-3 minutes after airway instrumentation), T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
Heart Rate
Time frame: T0 (baseline before induction), T1 (after induction before laryngoscopy), T2 (1-3 minutes after airway instrumentation), T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
Mean Arterial Pressure
Time frame: T0 (baseline before induction), T1 (after induction before laryngoscopy), T2 (1-3 minutes after airway instrumentation), T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
Sevoflurane dial setting
Sevoflurane dial setting refers to the vaporizer concentration setting used to deliver inhaled sevoflurane during maintenance of general anesthesia. In this study, sevoflurane concentration is adjusted intraoperatively according to anesthetic depth assessment and clinical monitoring parameters, including PRST score and BIS monitoring when applicable.
Time frame: T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
End-tidal minimum alveolar concentration (MAC) values
End-tidal minimum alveolar concentration (MAC) values represent the measured concentration of inhaled anesthetic agent in exhaled gas and are used as an indicator of anesthetic potency during general anesthesia. In this study, end-tidal MAC values are continuously monitored intraoperatively and recorded at predefined timepoints to evaluate anesthetic delivery and depth of anesthesia in relation to PRST score and BIS monitoring.
Time frame: T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).
Postoperative discomfort
Postoperative discomfort refers to patient-reported unpleasant physical or psychological experiences following general anesthesia and surgery. Assessment is performed postoperatively using structured interview questions evaluating discomfort related to anesthesia, intraoperative experience, or recovery period. Responses are recorded and compared between study groups.
Time frame: Immediately after recovery from general anesthesia
Dreaming
Dreaming refers to patient-reported dream experiences occurring during the peri-anesthetic period under general anesthesia. Assessment is performed postoperatively using structured interview questions adapted from the modified Brice interview to identify the presence or absence of dreaming during anesthesia and recovery. Responses are recorded and compared between study groups.
Time frame: Immediately after recovery from general anesthesia
Plan to share: Undecided
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Gadjah Mada University