Skip to main content
OpenTrials
Completed

NCT Number: NCT07590388

Validation of the PRST Score Against Bispectral Index

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:

1. Does the PRST score correlate with BIS values during general anesthesia? 2. Does visible BIS-guided monitoring improve anesthetic depth assessment compared with PRST-guided monitoring alone?

Researchers will compare patients managed using PRST-guided monitoring alone with patients managed using PRST plus visible BIS-guided monitoring.

Participants will:

1. Undergo elective surgery under general anesthesia 2. Receive intraoperative anesthetic depth monitoring using PRST score alone or PRST combined with BIS monitoring 3. Have PRST score, BIS, heart rate, and blood pressure recorded at predefined intraoperative timepoints 4. Complete a postoperative interview assessing recall, dreaming, and anesthesia-related discomfort

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Elective Surgeries BIS General Anesthesia

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

RSUP Dr. Sardjito

Yogyakarta, Special Region of Yogyakarta, 55281, Indonesia

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Scheduled for elective surgery under general anesthesia

Exclusion criteria

  • Unstable hemodynamic conditions
  • Contraindications to specific anesthetic agents or significant neurological disorders (e.g., Parkinson's disease, stroke, or dementia)
  • Receiving medications known to influence EEG activity, such as anticonvulsants
  • Unable to provide informed consent

Treatment and study plan

PRST Monitoring

Device

Clinical anesthetic depth monitoring using PRST score assessment without visible BIS-guided titration.

PRST + BIS Monitoring

Device

Clinical anesthetic depth monitoring using PRST score combined with visible BIS-guided anesthetic titration targeting BIS 40-60.

Primary outcomes

  1. PRST score

    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).

    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.

  2. BIS Score

    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).

    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.

Secondary outcomes

  1. 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).

  2. 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).

  3. Sevoflurane dial setting

    Time frame: T3 (before skin incision), T4 (5 minutes after incision), and T5-T6 (15 and 30 minutes during the maintenance phase).

    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.

  4. End-tidal minimum alveolar concentration (MAC) values

    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 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.

  5. Postoperative discomfort

    Time frame: Immediately after recovery from general anesthesia

    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.

  6. Dreaming

    Time frame: Immediately after recovery from general anesthesia

    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.

Sponsors and collaborators

Lead sponsor

Gadjah Mada University

Other

Registry information

Official study title

Validation of the PRST Score Against Bispectral Index During General Anesthesia: A Randomized Controlled Trial

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
May 15, 2026
Registry last updated
May 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.