NCT04965324

Brief Summary

Anaesthetic depth and complications after major surgery: an international, randomised controlled trial - The BALANCED trial. In this large, international, randomised controlled trial that enrolled patients aged 60 years and over with significant comorbidity and at increased risk of complications after major surgery, we found no evidence that light general anaesthesia (bispectral index 50) was superior to deep general anaesthesia (bispectral index 35) in reducing 1-year mortality. The BALANCED long term follow up study will look at whether depth of anesthesia affects long term (beyond 1 year) survival. The primary hypothesis is that targetting BIS 50 will result in superior long term survival compared to targetting BIS 35. The two secondary hypotheses are that BIS titration to BIS 50 will

  1. 1.reduce local cancer recurrence or metastatic spread and consequently improve long-term survival
  2. 2.reduce postoperative delirium and associated cognitive impairment and consequently improve long-term survival

Trial Health

75
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
6,644

participants targeted

Target at P75+ for all trials

Timeline
4mo left

Started Dec 2012

Longer than P75 for all trials

Geographic Reach
1 country

1 active site

Status
active not recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress98%
Dec 2012Aug 2026

Study Start

First participant enrolled

December 19, 2012

Completed
8.6 years until next milestone

First Submitted

Initial submission to the registry

July 7, 2021

Completed
9 days until next milestone

First Posted

Study publicly available on registry

July 16, 2021

Completed
5 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

June 30, 2026

Expected
2 months until next milestone

Study Completion

Last participant's last visit for all outcomes

August 31, 2026

Last Updated

April 8, 2026

Status Verified

April 1, 2026

Enrollment Period

13.5 years

First QC Date

July 7, 2021

Last Update Submit

April 3, 2026

Conditions

Post-Operative ConfusionLong Term Adverse EffectsSurgery--ComplicationsCognitive Dysfunction, Postoperative

Keywords

AnesthesiaDeliriumIncidenceLong Term Survival

Outcome Measures

Primary Outcomes (1)

  • Survival

    Survival

    Between one year and eight years after randomization to the BALANCED Trial

Study Arms (2)

Anaesthesia Depth BIS 35

BIS 35

Other: Anaesthesia Depth

Anaesthesia Depth BIS 50

BIS 50

Other: Anaesthesia Depth

Interventions

Anaesthesia DepthOTHER
Anaesthesia Depth BIS 35Anaesthesia Depth BIS 50

Eligibility Criteria

Age60 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodProbability Sample
Study Population

All participants who were recruited to the BALANCED Trial and who met the inclusion and no exclusion criteria for analysis of the long term outcome.

You may not qualify if:

  • Age over 60 years and over
  • ASA physical status 3 or 4
  • Surgery expected to last over 2 hours
  • Hospital length of stay expected to be 2 nights or more
  • General anaesthesia with or without major regional block
  • Able to monitor BIS throughout anaesthesia
  • Unable to monitor BIS
  • Unable to consent
  • Surgery with 'wake up' test
  • Propofol infusion for part or all of maintenance of anaesthesia
  • Previous enrolment in Balanced study
  • Participants were allocated to the BIS=50 group if the achieved median BIS is between 45 and 55 inclusive, and to the BIS=35 group if the achieved median BIS is between 30 and 40 inclusive. Participants who are not within these ranges will be excluded from these analyses.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Auckland City Hopsital

Auckland, Auckland, 1023, New Zealand

Location

MeSH Terms

Conditions

Long Term Adverse EffectsPostoperative Cognitive ComplicationsDelirium

Condition Hierarchy (Ancestors)

Pathologic ProcessesPathological Conditions, Signs and SymptomsPostoperative ComplicationsCognitive DysfunctionCognition DisordersNeurocognitive DisordersMental DisordersConfusionNeurobehavioral ManifestationsNeurologic ManifestationsNervous System DiseasesSigns and Symptoms

Study Officials

  • Timothy Dr Short

    Auckland City Hospital

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER GOV
Responsible Party
SPONSOR

Study Record Dates

First Submitted

July 7, 2021

First Posted

July 16, 2021

Study Start

December 19, 2012

Primary Completion (Estimated)

June 30, 2026

Study Completion (Estimated)

August 31, 2026

Last Updated

April 8, 2026

Record last verified: 2026-04

Data Sharing

IPD Sharing
Will share

Data sharing requests will be assessed by the Balanced Study Steering.Committee. Individual, deidentified participant data used in these analyses will be shared 2 years after publication by request from any qualified investigator after approval of a protocol, statistical analysis plan, and receipt of a signed data access agreement via the Research Office of Auckland District Health Board, New Zealand; and after obtaining the approval of the New Zealand Health and Disability Ethics Committees for the project and data release

Shared Documents
STUDY PROTOCOL, SAP, ICF
Time Frame
within 2 years
Access Criteria
Will be available on the clintrials.govt website

Locations

NZ(1)