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    Clinical Trial Results:
    Alpha 2 agonists for sedation to produce better outcomes from critical illness (A2B Trial): A randomised, parallel-group, allocation concealed, controlled, open, phase 3 pragmatic clinical and cost- effectiveness trial with internal pilot

    Summary
    EudraCT number
    2018-001650-98
    Trial protocol
    GB  
    Global end of trial date
    14 Dec 2023

    Results information
    Results version number
    v1(current)
    This version publication date
    23 Oct 2025
    First version publication date
    23 Oct 2025
    Other versions

    Trial information

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    Trial identification
    Sponsor protocol code
    AC1802
    Additional study identifiers
    ISRCTN number
    ISRCTN18035454
    US NCT number
    NCT03653832
    WHO universal trial number (UTN)
    -
    Other trial identifiers
    Eudra CT: 2018-001650-98
    Sponsors
    Sponsor organisation name
    The University of Edinburgh
    Sponsor organisation address
    Little France Road, Edinburgh, United Kingdom, EH16 4UX
    Public contact
    O'Mahony, University of Edinburgh, 0044 01312429418, fiach.o'mahony@ed.ac.uk
    Scientific contact
    O'Mahony, University of Edinburgh, 0044 01312429418, fiach.o'mahony@ed.ac.uk
    Sponsor organisation name
    NHS Lothian
    Sponsor organisation address
    Little France Road, Edinburgh, United Kingdom, EH16 4UX
    Public contact
    Kenneth Scott, NHS Lothian, 0044 01312423325, accord@nhslothian.scot.nhs.uk
    Scientific contact
    Kenneth Scott, NHS Lothian, 0044 01312423325, accord@nhslothian.scot.nhs.uk
    Paediatric regulatory details
    Is trial part of an agreed paediatric investigation plan (PIP)
    No
    Does article 45 of REGULATION (EC) No 1901/2006 apply to this trial?
    No
    Does article 46 of REGULATION (EC) No 1901/2006 apply to this trial?
    No
    Results analysis stage
    Analysis stage
    Final
    Date of interim/final analysis
    28 Jan 2025
    Is this the analysis of the primary completion data?
    Yes
    Primary completion date
    10 Dec 2023
    Global end of trial reached?
    Yes
    Global end of trial date
    14 Dec 2023
    Was the trial ended prematurely?
    No
    General information about the trial
    Main objective of the trial
    The primary objective was to determine whether intravenous sedation with the α2- agonist agents, dexmedetomidine or clonidine, can decrease the time to successful extubation from MV among adult critically ill patients.
    Protection of trial subjects
    This was a trial of ICU sedation. All patients were incapacitated when eligible for inclusion. The ethical framework used protected participants through the Clinical Trials Directive guidance about including patients lacking mental capacity. Consent was provide by Professional Legal Representative or Personal Legal Representative according to a process agreed with the ethics committee. Deferred consent was also permitted according to agreed circumstances. All patients were monitored for sedation state and comfort using validated tools. Clinicians adjusted therapy to achieve the desired level of sedation and analgesia. Any pain or distress was managed by clinical teams using clinical judgement and best practice.
    Background therapy
    All patients received the following according to individual need and clinical judgement: - Mechanical ventilation - Other forms of organ support to treat critical illness - Any other treatments indicated for critical illness, such as antibiotics for infection - All other treatments and therapies considered standard of care for ICU patients
    Evidence for comparator
    The comparator or usual care treatment was propofol-based sedation. This is the most widely used sedative in critical care practice, and is recommended as first line sedative in clinical guidelines.
    Actual start date of recruitment
    11 Dec 2018
    Long term follow-up planned
    Yes
    Long term follow-up rationale
    Scientific research
    Long term follow-up duration
    6 Months
    Independent data monitoring committee (IDMC) involvement?
    Yes
    Population of trial subjects
    Number of subjects enrolled per country
    Country: Number of subjects enrolled
    United Kingdom: 1404
    Worldwide total number of subjects
    1404
    EEA total number of subjects
    0
    Number of subjects enrolled per age group
    In utero
    0
    Preterm newborn - gestational age < 37 wk
    0
    Newborns (0-27 days)
    0
    Infants and toddlers (28 days-23 months)
    0
    Children (2-11 years)
    0
    Adolescents (12-17 years)
    0
    Adults (18-64 years)
    827
    From 65 to 84 years
    561
    85 years and over
    16

    Subject disposition

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    Recruitment
    Recruitment details
    Start of recruitment: 11 Dec 2018 End of recruitment: 27 Oct 2023 Recruited from ICU units at 38 UK sites: 4 sites in Scotland 2 sites in Wales 2 sites in Ireland 30 sites in England

    Pre-assignment
    Screening details
    Screening started as early as possible post-ICU admission, ideally within 6 hours. Screening continued for up to 48 hours following the start of Mechanical Ventilation (MV) in the ICU.

    Period 1
    Period 1 title
    Overall trial (overall period)
    Is this the baseline period?
    Yes
    Allocation method
    Randomised - controlled
    Blinding used
    Not blinded
    Blinding implementation details
    This was an open-label trial. Clinicians were not blinded from group allocation or from the treatment during its administration. Collection of the primary outcome and hospital-based secondary outcomes was not concealed or blinded from local research staff Collection of long term telephone based secondary outcomes was concealed from research staff

    Arms
    Are arms mutually exclusive
    Yes

    Arm title
    Dexmedetomidine
    Arm description
    Participants commenced intravenous infusion of open-label dexmedetomidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with dexmedetomidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once dexmedetomidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. The regimen followed the manufacturer’s guidance and regimens used in previous trials. No loading dose was administered. The starting dose was 0.7μg/kg/hour titrated to a maximum dose 1.4μg/kg/hour.
    Arm type
    Experimental

    Investigational medicinal product name
    Dexmedetomidine - Dexdor 100 micrograms/ml concentrate for solution for infusion
    Investigational medicinal product code
    PLGB 27925/0104
    Other name
    Pharmaceutical forms
    Solution for injection
    Routes of administration
    Intravenous use
    Dosage and administration details
    For dexmedetomidine, the regimen will follow the manufacturer’s guidance and regimens used in previous trials. No loading dose will be administered. The starting dose will be 0.7μg.kg-1.hour-1 titrated to a maximum dose 1.4μg.kg-1 hour-1.

    Arm title
    Clonidine
    Arm description
    Participants commenced intravenous infusion of open-label clonidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with clonidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once clonidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. For clonidine, the regimen was designed to be equipotent with dexmedetomidine based on known pharmacokinetics and pharmacodynamics. The chosen regimen is similar to that currently used in many UK ICUs as part of routine ‘off label’ practice. No loading dose was administered. The starting dose was 1.0μg/kg/hour titrated to a maximum dose of 2μg/kg/hour.
    Arm type
    Experimental

    Investigational medicinal product name
    Clonidine - Catapres Ampoules 150 micrograms in 1ml Solution for Injection
    Investigational medicinal product code
    PL 22824/0009
    Other name
    Pharmaceutical forms
    Solution for injection
    Routes of administration
    Intravenous use
    Dosage and administration details
    The regimen was designed to be equipotent with dexmedetomidine based on known pharmacokinetics and pharmacodynamics. The chosen regimen is similar to that currently used in many UK ICUs as part of routine ‘off label’ practice. No loading dose will be administered. The starting dose will be 1.0μg.kg-1.hour-1 titrated to a maximum dose of 2μg.kg-1.hour.

    Arm title
    Propofol
    Arm description
    Participants received intravenous propofol according to current usual care. The sedation targets, weaning, and sedation discontinuation procedures followed the same clinical targets as for the clonidine and dexmedetomidine groups.
    Arm type
    Active comparator

    Investigational medicinal product name
    Propofol 10mg/ml (1%) emulsion for injection or infusion
    Investigational medicinal product code
    PL 39699/0074
    Other name
    Pharmaceutical forms
    Emulsion for injection/infusion
    Routes of administration
    Intravenous use
    Dosage and administration details
    Patients will continue to receive intravenous propofol according to current usual care. The sedation targets, weaning, and sedation discontinuation procedures will follow the same clinical targets as for the clonidine and dexmedetomidine groups.

    Number of subjects in period 1
    Dexmedetomidine Clonidine Propofol
    Started
    457
    476
    471
    Completed
    457
    476
    471

    Baseline characteristics

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    Baseline characteristics reporting groups
    Reporting group title
    Dexmedetomidine
    Reporting group description
    Participants commenced intravenous infusion of open-label dexmedetomidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with dexmedetomidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once dexmedetomidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. The regimen followed the manufacturer’s guidance and regimens used in previous trials. No loading dose was administered. The starting dose was 0.7μg/kg/hour titrated to a maximum dose 1.4μg/kg/hour.

    Reporting group title
    Clonidine
    Reporting group description
    Participants commenced intravenous infusion of open-label clonidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with clonidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once clonidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. For clonidine, the regimen was designed to be equipotent with dexmedetomidine based on known pharmacokinetics and pharmacodynamics. The chosen regimen is similar to that currently used in many UK ICUs as part of routine ‘off label’ practice. No loading dose was administered. The starting dose was 1.0μg/kg/hour titrated to a maximum dose of 2μg/kg/hour.

    Reporting group title
    Propofol
    Reporting group description
    Participants received intravenous propofol according to current usual care. The sedation targets, weaning, and sedation discontinuation procedures followed the same clinical targets as for the clonidine and dexmedetomidine groups.

    Reporting group values
    Dexmedetomidine Clonidine Propofol Total
    Number of subjects
    457 476 471 1404
    Age categorical
    All subjects were aged between 18 and 92. No participants were under 18.
    Units: Subjects
        In utero
    0 0 0 0
        Preterm newborn infants (gestational age < 37 wks)
    0 0 0 0
        Newborns (0-27 days)
    0 0 0 0
        Infants and toddlers (28 days-23 months)
    0 0 0 0
        Children (2-11 years)
    0 0 0 0
        Adolescents (12-17 years)
    0 0 0 0
        Adults (18-64 years)
    288 274 265 827
        From 65-84 years
    164 195 202 561
        85 years and over
    5 7 4 16
    Age continuous
    Units: years
        arithmetic mean (standard deviation)
    58.8 ( 14.8 ) 59.6 ( 14.5 ) 59.2 ( 15.2 ) -
    Gender categorical
    Units: Subjects
        Female
    160 168 166 494
        Male
    297 308 305 910
    Subject analysis sets

    Subject analysis set title
    Dexmedetomidine
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Subject analysis set title
    Clonidine
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Subject analysis set title
    Propofol
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Subject analysis sets values
    Dexmedetomidine Clonidine Propofol
    Number of subjects
    457
    476
    471
    Age categorical
    All subjects were aged between 18 and 92. No participants were under 18.
    Units: Subjects
        In utero
    0
    0
    0
        Preterm newborn infants (gestational age < 37 wks)
    0
    0
    0
        Newborns (0-27 days)
    0
    0
    0
        Infants and toddlers (28 days-23 months)
    0
    0
    0
        Children (2-11 years)
    0
    0
    0
        Adolescents (12-17 years)
    0
    0
    0
        Adults (18-64 years)
    287
    272
    268
        From 65-84 years
    164
    193
    203
        85 years and over
    5
    7
    4
    Age continuous
    Units: years
        arithmetic mean (standard deviation)
    58.8 ( 14.8 )
    59.6 ( 14.5 )
    59.2 ( 15.2 )
    Gender categorical
    Units: Subjects
        Female
    160
    168
    166
        Male
    297
    308
    305

    End points

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    End points reporting groups
    Reporting group title
    Dexmedetomidine
    Reporting group description
    Participants commenced intravenous infusion of open-label dexmedetomidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with dexmedetomidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once dexmedetomidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. The regimen followed the manufacturer’s guidance and regimens used in previous trials. No loading dose was administered. The starting dose was 0.7μg/kg/hour titrated to a maximum dose 1.4μg/kg/hour.

    Reporting group title
    Clonidine
    Reporting group description
    Participants commenced intravenous infusion of open-label clonidine according to a weight-based dose regimen as early as possible post randomisation, and within a maximum of two hours. Bedside clinical staff transitioned patients to achieve sedation with clonidine as quickly as clinically feasible and safe, to replicate the way these drugs were used in routine practice. Additional opiate was used for analgesia using clinical judgement. Once clonidine was established, additional propofol was only used when the maximum α2-agonist dose was reached or because cardiovascular or other side-effects limited dose escalation. For clonidine, the regimen was designed to be equipotent with dexmedetomidine based on known pharmacokinetics and pharmacodynamics. The chosen regimen is similar to that currently used in many UK ICUs as part of routine ‘off label’ practice. No loading dose was administered. The starting dose was 1.0μg/kg/hour titrated to a maximum dose of 2μg/kg/hour.

    Reporting group title
    Propofol
    Reporting group description
    Participants received intravenous propofol according to current usual care. The sedation targets, weaning, and sedation discontinuation procedures followed the same clinical targets as for the clonidine and dexmedetomidine groups.

    Subject analysis set title
    Dexmedetomidine
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Subject analysis set title
    Clonidine
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Subject analysis set title
    Propofol
    Subject analysis set type
    Full analysis
    Subject analysis set description
    All participants randomised, analysed according to their allocated treatment group regardless of the treatment actually received, with the exception of the following groups of participants: (a) those randomised in error despite ineligibility; (b) erroneous duplicate randomisations; (c) those fully withdrawing from the trial who also requested that all of their data be deleted; (d) exclusions resulting from a serious breach event at site 45 relating to participant consent (14 participants). While professional legal representative consent was obtained for these participants, a notified serious breach arose in relation to processes followed locally to obtain consent to remain in the trial for these incapacitated patients.

    Primary: Time to successful extubation

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    End point title
    Time to successful extubation
    End point description
    Time to successful extubation (in hours post-randomization) Median (95% CI )
    End point type
    Primary
    End point timeframe
    During ICU stay.
    End point values
    Dexmedetomidine Clonidine Propofol
    Number of subjects analysed
    457
    476
    471
    Units: Hours
        median (full range (min-max))
    136 (117 to 150)
    146 (124 to 168)
    162 (136 to 170)
    Statistical analysis title
    Primary analysis: Dexmedetomidine versus Propofol
    Statistical analysis description
    For the primary analysis, performed on the full analysis set, a Fine and Gray proportional sub-distribution hazards regression model of time from randomisation to successful extubation was fitted to the data. Results are presented as sub-distribution hazard ratios for each of the dexmedetomidine and clonidine versus usual care comparisons, with corresponding 95% confidence intervals (CI) and p-values from the primary analysis model.
    Comparison groups
    Dexmedetomidine v Propofol
    Number of subjects included in analysis
    928
    Analysis specification
    Pre-specified
    Analysis type
    superiority [1]
    P-value
    = 0.196
    Method
    Fine and Gray proportional sub-distribut
    Parameter type
    Sub-distribution hazard ratio
    Point estimate
    1.093
    Confidence interval
         level
    95%
         sides
    2-sided
         lower limit
    0.955
         upper limit
    1.25
    Notes
    [1] - Fine and Gray proportional sub-distribution hazards regression analysis
    Statistical analysis title
    Primary analysis: Clonidine versus Propofol
    Statistical analysis description
    For the primary analysis, performed on the full analysis set, a Fine and Gray proportional sub-distribution hazards regression model of time from randomisation to successful extubation was fitted to the data. Results are presented as sub-distribution hazard ratios for each of the dexmedetomidine and clonidine versus usual care comparisons, with corresponding 95% confidence intervals (CI) and p-values from the primary analysis model.
    Comparison groups
    Clonidine v Propofol
    Number of subjects included in analysis
    947
    Analysis specification
    Pre-specified
    Analysis type
    superiority [2]
    P-value
    = 0.342
    Method
    Fine and Gray proportional sub-distribut
    Parameter type
    Sub-distribution hazard ratio
    Point estimate
    1.052
    Confidence interval
         level
    95%
         sides
    2-sided
         lower limit
    0.948
         upper limit
    1.167
    Notes
    [2] - Fine and Gray proportional sub-distribution hazards regression analysis

    Adverse events

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    Adverse events information
    Timeframe for reporting adverse events
    Daily during the intervention period and until ICU discharge.
    Assessment type
    Systematic
    Dictionary used for adverse event reporting
    Dictionary name
    MedDRA
    Dictionary version
    22.1
    Reporting groups
    Reporting group title
    Dexmedetomidine group
    Reporting group description
    -

    Reporting group title
    Clonidine group
    Reporting group description
    -

    Reporting group title
    Propofol group
    Reporting group description
    -

    Serious adverse events
    Dexmedetomidine group Clonidine group Propofol group
    Total subjects affected by serious adverse events
         subjects affected / exposed
    22 / 457 (4.81%)
    12 / 476 (2.52%)
    5 / 471 (1.06%)
         number of deaths (all causes)
    132
    145
    141
         number of deaths resulting from adverse events
    Injury, poisoning and procedural complications
    Pyrexia possibly due to Clonidine
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    1 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Vascular disorders
    Hypertension and subsequent hypotension
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Small bowel ischemia due to pseudo-obstruction
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    1 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Left MCA stroke
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
    Large cerebral bleed
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
    Cardiac disorders
    Bradycardic cardiac arrest
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    MItral regurgitation found on TOE requiring urgent repair SAE documented
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Whilst repositioning, patient bit endotracheal tube. Unable to ventilate patient. Saturations droppe
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Profound bradycardia requiring CPR
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Patient lost cardiac output on three occasions
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Bradycardia with loss of cardiac output
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Brady Arrhythmia
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    1 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Astystole
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Cardiac event
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Severe bradycardia with HR 28-30 bpm and hypotension with SBP 50-60s for a few minutes at 4AM on 01/
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    1 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Cardiac arrest
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
    Bradycardia
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    MI
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
    VF arrest likely due to sepsis with post myocardial infarction scarring
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
    Severe bradycardia with associated hypotension
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Cardiovascularly unstable. Bradycardia leading to episodes of asystole that resolved spontaniously.
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    1 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Atrial fibrillation with rapid ventricular response followed by ventricular pulseless tachycardia, r
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
    Compromised bradycardia
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    2 / 2
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    PEA Cardiac Arrest
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Nervous system disorders
    Cerebral Infarction
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
    Participant fond to have multiple infarcts on Head CT done due to reduced consciousness off sedation
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
    Sub acute left frontoparietal haematoma found on CT scan
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
    Unconscious
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
    New right occipital lobe PCA territory infarct
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    MCA infarct with occluded Right ICA
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    General disorders and administration site conditions
    Verified Death after deterioration with rapidly escalating oxygen requirement following vomit.
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
    Hyperthermia due to dexmedetomidine
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    1 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Gastrointestinal disorders
    UGI Bleed
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Oesophageal bleed
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Ischaemic bowel and bowel perforation-pt was palliated and died the same day, SAE has been recorded
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 1
    0 / 0
    Respiratory, thoracic and mediastinal disorders
    Significant bilateral pleural effusions causing patient to be peri arrest and requiring emergency re
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Patient had to be re intubated due to PE and CAP
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences causally related to treatment / all
    0 / 1
    0 / 0
    0 / 0
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Significant tracheostomy cuff leak with probable atelectasis post-op
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences causally related to treatment / all
    0 / 0
    0 / 0
    0 / 1
         deaths causally related to treatment / all
    0 / 0
    0 / 0
    0 / 0
    Frequency threshold for reporting non-serious adverse events: 5%
    Non-serious adverse events
    Dexmedetomidine group Clonidine group Propofol group
    Total subjects affected by non serious adverse events
         subjects affected / exposed
    28 / 457 (6.13%)
    14 / 476 (2.94%)
    13 / 471 (2.76%)
    Vascular disorders
    Vascular disorder
         subjects affected / exposed
    8 / 457 (1.75%)
    2 / 476 (0.42%)
    3 / 471 (0.64%)
         occurrences all number
    8
    2
    3
    Surgical and medical procedures
    Surgery
    Additional description: Immediate return to theatre following scan.
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences all number
    0
    1
    0
    General disorders and administration site conditions
    Hyperthermia
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences all number
    1
    0
    0
    Rapidly escalating oxygen requirement
    Additional description: Verified Death after deterioration with rapidly escalating oxygen requirement following vomit.
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences all number
    1
    0
    0
    Respiratory, thoracic and mediastinal disorders
    Respiratory disorder
         subjects affected / exposed
    6 / 457 (1.31%)
    1 / 476 (0.21%)
    5 / 471 (1.06%)
         occurrences all number
    8
    1
    8
    Psychiatric disorders
    Psychiatric disorder
         subjects affected / exposed
    3 / 457 (0.66%)
    2 / 476 (0.42%)
    1 / 471 (0.21%)
         occurrences all number
    4
    2
    1
    Injury, poisoning and procedural complications
    Pyrexia
    Additional description: Pyrexia possibly due to Clonidine
         subjects affected / exposed
    0 / 457 (0.00%)
    1 / 476 (0.21%)
    0 / 471 (0.00%)
         occurrences all number
    0
    1
    0
    Cardiac disorders
    Cardiac event
         subjects affected / exposed
    24 / 457 (5.25%)
    14 / 476 (2.94%)
    5 / 471 (1.06%)
         occurrences all number
    26
    15
    9
    Nervous system disorders
    Nervous system disorder
         subjects affected / exposed
    7 / 457 (1.53%)
    3 / 476 (0.63%)
    3 / 471 (0.64%)
         occurrences all number
    8
    3
    3
    Blood and lymphatic system disorders
    Bleeding from tracheostomy
    Additional description: Bleeding from tracheostomy and frank blood from NG
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences all number
    1
    0
    0
    Gastrointestinal disorders
    Gastrointestinal disorder
         subjects affected / exposed
    3 / 457 (0.66%)
    3 / 476 (0.63%)
    1 / 471 (0.21%)
         occurrences all number
    3
    3
    1
    Hepatobiliary disorders
    Hepatobiliary disorder
         subjects affected / exposed
    2 / 457 (0.44%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences all number
    2
    0
    1
    Renal and urinary disorders
    Acute kidney injury
         subjects affected / exposed
    0 / 457 (0.00%)
    0 / 476 (0.00%)
    1 / 471 (0.21%)
         occurrences all number
    0
    0
    1
    Endocrine disorders
    Endocrine disorder
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences all number
    1
    0
    0
    Infections and infestations
    Septic episode
    Additional description: Septic episode with haemodynamic instability.
         subjects affected / exposed
    1 / 457 (0.22%)
    0 / 476 (0.00%)
    0 / 471 (0.00%)
         occurrences all number
    1
    0
    0

    More information

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    Substantial protocol amendments (globally)

    Were there any global substantial amendments to the protocol? Yes
    Date
    Amendment
    22 Nov 2018
    Change of PI at Belfast, addition of 10 sites
    16 May 2019
    Addition of 13 sites and removal of one (Dorset)
    24 Oct 2019
    NIHR logo and statement updated, various protocol updates, new covering letters, 2 new sites added, PI at Hampton Hospitals changed
    27 May 2020
    Addition of 5 sites, change of PI at Royal Marsden, removal of one site (Royal Free)
    24 Aug 2020
    Change in PI at Oxford and St Georges
    01 Sep 2020
    SPC updated, Protocol: changes to follow-up, sites 90 day FU, booklets, reduce Q at 30 and 90 days. Covering letters for 90 day site FU. PIS changes: GDPR info included, sites can do 90 days FU
    21 Mar 2022
    SPC and Summary product Ch updated. 8 letters, PIS updated and protocol changes including co-enrolment to CTIMPS
    31 Aug 2022
    Am 7 documents resubmitted but removed co-enrolment to CTIMPs. SPC and Summary product Ch updated. 8 letters, PIS updated and protocol changes
    03 May 2023
    1. The protocol has been updated to change the sample size from 1737 to 1437. Additional updates to the protocol include:- a change in trial manager (the previous trial manager has moved onto a new study)- changes to the follow-up duration to truncate the follow up period - an email from the statistician has been included to confirm this will not cause a significant impact on the outcome of the trial- update to the total planned duration of the trial in line with the extension granted by the Funder to complete the trial- changes to section 3.4 Design and analytical/ conceptual framework in line with the revised sample size- changes to Section 10.1 Overview to Health Economic Evaluation to clarify the changes in cost of the drugs during the trials lifespan- changes in section 6.3.1 Replacing Diprivan with Propofol in line with the updated SPC V5.0 (detailed in number 3). - Change to the follow up duration truncating the follow up to 30 days only for participants recruited in October. There is an email from the statistician included to assure there will be no impact from truncating the follow up period.2. Changes to the PIS, Process Evaluation PIS and addition of two letters as detailed further on in the amendment tool.3. SPC updated: we wish to submit SPC V5.0 25042023. The Catapres and Propofol SPC has been updated with no changes to the RSI. The Dexdor SPC has also been updated with a change to the RSI - in section 4.8 (undesirable effects); Added to adverse reactions is diabetes insipidus (endocrine disorder) with unknown frequency. Removed is "Renal and urinary disorders: Polyuria (Not known)

    Interruptions (globally)

    Were there any global interruptions to the trial? Yes
    Date
    Interruption
    Restart date
    11 Mar 2020
    Recruitment to A2B was suspended at all sites from 11th March 2020 due to the COVID-19 pandemic.
    03 Jun 2020

    Limitations and caveats

    Limitations of the trial such as small numbers of subjects analysed or technical problems leading to unreliable data.
    None reported
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    The status and protocol content of GB trials is no longer updated since 1 January 2021. For the UK, as of 31 January 2021, EU Law applies only to the territory of Northern Ireland (NI) to the extent foreseen in the Protocol on Ireland/NI. Legal notice
    As of 31 January 2023, all EU/EEA initial clinical trial applications must be submitted through CTIS . Updated EudraCT trials information and information on PIP/Art 46 trials conducted exclusively in third countries continues to be submitted through EudraCT and published on this website.

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