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Alpha 2 Agonists for Sedation to Produce Better Outcomes From Critical Illness (A2B Trial)

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

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03653832
Acronym
A2B
Enrollment
1437
Registered
2018-08-31
Start date
2018-12-10
Completion date
2024-07-31
Last updated
2024-10-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Critical Illness

Keywords

Sedation, Ventilation

Brief summary

Many patients in intensive care (ICU) need help to breathe on a breathing machine and need pain killers and sedatives to keep them comfortable and pain free. However, keeping patients too deeply sedated can make their ICU stay longer, can cause ICU confusion (delirium) and afterwards may cause distressing memories. Ideally patients should be kept less sedated, but it is difficult to get the balance of sedation and comfort right. The investigators want to know whether starting an alpha2-agonist drug early in ICU can help keep patients more lightly sedated but still comfortable, and whether patients spend less time on the ventilator. The investigators also want to know how safe they are and if they can improve important outcomes during ICU stay and during recovery. The investigators also want to know if they are value for money.

Detailed description

Many patients in intensive care (ICU) need help to breathe on a breathing machine and need pain killers and sedatives to keep them comfortable and pain free. However, keeping patients too deeply sedated can make their ICU stay longer, can cause ICU confusion (delirium), and afterwards may cause distressing memories. Ideally, the investigators want to keep patients less sedated, but it is difficult to get the balance of sedation and comfort right. For sedation, most ICUs use a drug called 'propofol' that is good at reducing anxiety and making people sleepy, but is not a pain killer, so additional pain killers are needed. There are two other drugs used less often called 'alpha-2 agonists' that have both sedative and pain-killing actions, which may make it easier for patients to be more awake and comfortable on the ventilator. The two drugs are called clonidine and dexmedetomidine. The investigators want to know whether starting an alpha2-agonist drug early in ICU, and using this instead of propofol as much as possible, can help keep patients more lightly sedated but still comfortable, and whether patients spend less time on the ventilator with these drugs. The investigators also want to know how safe these drugs are and if improve important outcomes during ICU stay can be improved (like delirium, comfort, and safety) and during recovery (like bad memories, anxiety, and depression). The investigators also want to know if they are value for money. The trial will include 1437 participants needing to be on a ventilator for at least 2 days. Participants will be allocated to one of three groups by chance. One group will continue to receive propofol; one group will receive dexmedetomidine; and one group will receive clonidine. All participants will receive extra pain relief if needed, and participants in the dexmedetomidine and clonidine groups will continue to receive propofol if they need this in addition. Nurses and doctors will alter the doses of sedation drugs to try and reduce or stop them, but always aiming to have participants lightly sedated and comfortable. The trial will compare if participants on dexmedetomidine or clonidine come off the ventilator quicker than those just on propofol. The trial will examine whether there was a difference between the groups in the number of participants who experienced delirium in ICU, compare how comfortable participants were, and measure if participants memories of being in the ICU differed. Patients who were in the trial will be followed up for up to 180 days afterwards because the investigators want to compare if there were differences in the after-effects of being ill in ICU between the groups. Participants will be asked to complete questionnaires that will assess their memories of the ICU experience at 90 days after entering the trial. At 180 days, participants will be asked to complete questionnaires so that the investigators can detect how patients feel about their quality of life or if they suffer from anxiety, depression or stress. Note that for patients recruited during the final months of recruitment, the 90 and 180 days follow will be truncated and not collected. This was agreed with the TSC and funder to reduce trial costs and enable trial completion. Alongside this trial, investigators will be looking at value for money, which is important because clonidine, dexmedetomidine, and propofol costs are quite different. Clonidine, in particular, is relatively inexpensive. ICU nurses' and doctors' views on how easy or difficult it was to adjust and use the drugs will be obtained. This will give valuable practical information that can be shared with other ICUs, particularly if alpha2-agonists are found to be better and other ICUs want to start using them.

Interventions

DRUGDexmedetomidine

Patients will commence intravenous infusion of open-label study drug according to a weight-based dose regimen as early as possible post-randomisation, and within a maximum of two hours. Bedside clinical staff will transition patients to achieve sedation with the allocated α2-agonist agent as quickly as clinically feasible and safe, to replicate the way these drugs would be used in routine practice. Additional opiate will be used for analgesia using clinical judgement. Once established, additional propofol will only be used when the maximum α2-agonist dose is reached or because cardiovascular or other side-effects limit dose escalation.

DRUGClonidine

Patients will commence intravenous infusion of open-label study drug according to a weight-based dose regimen as early as possible post-randomisation, and within a maximum of two hours. Bedside clinical staff will transition patients to achieve sedation with the allocated α2-agonist agent as quickly as clinically feasible and safe, to replicate the way these drugs would be used in routine practice. Additional opiate will be used for analgesia using clinical judgement. Once established, additional propofol will only be used when the maximum α2-agonist dose is reached or because cardiovascular or other side-effects limit dose escalation.

DRUGPropofol

Patients will continue to receive intravenous propofol according to current usual care.

Sponsors

West Hertfordshire Hospitals NHS Trust
CollaboratorOTHER
Queen's University, Belfast
CollaboratorOTHER
The University of Queensland
CollaboratorOTHER
University Hospital of Wales
CollaboratorOTHER
Edinburgh Napier University
CollaboratorOTHER
King's College London
CollaboratorOTHER
University of Warwick
CollaboratorOTHER
University of Manchester
CollaboratorOTHER
Royal Surrey County Hospital NHS Foundation Trust
CollaboratorOTHER
University College, London
CollaboratorOTHER
NHS Lothian
CollaboratorOTHER_GOV
Imperial College London
CollaboratorOTHER
University of Cambridge
CollaboratorOTHER
University of Edinburgh
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

A randomised, parallel-group, allocation concealed, controlled, open, phase 3 pragmatic clinical and cost- effectiveness trial with internal pilot

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1. Patient requiring mechanical ventilation (MV) in an ICU 2. Aged 18 or over 3. Within 48 hours of first episode of mechanical ventilation in ICU 4. Requiring sedation with propofol 5. Expected to require a total of 48 hours of MV or more in ICU 6. Expected to require a further 24 hours of MV or more at the time of randomisation in the opinion of the responsible clinician

Exclusion criteria

1. Acute brain injury (traumatic brain injury; intracranial haemorrhage; ischaemic brain injury from stroke or hypoperfusion) 2. Post-cardiac arrest (where there is clinical concern about hypoxic brain injury) 3. Status epilepticus 4. Continuous therapeutic neuromuscular paralysis at the time of screening or randomisation 5. Guillain-Barre Syndrome 6. Myasthenia gravis 7. Home ventilation 8. Fulminant hepatic failure 9. Patient not expected to survive 24 hours by responsible clinician 10. Decision to provide only palliative or end-of-life care 11. Pregnancy 12. Known allergy to one of the study drugs 13. Untreated second or third degree heart block 14. Transferred from another Intensive Care Unit in which MV occurred for \>6 hours 15. Prisoners 16. Enrolled on another CTIMP 17. Previously enrolled on the A2B Trial 18. Patient known to have experienced a period with heart rate \<50 beats per minute for 60 minutes or longer since commencing mechanical ventilation in the ICU

Design outcomes

Primary

MeasureTime frameDescription
Time to first successful extubation post-randomisation (hours).Ventilation status will be recorded twice daily from the date of randomisation until the date of documented successful extubation, or 180 days, whichever comes first.How many hours are participants on the study ventilated for?

Secondary

MeasureTime frameDescription
Sedation quality as measured by Sedation Quality Assessment Tool (SQAT)Sedation quality will be assessed daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Two components of the SQAT assessment will be used in this trial to measure sedation quality.
Analgesia quality as measured by Richmond Agitation and Sedation Scale (RASS)Analgesia quality will be assessed 4 hourly during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Quality of Analgesia measured by Richmond Agitation and Sedation Scale (RASS). RASS scale ranges from -5 to +4. optimal score is between -2 and +1.
Analgesia quality as measured by Sedation Quality Assessment Tool (SQAT)Analgesia quality will be assessed daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Quality of Analgesia measured by Sedation Quality Assessment Tool (SQAT)
Number of hours to first optimum sedation as measured by a RASS score of -2 or greaterLevel of sedation will be assessed 4 hourly during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Number of hours to first optimum sedation as measured by a RASS score of -2 or greater
Number of days to first optimum sedation as assessed by the Sedation Quality Assessment Tool (SQAT)Level of sedation will be assessed daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Number of days to first optimum sedation as assessed by the Sedation Quality Assessment Tool (SQAT)
Ability to communicate painAbility to communicate pain will be assessed twice daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Binary assessment by bedside nurse
Ability to co-operate with careAbility to co-operate with care will be assessed twice daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Binary assessment by bedside nurse
Relative/Partner/Friend (PerLR) assessment of wakefulnessParticipant wakefulness will be assessed by a Relative/Partner/Friend daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.PerLR response to verbal question
Relative/Partner/Friend (PerLR) assessment of patient comfortComfort of participant will be assessed by a Relative/Partner/Friend daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.PerLR response to verbal question
Relative/Partner/Friend (PerLR) assessment of patient communicationParticipant communication will be assessed by a Relative/Partner/Friend daily during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.PerLR response to verbal question
Incidence of Drug-related adverse events - Bradycardia; hypotension; hypertension; cardiac arrhythmias; cardiac arrestThe incidence of drug-related adverse events as documented in the medical records will be recorded daily from the date of randomisation until the date of documented successful extubation, or 28 days, whichever comes first.Incidence of drug-related adverse events as documented in the medical records
Sedation quality as measured by Richmond Agitation and Sedation Scale (RASS)Sedation quality will be assessed 4 hourly during the period of ventilation from the date of randomisation until the participant is successfully extubated, or 28 days, whichever comes first.Sedation quality as measured by Richmond Agitation and Sedation Scale (RASS). RASS scale ranges from -5 to +4. optimal score is between -2 and +1.
Patient experience of ICU care measured at 90 days90 days post ICU dischargePatient experience of ICU care measured by Intensive Care Experience Questionnaire
Occurrence of Anxiety and depression at 180 days180 days post ICU dischargePatient anxiety and depression measured by Hospital Anxiety and Depression Scale (HADS) questionnaire
Occurrence of Post-traumatic stress at 180 days180 post ICU dischargeOccurence of post-traumatic stress measured by Impact of Events Scale-revised (IES-R)
Cognitive function assessed at 180 days using the Montreal Cognitive Assessment Tool (Postal or Telephone)180 days post ICU dischargeCognitive function assessed at 180 days using the Montreal Cognitive Assessment Tool (Postal or Telephone)
Health related Quality of Life (recalled) assessed by Euroqol tool (EQ-5D-5L)30 days post ICU discharge - recalled prior to hospital admissionHealth related Quality of Life (recalled) assessed by Euroqol tool (EQ-5D-5L). Scale is between 5-25 which lower scores having the better outcome.
Health related Quality of Life (30 day) assessed by Euroqol tool (EQ-5D-5L)30 days post ICU dischargeHealth related Quality of Life (30 day) assessed by Euroqol tool (EQ-5D-5L). Scale is between 5-25 which lower scores having the better outcome.
Health related Quality of Life (180 day) assessed by Euroqol tool (EQ-5D-5L)180 days post ICU dischargeHealth related Quality of Life (180 day) assessed by Euroqol tool (EQ-5D-5L). Scale is between 5-25 which lower scores having the better outcome.
Health related Quality of Life (90 day) assessed by Euroqol tool (EQ-5D-5L)90 days post ICU dischargeHealth related Quality of Life (90 day) assessed by Euroqol tool (EQ-5D-5L). Scale is between 5-25 which lower scores having the better outcome.
Length of ICU stayICU status will be recorded daily from the date of randomisation until the date of ICU discharge, or 180 days, whichever comes first.Number of days the participant is in ICU
Delirium prior to successful extubationDelirium will be assessed twice daily during ICU stay using the Confusion-Agitation method for ICU (CAM-ICU). Delirium will be assessed from the date of randomisation until the date of ICU discharge, or 28 days, whichever comes first.Did participants have delirium during ICU stay?
Duration of Delirium during ICU stayDelirium will be assessed twice daily during ICU stay using the Confusion-Agitation method for ICU (CAM-ICU). Delirium will be assessed from the date of randomisation until the date of ICU discharge, or 28 days, whichever comes first.How many days did participants have delirium during their ICU stay?
Incidence of MortalityThe incidence of death as documented in the medical records will be recorded from the date of randomisation until the date of the last follow-up visit at 180 days.Mortality data collected from medical records

Countries

United Kingdom

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 7, 2026