Induction of AnaesthesiaPhase 4NCT07168252
Developing a Physiology-Pharmacodynamic Model of Rocuronium Dose and Cardiac Output to Investigate the Onset Time of Neuromuscular Relaxation
A Phase 4 study testing Rocuronium dosing in people with Induction of Anaesthesia and Muscle Relaxants, run by Clare Hayes-Bradley.
Trial summary
After a patient is put to sleep, a breathing tube is often placed through the larynx (voice box) into the trachea (windpipe). To place a breathing tube requires the muscles of the jaw, voice box, and diaphragm to be relaxed. This relaxation is usually done with muscle relaxant drugs and called paralysis. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Induction of Anaesthesia, Muscle Relaxants, Rocuronium
- What is being tested?
- Rocuronium dosing
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 32 participants
- Where
- No sites listed yet
- Study dates
- 1 Dec 2025to 31 Dec 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- General anaesthesia utilising an arterial line and rocuronium at an approved study site hospital (WSLHD - Blacktown \& Mount Druitt hospitals)
- Expected procedure duration >1.5 hours
- no contraindications to rocuronium neuromuscular blockade
- no contraindications to propofol TCI anaesthesia
Who cannot join
- Unable to consent for themselves for procedure
- Need for hospital interpreter (not currently funded for research use)
- pregnancy or lactation
- BMI > 50
- neuromuscular condition (e.g. affecting muscle or neuromuscular junction)
- renal failure (eGFR <30)
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- chronic liver failure diagnosis
- epilepsy or antiepileptics
- lithium
- Atrial Fibrillation/Aflutter (regular rhythm needed for cardiac output monitor)
- gentamicin administered before induction
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
After a patient is put to sleep, a breathing tube is often placed through the larynx (voice box) into the trachea (windpipe). To place a breathing tube requires the muscles of the jaw, voice box, and diaphragm to be relaxed. This relaxation is usually done with muscle relaxant drugs and called paralysis. Which paralysis drug and what dose should be used has been the subject of many studies.
In certain situations it is important for the patient to be fully paralysed before being intubated. Trying to intubate a partially paralysed person may result in coughing that could spread aerosols (e.g. COVID-19), patient desaturation (dropping oxygen levels), greater physiological response to intubation (heart rate, blood pressure and intra-cranial pressure rises) as well as expose the patient to risk of harm through repeated intubation attempts.
Read more
Current standard practice for patients needing critical care is to use the drug rocuronium at 1-1.2 mg/kg and wait 60 seconds for paralysis to occur. Unfortunately, 1.2mg/kg rocuronium often fails to provide good intubating conditions at 60s in some patients. The early studies revealed that 1 mg/kg rocuronium paralysis at 60s to be 'adequate' rather than 'excellent', as judged by those doing the intubation. One suggestion from 2000, was that a dose of 1.8 - 2.3 mg/kg rocuronium may be required to achieve 'excellent' intubating conditions at 60s in the vast majority of patients as is necessary clinically. The question of whether larger doses might be better has not been further investigated.
One of the reasons that the paralysis does not seem to work as fast in some patients may be related to the speed with which the drug travels round the body, pumped around the circulation, to the muscles, by the heart. This speed of circulation called cardiac output can be measured in patients at the time of injection. It may be possible to create a mathematical model for onset of paralysis by combining the information cardiac output, patient size, rocuronium dose administered, and time to paralysis. Such a model has been started by earlier researchers. The model needs further data for completion.
Once available, the model may be able to explain how fast the onset of paralysis might be in certain cardiac outputs. It might also deduce whether giving larger doses might help speed up the onset of paralysis in those patients.
- Conditions
- Induction of Anaesthesia, Muscle Relaxants, Rocuronium
- Being tested
- Rocuronium dosing
- Keywords
- rocuronium, muscle relaxants, intubation
- Medical subject headings
- Muscle Hypotonia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Rocuronium dosingDrug
Rocuronium doses of 0.6ng/kg, 1.2mg/kg, 1.6mg/kg and 2.0 mg/kg will be compared for onset speed of muscle relaxation and information on speed, cardiac output and patient body size entered into a computer model
| Study group | Role | What they receive |
|---|---|---|
| 0.6 mg/kg rocuronium IV bolus | Active comparator | Not described Receives: Drug: Rocuronium dosing |
| 1.2 mg/kg rocuronium | Active comparator | Not described Receives: Drug: Rocuronium dosing |
| 1.6mg/kg rocuronium | Experimental | Not described Receives: Drug: Rocuronium dosing |
| 2.0 mg/kg | Experimental | Not described Receives: Drug: Rocuronium dosing |
What is being measured
The primary outcome is the main question the study is designed to answer.
Onset of paralysis
Time for neuromuscular transmission monitor (NMT) to reach 95% suppression in seconds from rocuronium injection.
Measured: periprocedural
Secondary outcomes (1)
Cardiac output at rocuronium injection
Arterial pulse wave analysis measured cardiac output
Measured: Periprocedural
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Sep 2025
- Study start1 Dec 2025 (estimated)
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Induction of AnaesthesiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 32 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Clare Hayes-Bradley
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Clare Hayes-Bradley, Monash University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07168252
- Sponsor's protocol ID
- 2025/PID00382 - 2025/ETH00325
- Status last verified
- Nov 2025
- First submitted
- 27 Aug 2025
- Last updated
- 25 Nov 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 25 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Developing a Physiology-Pharmacodynamic Model of Rocuronium Dose and Cardiac Output to Investigate the Onset Time of Neuromuscular Relaxation
- ClinicalTrials.gov ID
- NCT07168252
- Acronym / sponsor ID
- 2025/PID00382 - 2025/ETH00325
- Conditions
- Induction of Anaesthesia, Muscle Relaxants, Rocuronium
- Keywords
- rocuronium, muscle relaxants, intubation
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 32 participants (estimated)
- Lead sponsor
- Clare Hayes-BradleyUniversity, hospital or other
- Study start
- 1 Dec 2025 (estimated)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 11 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
After a patient is put to sleep, a breathing tube is often placed through the larynx (voice box) into the trachea (windpipe). To place a breathing tube requires the muscles of the jaw, voice box, and diaphragm to be relaxed. This relaxation is usually done with muscle relaxant drugs and called paralysis. Which paralysis drug and what dose should be used has been the subject of many studies.
In certain situations it is important for the patient to be fully paralysed before being intubated. Trying to intubate a partially paralysed person may result in coughing that could spread aerosols (e.g. COVID-19), patient desaturation (dropping oxygen levels), greater physiological response to intubation (heart rate, blood pressure and intra-cranial pressure rises) as well as expose the patient to risk of harm through repeated intubation attempts.
Current standard practice for patients needing critical care is to use the drug rocuronium at 1-1.2 mg/kg and wait 60 seconds for paralysis to occur. Unfortunately, 1.2mg/kg rocuronium often fails to provide good intubating conditions at 60s in some patients. The early studies revealed that 1 mg/kg rocuronium paralysis at 60s to be 'adequate' rather than 'excellent', as judged by those doing the intubation. One suggestion from 2000, was that a dose of 1.8 - 2.3 mg/kg rocuronium may be required to achieve 'excellent' intubating conditions at 60s in the vast majority of patients as is necessary clinically. The question of whether larger doses might be better has not been further investigated.
One of the reasons that the paralysis does not seem to work as fast in some patients may be related to the speed with which the drug travels round the body, pumped around the circulation, to the muscles, by the heart. This speed of circulation called cardiac output can be measured in patients at the time of injection. It may be possible to create a mathematical model for onset of paralysis by combining the information cardiac output, patient size, rocuronium dose administered, and time to paralysis. Such a model has been started by earlier researchers. The model needs further data for completion.
Once available, the model may be able to explain how fast the onset of paralysis might be in certain cardiac outputs. It might also deduce whether giving larger doses might help speed up the onset of paralysis in those patients.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| 0.6 mg/kg rocuronium IV bolus | Active comparator | Drug: Rocuronium dosing |
| 1.2 mg/kg rocuronium | Active comparator | Drug: Rocuronium dosing |
| 1.6mg/kg rocuronium | Experimental | Drug: Rocuronium dosing |
| 2.0 mg/kg | Experimental | Drug: Rocuronium dosing |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- General anaesthesia utilising an arterial line and rocuronium at an approved study site hospital (WSLHD - Blacktown \& Mount Druitt hospitals)
- Expected procedure duration >1.5 hours
- no contraindications to rocuronium neuromuscular blockade
- no contraindications to propofol TCI anaesthesia
Key exclusion criteria (11 listed)
- Unable to consent for themselves for procedure
- Need for hospital interpreter (not currently funded for research use)
- pregnancy or lactation
- BMI > 50
- neuromuscular condition (e.g. affecting muscle or neuromuscular junction)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Rocuronium dosingRocuronium doses of 0.6ng/kg, 1.2mg/kg, 1.6mg/kg and 2.0 mg/kg will be compared for onset speed of muscle relaxation and information on speed, cardiac output and patient body size entered into a computer model | Drug | 0.6 mg/kg rocuronium IV bolus, 1.2 mg/kg rocuronium, 1.6mg/kg rocuronium, 2.0 mg/kg |
Primary outcome
Onset of paralysis
Time frame: periprocedural
Time for neuromuscular transmission monitor (NMT) to reach 95% suppression in seconds from rocuronium injection.
1 secondary outcome
Cardiac output at rocuronium injection
Time frame: Periprocedural
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Nov 2025.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Rocuronium dosing in people with Induction of Anaesthesia and Muscle Relaxants, run by Clare Hayes-Bradley.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 25 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Clare Hayes-Bradley (+61 2 8670 8019, clare.hayes-bradley@monash.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Onset of paralysis (time frame: periprocedural). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Nov 2025.