HypotensionPhase 2/3NCT04025918
Closed-loop Double-vasopressor Automated System to Treat Hypotension During Spinal Anaesthesia for Caesarean Section
A Phase 2/3 study testing Vasopressor automated delivery system, Phenylephrine and Ephedrine in people with Hypotension, run by KK Women's and Children's Hospital.
Trial summary
Hypotension occurs commonly during spinal anesthesia for caesarean section with maternal and fetal adverse effects. The investigators developed a double-vasopressor automated system incorporating continuous non-invasive arterial pressure monitoring (CNAP, CNSystems, Austria). Read more about this study
- Who is it for?
- Ages 21 to 45 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Hypotension
- What is being tested?
- Vasopressor automated delivery system, Phenylephrine and Ephedrine
- Type of treatment
- Injection or infusion, Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 216 participants
- Where
- No sites listed yet
- Study dates
- Oct 2011to Jul 2012
- Phase
- Phase 2/3
- Are there results?
- None posted in the registry
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 21 to 45 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- age 21-45 years old,
- weight 40-90 kg,
- height 145-170 cm
Who cannot join
- contraindications to spinal anaesthesia,
- allergy to drugs used in the study, and
- those with uncontrolled medical conditions such as hypertension, diabetes mellitus, and cardiovascular disease
About this study
Official title: Closed-loop Double-vasopressor Automated System vs Manual Bolus Vasopressor to Treat Hypotension During Spinal Anaesthesia for Caesarean Section
Hypotension occurs commonly during spinal anesthesia for caesarean section with maternal and fetal adverse effects. The investigators developed a double-vasopressor automated system incorporating continuous non-invasive arterial pressure monitoring (CNAP, CNSystems, Austria).
Read the detailed description
Hypotension occurs commonly during spinal anesthesia for cesarean section with maternal and fetal adverse effects. The investigators developed a double-vasopressor automated system incorporating continuous non-invasive arterial pressure (CNAP, CNSystems, Austria) monitoring feeding hemodynamic data to a laptop computer, which triggers syringe pumps to deliver phenylephrine 50mcg or ephedrine 4mg (if heart rate<60 beats.min-1) every 30 seconds when systolic blood pressure fell to below 90% of baseline.
A randomised controlled trial was done to compare with manual bolus technique. With the manual bolus technique, phenylephrine 100mcg or ephedrine 8mg (if heart rate<60 beats.min-1) was given every 60 seconds by the attending anesthesiologist when systolic blood pressure was below 90% of baseline as measured by conventional intermittent non-invasive blood pressure monitoring.
- Conditions
- Hypotension
- Being tested
- Vasopressor automated delivery system, Phenylephrine, Ephedrine, Manual vasopressor delivery system
- Keywords
- hypotension, spinal anesthesia, cesarean section, phenylephrine, ephedrine, closed-loop system, continuous non-invasive monitor
- Medical subject headings
- Hypotension
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vasopressor automated delivery systemDevice
Also called CNAP
Novel closed-loop system incorporating:
- Continuous non-invasive arterial pressure (CNAP) monitor that measured and recorded hemodynamic data in real time.
- Controller algorithm loaded onto a laptop computer that monitored the hemodynamic data from CNAP and determined if vasopressors should be administered.
- Two syringe pumps loaded with phenylephrine and ephedrine that was activated by the controller algorithm.
PhenylephrineDrug
Phenylephrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of at least 60bpm.
EphedrineDrug
Ephedrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of less than 60bpm.
Manual vasopressor delivery systemDevice
Manual dosing system consisting:
- Non-invasive intermittent blood pressure monitor that measured and recorded blood pressure at 1-minute intervals.
- Attending anesthesiologist that noted the blood pressure readings and manually administered phenylephrine or ephedrine according to the algorithm.
| Study group | Role | What they receive |
|---|---|---|
| vasopressor delivery automated system | Experimental | vasopressor delivery automated system that administered phenylephrine and ephedrine based on data from continuous non-invasive hemodynamic monitor Receives: Device: Vasopressor automated delivery system; Drug: Phenylephrine; Drug: Ephedrine |
| manual vasopressor delivery | Active comparator | manual bolus that delivered phenylephrine and ephedrine based on data from non-invasive intermitted blood pressure monitor Receives: Drug: Phenylephrine; Drug: Ephedrine; Device: Manual vasopressor delivery system |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hypotension
Incidence of systolic blood pressure less than 80% of baseline systolic blood pressure
Measured: 1 day
Secondary outcomes (2)
Hypertension
Incidence of systolic blood pressure more than 120% of baseline systolic blood pressure
Measured: 1 day
Nausea and vomiting
Incidence of nausea and vomiting during cesarean section
Measured: 1 day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Jul 2019
- Study startOct 2011
- Primary completionJul 2012
- Study completionJul 2012
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for HypotensionStudies 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 2/3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 216 participants (actual)
Sponsor and investigators
- Lead sponsor
- KK Women's and Children's Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Sng Ban Leong, KK Women's and Children's Hospital
- Investigators
- Ban Leong Sng, FANZCA, Principal investigator, KK Women's and Children's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04025918
- Sponsor's protocol ID
- 2010/365/D
- Status last verified
- Aug 2026
- First submitted
- 17 Jul 2019
- Last updated
- 6 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Ngan Kee WD. Prevention of maternal hypotension after regional anaesthesia for caesarean section. Curr Opin Anaesthesiol. 2010 Jun;23(3):304-9. doi: 10.1097/ACO.0b013e328337ffc6.
PubMed 20173633Sia AT, Tan HS, Sng BL. Closed-loop double-vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: a preliminary study. Anaesthesia. 2012 Dec;67(12):1348-55. doi: 10.1111/anae.12000. Epub 2012 Sep 28.
PubMed 23020653Sng BL, Tan HS, Sia AT. Closed-loop double-vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial. Anaesthesia. 2014 Jan;69(1):37-45. doi: 10.1111/anae.12460. Epub 2013 Nov 20.
PubMed 24256483
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Closed-loop Double-vasopressor Automated System vs Manual Bolus Vasopressor to Treat Hypotension During Spinal Anaesthesia for Caesarean Section
- ClinicalTrials.gov ID
- NCT04025918
- Acronym / sponsor ID
- 2010/365/D
- Conditions
- Hypotension
- Keywords
- hypotension, spinal anesthesia, cesarean section, phenylephrine, ephedrine, closed-loop system, continuous non-invasive monitor
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 216 participants (actual)
- Lead sponsor
- KK Women's and Children's HospitalOther government
- Study start
- Oct 2011 (actual)
- Primary completion
- Jul 2012 (actual)
- Study completion
- Jul 2012 (actual)
- First posted
- 19 Jul 2019 (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.
Hypotension occurs commonly during spinal anesthesia for caesarean section with maternal and fetal adverse effects. The investigators developed a double-vasopressor automated system incorporating continuous non-invasive arterial pressure monitoring (CNAP, CNSystems, Austria).
Detailed description
Hypotension occurs commonly during spinal anesthesia for cesarean section with maternal and fetal adverse effects. The investigators developed a double-vasopressor automated system incorporating continuous non-invasive arterial pressure (CNAP, CNSystems, Austria) monitoring feeding hemodynamic data to a laptop computer, which triggers syringe pumps to deliver phenylephrine 50mcg or ephedrine 4mg (if heart rate<60 beats.min-1) every 30 seconds when systolic blood pressure fell to below 90% of baseline.
A randomised controlled trial was done to compare with manual bolus technique. With the manual bolus technique, phenylephrine 100mcg or ephedrine 8mg (if heart rate<60 beats.min-1) was given every 60 seconds by the attending anesthesiologist when systolic blood pressure was below 90% of baseline as measured by conventional intermittent non-invasive blood pressure monitoring.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| vasopressor delivery automated system | Experimental | Device: Vasopressor automated delivery system, Drug: Phenylephrine, Drug: Ephedrinevasopressor delivery automated system that administered phenylephrine and ephedrine based on data from continuous non-invasive hemodynamic monitor |
| manual vasopressor delivery | Active comparator | Drug: Phenylephrine, Drug: Ephedrine, Device: Manual vasopressor delivery systemmanual bolus that delivered phenylephrine and ephedrine based on data from non-invasive intermitted blood pressure monitor |
Who may qualify
- Ages
- 21 to 45 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- age 21-45 years old,
- weight 40-90 kg,
- height 145-170 cm
Key exclusion criteria (3 listed)
- contraindications to spinal anaesthesia,
- allergy to drugs used in the study, and
- those with uncontrolled medical conditions such as hypertension, diabetes mellitus, and cardiovascular disease
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 |
|---|---|---|
| Vasopressor automated delivery systemAlso: CNAPNovel closed-loop system incorporating: 1. Continuous non-invasive arterial pressure (CNAP) monitor that measured and recorded hemodynamic data in real time. 2. Controller algorithm loaded onto a laptop computer that monitored the hemodynamic data from CNAP and determined if vasopressors should be administered. 3. Two syringe pumps loaded with phenylephrine and ephedrine that was activated by the controller algorithm. | Device | vasopressor delivery automated system |
| PhenylephrinePhenylephrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of at least 60bpm. | Drug | manual vasopressor delivery, vasopressor delivery automated system |
| EphedrineEphedrine is a vasopressor drug that was administered when the participant's systolic blood pressure fell below 90% of baseline systolic blood pressure, with heart rate of less than 60bpm. | Drug | manual vasopressor delivery, vasopressor delivery automated system |
| Manual vasopressor delivery systemManual dosing system consisting: 1. Non-invasive intermittent blood pressure monitor that measured and recorded blood pressure at 1-minute intervals. 2. Attending anesthesiologist that noted the blood pressure readings and manually administered phenylephrine or ephedrine according to the algorithm. | Device | manual vasopressor delivery |
Primary outcome
Hypotension
Time frame: 1 day
Incidence of systolic blood pressure less than 80% of baseline systolic blood pressure
2 secondary outcomes
Hypertension
Time frame: 1 day
Nausea and vomiting
Time frame: 1 day
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Aug 2026.
- Background: PubMed 20173633Ngan Kee WD. Prevention of maternal hypotension after regional anaesthesia for caesarean section. Curr Opin Anaesthesiol. 2010 Jun;23(3):304-9. doi: 10.1097/ACO.0b013e328337ffc6.
- Background: PubMed 23020653Sia AT, Tan HS, Sng BL. Closed-loop double-vasopressor automated system to treat hypotension during spinal anaesthesia for caesarean section: a preliminary study. Anaesthesia. 2012 Dec;67(12):1348-55. doi: 10.1111/anae.12000. Epub 2012 Sep 28.
- Results publication: PubMed 24256483Sng BL, Tan HS, Sia AT. Closed-loop double-vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial. Anaesthesia. 2014 Jan;69(1):37-45. doi: 10.1111/anae.12460. Epub 2013 Nov 20.
- Individual participant dataSharing planned: No
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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. This study is not recruiting at the moment.
Ban Leong Sng, FANZCA principal investigator
KK Women's and Children's Hospital
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing Vasopressor automated delivery system, Phenylephrine and Ephedrine in people with Hypotension, run by KK Women's and Children's Hospital.
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 3 inclusion and 3 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: finished, as of the sponsor's last update on 6 Aug 2026. 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 combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hypotension (time frame: 1 day). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04025918, which also lists 3 linked publications.
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 6 Aug 2026.