Obesity, MorbidPhase 4NCT03781388

ED90 for Hyperbaric Bupivacaine in Super Obese Parturients

A Phase 4 study testing Bupivacaine in people with Obesity, Morbid and Spinal Anesthesia, run by Duke University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The aim of this study is to determine the ED90 of hyperbaric intrathecal bupivacaine for the super obese population undergoing cesarean section under a combined spinal epidural technique. Read more about this study

Who is it for?: Ages 18 to 45 years, women onlyHealthy volunteers can take part
Conditions the study is for: Obesity, Morbid, Spinal Anesthesia, Cesarean Delivery
What is being tested?: Bupivacaine
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 45 participants
Where: 1 siteUnited States
Study dates: 1 May 2019to 6 Dec 2022
Phase: Phase 4
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 45 years
Women only
Healthy volunteers accepted
Adult

Who may be able to join

American Society of Anesthesiology (ASA) class 2 and 3
English speaking
Gestational age > 36 weeks
Scheduled for cesarean delivery under combined spinal epidural anesthesia
18 years or older
BMI > 50 kg/m2

Who cannot join

History of past or current intravenous drug or chronic opioid abuse
Allergy or contraindication to any study medications
Intrapartum cesarean delivery under epidural anesthesia
Cesarean delivery under general anesthesia

Trial locations and contacts

1 site in 1 country.

United States1 site

Duke University Hospital
Durham, North Carolina, 27705

Other trials in United States

About this study

Official title: ED90 for Hyperbaric Bupivacaine in Spinal Anesthesia for Cesarean Delivery in Super Obese Parturients

The aim of this study is to determine the ED90 of hyperbaric intrathecal bupivacaine for the super obese population undergoing cesarean section under a combined spinal epidural technique.

Conditions: Obesity, Morbid, Spinal Anesthesia, Cesarean Delivery
Being tested: Bupivacaine
Keywords: Bupivacaine ED90, Cesarean Delivery, Obesity, Spinal Anesthesia
Medical subject headings: Obesity, Morbid, Obesity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

BupivacaineDrug
Determination of the dose will rely on the outcomes of the preceding 7 patients receiving the same dose, as the number of previous patients to consider is a function of the target dose. Among all patients who received a certain dose, a proportion of successful outcomes will be determined (P(d)); if P(d) <0.90, and at least one of the previous 7 patients who received the same dose had an unsatisfactory outcome, the next patient will receive a pre-determined increment of 0.75 mg of bupivacaine. Alternatively, if P(d) 0.90 and the previous 7 patients who received the same dose had successful outcomes, the next patient will receive a pre-determined decrement of 0.75mg of bupivacaine. Otherwise, the dose will remain the same.

Study groups in NCT03781388
Study group	Role	What they receive
Starting dose of Bupivacaine (9.75 mg)	Experimental	The starting dose of hyperbaric bupivacaine for the first patient in this study will be 9.75mg; the dose for the subsequent subject will be based on the response of the preceding subject as per the Narayana Rule, a modification of the biased-coin design (BCD) up-down sequential method (UDM). Receives: Drug: Bupivacaine
Subsequent dose	Experimental	Not described Receives: Drug: Bupivacaine

What is being measured

The primary outcome is the main question the study is designed to answer.

Number of Participants With Successful Blocks for Induction (Success Induction)
Bilateral T6 sensory level to pinprick
Measured: 10 minutes after intrathecal drug administration
Number of Participants With Successful Blocks for Operation (Success Operation)
Successful initial sensory level without requiring additional epidural anesthetic
Measured: during surgery up to 90 minutes after intrathecal injection
ED90 (90% Effective Dose) of Intrathecal Bupivacaine for Cesarean Delivery
Measured: 90 minutes

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

1 May 20196 Dec 2022

First posted19 Dec 2018
Study start1 May 2019
Primary completion6 Dec 2022
Study completion6 Dec 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Obesity, MorbidStudies of the same condition, open and under way.
More trials run by Duke UniversityThe sponsor's other registered studies.
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: Treatment
Allocation: Non-randomised
Intervention model: Sequential
Model description: The starting dose of hyperbaric bupivacaine for the first patient in this study will be 9mg; the dose for the subsequent subject will be based on the response of the preceding subject as per the Narayana Rule, a modification of the biased-coin design (BCD) up-down sequential method (UDM).
Masking: Triple blind
Who is masked: Participant, Care provider, Outcomes assessor
Enrolment: 45 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03781388
Sponsor's protocol ID: Pro00101530
Status last verified: Apr 2026
First submitted: 18 Dec 2018
Last updated: 17 Apr 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No

Publications

Tan HS, Fuller ME, Barney EZ, Diomede OI, Landreth RA, Pham T, Rubright SM, Ernst L, Habib AS. The 90% effective dose of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia in parturients with super obesity: an up-down sequential allocation study. Can J Anaesth. 2024 May;71(5):570-578. doi: 10.1007/s12630-024-02705-5. Epub 2024 Mar 4.
PubMed 38438681

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 17 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: ED90 for Hyperbaric Bupivacaine in Spinal Anesthesia for Cesarean Delivery in Super Obese Parturients
ClinicalTrials.gov ID: NCT03781388
Acronym / sponsor ID: Pro00101530
Conditions: Obesity, Morbid, Spinal Anesthesia, Cesarean Delivery
Keywords: Bupivacaine ED90, Cesarean Delivery, Obesity, Spinal Anesthesia
Phase: Phase 4
Study type: Interventional
Recruitment status: Completed
Enrolment: 45 participants (actual)
Lead sponsor: Duke UniversityUniversity, hospital or other
Study start: 1 May 2019 (actual)
Primary completion: 6 Dec 2022 (actual)
Study completion: 6 Dec 2022 (actual)
First posted: 19 Dec 2018 (actual)
Results: Posted 17 Apr 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The aim of this study is to determine the ED90 of hyperbaric intrathecal bupivacaine for the super obese population undergoing cesarean section under a combined spinal epidural technique.

Study design

Primary purpose: Treatment
Allocation: Non-randomised
Intervention model: Sequential
Masking: Triple blind (participant, care provider, outcomes assessor)
Number of arms: 2
Model description: The starting dose of hyperbaric bupivacaine for the first patient in this study will be 9mg; the dose for the subsequent subject will be based on the response of the preceding subject as per the Narayana Rule, a modification of the biased-coin design (BCD) up-down sequential method (UDM).

Arm	Type	Receives
Starting dose of Bupivacaine (9.75 mg)	Experimental	Drug: BupivacaineThe starting dose of hyperbaric bupivacaine for the first patient in this study will be 9.75mg; the dose for the subsequent subject will be based on the response of the preceding subject as per the Narayana Rule, a modification of the biased-coin design (BCD) up-down sequential method (UDM).
Subsequent dose	Experimental	Drug: Bupivacaine

Who may qualify

Ages: 18 to 45 years
Sex: Female only
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (6 listed)

American Society of Anesthesiology (ASA) class 2 and 3
English speaking
Gestational age > 36 weeks
Scheduled for cesarean delivery under combined spinal epidural anesthesia
18 years or older

Key exclusion criteria (4 listed)

History of past or current intravenous drug or chronic opioid abuse
Allergy or contraindication to any study medications
Intrapartum cesarean delivery under epidural anesthesia
Cesarean delivery under general anesthesia

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
BupivacaineDetermination of the dose will rely on the outcomes of the preceding 7 patients receiving the same dose, as the number of previous patients to consider is a function of the target dose. Among all patients who received a certain dose, a proportion of successful outcomes will be determined (P(d)); if P(d) <0.90, and at least one of the previous 7 patients who received the same dose had an unsatisfactory outcome, the next patient will receive a pre-determined increment of 0.75 mg of bupivacaine. Alternatively, if P(d) 0.90 and the previous 7 patients who received the same dose had successful outcomes, the next patient will receive a pre-determined decrement of 0.75mg of bupivacaine. Otherwise, the dose will remain the same.	Drug	Starting dose of Bupivacaine (9.75 mg), Subsequent dose

Primary outcome

Number of Participants With Successful Blocks for Induction (Success Induction)
Time frame: 10 minutes after intrathecal drug administration
Bilateral T6 sensory level to pinprick
Number of Participants With Successful Blocks for Operation (Success Operation)
Time frame: during surgery up to 90 minutes after intrathecal injection
Successful initial sensory level without requiring additional epidural anesthetic
ED90 (90% Effective Dose) of Intrathecal Bupivacaine for Cesarean Delivery
Time frame: 90 minutes

Results and safety

Results posted to the registry on 17 Apr 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Bupivacaine - 9.75 mg	1	1
Bupivacaine - 10.5 mg	3	3
Bupivacaine - 11.25 mg	27	27
Bupivacaine - 12 mg	11	11

Primary outcome: Number of Participants With Successful Blocks for Induction (Success Induction)

Time frame: 10 minutes after intrathecal drug administration. Count of participants. Unit: Participants

Measure	Bupivacaine - 9.75 mg n = 1	Bupivacaine - 10.5 mg n = 3	Bupivacaine - 11.25 mg n = 27	Bupivacaine - 12 mg n = 11
Value	1	3	27	11

Population analysed: All participants who received an optimized dose of Bupivacaine and completed the study.

Primary outcome: Number of Participants With Successful Blocks for Operation (Success Operation)

Time frame: during surgery up to 90 minutes after intrathecal injection. Count of participants. Unit: Participants

Measure	Bupivacaine - 9.75 mg n = 1	Bupivacaine - 10.5 mg n = 3	Bupivacaine - 11.25 mg n = 27	Bupivacaine - 12 mg n = 11
Value	0	2	21	11

Population analysed: All participants who received an optimized dose of Bupivacaine and completed the study.

Primary outcome: ED90 (90% Effective Dose) of Intrathecal Bupivacaine for Cesarean Delivery

Time frame: 90 minutes. Median (95% Confidence Interval). Unit: mg

Measure	Bupivacaine - Optimized Dose n = 42
Value	11.56 (11.16 to 11.99)

Population analysed: All participants who received an optimized dose of Bupivacaine and completed the study. It was necessary to combine the dosage groups to determine the ED90 of intrathecal bupivacaine for Cesarean delivery.

Adverse events

Time frame: 48 hours. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Bupivacaine - 9.75 mg	0 of 1 (0%)	0 of 1 (0%)	0 of 1
Bupivacaine - 10.5 mg	0 of 3 (0%)	0 of 3 (0%)	0 of 3
Bupivacaine - 11.25 mg	0 of 27 (0%)	0 of 27 (0%)	0 of 27
Bupivacaine - 12 mg	0 of 11 (0%)	0 of 11 (0%)	0 of 11

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 17 Apr 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 38438681Tan HS, Fuller ME, Barney EZ, Diomede OI, Landreth RA, Pham T, Rubright SM, Ernst L, Habib AS. The 90% effective dose of intrathecal hyperbaric bupivacaine for Cesarean delivery under combined spinal-epidural anesthesia in parturients with super obesity: an up-down sequential allocation study. Can J Anaesth. 2024 May;71(5):570-578. doi: 10.1007/s12630-024-02705-5. Epub 2024 Mar 4.
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.

Ashraf S Habib, MD principal investigator

Duke University

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Bupivacaine in people with Obesity, Morbid and Spinal Anesthesia, run by Duke University at 1 site in United States.

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 6 inclusion and 4 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 17 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

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?

Yes. Results are posted in the registry (first posted 17 Apr 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Number of Participants With Successful Blocks for Induction (Success Induction) (time frame: 10 minutes after intrathecal drug administration). The study lists 3 primary outcomes in all. 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 NCT03781388, which also lists 1 linked publication.

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 17 Apr 2026.