D-FAB-POUR Trial: Dexmedetomidine vs Fentanyl as Adjuvants to Bupivacaine on Postoperative Urinary Retention

NCT07117565 | Not Yet Recruiting Phase 4

• 1 other identifier: D-FAB-POUR Trial
• Study Type: interventional
• Target: 190
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to compare two medications, dexmedetomidine and fentanyl, when used alongside a commonly used spinal anesthetic called bupivacaine in patients undergoing lower limb surgery. The main focus of the study is to see which combination causes fewer problems with urination after surgery - a condition known as postoperative urinary retention (POUR). POUR can lead to discomfort, delayed recovery, and a need for catheterization. Dexmedetomidine is a newer drug that may help reduce this problem compared to fentanyl, which is more commonly used but may increase the risk of urinary retention. This trial will help determine which medication combination provides better pain relief while reducing urinary side effects. The study is being conducted as a randomized, double-blind trial at a hospital in Nepal and will include 190 adult patients. \-

Conditions

Spinal Anesthesia; Postoperative Complications; Dexmedetomidine; Fentanyl; Anesthesia, Spinal; Bupivacaine; POUR; Orthopedic Surgery; Urinary Retention Postoperative

Keywords

Postoperative urinary retention; Spinal anesthesia; Intrathecal adjuvants; Dexmedetomidine; Fentanyl; Perioperative complications

Outcome Measures

Primary Outcomes (1)

• Incidence of Postoperative Urinary Retention (POUR) at the 3rd Postoperative Hour

  The primary outcome is the number of participants who are unable to void urine at the 3rd postoperative hour with a urinary bladder (UB) volume of ≥600 mL, confirmed by bladder ultrasound. Participants meeting this criterion will be considered to have postoperative urinary retention and will undergo in-out catheterization.

  3 hours after spinal anesthesia

Secondary Outcomes (1)

• Requirement of Urinary Catheterization at 6th Postoperative Hour

  6 hours after spinal anesthesia

Study Arms (2)

Arm 1: Dexmedetomidine Group (Group BD)

EXPERIMENTAL

Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 10 mcg (0.5 mL) of dexmedetomidine intrathecally. The total injected volume will be 3.5 mL.

Drug: Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine

Arm 2: Fentanyl Group (Group BF)

ACTIVE COMPARATOR

Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 25 mcg (0.5 mL) of fentanyl intrathecally. The total injected volume will be 3.5 mL.

Drug: Intervention 2: Intrathecal Fentanyl with Bupivacaine

Interventions

Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine DRUG

Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine Detailed Description: This intervention consists of a single intrathecal injection of 10 micrograms of dexmedetomidine combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anaesthesia for lower limb surgery. The total volume administered is 3.5 mL. Dexmedetomidine is an alpha-2 non-opioid adjuvant used as a spinal adjuvant for enhancing analgesia

Arm 1: Dexmedetomidine Group (Group BD)

Intervention 2: Intrathecal Fentanyl with Bupivacaine DRUG

This intervention consists of a single intrathecal injection of 25 micrograms of fentanyl combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anesthesia for lower limb surgery. The total volume administered is 3.5 mL. Fentanyl is a lipophilic opioid commonly used as a spinal adjuvant for enhancing analgesia. This arm is being compared with dexmedetomidine to evaluate differences in POUR incidence, analgesic effectiveness, and side effect profiles.

Arm 2: Fentanyl Group (Group BF)

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Adults aged 18 to 60 years
• Scheduled for elective lower limb surgery under spinal anesthesia
• Classified as American Society of Anesthesiologists (ASA) physical status II or III
• Minimum height of 150 cm (to ensure uniform drug volume)
• Able to understand the study procedures and provide written informed consent (in English or Nepali)

You may not qualify if:

• Contraindications to spinal anesthesia (e.g., coagulopathy, infection at injection site, hemodynamic instability)
• Known allergy or hypersensitivity to bupivacaine, fentanyl, or dexmedetomidine
• Chronic pain conditions or long-term opioid use
• Neurological, Cardiac, Renal, or uncontrolled diabetic conditions
• Current treatment for prostatic pathology or use of alpha-2 blockers
• Presence of a Foley's catheter preoperatively
• Estimated surgical duration: \>2.5 hours
• Inability or unwillingness to provide informed consent

Sponsors & Collaborators

• Tribhuvan University Teaching Hospital, Institute Of Medicine.: lead

Study Sites (1)

Om Sai Pathibhara Hospital

Bhadrapur, Koshi, 57200, Nepal

Location

MeSH Terms

Conditions

Postoperative Complications

Interventions

Bupivacaine

Condition Hierarchy (Ancestors)

Pathologic Processes; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Anilides; Amides; Organic Chemicals; Aniline Compounds; Amines

Central Study Contacts

Sujan Dhakal, MBBS,MD

CONTACT

+9779851325896; szndkl44@gmail.com

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Masking Details: In this double-blind study, both the participants and the care providers (anesthesiologists) will be blinded to group allocation. The study drugs will be prepared in identical syringes by an independent assistant who is not involved in patient care or outcome assessment. Outcome assessors responsible for measuring postoperative urinary retention and other clinical parameters will also be masked. However, the data analyst will not be blinded to group assignments during statistical analysis, as unblinded data will be required for appropriate group comparisons.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: This is a parallel assignment interventional study in which participants are randomly assigned to one of two groups in a 1:1 ratio. One group receives intrathecal dexmedetomidine as an adjuvant to bupivacaine, and the other group receives intrathecal fentanyl with bupivacaine. Each participant receives only one of the study interventions throughout the trial, and no crossover occurs between groups. The study follows a prospective, double-blind, randomized controlled trial design, ensuring both the participants and investigators are blinded to group allocation.

Study Record Dates

• First Submitted: June 30, 2025
• First Posted: August 12, 2025
• Study Start: September 15, 2025
• Primary Completion (Estimated): September 14, 2026
• Study Completion (Estimated): November 25, 2026
• Last Updated: August 12, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, CSR
• Time Frame: 6 months after publication of the primary study results in a peer-reviewed journal.
• Access Criteria: Who will have access: Qualified researchers, academic collaborators, and clinicians involved in similar fields of study may request access to the de-identified individual participant data (IPD). What will be accessible: De-identified datasets related to primary and secondary outcomes - including incidence of postoperative urinary retention (POUR), hemodynamic data, sedation scores, rescue analgesic use, and adverse events. Supporting documents such as the study protocol, statistical analysis plan, and case report forms (CRFs) may also be shared upon request. How to access: Interested researchers must submit a formal written request to the principal investigator (Dr. Sujan Dhakal, szndkl44@gmail.com) explaining the purpose and scope of the intended data use. Requests will be reviewed by the study team and ethics oversight body. Upon approval, access will be granted through a secure data-sharing agreement, ensuring compliance with confidentiality and ethical standards.

Locations

NE (1)