The Analgesic Efficacy of Dexmedetomidine Versus Fentanyl as an Adjuvant to Bupivacaine in Ultrasound Guided Peripheral Nerve Blocks as a Solo Anesthetic Technique in High Risk Patients Undergoing Unilateral Above Knee Amputation .

The Analgesic Efficacy of Dexmedetomidine Versus Fentanyl as an Adjuvant to Bupivacaine in Ultrasound Guided Peripheral Nerve Blocks as a Solo Anesthetic Technique in High Risk Patients Undergoing Unilateral Above Knee Amputation : A Randomized Double Blinded Study

The aim of this study is to compare the analgesic efficacy and safety of dexmedetomidine versus fentanyl as adjuvants to bupivacaine in ultrasound-guided combined supra-inguinal fascia iliaca and proximal sciatic nerve blocks used as a solo anesthetic technique in high-risk patients undergoing unilateral above knee amputation.

Study Overview

• Status: Not yet recruiting
• Conditions: Above Knee Amputation; Analgesia Assessment; Fentanyl vs Dexmedetomidine
• Intervention / Treatment: Drug: Dexmedetomidine; Drug: Fentanyl (as Citrate)

Detailed Description

Above knee amputation (AKA) is a major surgical procedure often performed for non salvageable lower limb such as severe trauma , peripheral arterial diseases or infection . however it carries significant risks and complications . The overall mortality and morbidity rates are also substantial, with one-year mortality rates reported as high as 40-50% in some populations.

Anesthesia in above-knee amputation procedures poses its own set of risks, especially in patients with advanced age or multiple comorbidities. General anesthesia (GA) may be associated with postoperative pulmonary complications, prolonged recovery, and hemodynamic instability. On the other hand, spinal anesthesia offers benefits such as reduced thromboembolic events and faster postoperative recovery, but carries risks including hypotension, spinal hematoma, and post-dural puncture headache .

Peripheral nerve blocks (PNBs) as a solo anesthetic technique offer significant hemodynamic advantages compared to neuroaxial and general anesthesia , this makes them especially beneficial for patients with cardiovascular compromise or bad chest conditions.

Effective pain management is crucial to improve patient outcomes, promoting early mobilization, and reducing the risks of complications such as deep vein thrombosis or chronic pain syndromes .

Patients with multiple risk factors such as cardiovascular disease, respiratory problems have a higher risk of complications when general or spinal anesthesia is used. In such cases ultrasound guided regional anesthesia becomes an excellent alternative .. So The combination of supra-inguinal fascia iliaca block and sciatic nerve block has emerged as a promising regional anesthetic approach for above-knee amputation, particularly in patients who are poor candidates for general or neuraxial anesthesia. This technique provides comprehensive coverage of the femoral, lateral femoral cutaneous, obturator, and sciatic nerves, allowing for adequate surgical anesthesia without the need for airway manipulation. It offers advantages such as hemodynamic stability, reduced opioid consumption, and fewer respiratory complications, making it especially beneficial in elderly and high-risk patients. When performed under ultrasound guidance, this approach enhances block accuracy and safety, positioning it as a viable solo anesthetic technique for AKA. The technique allows for adequate surgical anesthesia with preserved hemodynamic stability and minimal systemic drug exposure. Clinical reports have demonstrated its success in providing effective anesthesia with high patient and surgeon satisfaction, especially when performed under ultrasound guidance.

Dexmedetomidine is a selective alpha 2- adrenoceptor agonist possessing sedative, anxiolytic, and analgesic properties which could improve the quality of the block while reducing opioid consumption and their associated side effects. It reduces pain after knee arthroscopy mainly by peripheral and central mechanisms through stimulation of presynaptic α2- adrenoceptors .

On the other hand, fentanyl, an opioid, is commonly used to provide potent analgesia in regional blocks but carries risks of respiratory depression and other opioid-related complications . There over, this study aims to compare dexmedetomidine versus fentanyl as adjuvant to bupivacaine in ultrasound-guided supra inguinal fascia iliaca and sciatic nerve block for anesthetic management for unilateral above knee amputation in high risk patients as a solo anesthetic technique ..

While several studies have evaluated the efficacy of peripheral nerve blocks in lower limb surgeries, few have investigated their use as a sole anesthetic technique specifically in high-risk patients undergoing above-knee amputation (AKA). Moreover, the comparative role of different adjuvants such as dexmedetomidine versus fentanyl in this setting remains underexplored. There is a clear need for well-designed randomized trials to guide anesthetic decision-making in this fragile patient population.

• Study Type: Interventional
• Enrollment (Estimated): 64
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: paula atef gobran kamil, MBBCH, M.SC; Phone Number: 0201276604277; Email: paula.atef.gobran.1995@gmail.com
• Study Contact Backup: Name: tamer ibrahem rouk, MD; Phone Number: 01006216826; Email: tamer_rouk@yahoo.com

Study Locations

• Egypt
  • Cairo, Egypt
    • KasrELainiH

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• - Age ≥18 years
• Both sexes
• ASA III-IV
• Documented cardiac disease (e.g., EF < 40%, NYHA II or higher)
• Documented pulmonary disease (e.g., COPD with FEV1 < 60%)
• Scheduled for above-knee amputations

Exclusion Criteria:

• Neurological or intellectual disability
• Drug abuse
• Allergy to study drugs
• Pregnancy
• Contraindications to regional anesthesia (e.g., coagulopathy, local infection)
• Significant renal or hepatic impairment( plts <75000 or INR >1.5)
• Current anticoagulant therapy
• severe haemodynamically unstability at the time of block performance, defined as map > 65 mmhg but achieved by high-dose vasopressors (e.g., norepinephrine ≥ 0.1 mcg/kg/min) after fluid ressuscitation .

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: dexmedetomidine group; patients receiving peripheral nerve blocks for above-knee amputation with dexmedetomidine added to the local anesthetic solution	Drug: Dexmedetomidine; Dexmedetomidine added as an adjuvant to the local anesthetic solution during peripheral nerve block for above-knee amputation surgery.
Active Comparator: fentanyl group; patients receiving peripheral nerve blocks for above-knee amputation with fentanyl added to the local anesthetic solution	Drug: Fentanyl (as Citrate); Fentanyl added as an adjuvant to the local anesthetic solution during peripheral nerve block for above-knee amputation surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to the first request for the rescue analgesia	the first time the patient needs analgesia postoperative	24 hours postoperative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total morphine consumption postoperative.	the total dose of morphine given to the patient in the 24 hours postoperative	24 hours postoperative
Intraoperative Pain score (VAS).	assessment of pain intensity using the visual analogue score (VAS) ranging from 0 to 10 where 0 indicates no pain and 10 indicate the worst pain imaginable , higher scores indicate worse pain	from block performance till 24 hours postopertaive
Patient satisfaction	by a scale from 1 to 5 where is 1 is very dissatisfied and 5 is very satisfied higher scores indicate greater patient satisfaction	24 hours postoperative
intraoperative heart rate	measurments of intraoperative HR every 5 mins	intraoperative
Complications ( nausea - vomiting - bradycardia - hypotension .... )	Any complication that happened intra or post operative	24 hours post operative
intraoperative mean arterial blood pressure	measurment of MAP every 5 mins	intraoperative

Collaborators and Investigators

• Sponsor: Kasr El Aini Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: May 28, 2026
• First Submitted That Met QC Criteria: June 6, 2026
• First Posted (Actual): June 10, 2026

Study Record Updates

• Last Update Posted (Actual): June 10, 2026
• Last Update Submitted That Met QC Criteria: June 6, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: dexmedetomidine vs fentanyl PNBs AKA
• Additional Relevant MeSH Terms: Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Azoles; Imidazoles; Piperidines; Dexmedetomidine; Fentanyl
• Other Study ID Numbers: MD-247-2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No