The Prolonging Effect of Dexmedetomidine on Spinal Anesthesia Through Different Routes if Administrations

January 7, 2025 updated by: Hebah Musalem, King Abdulaziz Medical City

The Prolonged Effects of Spinal Dexmedetomidine Versus Intravenous Dexmedetomidine on Spinal Anesthesia With Isobaric Bupivacaine: A Comparative Study

This prospective, double-blinded, randomized clinical trial aims to examine the effects of combining isobaric bupivacaine with dexmedetomidine administered intrathecally (IT), compared to the combination of isobaric bupivacaine administered intrathecally and dexmedetomidine administered intravenously (IV), on spinal anesthesia prolongation time in minutes, time of regression from Bromage score 3 to 0.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Dexmedetomidine, an α2-adrenergic agonist, is commonly used in anesthetic practice for various applications, including premedication, as an adjunct to general anesthesia, sole anesthetic agent, and sedation in intensive care settings. Its effects include enhancing the efficacy of other anesthetic drugs, inducing perioperative sympatholysis, and lowering blood pressure by stimulating central α2 and imidazoline receptors.

Spinal anesthesia is a type of regional anesthesia that involves administering a local anesthetic directly into the cerebrospinal fluid surrounding the spinal cord and nerve roots. It is primarily used for procedures below the umbilicus, such as orthopedic surgeries involving joints and bones.

The 0.5% isobaric formulation of bupivacaine is characterized by a slower onset compared to hyperbaric formulations but provides a longer duration of both sensory and motor blockade. Achieving successful spinal anesthesia (SA) depends on selecting the appropriate dose of isobaric bupivacaine. Administering an excessive dose can lead to high spinal anesthesia, while an insufficient dose may result in inadequate cephalad spread.

A retrospective observational study involving 1,079 adult patients who received spinal anesthesia with 0.5% isobaric bupivacaine between 2018 and 2021 investigated the relationship between the bupivacaine dose and block height. The study concluded that for patients younger than 60 years, doses of 15-17 mg (3.0-3.4 mL) were optimal, while doses of 10.5-16 mg (2.1-3.2 mL) were suitable for patients aged 60 years or older. These doses achieved a T5-T10

Over the years, various agents have been combined with local anesthetics (LA) to extend the duration of action in both spinal anesthesia via intrathecal (IT) administration and peripheral nerve blocks (PNB), achieving varying levels of success. Dexmedetomidine, a highly selective α2-adrenergic receptor agonist, offers several advantages as an adjuvant. These include its sedative and analgesic effects (acting at both spinal and supraspinal levels), anti-anxiety properties, inhibition of sympathetic activity, mild respiratory depression, and hemodynamic stability.

Intrathecal α2-adrenergic receptor agonists, including dexmedetomidine, have been shown to exhibit antinociceptive properties for both somatic and visceral pain. Studies using small doses of intrathecal dexmedetomidine (e.g., 3 µg) in combination with bupivacaine for spinal anesthesia demonstrated faster motor block onset, prolonged motor as well as sensory block durations, and preserved hemodynamic stability without causing significant sedation.

The dose-dependent effects of dexmedetomidine have been extensively studied. Randomized clinical trials (RCTs) comparing doses (e.g., 3 µg vs. 5 µg with isobaric Ropivacaine and 5 µg vs. 10 µg with isobaric bupivacaine) consistently concluded that higher doses of dexmedetomidine enhanced the onset and prolonged the duration of sensory and motor block when used as an adjuvant in spinal anesthesia.

Intravenous dexmedetomidine has also been shown to prolong the sensory and motor block of bupivacaine through its supraspinal anesthetic and analgesic actions. However, its intravenous administration is associated with a dose-dependent risk of bradycardia. A systematic review and meta-analysis conducted in 2013, which included 364 patients from seven randomized controlled trials of intermediate to high quality, examined the effects of intravenous dexmedetomidine on spinal anesthesia duration. The analysis found that motor block duration increased by approximately 21% (P < 0.00001). Importantly, no significant differences in the incidence of hypotension or postoperative sedation were observed between the dexmedetomidine and placebo groups, and none of the patients experienced respiratory depression.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
75

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

  • Name: Mohammad Al Harbi, Anesthesia Consultant,
  • Phone Number: 00966508818000
  • Email: HarbiMK@mngha.med.sa

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Male and female patients in adult age group more than 18 years old
  • ASA classification I, II, and III.
  • Orthopedic surgery, including total hip replacement (THR) and total knee replacement (TKR).
  • No history of Obstructive sleep apnea

Exclusion Criteria:

  • Patient below 18 years old of both genders.
  • ASA classification of IV and more.
  • Patients with a height of less than 150 cm.
  • Patients on alpha-two antagonist ACE inhibitors and CCB.
  • Patient received intrathecal morphine, intravascular dexamethasone, or Midazolam
  • Patient who can't tolerate fluid challenge. Example: ESRD, HF…etc.
  • Any contraindication for neuraxial procedure. Examples: coagulopathy, severe AS, sepsis…etc.
  • Psychiatric patients.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: Controlled

Group A: Control group. Receiving plain isobaric "Bupivacaine 0.5%", "Bucaine®," (2.4 ml) + 0.15 ml of normal saline (placebo), total volume = 2.4 ml.

Through IV, 15 ml of normal saline ( placebo) will be received over 30 mins.
Experimental: Dexmedetomidine HCL IT

Group B: RECEIVING IT "Dexmedetomidine HCL," "Demexa®," Through IT, receiving plain isobaric "Bupivacaine 0.5%", "Bucaine®," (2.4 ml) +3mcg of "Dexmedetomidine HCL, (0.15 ml), total volume = 2.4 ml.

Through IV, 15 ml of normal saline ( placebo) will be received over 30 mins.
Drug: Interventional group#1

The intrathecal mixture of spinal anesthesia: 12 mg of isobaric "Bupivacaine 0.5%", "Bucaine®," (2.4 ml) + 20 mcg of "Fentanyl," "Martindale pharma Fentanyl®," 50mcg/ml (0.4ml) + 3 mcg of "Dexmedetomidine HCL," "Demexa®," 4mcg/ml (0.75 ml) total volume = 3.55 ml.

The Bromage score will be assessed by the anesthesiologist every 5 minutes after positioning the patient supine until the first incision. The Bromage score is a clinical scale used to determine motor block during regional anesthesia by evaluating lower limb movement: Grade 0: Full movement of hips, knees, and ankles (no block). Grade 1: Unable to lift the leg but can move knees and ankles (partial block). Grade 2: Unable to bend the knee but can move ankles (near-complete block). Grade 3: No movement in hips, knees, or ankles (complete block). Dermatomal coverage will be assessed simultaneously till it reaches the L1-L2 level. Also, The Ramsay Sedation Scale (RSS) will be used to evaluate the sedation depth, if any.

Other Names:
  • Intrathecal "Dexmedetomidine HCL," "Demexa®,"
Experimental: Dexmedetomidine HCL IV

Group C: RECEIVING IV "Dexmedetomidine HCL," "Demexa®,"

Through IT, receiving plain isobaric "Bupivacaine 0.5%", "Bucaine®," (2.4 ml) + Placebo of normal saline (0.15 ml), total volume = 2.4 ml.

Through IV, 0.5 mcg/kg of "Dexmedetomidine HCL" is prepared in a concentration of 2 mcg/ml ( maximum of 15 ml, 30 mcg) over 30 mins.
Drug: Interventional group#2

The intrathecal mixture of spinal anesthesia: 12 mg of isobaric "Bupivacaine 0.5%", "Bucaine®," (2.4 ml) + 20 mcg of "Fentanyl," "Martindale pharma Fentanyl®," 50mcg/ml (0.4ml) total volume = 2.8 ml.

The intravascular mixture consists of 0.5 mcg/kg of "Dexmedetomidine HCL," "Demexa®," and a maximum of 30 mcg diluted to 4 mcg/ml. According to body weight, the total volume is 7.5 ml or less and given using a syringe pump over 30 minutes. The anesthesiologist will start the infusion once the patient is positioned supine post-spinal anesthesia and has stable hemodynamics. The Bromage score will be assessed by the anesthesiologist every 5 minutes after positioning the patient supine until the first incision reaches grade 3: No movement in hips, knees, or ankles (complete block). The anesthesiologist will assess dermatomal coverage until it reaches the L1-L2 and calculate the Ramsay Sedation Scale (RSS) of the depth of sedation aiming for level 2: Patient is cooperative, oriented, and calm

Other Names:
  • Intravascular "Dexmedetomidine HCL," "Demexa®,"

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Regression time of Bromage score from 3 to 0
Time Frame: Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.

This double-blind study will include 75 participants divided equally into three groups: A, B, and C. The IT medication injection / IV infusion start time is considered time zero. The Bromage score will be assessed at the motor block's onset, representing a Bromage score of 3, recorded in minutes. The record of the time to reach Bromage 3 represents the spinal anesthesia's onset time.

The Bromage scale is a clinical scale used to determine motor block during regional anesthesia. It evaluates lower limb movement, grade 0, no motor block, to grade 3, complete motor block.

Bromage 0; the patient can move hip, knee, and ankle. No motor block Bromage 1: the patient cannot move the hip but can move the knee and ankle. Partial block Bromage 2: the patient cannot move the hip and knee but can move the ankle. partial block Bromage 3: the patient cannot move the hip, knee, and ankle. Complete motor block A Bronage score regression to 0 during a PACU stay will represent a spinal anesthesia offset
Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Hypotension, bradycardia and desaturation with dermatome coverage <T4 or >T4, checked by Ice test.
Time Frame: Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.

Investigators will monitor the side effects associated with each route of administration through close hemodynamic monitoring for heart rate (HR) in Beat per minute (BPM), Oxygen saturation (SpO2) presented in percentage (%), and blood pressure (BP) presented in millimeter mercury (mmHg), aiming for HR above 50 bpm, oxygen saturation >94%, and BP 15% around the patient's baseline blood pressure. All data will be recorded on the data collection sheet.

To differentiate high spinal-related hemodynamic instability ( dermatome >4) versus dexmedetomidine (dermatome less than T4), the sensory block level will be checked with an ICE test, where the dermatomal coverage will be checked along the midaxillary line with an ice bag, as nipple line is representing dermatome T4.

HR limits: 60 to 100 bpm. Lower bradycardia, higher tachycardia. BP limits, systolic 100 - 120 mmHg. Lower hypotension, higher hypertension. SpO2 limit: 100-94%, 100% standard, <94% desaturation.
Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.
Sedation score using Ramsay sedation score, aiming for score 2; calm and oriented.
Time Frame: Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.

The Investigators will check the Ramsay Sedation Scale (RSS) throughout the procedure. It is used to evaluate the depth of sedation in patients and divided into six scales (from scale no.1, anxious to scale no.6, no response), aiming for scale no.2: cooperative, oriented, and calm. All data will be recorded on the data collection sheet every 10 minutes for the first hour of "Dexmedetomidine" administration and 45 minutes in PACU.

The scale is getting worse while the moving up in the scale Score 1: anxious, agitated, and restless. Score 2: Cooperative-oriented and tranquil. Score 3: The patient responds to commands only. Score 4: The patient responds to a brisk response to a light glabellar tap or loud auditory stimulation.

Score 5: Patient sluggishly responds to a light glabellar tap or loud auditory stimulus.

Score 6: The patient exhibits no response.
Patients' recruitment and participation in the study will be over 3-4 month, as the load of lower limb surgery at KAMC is high. Subjects' participation will be throughout the surgery time and 45 mins later in PACU if there was not a reason for delay.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
King Abdulaziz Medical City

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

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Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 15, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 2, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 7, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 25, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 25, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 7, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ICTR24/001/11

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data interpretation, analysis, and results

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Conditions

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