Optimal Single Dose Intrathecal Dexmedetomidine for Postoperative Analgesia

Mansoura University15 enrolled

Overview

Spinal anesthesia is a commonly used technique for lower limb surgeries offering better quality of postoperative analgesia, lower incidence of side effects, and shorter post-anesthesia care unit stay than general anesthesia. However, the relatively short duration of action of the currently available local anesthetics (LAs) make these advantages short-lived. The risk for local anesthetic toxicity (LAST) increases with the trials to use higher concentrations or volumes of intrathecal local anesthetics to increase the duration of analgesia. Dexmedetomidine has the potential to prolong the duration of perioperative analgesia without the need for using high doses of local anesthetics and hence with decreasing the potential risk of local anesthetic, but the increased likelihood adverse effects such as short term bradycardia and prolonged duration of motor block may offset these benefits.

The aim of this study is to determine the optimal single-dose of intrathecal dexmedetomidine that prolongs the analgesic duration with the least possible side effects. With the patients in the sitting position and the use of complete aseptic technique, 25G Whitacre spinal needles will be introduced through L2-L4 interspaces and after observing free flow of the CSF, a 3ml volume including bupivacaine 12.5mg in conjunction with dexmedetomidine (3 µg) will be injected in the first case, then the patient will be turned supine. The dose of intrathecal DEX given to the next patient will be guided by modified Dixon's up-and-down method using 1.5 mg as a step size, which assumed to be of clinical importance.

Study Type

INTERVENTIONAL

Allocation

Purpose

PREVENTION

Masking

NONE

Enrollment

Conditions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * American Society of Anesthesiologists physical class I to II. * Patients scheduled for elective lower limb surgeries. Exclusion Criteria: * Morbid obese patients. * Severe or uncompensated cardiovascular disease. * Significant renal disease. * Significant hepatic disease. * Pregnancy. * Lactating . * Heart block. * Bradyarrhythmias. * Receiving adrenergic receptor antagonist medications. * Receiving calcium channel blockers. * Patients with pacemakers. * Patients with implanted cardioverter defibrillator. * Allergy to the study medications. * Psychological disease. * Neurological disorders. * Communication barrier. * Mental disorders. * Epilepsy. * Drug or alcohol abuse. * Contraindications to spinal anaesthesia. * Receiving opioid analgesic medications within 24 h before the operation.

Outcomes

Primary Outcomes

Duration of analgesia

The duration of analgesia, defined as the time from administering of intrathecal study solution (T0) to the time for the first rescue analgesic request

Time frame: For 13 hours after surgery

Secondary Outcomes

Postoperative pain score

Using visual analog scale

Time frame: For 24 hours after surgery

Onset of sensory blockade

Onset of sensory block time defined as the time elapsed from T0 to achieve the adequate sensory level for the planned surgery.

Time frame: For 1 hour after initiaion of spinal anesthesia

Onset of motor blockade

Onset of motor block time defined as the time elapsed from T0 to achieve the Bromage scale of 3

Time frame: For 2 hours after initiation of spinal anesthesia

Highest dermatome level of sensory blockade

The highest dermatome level of sensory blockade and the time needed to achieve this level from the time of injection as well as time to two segment sensory regression after T0 will be recorded

Time frame: For 4 hours after initiation of spinal anesthesia

Time to motor regression

Time to motor regression to a Bromage scale of 2

Time frame: For 6 hours after initiation of spinal anesthesia

Sedation score

Sedation scores will be assessed using a sedation scale (awake and alert= 0; quietly awake= 1; asleep but easily roused= 2; deep sleep= 3).

Time frame: For 24 hours after initiation of spinal anesthesia

Postoperative nausea and vomiting

The degree of nausea and vomiting. Nausea will be measured using a numerical rating system (none= 0; mild= 1; moderate= 2; severe= 3)

Time frame: For 24 hours after initiation of spinal anesthesia

Cumulative tramadol consumption

Time frame: For 24 hours after surgery

Intraoperative bradycardia

Time frame: For 4 hours after initiation of spinal anesthesia

Intraoperative use of ephedrine

Time frame: For 4 hours after initiation of spinal anesthesia

Intraoperative use of atropine

Time frame: For 4 hours after initiation of spinal anesthesia

Intraoperative use of supplemental fentanyl

Time frame: For 4 hours after initiation of spinal anesthesia

Intraoperative use of midazolam

Time frame: For 4 hours after initiation of spinal anesthesia

Optimal Single Dose Intrathecal Dexmedetomidine for Postoperative Analgesia

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts