Adjuncts for Adductor Block: Dexamethasone,Dexmedetomidine, or Combination to Reduce Pain

Women's College Hospital3 enrolled

Overview

The aim of this multi-centered study is to evaluate the effects of two distinct Adductor Canal Block (ACB) adjuncts, dexamethasone and dexmedetomidine, and their combination, on postoperative analgesia in patients undergoing Anterior Cruciate Ligament (ACL) Repair.

Anterior cruciate ligament repair (ACLR) is a surgical procedure of the knee associated with moderate to severe postoperative pain lasting beyond 24 hours following surgery. Provision of adequate postoperative analgesia is a prerequisite for performing this procedure on outpatient basis. By virtue of their analgesic effects, peripheral nerve blocks (PNBs), such as adductor canal block (ACB), have thus become part of the care standard for this surgical procedure. Though ACB provides effective pain relief, the duration of analgesia associated with this block is limited to eight hours postoperatively. As a result, patients having outpatient ACLR may experience severe pain following discharge, require additional opioid analgesics to control their pain, and even visit the emergency department for acute pain management. Consequently, perioperative care for the young outpatient population undergoing this procedure is an area where improvement is needed. Mixing adjuncts with local anesthetics can prolong the duration of analgesia of PNBs; both dexmedetomidine and dexamethasone have been shown to effectively extend the duration of PNB analgesia by 60% and 80% hours, respectively. The use of dexamethasone is wide spread, and dexmedetomidine is progressively gaining popularity. At Toronto Western Hospital, the use of adjuncts is left to the discretion of the anesthesiologists administering PNB; and dexamethasone is occasionally used to prolong block duration. The alternative approach to prolonging block duration is using ambulatory ACB catheters, but this is an expensive option that is applicable to select patients, and it is not available at the TWH. Importantly, these adjuncts seem to exert their effect through independent mechanisms; thus there may be an advantage to combining adjuncts together. Further prolongation of the duration of analgesia is desirable, as the prolongation of block duration associated with each of these two adjuncts, alone, falls short of the duration of worst postoperative pain following ACLR. Consequently, the investigators aimed to explore whether the combination of these two adjuncts offers an incremental benefit over either of them alone, by examining their potential additive or synergistic effect. This randomized controlled trial compares the effect of using perineural dexamethasone, dexmedetomidine, and their combination to Control on the duration of postoperative analgesia in patients having ambulatory ACLR with ACB.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

OTHER

Masking

DOUBLE

Enrollment

Conditions

ACL Injury

Interventions

Dexamethasone 4mgDRUG

To guarantee rapid onset as well as effective postoperative analgesia, a 20 mL volume of local anesthetic has been selected for performing the ACB. The block solution will be a 20 ml volume for all groups, prepared by mixing 18 ml of ropivacaine 0.5% mixed with an additional 2 ml prepared according to the randomization.

DexmedetomidineDRUG

SalineOTHER

Control/Placebo intervention

Eligibility

Sex: ALLMin age: 18 YearsMax age: 50 Years

Medical Language ↔ Plain English

Inclusion Criteria: * English Speaking * ASA 1-3 patients * BMI \<40 Exclusion Criteria: * Refusal or inability to provide informed consent * Any contraindication to regional anesthesia including coagulopathy or bleeding diathesis, allergy to local anesthetics, infection, nerve injury or malignancy at the site of the block * History of alcohol/drug dependence * History of long term opioid intake or chronic pain disorder * History of preexisting neuropathy in the operative leg * History of significant psychiatric conditions that may affect patient assessment * Inability to understand the informed consent and demands of the study * Allergy to any of the components of the multimodal analgesic regimen * Revision of ACL repair * Diabetes * Significant bradycardia (baseline heart rate ≤ 40 beats per minute)

Locations (1)

Women's College Hospital

Toronto, Ontario, Canada

Outcomes

Primary Outcomes

Oral opioid consumption

Cumulative 24 hour oral morphine equivalent consumption

Time frame: time of the block to 24 hours after

Secondary Outcomes

Intra-operative opioid consumption

Cumulative intra-operative opioid consumption in morphine equivalent

Time frame: Duration of surgery: From start of surgery (defined as anesthesia start) to end of surgery (defined as anesthesia end)

PACU opioid consumption

Cumulative oral morphine equivalent consumption during time stayed in PACU

Time frame: From time of arrival (hh:mm) in PACU to time of PACU discharge (hh:mm) assessed up to 24 hours

Time to first analgesic request in PACU

The time (hh:mm) first pain medication given in PACU

Time frame: From time of arrival in PACU (hh:mm) up to time of PACU discharge (hh:mm) assessed in minutes up to 24 hours ((e.g. patient arrives in PACU 12:00 then patient is given first pain medication in PACU at 12:30; Time to first analgesic request = 30 min)

Time to PACU discharge

how fast patient recovered and discharged from PACU (measured in minutes)

Time frame: From time of arrival (hh:mm) in PACU to time discharged (hh:mm) from PACU assessed in minutes (e.g. patient arrives in PACU 12:00 then patient discharged from PACU 12:30; Time to PACU discharge = 30 min)

Visual Analogue Scale-Pain scores - minimum score = 0 and maximum score = 10

pain scores at 0, 2, 4, 6, 12, 24, 36, and 48 hours postoperatively

Time frame: discharge from hospital to 2 days after surgery

Data from ClinicalTrials.gov

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