The transversus abdominis plane (TAP) block is most often used to provide surgical anesthesia
for minor, superficial procedures on the lower abdominal wall, or postoperative analgesia for
procedures below the umbilicus providing anesthesia to the ipsilateral lower abdomen below
the umbilicus.
In a recent meta-analysis, the TAP block was shown to reduce the need for postoperative
opioid use, increase the time to the first request for further analgesia, and provide more
effective pain relief, while decreasing opioid-related side effects such as sedation and
postoperative nausea and vomiting. The provision of effective postoperative analgesia is of
key importance to facilitate early ambulation and prevention of postoperative morbidity. The
analgesic regimen needs to meet the goals of providing safe, effective analgesia, with
minimal side effects. Many additives to local anesthetics used to prolong the duration of
analgesia for peripheral nerve blocks have been studied as dexamethasone, dexmedetomidine
Dexmedetomidine is a lipophilic α2 agonist derivative with a higher affinity for α2-receptors
than clonidine (α2: α1 specificity ratio is 200:1 for clonidine and 1600:1 for
dexmedetomidine). It has sedative, analgesic, and sympatholytic effects that blunt many of
the cardiovascular responses seen during the perioperative period. Animal and human studies
have shown safety and efficacy of adding dexmedetomidine to local anesthetics in various
regional anesthetic procedures. The addition of dexmedetomidine to bupivacaine in TAP block
achieves better local anesthesia and provides better pain control postoperatively without any
major side-effects.
Dexamethasone is a systemic glucocorticoid that improves the quality of recovery after
surgery by reducing pain, nausea, and vomiting. When added to local anesthetics as an
adjuvant in peripheral blocks, it prolongs the analgesia time. Mechanism of action may be
through the anti-inflammatory action, the increase of the local efficiency, and to slow down
of the absorption.
Objective:
The objective is to compare and evaluate efficacy and safety of dexmedetomidine and
dexamethasone as a local anesthetic adjuvant to bupivacaine in ultrasound-guided TAP block
for patients scheduled for total abdominal hysterectomies.