The Effect of Esmolol Versus Dexmedetomidine on Postoperative Pain Control in Endoscopic Sinus Surgery: A Randomized Trial

Hypotensive techniques are associated with certain disadvantages. Hence, anesthesiologists are still in search of drugs with fewer side effects.

Various drugs such as high-concentration volatile anesthetics, magnesium sulfate, remifentanil, clonidine, calcium channel blockers, tranexamic acid, intravenous nitroglycerin, and sodium nitroprusside have been evaluated to control blood pressure and decrease blood loss during surgery, thereby improving the surgical field quality.

Opioids are the mainstay of treatment for perioperative pain, but their administration increases the incidence of respiratory complications, slows down normal gastrointestinal motility, and prolongs hospital stay. With the development of enhanced recovery after surgery (ERAS), reducing the use of opioids in the perioperative period has become the common goal of anesthesiologists. The dosage of opioids should be strictly controlled whenever possible, which should not only meet the needs of analgesia perioperatively, but also minimize the incidence of adverse reactions.

Opioid-free anesthesia (OFA) represents a step forward in anesthetic practice as it potentially spares the use of opioids by administrating nonopioid agents and adjuncts. The rationale to propose OFA is based on the aim to avoid the negative impact of intraoperative opioids on a patient's postoperative outcomes.

Several studies showed that β adrenergic receptor antagonists withhold the upsurge of catecholamines circulating in blood which induced by surgery, as well as having analgesic sparing effect itself. Esmolol is an ultrashort acting β1 blocking drug that has been uncovered to own opioid-sparing effects likely due to resemblances in its structure with local anesthetic agents. Esmolol's short course of action and titrability offer it as an attractive drug to use, although the mechanism of action of its analgesic effect has yet to be established.

Dexmedetomidine hydrochloride is a specific alpha-2 adrenoreceptor agonist that has intrinsic analgesic and sedative properties coupled with anxiolytic and sympatholytic effects. It minimizes the hemodynamic and neuroendocrine responses to anesthesia and surgery by suppressing the sympathetic tone. This hemodynamic stability can improve the surgical outcome as well as both patient and surgeon satisfaction. Dexmedetomidine accompanied by other anesthetics causes a controlled reduction in blood pressure and heart rate and improves the quality of the surgical field.

Alpha-2 adrenergic agonists (dexmedetomidine) have pharmacologic characteristics (sedation, hypnosis, anxiolysis, sympatholytic, and analgesia) that make them suitable as adjuvants to multimodal analgesia.

Their anti-nociceptive effect is attributed to the stimulation of a2- adrenoceptors located in the central nervous system. Dexmedetomidine is a highly selective and potent a2-adrenoceptor agonist. Its intrathecal administration leads to anti-nociceptive effects, although it does have some undesired side effects (e.g., hypotension, bradycardia, and sedation).