The Effect of Intraoperative Infusion of Dexmedetomidine Versus Low Dose Ketamine

The primary objective of anesthesia is balancing the patient's hemodynamics with the best possible surgical outcome. In modern anesthesia, a multimodal approach to balanced anesthesia is targeted with combined general anesthetics and systemic drugs.

Trans-nasal endoscopic surgery (TNES) is a helpful diagnostic and therapeutic modality in paranasal sinus diseases. TNES are associated with significant intraoperative bleeding, pain, epistaxis, and transient headaches .

Intra-operative surgical site bleeding is one major complication and all anesthetic techniques pursue the objective to reduce it to achieve better precision, reduced operative time, and faster postoperative wound healing.

Topical medications, surgical positioning, nasal packing, inhalational anesthetics, and systemic drugs are some of the documented methods.

Controlled hypotension is one of the methods to control bleeding. It reduces blood loss, enhances the operative field quality (dryness) and studies on hypotensive anesthesia have shown a statistically significant reduction in blood loss .

Several systemic drugs have been used to achieve controlled hypotension. However, they have their own set of limitations .

Dexmedetomidine, a highly selective α2 adrenoreceptor agonist, has anxiolytic, sedative, anesthetic, and analgesic properties. It has limited side effects in terms of respiratory depression. Because of these favorable properties, it is commonly used in a wide variety of procedures .

Dexmedetomidine is a relatively new drug approved at the end of 1999 by the Food and Drug Administration (FDA) for humans use for short-term sedationand analgesia (<24 hours) in the intensive care unit (ICU). Dexmedetomidine is a useful sedative agent with analgesic properties, hemodynamic stability and ability to recover respiratory function in mechanically ventilated patients facilitating early weaning .

Ketamine hydrochloride, a well-known anesthetic agent, has been in clinical use for more than four decades . Its antinociceptive-hypnotic effects are most likely the result of the noncompetitive antagonism at the N-methyl-D-aspartate (NMDA) receptor of the central nervous system .

Ketamine is used as an analgesic in low doses and as an anesthetic in high doses. It is suggested that ketamine maintains analgesia and reduces postoperative opioid use, whether used alone or in combination with other anesthetic agents, The perioperative use of ketamine in surgery with moderate-to-severe postoperative pain is recommended by the American Society of Regional Anesthesia and Pain Medicine, American Academy of Pain Medicine, and American Society of Anesthesiologists.

Cytokines regulate the host response to infection, the immune response, inflammation, and trauma. Surgical stress has been reported to be associated with elevated cytokines response. IL-6 is highly expressed during inflammatory responses to conditions of stress, and can be used to assess the severity of surgical trauma.

The stress response to surgery is characterized by increased secretion of pituitary hormones and activation of the sympathetic nervous system, For example, release of corticotrophin from the pituitary stimulates cortisol secretion from the adrenal cortex .