Comparison of Nebulized Ketamine With Nebulized Magnesium Sulfate for the Prevention of Postoperative Sore Throat

Post-operative sore throat (POST) is a common complication seen in patients after general anesthesia with endotracheal intubation although clinicians often regard it as a minor complication. The incidence of POST is estimated to be 21%-65% in different studies . The primary cause of POST is airway irritation and inflammation or trauma caused by an endotracheal tube; however, the airway may be extremely sensitive due to a preexisting comorbid condition. Regardless of its incidence and some preventive measures, POST is listed from the top as patients' most undesirable outcome in the postoperative period. POST is well recognized that reporting of sore throat is affected by the method of questioning that is whether the questions asked directly or indirectly .

The expression of POST constitutes a number of signs and symptoms. For example, sore throat is an ordinary expression of pharyngitis, which by itself can have a number of causes. It may also include a variety of symptoms including pain and discomfort, laryngitis, tracheitis, hoarseness, cough, or dysphagia. This leads to an increase in morbidity and causes further complications in patients .

Various pharmacological and nonpharmacological methods have been tried to decrease the incidence of POST with varying success rates. The pharmacological methods used for the prevention of POST are the use of inhalational, intravenous or topical agents that include beclomethasone gel, magnesium sulfate gargle, ketamine gargle, nebulized ketamine, magnesium sulfate nebulization, and lidocaine spray .

Nebulized medication administration is strongly recommended over intranasal delivery that is inhaled into the lungs and respiratory tract and is an important strategy for various respiratory problems and diseases. It reduces cough, temporary nasal discomfort, and vocal cord irritation. N-methyl-D-aspartate (NMDA) receptors had a crucial part in inflammation and nociception in the body. NMDA receptors exist in both peripheral nervous system (PNS) neurons and the central NS (CNS) .

Ketamine, an NMDA receptor antagonist, is commonly administered as a nebulizer to decline the severity and frequency of POST owing to its antinociceptive and anti-inflammatory properties .

Magnesium is also another NMDA receptor antagonist that plays a significant role in decreasing the incidence of POST. It is used as nebulizer; it is accessible and easily available in hospitals. The efficacy of preoperative nebulization of magnesium sulfate was assessed and found that the incidence and severity of POST were reduced at rest and on swallowing through 24 hours post extubation (8). Some studies showed that ketamine and magnesium can be used for attenuation of postoperative sore throat .

Inclusion criteria

• Age from 18 to 65 years old.
• Both sexes.
• American Society of Anesthesiologists (ASA) physical status I-II.
• Elective surgery requiring GA with endotracheal intubation.

• Exclusion Criteria:
• Surgery involves the oral cavity, nasopharynx, larynx, and neck regions.
• Surgery requires prone position.
• Surgery lasted more than 3 hours.
• History of preoperative sore throat, common cold.
• Anticipated difficult airway.
• Any known allergies to study drugs.
• Recent non-steroidal anti-inflammatory drugs use.
• Pregnancy.