Postoperative sore throat (POST) is defined as pain, discomfort, or irritation in the throat after general anesthesia and tracheal intubation that worsens with swallowing. Etiological factors playing a significant role in this anesthetic complication are: Size of the endotracheal tube, design and pressure of cuff, the use of nasogastric tubes, lubricants, muscle relaxants, duration of surgery, surgery in and around the oral cavity, trauma arising from laryngoscopy, and use of pharyngeal packs. Pharyngeal packs are commonly used during nasal surgeries to prevent aspiration, tracheal contamination and passage of blood into the stomach. They are disputed to increase the incidence of postoperative sore throat (POST), but surgery in and around the oral cavity necessitates them to soak blood and debris that result as consequence of surgery and decrease post operative nausea and vomiting. Nausea and vomiting are important postoperative complications in all surgical settings and more in nasal surgery due to the presence of blood in the stomach, pain and inflammation of the uvula and throat, and the occasional use of opioids for pain control are all contributing factors. Many interventions can be used to decrease incidence of POST. These include using smaller endotracheal tube size including video laryngoscopy in intubation process, limiting endotracheal cuff pressure and perioperative use of steroids (intravenous, topical or inhaled). Also pharyngeal packs soaked with agents with analgesic effect can be used to decrease post operative sore throat, nausea and vomiting. N methyl D aspartate (NMDA) receptors are present in the central nervous system and also in the peripheral nervous system . These receptors contribute in inflammatory pain. Ketamine and Magnesium sulphate are NMDA antagonist with antinociceptive and anti-inflammatory effect, which may be a possible mechanism in prevention of postoperative sore throat (POST).
The aim of this study is to compare the effect of ketamine or magnesium sulphate soaked throat pack on the incidence and severity of post operative sore throat as a primary outcome, post operative nausea and vomiting as a secondary outcome following elective nasal surgery under general anesthesia.