The Preemptive Effect of Magnesium Sulfate Gargle, Ketamine Gargle or Dexamethasone Intravenous Injection on Sore Throat Following Surgery in Patients undergoing Surgery with General Anesthesia

  Sore throat is a common complication following surgery. The aim of this study was to determine the preventive effect of magnesium sulfate gargle, ketamine glucose gargle or dexamethasone intravenous injection on postoperative sore throat in patients undergoing general anesthesia and to compare it with the control group. In a clinical trial study, four groups of 35 patients undergoing surgery were treated with gargling 40 mg ketamine dissolved in 30 ml normal saline, gargling 40 mg of magnesium sulfate dissolved in 320 ml normal saline, or intravenous injection of 8 mg dexamethasone and gargling 320 ml normal saline half an hour before the surgery. The incidence and severity of postoperative sore throat were compared between the four groups. Findings: The frequency of postoperative sore throat was significantly different in four groups of magnesium sulfate (21.4%), ketamine (16.1%), dexamethasone (24.2%), and control (42.9%) (P = 0.024). But the severity of sore throat did not differ significantly between the groups (P = 0.210). The use of preoperative magnesium sulfate as gargle reduces the incidence of postoperative sore throat, decreases drug intake, and increases the first time of drug intake compared with ketamine gargle and intravenous dexamethasone. Therefore, the use of magnesium sulfate gargle seems preferable to dexamethasone injections and ketamine.