Comparison of the Effect of Magnesium Sulfate Gargle and Compound Lidocaine Cream Smeared in Preventing Postoperative Sore Throat

OBJECTIVE To compare the effect of magnesium sulfate gargle and compound lidocaine cream smeared in preventing postoperative sore throat(POST). METHODS A total of 120 patients with elective laparoscopic ovarian cyst surgery were randomized into control group, magnesium sulfate group, and compound lidocaine cream group. Patients in magnesium sulfate group received magnesium sulfate gargle (20 mg·kg^-1 up to 30 mL dextrose water 20%) 15 min before the operation. Patients in compound lidocaine cream group received compound lidocaine cream uniformly smeared on the formost third of endotracheal tubes 5 min before the intubation. Patient complaint of postoperative sore throat, and its severity measured by visual analogue scale (VAS) were recorded at the moment of extubation immediately (T₁) and then 6(T₂), 24(T₃), and 48(T₄) hours after extubation. The incidence rates of hoarseness of voice and dysphagia were observed at T₁, T₂, T₃ and T₄. The glottis of all patients was examined by indirect laryngoscopy 6h after extubation and the incidence rate of vocal congestion and/or vocal edema were recorded. Venous blood of patient was extracted before surgery(T₀), T₁, T₂, T₃ and T₄ individually to test the concertration of TNF-α, IL-6 and IL-10. RESULTS The incidence rate and sore VAS of sore throat were significantly lower in magnesium sulfate group than that in other groups at T₁, T₂ and T₃(P<0.05). The incidence rate of hoarseness of voice and dysphagia were significantly lower magnesium sulfate group than that in other groups at T₁, T₂ and T₃(P<0.05). The incidence rate of vocal congestion and/or vocal edema was significantly lower in magnesium sulfate group than that in other groups at T₂(P<0.05). The concertration of TNF-α and IL-6 were significantly lower in magnesium sulfate group than that in other groups at T₁ and T₂. The concertration of IL-10 were significantly higher in magnesium sulfate group than that in other groups at T₁ and T₂(P<0.05). The concertration of IL-6 was significantly lower in compound lidocaine cream group than that in control group at T₂(P<0.05). CONCLUSION Magnesium sulfate gargle can effectively attenuated the incidence and severity of POST by its anti-inflammatory effects. However compound lidocaine cream smeared on the endotracheal tubes does not prevent POST.