Effects Of Incidence Of Postoperative Sore Throat Between TaperGuard And Cylindrical-Shaped Endotracheal Tube Under Different Cuff Pressures

Objective: Postoperative sore throat(POST)often occurs as an airway complication related to endotracheal intubation.Risk factors that may contribute to incidence of POST are varies.As one of the common risk factors,high cuff pressure is shown to have strong correlation with the incidence of POST.It is difficult to popularize the use of monitoring the cuff pressure due to the limited use of the calibrated cuff manometer.The ratio of patients with cuff pressure exceeding 40 cm H2 O was more than half using subjective judgment without the calibrated cuff manometer.However,it is not known whether the cuff design and cuff pressure are associated with more airway complications.Thereby,we evaluated the incidence of postoperative sore throat following general anesthesia using Taper Guard and Cylindrical-shaped ETT with different endotracheal tube cuff pressures(30 cm H2 O vs.40 cm H2O)in this study.It is aimed at exploring a new method to reduce the incidence of Postoperative Sore Throat.Methods: A total of eighty patients were enrolled in the study(aged from 18 to 75 years old with ASA class I or II)and had elective non-throat and non-neck surgery.The patients were consecutively allocated into two groups,Group I(the cuff pressure was set to 30 cm H2O;n=40)and Group II(the cuff pressure was set to 40 cm H2O;n=40).Then,the patients of each group were tracheal intubation with the Taper Guard ETT(Covidien,United States)(Group T;n=20)or the Cylindrical-shaped ETT(Group C;n=20)using a random digital table(Fig.1).Assignment of the groups had beencompleted before surgery.The general anesthesia was induced as common,the patients intubated with the corresponding type of ETT,which had been randomly assigned before the surgery.An ETT with a 7.5-mm internal diameter(ID)was used for male patients and a 7.0-mm internal diameter(ID)for female patients Then,inflated ETT cuff to two different pressures,i.e.30 cm H2O(cuff pressure I;n=40)and 40 cm H2O(cuff pressure II;n=40)respectively.For each group,the cuff pressure was measured without mechanical ventilation by a calibrated cuff manometer at two different time points: 1)after the intubation was completed(cuff pressure Ia or IIa)and 2)before endotracheal tube was removed at the end of surgery(cuff pressure Ib or IIb).The head and neck positions of the patients were kept neutral and not moved during the surgery.The cuff pressures,inflating volume,dose of fentany and csatracurium should be recorded.Further,the incidence and severity of postoperative sore throat(POST),hoarseness,coughing were evaluated by a single independent investigator blinded to the experiment at 0,1,6,12,and 24 hours post surgery.Results: In our study,there was no difference in overall incidence of the POST between Group T and Group C at different cuff pressures(cuff pressure I,the cuff pressure was set to 30 cm H2O: 25% of Group T vs.45 % of Group C.cuff pressure II:the cuff pressure was set to 40 cm H2O:25% of Group T vs.50% of Group C.P>0.05 in both groups).However,the incidence(15% of Group T vs.50% of Group C,P<0.05)and severity of POST and hoarseness between the two groups at cuff pressure II(40cm H2O)were significantly different at one hour postoperatively.Among these 20 patients,3 were mild of Group T,10 were mild of Group C for the severity of POST at one hour postoperatively,and there was significantly different between two groups(P<0.05).Conclusions: There was no difference in overall incidence of the POST between Group T and Group C at different cuff pressures(cuff pressure I and cuff pressure II).The Taper Guard ETT may reduce the incidence and severity of POST,as compared to Cylindrical-shaped ETT under higher ETT cuff pressure at one hour postoperatively.