Comparison Between Cuff Pressures of Endotracheal Tubes Inflated with Saline or Air in Low-Flow Anesthesia

Objective: Depending on the increase in inspired fractionated nitric oxide fraction (FiN2O), cuff pressures in intubated patients are increased with diffusion into endotracheal cuff during low-flow anesthesia (LFA) with nitrous oxide (N2O). We compared pressures of air- and saline-inflated endotracheal tube cuffs during LFA with N2O in our study. Methods: We included 60 adult patients who were classified by the American Society of Anesthesiologists as I/II in the study. After induction of anesthesia, endotracheal cuffs of patients who were intubated were inflated with air (Group A=30) and saline (Group S=30) to 25 cm water. Thus, two equal randomized groups were separated. The anesthesia technique was maintained with LFA and N2O. Endotracheal cuff pressures were continuously measured with a pressure manometer, and inspired oxygen and N2O levels and also 2 and 24 h after surgery for sore throat were recorded. Results: There was no significant difference about demographic and intraoperative data between the groups. Cuff pressures were significantly higher in Group A than in Group S during all periods (p10 min=0.02, p<0.0001 for others). Group S had significantly higher values than Group A when maximum cuff pressures were compared (37.60±3.16 vs. 29.96±3.34, respectively; p<0.0001). There was a 51.9% positive correlation between cuff pressure and FiN2O in Group A (r=0.519, p=0.048). Group Ahad significantly higher level than Group S at postoperative 2 and 24 h when groups were compared for postoperative sore throat without swallowing and swallowing (p<0.05). Conclusion: Under LFA with N2O, endotracheal cuff pressures during operation and postoperative sore throat incidences in our study were significantly higher in Group S than in Group A