ABSTRACT
PURPOSE: A stylet aids intubation as a glottis by changing and maintaining the bending inside the endotracheal tube and is used as an auxiliary device in intubation. The aim of this experimental study is to evaluate resistance differences among endotracheal tube sizes and the usefulness of lubricant for stylet removal. METHODS: Depending on endotracheal tube size and lubricant use status, the subjects were divided into the control (n=10, each 7 tube sizes), lidocaine gel (n=70), and saline groups (n=70). Using a tensile strength meter, the work and the peak withdrawal force consumed for retracting a stylet were measured. RESULTS: When the work dependent on the endotracheal tube size and stylet coating was compared, significantly less work was consumed for 6.0-, 6.5-, 7.0-, 8.0-, 8.5 mm stylet group coated with lidocaine gel (p=0.029, p=0.002, p=0.001, p=0.001, p<0.001, p<0.001) or 6.0-, 6.5-, 8.0-, 8.5 mm stylets coated with saline compared to the control group (p=0.002, p<0.001, p<0.001, and p<0.001). In comparison of the peak withdrawal force dependent on the endotracheal tube size and stylet coating, significantly less peak withdrawal force was consumed for the 6.0- or 8.0- mm stylet group coated with lidocaine gel (p=0.004, p<0.001) or 6.0-, 6.5-, 7.5-, or 8.0 mm stylets coated with saline compared to the control group (p=0.025, p=0.001, p=0.008, and p=0.001). CONCLUSION: We found that the effectiveness of lubricant resulted in various sized tubes. Less work was consumed for five tube sizes (6.0-, 6.5-, 7.0-, 8.0-, 8.5 mm) in lidocaine gel groups and four tube sizes (6.0-, 6.5-, 8.0-, 8.5 mm) in saline groups. Less peak withdrawal force was consumed for two tube sizes (6.0-, 8.0 mm) in lidocaine gel groups and four tube sizes (6.0-, 6.5-, 7.5-, 8.0 mm) in saline groups.