PURPOSE: This study sought to investigate the effects of the McKenzie exercise program on forward head posture and respiratory function. METHODS: Thirty adult men and women with forward head posture, aged 20-29 years, were randomly assigned to the experimental group (N=15) or the control group (N=15). Subjects in the experimental group performed the McKenzie exercises three times a week for four weeks, while subjects in the control group did not receive any intervention. Craniovertebral angle (CVA) was measured to quantify forward head posture, and forced vital capacity (FVC), FVC % predicted, forced expiratory volume at one second (FEV1), and FEV1 % predicted were measured to determine changes in respiratory function. The Mann-Whitney U-test was used to analyze pre-test differences in forward head posture and respiratory function between the two groups, and the Wilcoxon signed-rank test was used to analyze differences in forward head posture and respiratory function within the groups before and after intervention. The significance level (α) was set to 0.05. RESULTS: A comparison of pre- and post-test measures showed that CVA significantly increased in the experimental group (p=0.001) denoting postural improvement, whereas no significant difference was found in the control group (p=0.053). All respiratory measures, i.e.,FVC, FVC %pred, FEV₁, and FEV₁ %pred, were significantly improved in the experimental group, whereas there were no significant differences in the control group. CONCLUSION McKenzie exercise can be effective in improving forward head posture and respiratory function.

Background: Direct insertion of a double-lumen tube (DLT) using a flexible fiberoptic bronchoscope (FOB) is an option for DLT intubation. The difficult process of fiberoptic intubation is that the different properties of polyvinyl chloride and silicone DLTs may affect railroading differently. Therefore, we aimed to compare intubation using polyvinyl chloride and silicone DLTs over an FOB. Methods: Patients aged 19–75 years who required one-lung ventilation under general anesthesia were enrolled in this study. After induction of anesthesia, the anesthesiologist intubated the DLT using FOB. The primary outcome was the difficulty of railroading over the flexible FOB scaled into five grades (I, II-1, II-2, III, and IV). Additionally, the intubation time and mucosal damage were recorded. Results: A total of 46 patients participated in this study, 23 each in the silicone and polyvinyl groups. The difficulty of railroading over the FOB was significantly different between the two groups (P < 0.001). In the silicone group, the grades of difficulty in railroading were limited to I and II-1; 20 patients (87%) presented no difficulty in advancing the tube. In contrast, in the polyvinyl group, 13 patients (57%) had scores of II-2 and III. Both the intubation time and mucosal damage were significantly better in the silicone group than in the polyvinyl group. Conclusions Intubation using a silicone DLT over an FOB was easier and faster than that with a polyvinyl chloride DLT with lesser trauma around the glottis.