BACKGROUND: There are limited data about how to choose the correct size of a double-lumen tube (DLT). It is especially difficult to select an appropriate DLT for Asian women because of their small stature. The primary aim of this study was to compare the overall accuracy of the DLT selected based on the combination of transverse diameter of cricoid ring and the equivalent diameter of the left main bronchus (ED-LMB) with that based on the ED-LMB alone for Asian women. METHODS: In this study, 80 consecutive and blinded female patients were assigned randomly to 2 groups. The overall accuracy of the selection of DLT was compared between the Combined group and LMB group. The accuracy of the selection of tracheal segment and bronchial segment was also compared between the 2 groups. The postoperative hoarseness and sore throat were investigated by blinded assessors. RESULTS: The overall accuracy of selection of the DLTs was higher in the Combined group than that in the LMB group (87.5% vs 60.0%; P = .010). The accuracy of selection of tracheal segment was also higher in the Combined group (92.5% vs 67.5%; P = .010). The accuracy of selection of bronchial segment was similar between the groups (95.0 % vs 86.1%; P = .246). The severity of sore throat was higher in the LMB group at 24 hours after the operation (P = .001). CONCLUSIONS: The correct size of DLT for Asian women should be selected based on the combination of transverse diameter of cricoid ring and the ED-LMB.

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BackgroundThe rigid cricoid cartilage is functionally the narrowest portion of the larynx. There is some controversy over the shape of the pediatric cricoid cartilage in the transverse plane. It is important to understand the development of the cricoid cartilage so that endo‐traceheal tubes can be used more safely.AimTo determine changes in the internal diameter and shape of the cricoid cartilage during development and explore the implications of those changes for the selection of ETT type and size for children.MethodsThe cervical computed tomography scans were reviewed in patients aged 1‐20 years. After performing the multiplanar reconstruction and correcting the slant, the transverse and anteroposterior internal diameters of the inlet and outlet of the cricoid cartilage were measured, respectively. The angle between the arch and the lamina of the cricoid cartilage in the middle sagittal plane was measured. The ratios of transverse to anteroposterior diameter for the inlet and outlet of the cricoid cartilage were calculated, respectively.ResultsIn females, the internal diameters of the cricoid cartilage increased linearly with age. In males, the internal diameters of the cricoid cartilage exhibited a growth spurt during adolescence. The transverse diameter of the inlet was the smallest diameter of the cricoid cartilage, and the predicting formula of the transverse diameter of the inlet for children aged 1‐12 was 0.4 × age (year) + 5.1, R2 = .758. The angle between the arch and lamina of the cricoid cartilage and the ratios of transverse to anteroposterior diameter correlated weakly with age.ConclusionThe transverse inner diameter of the inlet is the smallest diameter of the cricoid cartilage. The “funnel shape” of the cricoid cartilage remains unchanged during development. The outer diameter should be considered when selecting an endotracheal tube.

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BackgroundThe purpose of this study was to investigate the anisotropic features of fetal pig cerebral white matter (WM) development by magnetic resonance diffusion tensor imaging, and to evaluate the developmental status of cerebral WM in different anatomical sites at different times.MethodsFetal pigs were divided into three groups according to gestational age: E69 (n = 8), E85 (n = 11), and E114 (n = 6). All pigs were subjected to conventional magnetic resonance imaging (MRI) and diffusion tensor imaging using a GE Signa 3.0 T MRI system (GE Healthcare, Sunnyvale, CA, USA). Fractional anisotropy (FA) was measured in deep WM structures and peripheral WM regions. After the MRI scans,the animals were sacrificed and pathology sections were prepared for hematoxylin & eosin (HE) staining and luxol fast blue (LFB) staining. Data were statistically analyzed with SPSS version 16.0 (SPSS, Chicago, IL, USA). A P-value < 0.05 was considered statistically significant. Mean FA values for each subject region of interest (ROI), and deep and peripheral WM at different gestational ages were calculated, respectively, and were plotted against gestational age with linear correlation statistical analyses. The differences of data were analyzed with univariate ANOVA analyses.ResultsThere were no significant differences in FAs between the right and left hemispheres. Differences were observed between peripheral WM and deep WM in fetal brains. A significant FA growth with increased gestational age was found when comparing E85 group and E114 group. There was no difference in the FA value of deep WM between the E69 group and E85 group. The HE staining and LFB staining of fetal cerebral WM showed that the development from the E69 group to the E85 group, and the E85 group to the E114 group corresponded with myelin gliosis and myelination, respectively.ConclusionsFA values can be used to quantify anisotropy of the different cerebral WM areas. FA values did not change significantly between 1/2 way and 3/4 of the way through gestation but was then increased dramatically at term, which could be explained by myelin gliosis and myelination ,respectively.