Tracheo-bronchial angles in the human fetus -- an anatomical, digital, and statistical study

Residual airway foreign bodies in children who underwent rigid bronchoscopy

OBJECTIVE

To analyze the causes of residual airway foreign bodies in children who underwent rigid bronchoscopy in order to improve the success rate of primary surgery.

METHODS

Clinical data from 1130 children with airway foreign bodies, including 736 males and 394 females aged 0.42-14 years, who underwent rigid bronchoscopy in our hospital from January 2015 to May 2018 were retrospectively collected and analyzed by cluster sampling. Clinical characteristics including sex, age, time of onset, location of the foreign body, type of foreign body and experience of surgeon were gathered. All patients were classified into two groups as Group A (with residual airway foreign bodies) and Group B (without residual airway foreign bodies) according to chest CT scans and fiberoptic bronchoscope examinations after rigid bronchoscopy. The values were compared between the two groups.

RESULTS

Thirty-one patients with residual foreign bodies were confirmed by fiberoptic bronchoscopy among 1130 children with airway foreign bodies who underwent rigid bronchoscopy under general anesthesia. The percentage of residual airway foreign body was 2.7%. The mean age was 1.55 ± 0.46 years (range 1-3 years). There were 24 male patients (77.4%), and 7 female patients (22.6%), with a male/female ratio of 3.43:1. The time of onset was 1.0 (interquartile range: 1.0-8.0) day. There were no significant difference in age, sex and time of onset between the two groups. Most residual foreign bodies were food-related: nuts (n = 27, 87.1%), beans (n = 3, 9.7%), and one case was unclear in nature (3.2%). The residual incidence of fragile foreign bodies was higher than non-friable foreign bodies (P = 0.028). The most common residual foreign body locations were left superior lobar bronchi (32.3%), left inferior lobar bronchi (25.8%) and right inferior lobar bronchi (25.8%). The residual rate of foreign bodies for surgeons with more than 5 years of operative experience was 1.92%, and 4.25% for surgeons with less than 5 years of operation experience, showing a significant difference (P = 0.022).

CONCLUSION

Friable foods, the complicated structure of the bronchus tree and the surgeon's experience are important causes of residual foreign bodies in the airway. Surgeons with sufficient experience are important for the success of the procedure, which is supported by chest CT and flexible bronchoscopy.

3D-measurement of tracheobronchial angles on inspiratory and expiratory chest CT in COPD: respiratory changes and correlation with airflow limitation

Purpose

To assess tracheobronchial angles and their changes on combined inspiratory and expiratory thoracic computed tomography (CT) scans and to determine correlations between tracheobronchial angles and several indices of chronic obstructive pulmonary disease (COPD).

Materials and methods

A total of 80 smokers underwent combined inspiratory and expiratory CT scans. Of these, 65 subjects also performed spirometry and 55 patients were diagnosed with COPD. On CT scans, 3-dimensinal tracheobronchial angles (trachea–right main bronchus [RMB], trachea–left main bronchus [LMB], and RMB–LMB) were automatically measured by software. Lung volumes at inspiration and expiration were also automatically calculated. Changes in tracheobronchial angles between inspiration and expiration were assessed by the Mann–Whitney test. Correlations of the angles with lung volume, airflow limitation, and CT-based emphysema index were evaluated by Spearman rank correlation.

Results

The trachea–LMB angle was significantly smaller and the RMB–LMB angle was significantly larger at expiration than inspiration (P<0.0001). The trachea–LMB and RMB–LMB angles were significantly correlated with lung volume, particularly at expiration. The RMB–LMB angle was significantly correlated with airflow limitation and CT emphysema index (P<0.001–0.05) at inspiration and expiration, suggesting that narrowed RMB–LMB angle indicates more severe airflow limitation and larger extent of emphysema.

Conclusion

Tracheobronchial angles change during respiration and are correlated with severity of COPD and emphysema.

Airway dimensions from fetal life to adolescence-A literature overview

BACKGROUND

Data on airway dimensions in pediatric patients are important for proper selection of pediatric airway equipment such as endotracheal tubes, double-lumen tubes, bronchial blockers, or stents. The aim of the present work was to provide a synopsis of the available data on pediatric airway dimensions.

METHODS

A systematic literature search was carried out in the PubMed database, Scopus, Embase, Web of Science, Prisma, and Google Scholar and secondarily completed by a reference search. Based on inclusion and exclusion criteria, a final selection of 109 studies with data on pediatric airway dimensions published from 1923 to 2018 were further analyzed.

RESULTS

Six different airway measurement methods were identified. They included anatomical examinations, chest X-ray, computed tomography, magnetic resonance tomography, bronchoscopy, and ultrasound. Anatomical studies were more abundant compared to other methods. Data provided were very heterogeneously presented and powered. In addition, due to different study conditions, they are hardly comparable. Among all, anatomical and computer tomography studies are thought to provide the most reliable data. Ultrasound is an upcoming technique to estimate airway parameters of fetus and premature infants. There was, in general, a lack of comprehensive studies providing a complete range of airway dimensions in larger groups of patients from birth to adolescence.

CONCLUSIONS

This work revealed a large heterogeneity of studies providing data on pediatric airway dimensions, making it impossible to compare, or assemble them to normograms for clinical use. Comprehensive studies in large population of children are needed to provide full range nomograms on pediatric airway dimensions.

Tracheobronchial angles in children: Three-dimensional computed tomography-based measurements

BACKGROUND

Studies have shown significant variation in the tracheobronchial angles in pediatric-aged patients. The current study revisits tracheobronchial angle measurements in children using accurate computed tomography-based 3-dimensional images to add clarity to the understanding of tracheobronchial angles. The primary objective of the current study was to measure the right and left bronchial angle take off from the trachea using 3-dimensional computed tomography-based images of the air column in the tracheobronchial tree.

METHODS

Computed tomography-based images of 45 children younger than 8 years were reviewed. The children were evaluated during spontaneous ventilation either during natural sleep or with sedation. The right and left bronchial angles were computed between the central axes of the respective main bronchi and a vertical line passing through the central axis of the longitudinal tracheal air column. The right and left bronchial angles were compared using paired t tests, and the age dependence of the right bronchial angle and left bronchial angle difference was evaluated using Pearson's correlation coefficient.

RESULTS

The study cohort included 18 males and 27 females with an average age of 49 ± 25 months. The right bronchial angle ranged from 23° to 56° (mean 42 ± 7°), whereas left bronchial angle varied between 25° and 68° (mean 43 ± 9°). The difference in means of 1 degree was not statistically significant (95% confidence interval of difference: -1°, 4°; P = .282). No association was found between left and right bronchial angle difference and patient age (r = -.019).

CONCLUSION

According to computed tomography-based 3-dimensional imaging, right and left bronchial angles are virtually identical in children up to 8 years of age, and the difference between right and left bronchial angles does not vary with age in this population.

A Novel Technique for the Placement of Endobronchial Watanabe Spigots Into the Bronchus: Side-Grasping Method

BACKGROUND

Bronchial occlusion with an endobronchial Watanabe spigot (EWS) is effective for the management of persistent pulmonary air leaks; however, an optimal procedure for placing the spigot at the target bronchus remains debatable. The procedure most currently applied involves grasping the middle of the graspable part of the EWS with grasping forceps (conventional method). In this study, we assess a new technique, the side-grasping method, to maneuver the spigot into the target bronchus by using rotatable biopsy forceps to grasp the edge of the graspable part of the EWS. The aim of this study is to evaluate the effectiveness of this new technique for the simple placement of the EWS.

METHODS

To compare the number of bronchoscopists who were able to place the EWS correctly within 10 minutes, and the time needed to place each spigot for both methods into 4 canine bronchi.

RESULTS

More bronchoscopists correctly placed the EWS within 10 minutes using the side-grasping method compared with the conventional method (35/40 vs. 15/40, P<0.01). The total time needed to place spigots into all bronchi using the side-grasping method was 13±2.2 minutes versus 27.8±3.6 minutes using the conventional method (P<0.01).

CONCLUSION

The side-grasping method described in this study was a simple and effective technique for correctly placing an EWS spigot into the target bronchus.

Tracheobronchial Angle Measurements in Children: An Anthropometric Retrospective Study With Multislice Computed Tomography

OBJECTIVES

The purpose of this study is to investigate if any change exists in the values of tracheal bifurcation angles (subcarinal angle [SCA] and interbronchial angle [IBA]), right and left bronchial angles (RBA and LBA) in different pediatric age groups.

METHODS

Chest computed tomography (CT) images of children aged 18 years and younger were reviewed retrospectively by two radiologists who were blinded to each other's measurements. One hundred and eighteen children were involved. RBA, LBA, SCA, and IBA were measured on coronal reformatted images. Subjects were classified into three groups according to their age. Measurement of IBA was done by measuring the angle between the lines drawn along the central axis of right and left main bronchi over their length. RBA and LBA were measured at the intersection points of the lines drawn along the inferior borders of the right and left main bronchi and the line passing through the longitudinal axis of trachea. Sums of RBA and LBA gave SCA. Interobserver agreement was also analyzed.

RESULTS

SCA, IBA, and RBA values were statistically significant between children of ages less than 10 years and over 10 years P<0.01). Interobserver agreement was excellent with an intraclass correlation coefficient score of 0.87 (95% confidence interval) for RBA, SCA, and IBA measurements.

CONCLUSION

We concluded that tracheal bifurcation angles are wider in children of age 10 years and younger. As age increases values of SCA, IBA, and RBA decrease.

Novel patterns for the growing main bronchi in the human fetus: an anatomical, digital and statistical study

Purpose

Intensive progress in prenatal medicine results in performing airway management in the fetus affected by life-threatening congenital malformations. This study aimed to examine age-specific reference intervals and growth dynamics for length, proximal and distal external transverse diameters, and projection surface areas of the two main bronchi at varying gestational ages, including their relative growth in length and projection surface area.

Materials and methods

Using anatomical dissection, digital image analysis and statistics, length, proximal and distal external transverse diameters, and projection surface areas of the right and left main bronchi were examined in 73 human fetuses (39 males, 34 females) aged 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

Statistical analysis showed no sex differences. Between the 14 and 25th week of gestation, the lengths of the right and left main bronchi increased from 1.43 ± 0.18 to 3.18 ± 0.39 mm, and from 2.97 ± 0.16 to 7.58 ± 1.95 mm, in accordance with the functions: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 4.850 + 2.452 x \; \text{ln}\left( {\text{Age}} \right) \pm 0.400\;{\text{and}}\;y = - 15.005 + 7.093x \; \text{ln} \left( {\text{Age}} \right) \pm 0.579 $$\end{document}y=−4.850+2.452xln(Age)±0.400andy=−15.005+7.093xln(Age)±0.579, respectively. The proximal external transverse diameters of the right and left main bronchi varied from 2.13 ± 0.41 to 4.24 ± 0.20 mm, and from 1.84 ± 0.06 to 3.67 ± 0.66 mm, following the logarithmic models: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.666 + 4.018x \; \text{ln}{\rm (Age)} \pm 0.367\;{\text{and}}\;y = - 6.938 + 3.305x{\text{ ln(Age) }} \pm 0.323 $$\end{document}y=−8.666+4.018xln(Age)±0.367andy=−6.938+3.305xln(Age)±0.323, respectively. The distal external transverse diameter rose from 2.09 ± 0.47 to 4.24 ± 0.20 mm, as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 8.723 + 4.021x{\text{ ln(Age)}} \pm 0.392 $$\end{document}y=−8.723+4.021xln(Age)±0.392 for the right main bronchus, and from 1.85 ± 0.04 to 3.67 ± 0.66 mm, like \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 6.924 + 3.280x{\text{ ln(Age)}} \pm 0.348 $$\end{document}y=−6.924+3.280xln(Age)±0.348 for the left one. On either side, there were no statistically significant differences between values of the proximal and distal transverse diameters of the main bronchus. The projection surface areas of the right and left main bronchi ranged from 2.95 ± 0.19 to 13.34 ± 2.12 mm², and from 5.57 ± 0.21 to 28.52 ± 5.24 mm², as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 10.212 + 0.943x{\text{ Age}} \pm 1.739 $$\end{document}y=−10.212+0.943xAge±1.739 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ y = - 19.119 + 1.875x{\text{ Age}} \pm 3.054 $$\end{document}y=−19.119+1.875xAge±3.054. The two main bronchi revealed a proportionate increase in both length and projection surface area, since the right-to-left bronchial length ratio and the right-to-left bronchial projection surface area ratio were stable, 0.41 ± 0.07 and 0.47 ± 0.08, respectively, throughout the analyzed period.

Conclusions

The main bronchi show no sex differences. The right and left main bronchi grow logarithmically in length and external transverse diameter, and linearly in projection surface area. The right and left main bronchi evolve proportionately, with the right-to-left bronchial ratios of 0.41 ± 0.07 for length, and 0.47 ± 0.08 for projection surface area.