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INTRODUCTION: Bronchoalveolar lavage (BAL) is frequently used in pulmonary medicine though it requires further optimization. Practical obstacles such as patient safety and procedural limitation have to date precluded large, controlled trials aimed at standardization of BAL procedure. Indeed, BAL guidelines are based on observational data. Innovative research methods are necessary to advance the clinical practice of BAL. METHODS: In our study, we evaluated the effect of injecting a gelatinized barium solution into different lobes and segments of cadaveric lungs. As the technique requires an irreversible injection into lung airspaces, it is not suitable for in vivo purposes. We measured the volume returned from BAL as well as the distribution of BAL injection via dissection. Segmental anatomic orientation was compared to a radiologist's impression of plain film radiographs taken of injected lungs. RESULTS: Mean injected volume distributions were greatest in the upper lobes and lowest in the lower lobes; mean ratios of injected volume distribution to lung lobe volume also followed this trend. Cannulated bronchi orders favored lower branches in the upper lobe and higher branches in the lower lobes. Segmental anatomy varied by the lung lobe injected and was most varied in the lower lobes. CONCLUSION: This novel gelatinized-barium injection technique provides a minimally complex method to yield clinically meaningful feedback on the performance of BAL. The technique is also adaptable to study of procedural parameters in the context of variable lung anatomies and pathologies.

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OBJECTIVE: The subsuperior segment is an atypical pulmonary segment of the lung lower lobe. With the increased application of segmentectomy, it has received increased attention from thoracic surgeons. Studies of the subsuperior segment are scarce and mostly on the basis of small-sample autopsy studies, whose described characteristics are inconsistent with intraoperative observations. Our objective was to accurately define the subsuperior segment and elucidate its prevalence and anatomical characteristics in detail. METHODS: A total of 2194 chest computed tomography images were obtained using separate random sampling on the basis of the amount of data available to each of the 6 thoracic surgery institutions in different provinces covering various regions of China. All of the images were reconstructed in 3 dimensions. Subsuperior segments were screened according to their new definition and statistically analyzed for their prevalence and anatomical characteristics. RESULTS: The prevalence of subsuperior segments was 32.04%, with 413 on the right (18.79%); the value was higher than that on the left (347; 15.81%). The average volume of the subsuperior segment was 52.81 ± 21.96 cm3. Only 1 bronchus was detected in the unilateral subsuperior segment, with an average diameter of 2.53 ± 0.61 mm. Only 1 pulmonary artery was observed in most of the subsuperior segments (89.34%), but 81 cases (10.66%) had 2 in our study. One intersegmental vein of the subsuperior segment was the most common situation on both sides. CONCLUSIONS: Using a multicenter large-sample study, we calculated a 32.04% prevalence and systematically detailed the anatomical characteristics of the subsuperior segment in the lung lower lobe, corrected previous reports, and supplemented pulmonary anatomical studies.

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Background: This study aimed to explore the coordinated and independent actions of lung lobes during respiration using quantitative computed tomography (CT) in order to increase our in vivo understanding of pulmonary anatomy. Methods: Cases for whom test results showed normal pulmonary function tests (PFTs) results, and normal paired inspiratory-expiratory chest CT findings, as assessed by 2 radiologists, were retrospectively included in this study. From the chest CT results, we measured quantitative indices of lung volume (LV) and mean lung density (MLD) for the total lung (TL), left lung (LL), right lung (RL), and 5 lobes in inspiratory and expiratory phases. The differences of these measures between bilateral lungs and among the lobes were evaluated to study whether they were consistent or different during respiration. Results: A total of 70 cases were included {median age of 49.5 [interquartile range (IQR), 38.0 to 60.3] years; 32 males; 38 females}. Overall, the inspiratory and expiratory volumes of the LL were smaller than those of the RL (both P<0.001). For the ventilation workload (λ, which indicates the ratio of lobar volume to total LV), the end-expiratory volume ratio (λex ) of the LL was 0.44 (IQR, 0.43 to 0.46), while the end-inspiratory volume ratio (λin ) had risen to 0.46 (IQR, 0.45 to 0.47) (P<0.001). Comparing the 5 lobes, not all lobes shared the same LV. However, the left lower lobe (LLL) and right lower lobe (RLL) showed some similarities. The λin-LLL and λin-RLL was higher than λex-LLL and λex-RLL , respectively (both P<0.001), while the ratios of the other lobes reduced. The pairwise mean absolute difference (PMAD) on λin and λex of the bilateral lower lobes was low in inspiration (0.0288) and expiration (0.0346). The MLD of bilateral lower lobes showed consistency in inspiration or in expiration (inspiration: P>0.999; expiration: P=0.975). In addition, the PMADs between the right middle lobe (RML) and other lobes were significantly larger than the PMAD between other pairs of lobes in both inspiration and expiration. Beyond that, the expiratory MLD of RML [-789.6 (IQR, -814 to -762.05) HU] was the lowest among the 5 lobes. Conclusions: We found that the LL assumes a higher workload during ventilation than it does during respiration. The 5 normal lobes were non-synchronous during respiration and contributed differently to ventilation. The bilateral lower lobes showed similarities and had a high-ventilation function, while and the LV and MLD of the RML showed the least changes within a respiration cycle.

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We studied the macroscopic anatomy of the lower respiratory tract of the endangered Saimaa ringed seal (Phoca hispida saimensis). Examination of one adult and one young individual found dead showed that trachea had 85 and 86 complete cartilage rings. The adjacent cartilages exhibited very few random anastomoses. There was variation in the confirmation of the trachea between the cranial and caudal part of the trachea. The right lung was divided by partly incomplete inter-lobar fissures into cranial, middle, caudal, and accessory lobes. The left lung consisted of cranial, middle, and caudal lobes. The lungs were characterized by a high amount of interlobular connective tissue. Silicone casts were prepared of the two specimens to visualize the tracheobronchial branching which was similar to that of marine ringed seals but in the Saimaa ringed seal the right middle lobar bronchus originated at the same level as the accessory lobar bronchus.

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We show-in contrast to the traditional textbook contention-that the first amniote lungs were complex, multichambered organs and that the single-chambered lungs of lizards and snakes represent a secondarily simplified rather than the plesiomorphic condition. We combine comparative anatomical and embryological data and show that shared structural principles of multichamberedness are recognizable in amniotes including all lepidosaurian taxa. Sequential intrapulmonary branching observed during early organogenesis becomes obscured during subsequent growth, resulting in a secondarily simplified, functionally single-chambered lung in lepidosaurian adults. Simplification of pulmonary structure maximized the size of the smallest air spaces and eliminated biophysically compelling surface tension problems that were associated with miniaturization evident among stem lepidosaurmorphs. The remaining amniotes, however, retained the multichambered lungs, which allowed both large surface area and high pulmonary compliance, thus initially providing a strong selective advantage for efficient respiration in terrestrial environments. Branched, multichambered lungs instead of simple, sac-like organs were part and parcel of the respiratory apparatus of the first amniotes and pivotal for their success on dry land, with the sky literally as the limit.

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