Determinants of the esophageal-pleural pressure relationship in humans.
- 作者列表："Pasticci I","Cadringher P","Giosa L","Umbrello M","Formenti P","Macri MM","Busana M","Bonifazi M","Romitti F","Vassalli F","Cressoni M","Quintel M","Chiumello D","Gattinoni L
:Esophageal pressure has been suggested as adequate surrogate of the pleural pressure. We investigate after lung surgery the determinants of the esophageal and intrathoracic pressures and their differences. The esophageal pressure (through esophageal balloon) and the intrathoracic/pleural pressure (through the chest tube on the surgery side) were measured after surgery in 28 patients immediately after lobectomy or wedge resection. Measurements were made in the nondependent lateral position (without or with ventilation of the operated lung) and in the supine position. In the lateral position with the nondependent lung, collapsed or ventilated, the differences between esophageal and pleural pressure amounted to 4.4 ± 1.6 and 5.1 ± 1.7 cmH2O. In the supine position, the difference amounted to 7.3 ± 2.8 cmH2O. In the supine position, the estimated compressive forces on the mediastinum were 10.5 ± 3.1 cmH2O and on the iso-gravitational pleural plane 3.2 ± 1.8 cmH2O. A simple model describing the roles of chest, lung, and pneumothorax volume matching on the pleural pressure genesis was developed; modeled pleural pressure = 1.0057 × measured pleural pressure + 0.6592 (r2 = 0.8). Whatever the position and the ventilator settings, the esophageal pressure changed in a 1:1 ratio with the changes in pleural pressure. Consequently, chest wall elastance (Ecw) measured by intrathoracic (Ecw = ΔPpl/tidal volume) or esophageal pressure (Ecw = ΔPes/tidal volume) was identical in all the positions we tested. We conclude that esophageal and pleural pressures may be largely different depending on body position (gravitational forces) and lung-chest wall volume matching. Their changes, however, are identical.NEW & NOTEWORTHY Esophageal and pleural pressure changes occur at a 1:1 ratio, fully justifying the use of esophageal pressure to compute the chest wall elastance and the changes in pleural pressure and in lung stress. The absolute value of esophageal and pleural pressures may be largely different, depending on the body position (gravitational forces) and the lung-chest wall volume matching. Therefore, the absolute value of esophageal pressure should not be used as a surrogate of pleural pressure.
: 食管压力被认为是胸膜压力的充分替代。我们研究了肺手术后食管和胸内压力的决定因素及其差异。对 28 例肺叶切除或楔形切除患者术后即刻食管压 (通过食管球囊) 和胸内/胸膜压 (通过手术侧胸管) 进行测量。在非依赖性侧卧位 (无或有手术肺通气) 和仰卧位进行测量。在侧卧位，非依赖性肺，塌陷或通气时，食管和胸膜压差分别为 4.4 ± 1.6 和 5.1 ± 1.7 cmH2O。在仰卧位，差异达 7.3 ± 2.8 cmH2O。在仰卧位，估计对纵隔的压缩力为 10.5 ± 3.1 cmH2O，对等重力胸膜平面的压缩力为 3.2 ± 1.8 cmH2O。建立了一个描述胸、肺、气胸体积匹配对胸膜压力发生作用的简单模型; 模拟胸膜压力 = 1.0057 × 测量胸膜压力 + 0.6592 (r2 = 0.8)。无论位置和呼吸机设置如何，食管压力随胸膜压力的变化呈 1:1 比变化。因此，在我们测试的所有位置中，通过胸内 (Ecw = Δ ppl/潮气量) 或食管压力 (Ecw = Δ pes/潮气量) 测量的胸壁弹性 (Ecw) 是相同的。我们得出结论，食管和胸膜压力可能在很大程度上不同，这取决于体位 (重力) 和肺-胸壁容积匹配。然而，他们的变化是相同的。新的 & 值得注意的食管和胸膜压力变化发生在 1:1 的比例，完全证明使用食管压力来计算胸壁弹性以及胸膜压力和肺应力的变化是合理的。食管和胸膜压力的绝对值可能有很大差异，这取决于身体位置 (重力) 和肺-胸壁体积匹配。因此，食管压力的绝对值不应作为胸膜压力的替代。
METHODS:BACKGROUND AND PURPOSE:A critical role for sphingosine kinase/sphingosine-1-phosphate (S1P) pathway in the control of airway function has been demonstrated in respiratory diseases. Here, we address S1P contribution in a mouse model of mild chronic obstructive pulmonary disease (COPD). EXPERIMENTAL APPROACH:C57BL/6J mice have been exposed to room air or cigarette smoke up to 11 months and killed at different time points. Functional and molecular studies have been performed. KEY RESULTS:Cigarette smoke caused emphysematous changes throughout the lung parenchyma coupled to a progressive collagen deposition in both peribronchiolar and peribronchial areas. The high and low airways showed an increased reactivity to cholinergic stimulation and α-smooth muscle actin overexpression. Similarly, an increase in airway reactivity and lung resistances following S1P challenge occurred in smoking mice. A high expression of S1P, Sph-K2 , and S1P receptors (S1P2 and S1P3 ) has been detected in the lung of smoking mice. Sphingosine kinases inhibition reversed the increased cholinergic response in airways of smoking mice. CONCLUSIONS AND IMPLICATIONS:S1P signalling up-regulation follows the disease progression in smoking mice and is involved in the development of airway hyperresponsiveness. Our study defines a therapeutic potential for S1P inhibitors in management of airways hyperresponsiveness associated to emphysema in smokers with both asthma and COPD.
METHODS::The interim results from this 90-day multi-dose, inhalation toxicology study with life-time post-exposure observation has shown an important fundamental difference in persistence and pathological response in the lung between brake dust derived from brake-pads manufactured with chrysotile, TiO2 or chrysotile alone in comparison to the amphiboles, crocidolite and amosite asbestos. In the brake dust exposure groups no significant pathological response was observed at any time. Slight macrophage accumulation of particles was noted. Wagner-scores, were from 1 to 2 (1 = air-control group) and were similar to the TiO2 group. Chrysotile being biodegradable, shows a weakening of its matrix and breaking into short fibers & particles that can be cleared by alveolar macrophages and continued dissolution. In the chrysotile exposure groups, particle laden macrophage accumulation was noted leading to a slight interstitial inflammatory response (Wagner-score 1-3). There was no peribronchiolar inflammation and occasional very slight interstitial fibrosis. The histopathology and the confocal analyses clearly differentiate the pathological response from amphibole asbestos, crocidolite and amosite, compared to that from the brake dust and chrysotile. Both crocidolite and amosite induced persistent inflammation, microgranulomas, and fibrosis (Wagner-scores 4), which persisted through the post exposure period. The confocal microscopy of the lung and snap-frozen chestwalls quantified the extensive inflammatory response and collagen development in the lung and on the visceral and parietal surfaces. The interim results reported here, provide a clear basis for differentiating the effects from brake dust exposure from those following amphibole asbestos exposure. The subsequent results through life-time post-exposure will follow.
METHODS::The respiratory tract is lined by a pseudo-stratified epithelium from the nose to terminal bronchioles. This first line of defense of the lung against external stress includes five main cell types: basal, suprabasal, club, goblet and multiciliated cells, as well as rare cells such as ionocytes, neuroendocrine and tuft/brush cells. At homeostasis, this epithelium self-renews at low rate but is able of fast regeneration upon damage. Airway epithelial cell lineages during regeneration have been investigated in the mouse by genetic labeling, mainly after injuring the epithelium with noxious agents. From these approaches, basal cells have been identified as progenitors of club, goblet and multiciliated cells, but also of ionocytes and neuroendocrine cells. Single-cell RNA sequencing, coupled to lineage inference algorithms, has independently allowed the establishment of comprehensive pictures of cell lineage relationships in both mouse and human. In line with genetic tracing experiments in mouse trachea, studies using single-cell RNA sequencing (RNAseq) have shown that basal cells first differentiate into club cells, which in turn mature into goblet cells or differentiate into multiciliated cells. In the human airway epithelium, single-cell RNAseq has identified novel intermediate populations such as deuterosomal cells, 'hybrid' mucous-multiciliated cells and progenitors of rare cells. Novel differentiation dynamics, such as a transition from goblet to multiciliated cells have also been discovered. The future of cell lineage relationships in the respiratory tract now resides in the combination of genetic labeling approaches with single-cell RNAseq to establish, in a definitive manner, the hallmarks of cellular lineages in normal and pathological situations.