Sousa A S, Moll R J, Pontes C F, Saldiva P H, Zin W A
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
Eur Respir J. 1995 Jan;8(1):99-104. doi: 10.1183/09031936.95.08010099.
Respiratory changes resulting from stepwise intrathoracic injections of 4 ml of either room air or warm (37 degrees C) Haemaccel, simulating pneumothorax and pleural effusion, respectively, were evaluated in anaesthetized, paralysed, and mechanically-ventilated rats. Respiratory system, lung, and chest wall resistances and elastances (static and dynamic) were determined in 14 animals. For this purpose, the end-inflation occlusion during constant inspiratory flow method was used. Chest wall configuration at both functional residual capacity (FRC) and end-inspiration tidal volume (i.e. FRC+(VT)) was also evaluated in: 1) 15 rats by measurements of lateral and anteroposterior diameters, and circumferences at the 3rd intercostal space and xiphoid levels; and 2) in 16 rats by measurements of thoracic cephalocaudal diameter. In addition, changes in functional residual capacity were measured. Both in pneumothorax and pleural effusion, resistances were not altered, but static and dynamic respiratory system and lung elastances increased progressively. Morphometric changes were similar at both functional residual capacity and end-inspiration; however, whereas pleural effusion increased all diameters, pneumothorax did not modify lateral diameter. Functional residual capacity was decreased in both conditions. In conclusion, pneumothorax and pleural effusion induced similar mechanical changes, but thoracic configuration was differently affected, since lateral diameters were increased in pleural effusion only.
在麻醉、麻痹并接受机械通气的大鼠中，评估了分别模拟气胸和胸腔积液的情况，即向胸腔内逐步注射4毫升室温空气或温热（37摄氏度）贺斯（Haemaccel）后所导致的呼吸变化。对14只动物测定了呼吸系统、肺和胸壁的阻力及弹性（静态和动态）。为此，采用了恒定吸气流量法中的吸气末阻断法。还对以下两种情况的胸壁形态进行了评估：一是在功能残气量（FRC）和吸气末潮气量（即FRC +（VT））时，对15只大鼠测量第3肋间和剑突水平的左右径、前后径及周长；二是对16只大鼠测量胸段头尾径。此外，还测量了功能残气量的变化。在气胸和胸腔积液时，阻力均未改变，但静态和动态的呼吸系统及肺弹性均逐渐增加。在功能残气量和吸气末时，形态学变化相似；然而，胸腔积液时所有直径均增加，而气胸时左右径未改变。两种情况下功能残气量均降低。总之，气胸和胸腔积液引起了相似的力学变化，但胸腔形态受到的影响不同，因为只有胸腔积液时左右径增加。
