Indian J Med Microbiol Close
 

Figure 2: Curves obtained by manometry, with elastance value, in a normal lung (a), in a lung entrapment process (b), and in a trapped lung (c). When pleural effusion occurs in a normal lung (a), initial pleural pressure will be slightly positive. As fluid is withdrawn, pleural pressure will drop slowly and the lung will expand gradually. Once the entire effusion has been removed, the lung will make contact with the chest wall and the elastance obtained will be normal. In the lung entrapment process (b), the visceral pleura is slightly thickened and pleural pressure will be slightly positive, as in the normal lung. On fluid removal, initially, the lung will gradually expand and pleural pressure will drop slowly. At some point, the lung becomes trapped, unable to expand any further and the pressure will drop rapidly leading to high elastance with a bimodal pressure/volume curve. In the case of a trapped lung, the visceral pleura has a thicker layer of fibrin which prevents the lung from expanding, so the initial pressure is negative (c). The removal of liquid, on the one hand, and the rigidity of the lung, on the other hand, causes a rapid decrease in pleural pressure resulting in high elastance

Figure 2: Curves obtained by manometry, with elastance value, in a normal lung (a), in a lung entrapment process (b), and in a trapped lung (c). When pleural effusion occurs in a normal lung (a), initial pleural pressure will be slightly positive. As fluid is withdrawn, pleural pressure will drop slowly and the lung will expand gradually. Once the entire effusion has been removed, the lung will make contact with the chest wall and the elastance obtained will be normal. In the lung entrapment process (b), the visceral pleura is slightly thickened and pleural pressure will be slightly positive, as in the normal lung. On fluid removal, initially, the lung will gradually expand and pleural pressure will drop slowly. At some point, the lung becomes trapped, unable to expand any further and the pressure will drop rapidly leading to high elastance with a bimodal pressure/volume curve. In the case of a trapped lung, the visceral pleura has a thicker layer of fibrin which prevents the lung from expanding, so the initial pressure is negative (c). The removal of liquid, on the one hand, and the rigidity of the lung, on the other hand, causes a rapid decrease in pleural pressure resulting in high elastance