Regional lung recruitability during pneumoperitoneum depends on chest wall elastance - A mechanical and computed tomography analysis in rats

Laparoscopic surgery has been increasingly used as an alternative to open surgery for its well-known post-operative benefits. However, it is associated to intra-operative respiratory impairment (Valenza et al., 2010). Mechanical ventilation management is a challenge for the anesthetist in this scenario of intra-abdominal hypertension, because it is not clear how the modification of the ventilation parameters affects the different components of the respiratory system. The respiratory system is composed of two elastic elements in series: the lung and the chest wall. The latter, in turn, is made up of two parallel components: the rib cage and the diaphragm, which is also part of the abdominal wall. Disregarding airflow resistances, the positive pressure applied to the respiratory system during mechanical ventilation distends all these elements. How the applied pressure is distributed within the respiratory system depends on the compliance of each single element (Cortes-Puentes et al., 2015) and its distribution within the lungs depends on the compliance of the lung zones, i.e., regional compliance (Mutoh et al., 1991; Lowhagen et al., 2010).