The pulmonary response to trauma and mechanical ventilation: its consequences on hemodynamic function.

Abstract

AbstractThe lung and heart, including the right ventricle (RV) and left ventricle (LV), must be regarded as an integrated system. A change in function of any one, including the addition of mechanical ventilation, will induce a change in function of the other. Interaction between RV and LV primarily via the septum and initially independent of pericardial constraints, is now a fact of life that complicates the evaluation of either left or right ventricular function as an isolated system. In this setting, an increase in LV filling pressure at constant stroke volume need not reflect straightforward myocardial depression. A change in motion of the interventricular septum represents an important variable that modifies the usual evaluation of function based on the Frank‐Starling relationship.The RV is susceptible to large changes in volumes with small changes in filling pressure. These variations can have a significant effect on LV end‐diastolic compliance and may result in RV ischemia due to an excessive elevation of RV free wall stress when right coronary artery disease or an inadequate systemic perfusion pressure is present.