The pulmonary and cardiovascular systems have profound effects on each other. Overall cardiac function is determined by heart rate, preload, contractility, and afterload. Changes in lung volume, intrathoracic pressure (ITP), and hypoxemia can simultaneously change all of these four hemodynamic determinants for both ventricles and can even lead to cardiovascular collapse. Intubation using sedation depresses vasomotor tone. Also, the interdependence between right and left ventricles can be affected by lung volume-induced changes in pulmonary vascular resistance and the rise in ITP. An increase in venous return due to negative ITP during spontaneous inspiration can shift the septum to the left and cause a decrease in left ventricle compliance. During positive pressure ventilation, the increase in ITP causes a decrease in venous return (preload), minimizing ventricular interdependence and will decrease left ventricle afterload augmenting cardiac output. Thus, positive pressure ventilation is beneficial in acute heart failure patients and detrimental in hypovolemic patients where it can cause a significant decrease in venous return and cardiac output. Recently, this phenomenon has been used to assess patient's volume responsiveness to fluid by measuring pulse pressure variation and stroke volume variation. Heart–lung interaction is very dynamic and changes in lung volume, ITP, and oxygen level can have various effects on the cardiovascular system depending on preexisting cardiovascular function and volume status. Heart failure and either hypo or hypervolemia predispose to greater effects of ventilation of cardiovascular function and gas exchange. This review is an overview of the basics of heart–lung interaction.

肺部和心血管系统相互影响深远。总体心脏功能由心率、前负荷、收缩力和后负荷决定。肺容量、胸内压（ITP）和低氧血症的变化可以同时改变两个心室的所有这四个血流动力学决定因素，甚至可以导致心血管衰竭。使用镇静剂插管可抑制血管舒缩张力。此外，右心室和左心室之间的相互依赖性可能受到肺容量引起的肺血管阻力变化和 ITP 升高的影响。自主吸气期间因 ITP 阴性而导致静脉回流增加，可使隔膜向左移动，导致左心室顺应性降低。在正压通气期间，ITP 增加会导致静脉回流（前负荷）减少，最大限度地减少心室相互依赖性，并减少左心室后负荷，增加心输出量。因此，正压通气对急性心力衰竭患者有益，但对低血容量患者不利，因为它会导致静脉回流和心输出量显着减少。最近，这种现象已被用来通过测量脉压变化和每搏输出量变化来评估患者对液体的容量反应。心肺相互作用是非常动态的，肺容量、ITP 和氧水平的变化会对心血管系统产生各种影响，具体取决于先前存在的心血管功能和容量状态。心力衰竭和低血容量或血容量过多容易对心血管功能和气体交换的通气产生更大的影响。这篇综述概述了心肺相互作用的基础知识。