Effects of mechanical ventilation on right and left ventricular function.

We have discussed the complex hemodynamic changes that occur throughout the respiratory cycle during mechanical ventilation and have reviewed the physiologic changes associated with spontaneous respiration. In patients, many cumulative factors account for the total hemodynamic burden of mechanical inspiration and expiration. Thus, the change in pleural pressure, respiratory rate, mode of ventilation, amount of spontaneous ventilation, underlying lung and cardiac disease, and intravascular volume status all affect cardiocirculatory equilibrium during the respiratory cycle. Knowledge of the effects presented in this article will aid the physician in choosing the therapeutic options in instrumented, mechanically ventilated patients.