Physiologic changes after brain death.

Although hemodynamic instability and cardiac dysfunction after brain death are reported in the potential organ donor, the underlying mechanisms, such as neuro-humoral changes, myocardial injury, and altered loading conditions, are discussed contrarily. The physiologic regulatory mechanisms that may contribute to the reduction of cardiac function after brain death are reviewed. Special emphasis is focused on the framework of pre- and afterload conditions and coronary perfusion as main determinants of myocardial contractility. On the basis of recent experimental and clinical data, the reduced myocardial contractility after brain death might be seen as a physiologic response to decreased pre- and afterload and coronary perfusion.