Augmentation of ventricular preload during treatment of cardiovascular collapse and cardiac arrest.

Despite aggressive measures for the treatment of cardiovascular collapse and cardiac arrest, the hypotension associated with these malignant processes usually leads to profound vital-organ ischemia and death. A fundamental therapeutic challenge of such life-threatening processes is the restoration of adequate blood flow to the heart and the brain. However, to maintain adequate forward blood flow out of the heart, venous blood return must be drawn back into the heart. With the exception of administration of exogenous fluid replacement, there are limited ways to enhance blood flow back to the heart during prolonged hypotension. This article describes the potential value of a new impedance threshold valve for the treatment of cardiac arrest and hypotension. The valve was designed to create a vacuum within the thorax during the decompression phase of cardiopulmonary resuscitation or during inhalation. By transiently blocking inspiratory gas exchange during the decompression phase of cardiopulmonary resuscitation, after phrenic nerve-stimulated gasping, or during spontaneous ventilation, the impedance-valve concept may have clinical value in the treatment of patients in cardiac arrest, hemorrhagic shock, and cardiovascular collapse secondary to a number of life-threatening clinical processes.