ABSTRACT
BACKGROUND: Cardiac transplantation is limited to an ischemic time of around 6 hours by available preservation solution and technique. Complex organ preservation devices have been developed that extend this time to 24 hours or more, but are clinically impractical. This study evaluates a portable oxygen-driven organ perfusion device weighing approximately 13.5 kg. METHODS: Organs are perfused with the University of Wisconsin solution at low perfusion pressure using less than 400 L of oxygen per 12 hours. Left ventricular parameters were measured in anesthetized adult beagles to establish control values (n = 5). Hearts were procured after cardioplegia with 4 degrees C University of Wisconsin solution, weighed, then stored for 12 hours in University of Wisconsin solution at 4 degrees C. Hearts were perfused (n = 3) or nonperfused (n = 2) during storage. Organ temperature, partial pressure of oxygen in the aorta and right atrium, perfusion pressure, and aortic flow were recorded hourly in perfused hearts. After 12 hours, hearts were transplanted into littermates and left ventricular parameters measured after stabilization off bypass. RESULTS: Organ weight for both groups was unchanged. Nonperfused hearts required both pump and pharmacologic support with significantly depressed left ventricular function. Perfused hearts needed minimal pharmacologic support, with left ventricular end-diastolic pressure, cardiac output, and rate of change of left ventricular pressure showing no statistical difference from control. CONCLUSIONS: These findings confirm the potential for extended metabolic support for ischemia-intolerant organs in a small, lightweight, easily portable preservation system.
Subject(s)
Heart Transplantation , Heart , Organ Preservation Solutions , Organ Preservation/instrumentation , Perfusion/instrumentation , Adenosine/pharmacology , Allopurinol/pharmacology , Animals , Cardioplegic Solutions/pharmacology , Dogs , Glutathione/pharmacology , Heart Transplantation/physiology , Insulin/pharmacology , Myocardial Reperfusion Injury/prevention & control , Organ Size , Raffinose/pharmacology , Time Factors , Ventricular Function, Left/physiologyABSTRACT
Cardiopulmonary bypass surgical techniques that allow a surgeon to operate on the infant's heart use an extracorporeal circuit consisting of a pump, oxygenator, arterial and venous reservoirs, cannulae, an arterial filter, and tubing. The extracorporeal technique currently used in infants and neonates is sometimes associated with neurologic damage. We are developing a modified cardiopulmonary bypass system for neonates that has been tested in vitro and in one animal in vivo. Unlike other extracorporeal circuits which use steady flow, this system utilizes pulsatile flow, a low prime volume (500 ml) and a closed circuit. During in vitro experiments, the pseudo patient's mean arterial pressure was kept constant at 40 mmHg and the extracorporeal circuit pressure did not exceed a mean pressure of 200 mmHg. In our single in vivo experiment, the primary objective was to determine whether physiologic pulsatility with a 10 F (3.3 mm) aortic cannula could be achieved. The results suggest that this is possible.
Subject(s)
Cardiopulmonary Bypass , Pulsatile Flow/physiology , Animals , Equipment Design , Extracorporeal Circulation/adverse effects , Humans , In Vitro Techniques , Infant , Infant, Newborn , Membranes, Artificial , Oxygen Consumption/physiology , Oxygenators, Membrane/standards , Polyvinyl ChlorideABSTRACT
Hemorrhage from the heart and great vessels is a potentially lethal complication of post-sternotomy mediastinitis. We report 2 cases in which a cryopreserved descending thoracic aortic homograft was used successfully to repair defects of the ascending aorta and right ventricle in the setting of active mediastinal infection. An overview of mediastinitis and management strategies for life-threatening mediastinal bleeding is included.
