The effects of positive and negative extrathoracic pressure ventilation on pulmonary blood flow after the total cavopulmonary shunt procedure.

Pulmonary blood flow patterns were studied during the application of varying extrathoracic pressure in 2 patients after total cavopulmonary anastomosis. The application of negative extrathoracic pressure was associated with large increases in pulmonary blood flow, while positive extrathoracic pressure, caused retrograde flow away from the lungs. These preliminary observations suggest that negative extrathoracic pressure may be useful as a means of respiratory support in patients after right heart bypass procedures.