Continuous recording of pulmonary artery diastolic pressure and cardiac output using a novel ultrasound transducer.

Background: The feasibility of hands-free transthoracic continuous determination of pulmonary artery (PA) diastolic pressure (PAD) and cardiac output (CO) by Doppler ultrasound has not been previously demonstrated. We developed a 2.5-MHz spherical transducer mounted in an external housing to permit steering in 360 degrees (Contison).