Pulmonary Artery Acceleration Time in Cardiac Surgical Patients

To examine the potential for using pulmonary Doppler to assess the hydraulic forces opposing right ventricular ejection in a perioperative setting.

A prospective, observational study.

A university hospital tertiary-care center.

Participants included 74 patients: 62 undergoing coronary artery bypass grafting and 12 undergoing mitral valve surgery.

None.

After induction of anesthesia, a pulmonary artery catheter was used to assess pulmonary artery pressures, cardiac output, and pulmonary vascular resistance. Transesophageal echocardiography was performed to measure pulsed-wave Doppler-derived acceleration time (AT) in 3 locations: the right ventricular outflow tract, the main pulmonary artery, and the right pulmonary artery. Flow reversal was observed in the main pulmonary artery in 96% of patients and possibly was responsible for the shorter ATs seen in this location. The best correlations between AT and pulmonary hemodynamic parameters were found in the right pulmonary artery. The relationships were strengthened in a subgroup of patients with elevated pulmonary capillary wedge pressure (PCWP). An acceleration time of 90 ms was associated with elevated pulmonary artery pressure and pulmonary vascular resistance.

Flow reversal occurred frequently in the main pulmonary artery. AT in the right pulmonary artery yielded the best correlation with invasive hemodynamic parameters that were strengthened in patients with elevated PCWP. The addition of a PCWP measurement improved the reliability of AT in this patient population.