Intra-aortic balloon (IAB) counterpulsation can augment the cardiac output. However, the effect of different IAB volumes on cardiac performance has not been adequately evaluated in humans. Eighty-two patients (52 males [63%]; mean age, 65 +/- 12 years; mean body surface area [BSA], 1.8 +/- 0.2 m(2)) had IAB counterpulsation for cardiogenic shock, refractory angina, and preoperatively for high-risk cardiac surgery. Cardiac hemodynamics were prospectively studied during IAB with inflation volumes of 32 vs. 40 cc. Hemodynamic data collected included aortic pressure, pulmonary artery pressure, systemic and mixed venous oxygen saturations, and cardiac output (by Fick). Transthoracic echocardiography (TTE) was used to obtain both velocity time integrals (VTIs) and the area of the left ventricular outflow tract (LVOT). Left ventricular stroke volume was then calculated as LVOT area x VTI. Cardiac output (CO) determined by the Fick method and VTI did not differ significantly (P = NS) between the two inflation volumes (y = 0.002 + 0.97x). In a subgroup of 33 patients with BSA <or= 1.8 m(2), the CO (by VTI) was slightly lower with IAB inflation volume of 32 vs. 40 cc (P = 0.05). Overall, smaller IAB inflation volumes do not affect the hemodynamic improvement seen during IAB counterpulsation. However, in patients with smaller BSA, larger inflation volumes may further augment CO.
Copyright 2002 Wiley-Liss, Inc.