S. Pothula¹, K. R. Ediale¹, V. Kumar¹, V. T. Sanchala¹, M. A. Inchiosa, Jr.^1,2
1Department of Anesthesiology and ²Department of Pharmacology, New York Medical College, Valhalla, New York, USA
[Applied Cardiopulmonary Pathophysiology 14: 21-28, 2010]

Abstract

Common hemodynamic changes following cardiopulmonary bypass (CPB) include decreases in the radial artery-to-aortic pressure gradient (R-A), decreases in systemic vascular resistance (SVR), and increases in cardiac index (CI).  To help evaluate the clinical significance of a decreased R-A gradient, we compared oxygen delivery (DO2) pre- and post-CPB.
As a pilot study, data were collected from 20 consecutive patients undergoing routine cardiac surgery.  Radial and aortic pressures (R-A gradient), DO2, CI, and SVR were determined five minutes before and after CPB.
Average systolic R-A gradients changed from positive pre-CPB (+13.85 mmHg) to negative post-CPB (-3.85) (p< 0.001).  Mean pressure gradients showed the same reversal (p < 0.001).  CI increased pre- to post-CPB, 2.14 liters min-1 m-2 to 3.02; p< 0.001.  SVR decreased, 1342 dynes-sec-cm-5 to 827; p< 0.001. Average DO2 was unchanged (604.4 and 669.8 ml min-1). 
However, a subgroup of patients showed marked increases in DO2 despite decreases in R-A gradients.

Key words: cardiac index, oxygen delivery, radial-aortic pressure gradients, systemic vascular resistance, vasoplegic syndrome


Address for corresponding: 
Mario A. Inchiosa, Jr., Ph.D., Department of Pharmacology, New York Medical College, Valhalla, New York 10595, USA
mario_inchiosa@bitte-keinen-spamnymc.edu