Effect of cardiopulmonary bypass on hand and forearm blood flow

Abstract

We have assessed the relationship between the aorto-radial pressure difference at the conclusion of cardiopulmonary bypass and blood flow to the hand. Hand blood flow was estimated from the difference between forearm blood flow measured without and with exclusion of the hand circulation. On the same hand, the skin temperature on the palm and on the middle finger was recorded, with the amplitude of the finger pulse oximeter trace. The aorto-radial pressure difference, after cardiopulmonary bypass, correlated with hand blood flow (r = 0.59, P = 0.002). There was a significant (P < 0.0001) palm-finger temperature gradient before and after cardiopulmonary bypass. In conclusion, while the mean aorto-radial pressure difference after bypass results from increased hand blood flow, the finger is not a reliable site to assess the state of the systemic circulation, before or after cardiopulmonary bypass.