EFFECT OF CARDIOPULMONARY BYPASS ON HAND AND FOREARM BLOOD-FLOW

We have assessed the relationship between the aorto-radial pressure di fference at the conclusion of cardiopulmonary bypass and blood flow to the hand. Hand blood flow was estimated from the difference between f orearm blood flow measured without and with exclusion of the hand circ ulation. On the same hand, the skin temperature on the palm and on the middle finger was recorded, with the amplitude of the finger pulse ox imeter trace. The aorto-radial pressure difference, after cardiopulmon ary bypass, correlated with hand blood flow (r = 0.59, P = 0.002). The re was a significant (P < 0.0001) palm-finger temperature gradient bef ore and after cardiopulmonary bypass. In conclusion, while the mean ao rto-radial pressure difference after bypass results from increased han d blood flow, the finger is not a reliable site to assess the state of the systemic circulation, before or after cardiopulmonary bypass.