Transcutaneous oxymetry measurements during acute blood loss

Transcutaneous PO2 (TcPO2) was measured in healthy adult blood donors to test the sensitivity of this method as a noninvasive means of diagnosing occult blood loss. TcPO2, the energy required to heat the electrode (MW), and postural changes in blood pressure and pulse, were measured before and after a 450-ml blood donation. There was a significant increase (P less than .005) in postural pulse of 4.8/min, but no significant change (P greater than .05) in postural blood pressure. There was no significant change (P greater than .05) in TcPO2, but there was a significant decrease (P less than .001) in MW. These MW changes probably reflect physiologic changes associated with blood loss.