Fig. 1. Generation of the pressure pulse signal elicited by the transducer during compression and release over the radial pulse. The pulsatile waveform detected during the period of maximum energy transfer (elicitation of the maximum pressure pulse wave with minimal sensor compression) is used to provide accurate blood pressure information. Shown in the inset are two samples of waveforms of blood pressure readings (Vasotrac,  left , and intraarterial BP,  right ) of a patient intraoperatively at different times during surgery. Note the similarity in the waveforms.