Early detection of hemorrhage via central pulse pressure derived from a non-invasive peripheral arterial blood pressure waveform

There is a profound need for early and convenient detection of hemorrhage in both civilian and military medicine. Due to wave reflection timing, central pulse pressure (PP), but not peripheral PP, is a surrogate of stroke volume (SV) and therefore an early marker of blood loss. However, only peripheral PP is convenient to measure. We tested an adaptive transfer function technique for deriving the central arterial blood pressure (ABP) waveform from a non-invasive peripheral ABP waveform in healthy humans subjected to lower body negative pressure (LBNP), a safe model of early hemorrhage. Our results showed that the derived central PP provided an earlier and more sensitive marker of progressive LBNP and a far more accurate measure of SV than measured peripheral PP.