Aspects of the invention relates to systems and methods for hypovolemia and/or hypervolemia detection of a living subject using peripheral intravenous waveform analysis. In one embodiment, the method includes: acquiring, from a vein of the living subject, peripheral venous signals performing a spectral analysis on the acquired peripheral venous signals to obtain a peripheral venous pressure frequency spectrum and performing a statistical analysis on amplitudes of peaks of the peripheral venous pressure frequency spectrum to determine the blood volume status of the living subject in real time. Specifically, at least two peaks, respectively corresponding to a first frequency and a second frequency, are obtained on the peripheral venous pressure frequency spectrum. Amplitude change of the second peak is used to determine the blood volume status of the living subject. Hemorrhage may be detected when a significant amplitude decrease is detected from the second baseline peak to the second peak.
