Pulse Rate Variability Analysis During Hemorrhage in an Experimental Porcine Model

During the acute phase of hemorrhage, heart rate and peripheral resistance increases to maintain proper oxygen delivery to vital organs. This response is mediated by the autonomic nervous system. Heart rate variability (HRV) has become a widely utilized measure to determine the autonomic nervous system control over the heart. Recently, pulse rate variability (PRV) has been suggested to serve as a surrogate for HRV. This study evaluates the ability of PRV obtained from peripheral arterial pressure waveforms as a method for detecting hemorrhage. Time domain and frequency domain metrics were evaluated for 5-minute and 15-minute arterial pressure waveform signals prior to hemorrhage, during acute hemorrhage, and after the commencement of hemorrhage in four porcine subjects. PRV analysis demonstrates an increase in time domain and frequency domain metrics at the onset of hemorrhage, followed by an opposing decrease at the commencement of hemorrhage. The frequency domain metrics associated with sympathetic input increased at the onset of hemorrhage and decreased once hemorrhage ended. These results suggest that PRV metrics obtained from arterial pressure waveforms have the potential to serve as a diagnostic method for acute hemorrhage