Blood Pressure Estimation Based on Pulse Arrival Time and Heart Rate : A Correlation Analysis for Critically Ill Patients

Arterial blood pressure (ABP) is a vital hemodynamic signal to be monitored in general population- especially in critically ill patients. Pulse arrival time (PAT) has been widely used for the noninvasive measurement of systolic blood pressure (SBP) and diastolic blood pressure (DBP) and has shown excellent results for a healthy person as compared to the existing gold standard methods. In this study, we have used correlation analysis to study the feasibility of using PAT and heart rate (HR) for noninvasive BP (SBP and DBP) measurement for critically ill subjects. Physiological signals used for this study were collected from the MIMIC-II database of Physionet. Initially, we conducted a correlation analysis and then tried to estimate BP using linear regression. We found that the BP correlation with HR is more as compared with PAT. However, these correlations are not consistent. We have also found that PAT and HR can track the BP change as long as the correlation coefficient lies between +/- 0.7 and +/- 1. When the correlation falls below, this noninvasive BP estimation using PAT and HR needs to be revisited and improved for clinical applicability.