The pulse arrival time approach for non-invasive hemodynamic monitoring in low-acuity settings

Hemodynamic monitoring in hospitalized patients is crucial since in clinical practice unexpected deterioration of cardiovascular function (e.g. pulmonary embolism resulting in syncope) remains a serious problem and an important cause of death. Standard pulse oximetrie in low acuity settings is nowadays predominately used to monitor peripheral oxygen saturation. Of note, there is evidence that additional analyses of pulse wave characteristics might be a valuable source of information to generate additional insights into the cardiorespiratory status of the patient.

Herein, we present our initial experience using a hemodynamic surrogate measure called pulse arrival time (PAT) derived from standard photoplethysmography (PPG), single-lead electrocardiogram (ECG), and context information based on a small body-worn monitoring system for continuous unsupervised monitoring during short-term physical exercise and posture changes.

This paper presents examples of using PPG signals for continuous non-invasive monitoring and discusses PAT and heart rate responses observed during short-term physical exercise, posture changes, and tilt table testing resulting in syncope.

Our results indicate that hemodynamic adaptatations being detected by PPG and ECG analysis might be useful to monitor high-risk patients in low acuity settings. Context information on posture and physical activity is imperatively needed to interpret PAT monitoring.