Beyond Mean Arterial Pressure: The Pulse Energy Ratio as a Potential Framework for Perioperative Hemodynamic Interpretation

Continuous arterial pressure monitoring is common during anesthesia, yet interpretation remains largely centred on systolic, diastolic, and mean arterial pressure (MAP). We have recently proposed the Pulse Energy Ratio (PER) as a dimensionless descriptor of the pulsatile contribution to arterial pressure. While validation studies are underway, PER may have particular relevance to anesthesia, where rapid changes in loading conditions, cardiac performance, vascular tone, ventilation, and surgical conditions create an accelerated microcosm of hemodynamic disturbance. We hypothesize that directional changes in PER could identify moments at which structured physiological reassessment is warranted. A decreasing PER may precede overt hypotension, although this temporal relationship has not yet been demonstrated. During hypotension, a concomitant decrease in PER could prompt assessment of ventricular ejection and venous return, whereas a preserved or increasing PER could raise the possibility of predominant vasodilation. PER is hypothesized to provide a continuous signal that may prompt physiological reassessment before conventional hypotension thresholds are crossed. These hypothesized patterns are proposed as prompts for focused physiological assessment rather than diagnostic phenotypes or treatment directives and require prospective validation.