Method and system enabling photoplethysmograph measurement of volume status

A microprocessor implemented method for photoplethysmograph measurement of volume status and changes, comprising:

• measuring, at a monitoring site, oscillatory changes in a DC component of a photoplethysmographic signal;
• measuring, at a monitoring site, changes resulting from changes in cardiac ejection of pulse as indicated by stroke volume, cardiac output, blood pressure or pulsatile component of a peripheral monitor;
• comparing oscillations in the DC component to changes in cardiac ejection of pulse as indicated by stroke volume, cardiac output, blood pressure or pulsatile component of a peripheral monitor to provide a ratio that noninvasively provides a measure of oscillations in preload to changes in blood ejection by the heart;
• establishing cutoffs for clinically meaningful positive and negative responses to a challenge or intervention based upon SV assessment/DC measurement ratio and ΔSV assessment/ΔDC measurement ratio;
• assigning values to quadrant of one of a series of SV assessment/DC measurement and ΔSV assessment/ΔDC measurement quadrant maps;
• and
• monitoring systemic vessel physiology, pharmacology, cardiac function, and blood volume based upon the measure of oscillations in preload to changes in blood ejection by the heart to identify and monitor hypovolemic conditions.

A microprocessor implemented method for photoplethysmograph measurement of volume status and changes, comprising:

• measuring, at a monitoring site, a DC component of a photoplethysmographic signal and a AC component of photoplethysmographic signal;
• determining a baseline, estimated baseline or a preintervention value of the DC component;
• determining a baseline, estimated baseline or a preintervention value of the AC component;
• establishing cutoffs for clinically meaningful positive and negative responses to a challenge or intervention based upon SV assessment/DC measurement ratio and ΔSV assessment/ΔDC measurement ratio;
• assigning values to quadrant of one of a series of SV assessment/DC measurement and ΔSV assessment/ΔDC measurement quadrant maps;
• and
• wherein conditions of altered volume and guide treatment of vessel physiology, cardiac function, or blood volume are identified and monitored by comparing a difference in the DC component from the baseline, estimated baseline or preintervention value to a difference in the AC component from the baseline, estimated baseline or its preintervention value to identify and monitor conditions of altered volume and guide treatment of vessel physiology, cardiac function, or blood volume.