What are the advantages/disadvantages of monitoring at the ear vs the finger?
Because the distance between the chest and the ear lobe is shorter and the vascular impedance is lower, we see blood activity in the ear lobe align very closely (in near real time) with respiration. Because the finger tip or thumb is further away and the vascular system is narrower, there may be a delay of several seconds as observed, relative to respiration. In other words, both Valsalva Wave and heart rate cycles may lag respiration by 3-6 seconds depending on the state of the body.
