The detection of peripheral venous pulsation using the pulse oximeter as a plethysmograph.

The pulse oximeter can serve as a sensitive photoelectric plethysmograph in the operating room. It was noted in several cases that the plethysmographic waveform showed a high degree of variability during diastole. Three patients are described with discrete diastolic peaks on the plethysmograph. Further investigation revealed that these diastolic peaks appear to correlate with peripheral venous pulsation, which seems to have a central venous origin. Evidence is presented that the plethysmographic detection of the venous-pulse may be useful in estimating the changing volume status of the patient.