Purpose of review: To evaluate the recent literature on the utility of the pulse oximetry plethysmographic curve to assess macrocirculation and microcirculation monitoring in intensive care patients.
Recent findings: In patients with sinus rhythm who are hypotensive, deeply sedated, mechanically ventilated, critically ill and in the operation room, plethysmographic pulse variation related to mechanical breath is a recent noninvasive indicator of preload dependency.
Summary: A growing number of recent clinical studies demonstrated that plethysmographic dynamic indices are useful methods to assess fluid responsiveness. Any alternating signal processing of the raw data curves, however, may be detrimental for this purpose, as significant clinically relevant information could be lost after perpetual adjustment of filtering. Hence, time will tell if the pulse oximetry plethysmographic curve will succeed other methods as a noninvasive approach to monitor haemodynamics of critically ill patients.