Measuring venous oxygenation using the photoplethysmograph waveform.
Summary of "Measuring venous oxygenation using the photoplethysmograph waveform."
Objective. We investigate the hypothesis that the photoplethysmograph (PPG) waveform can be analyzed to infer regional venous oxygen saturation. Methods. Fundamental to the successful isolation of the venous saturation is the identification of PPG characteristics that are unique to the peripheral venous system. Two such characteristics have been identified. First, the peripheral venous waveform tends to reflect atrial contraction. Second, ventilation tends to move venous blood preferentially due to the low pressure and high compliance of the venous system. Red (660 nm) and IR (940 nm) PPG waveforms were collected from 10 cardiac surgery patients using an esophageal PPG probe. These waveforms were analyzed using algorithms written in Mathematica. Four time-domain saturation algorithms (ArtSat, VenSat, ArtInstSat, VenInstSat) and four frequency-domain saturation algorithms (RespDC, RespAC, Cardiac, and Harmonic) were applied to the data set. Results. Three of the algorithms for calculating venous saturation (VenSat, VenInstSat, and RespDC) demonstrate significant difference from ArtSat (the conventional time-domain algorithm for measuring arterial saturation) using the Wilcoxon signed-rank test with Bonferroni correction (p < 0.0071). Conclusions. This work introduces new algorithms for PPG analysis. Three algorithms (VenSat, VenInstSat, and RespDC) succeed in detecting lower saturation blood. The next step is to confirm the accuracy of the measurement by comparing them to a gold standard (i.e., venous blood gas).
Department of Anesthesiology, Yale University School of Medicine, 333 Cedar Street, P.O. Box 208051, New Haven, CT, 06520-8051, USA.
This article was published in the following journal.
Name: Journal of clinical monitoring and computing
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20644985
- DOI: http://dx.doi.org/10.1007/s10877-010-9248-y
Medical and Biotech [MESH] Definitions
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.
Rare vascular anomaly involving a communication between the intracranial and extracranial venous circulation via diploe, the central spongy layer of cranial bone. It is often characterized by dilated venous structures on the scalp due to abnormal drainage from the intracranial venous sinuses. Sinus pericranii can be congenital or traumatic in origin.
Central Nervous System Venous Angioma
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