Photoplethysmographic Waveform in Hyperbaric Environment

• Published in: 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) Vol. 2019; pp. 3490 - 3493
• Main Authors: Pelaez Coca, Maria Dolores, Hernando, Alberto, Sanchez, Carlos, Albalate, Maria Teresa Lozano, Izquierdo, David, Gil, Eduardo
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 01-07-2019
• Subjects: Adult; Air Pressure; Atmospheric waves; Blood; Blood Pressure; Estimation; Female; Heart Rate; Humans; Male; Photoplethysmography; Physiology; Signal Processing, Computer-Assisted; Three-dimensional displays; Young Adult
• ISSN: 1557-170X; 1558-4615
• DOI: 10.1109/EMBC.2019.8856400

The objective of this work is the identification of significant variations of morphological parameters of the photoplethysmographic (PPG) signal when the subjects are exposed to an increase in atmospheric pressure. To achieve this goal, the PPG signal of 26 subjects, exposed to a hyperbaric environment whose pressure increases up to 5 atm, has been recorded. From this record, segments of 4 minutes have been processed at 1 atm, 3 atm and 5 atm, both in the descending (D) and ascending (A) periods of the immersion. In total, four states (3D, 5, 3A and 1A) normalized to the basal state (1D) have been considered. In these segments, six morphological parameters of the PPG signal were studied. The width, the amplitude, the widths of the anacrotic and catacrotic phases, and the upward and downward slopes of each PPG pulse were extracted. The results showed significant increases in the three parameters related to the pulse width. This increase is significant in the four states analysed for the anacrotic phase width. Furthermore, a significant decrease in the amplitude and in both slopes (in the states 1A) was observed. These results show that the PPG width responds rapidly to the increase in pressure, indicating an activation of the sympathetic system, while amplitude and pulse slopes are decreased when the subjects are exposed to the hyperbaric environment for a considerable period of time.