Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2000
Influence of tidal volume and thoraco-abdominal separation on the respiratory induced variation of the photoplethysmogram.
The present study was aimed at determining the relative influences of tidal volume and thoraco-abdominal separation (relative thoracic and abdominal contribution to the tidal volume) on the respiratory induced intensity variation (RIIV) of the photoplethysmographic signal. The effects were studied in two body positions. ⋯ The effects on the RIIV signal following changes in thoraco-abdominal separation and tidal volume are of the same order of magnitude. In the supine position, the influence of thoracic versus abdominal contribution to the tidal volume is not as significant as in the sitting position. Photoplethysmography is a promising technique for combined monitoring of several respiratory parameters, including tidal volume. In situations where the relative thoracic and abdominal contributions are likely to vary, the tidal volume information becomes less reliable.