DECRO Respiratory Inductive Plethysmography
2Pages

Zoom on DECRO Respiratory Inductive Plethysmography Respiratory Inductive Plethysmography (RIP) was a well-known technology used in human since 1970, but was not yet adapted and tested in small mammals. However, respiratory function is a major subject of interest in a wide set of research fields (pharmacology, pathology...) and despite several technics have been developed for its monitoring, they also have several drawbacks such as invasiveness, high cost of use or confinement of the animals. DECRO Respiratory inductive plethysmography The DECRO External Telemetry Solution enables the external monitoring and recording of respiratory volume variations, providing access to high-quality data with low noise and high resolution (32 bits) and sampling rate (200 Hz) in freely-moving animals used in the field of medical research. Instantaneous respiratory signal of a resting rat (in ms) (top). Orange markers = end of inspiration, green markers = end of expiration. The software calculates the respiratory rate (in bpm) based on the detection of respiratory cycles. DECRO stretch and soft jacket contains two RIP sensors that encompass the thorax (THX) and abdomen (ABD) of the animal. As the animal breathes, the volume of its trunk changes, causing changes in its cross-section. These changes are detected as proportional variations in the inductance of the RIP sensors. Then, the respiratory volume or airflow variation is reconstructed by combining the signals from the two sensors together [1]. DECRO jacket embedding two RIP sensors. The DECRO software includes algorithms that performs RIP signal preprocessing, involving noise removal and elimination of baseline wander. It then, automatically identifies respiratory cycles and calculates volume and timing derived respiratory parameters. What are the signals and physiological respiratory parameters I have access to? (a) anatomical position of the coins for the implementation of a thoracic PCRI in rats and (b) the thoraco-abdominal model of the trunk. DECRO RIP provides access to the volume variation signal, as well as the airflow signal. DECRO software automatically detects the inspiratory and expiratory fiducial points, allowing for the determination of respiratory cycles and derived variables. These variables include respiratory cycle time (ms), respiratory rate (bpm), tidal volume (arb.u or mL), minute volume (arb.u/min) and inspiratory and expiratory time (s). The signal provided by DECRO RIP is expressed in relative units (or arbitrary units (arb.u)), and is suitable for relative variations evaluations [2]. However, using relative variations may not be sufficient for certain situations. Thus, 2 methods to transform (calibrate) these arbitrary units into mililiters (mL) are available in the software: automatic and reference measurement calibration. Each method has been validated and provides reliable results.

Test and validation of DECRO RIP measurement Equivalence with reference technics DECRO has been successfully compared to reference technics, including pneumotachograph (PNT) direct airflow measurement [3] and Unrestrained Whole Body Plethysmography (UWPB) [4], demonstrating that RIP can effectively be calibrated and that performances are similar to those generally observed in humans. The comparison with PNT in anesthetized animals showed a 93% fit with PNT and jacket respiratory signals and a 81% agreement on the tidal volume measurement. Comparison between a Pneumotachograph (green) and...