Analysis and experimental simulation of blood pressure signal distortions observed on intensive care patients monitored by a catheter in radial artery.

The follow-up of patients with hemodynamic instability in intensive care units most often requires blood pressure measurement using a fluid-filled catheter in the radial artery and a fluid-filled tubing connected to a pressure transducer. However, in this usual setup major distortions frequently occur that may alter the pressure signal. Underdamping and overdamping have been well described whereas other types of distortions, including attenuations and varied envelopes of pulse pressure, have been less studied. This study proposes 1) a classification of signal distortions observed on intensive care patients, and 2) several experimental procedures modifying the catheter lumen and the fluid-filled tubing in order to generate a large variety of pressure distortions to more closely mimic the clinical observations.

Contribution to structural intensity tool: application to the cancellation of ECG interference in diaphragmatic EMG.

This paper is concerned with the problem of localizing the typical features of a signal when it is observed with noise in order to align a set of curves. Structural intensity (SI) is a recent tool that computes the "density" of the location of the modulus maxima of a wavelet representation along various scales in order to identify singularities of an unknown signal. As a contribution to this novel approach we establish a modified SI using the Berkner transform which allows maxima linkage to insure accurate localization of singularities. An application to cancellation of ECG interference in diaphragmatic EMG is also proposed.