Method and device for monitoring blood pressure measurement by arterial catheterization of a patient

A continuous monitoring device for evaluating quality of the blood arterial pressure measurement done by:

• (i) a system comprising:
• a pressure transducer connected, by a hydraulic connection, to a catheter introduced into an artery of a patient, the hydraulic connection transmitting to the transducer an arterial pressure signal of the patient, applied to an arterial inlet of the catheter, and the transducer transforming the signal transmitted by the hydraulic connection into an electric signal;
• (ii) the continuous monitoring device further comprising:
• a casing configured to be plugged between the pressure transducer and a monitor displaying the measured signal,
• a processor enclosed in the casing, the processor being configured to:
• determine, from a measured signal, dynamic parameters of a hydraulic connection, the parameters comprising a natural frequency and the damping coefficient of the hydraulic connection,
• analyze the frequential content of an incident signal so as to determine a maximal frequency component of the signal to be transmitted,
• detect, from at least the dynamic parameters of the hydraulic connection, each one of the following three situations when or if it occurs:
• (a) an aptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion lower than a threshold;
• (b) an aptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion greater than the threshold and the aptitude of the processor to correct the measured signal;
• (c) an inaptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion lower than the threshold and the inaptitude of the processor to correct the measured signal;
• a user interface configured to display a visual information indicative of each one of the situations (a), (b) or (c) when or if it occurs, the visual information being different for each situation;
• and
• an actuator enclosed in the casing, the actuator being adapted to periodically apply first and second mechanicals action to the outer wall of the tubing which forms the hydraulic connection,
• wherein the actuator is configured to apply the first mechanical action as a percussion of the outer wall of the tubing which forms the hydraulic connection, and the processor determines the natural frequency of the hydraulic connection by analyzing a measured signal in response to the first mechanical action;
• and
• the actuator is further configured to apply the second mechanical action as a series of sinusoidal stresses of variable frequency applied to the outer wall of the tubing which forms the hydraulic connection, and the processor determines the damping coefficient of the hydraulic connection by analyzing a measured signal in response to the second mechanical action.

A continuous monitoring method comprising:

• evaluating quality of an arterial pressure measurement made by a pressure transducer connected to a catheter via a hydraulic connection which transmits to the transducer an incident signal applied to an arterial inlet of the catheter and the transducer transforming the signal transmitted by the hydraulic connection into a measured signal, the evaluating comprising:
• (a) determining, from the measured signal, dynamic parameters of the hydraulic connection, the parameters comprising a natural frequency and a damping coefficient of the hydraulic connection, and the hydraulic connection being modelled by a second order physical system;
• (b) analyzing the frequential content of the incident signal so as to determine a maximal frequency component;
• (c) detecting, from at least the dynamic parameters of the hydraulic connection, each of the following possible situations:
• (i) an aptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion lower than a threshold;
• (ii) an aptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion greater than the threshold;
• (iii) an inaptitude of the hydraulic connection to transmit the incident signal to the transducer with distortion lower than the threshold;
• (d) displaying visual information indicative of each one of the situations (i), (ii) or (iii) when or if it occurs, the visual information being different for each situation;
• (e) periodically applying first and second mechanical actions on an outer wall of tubing which forms the hydraulic connection and updating the dynamic parameters of the hydraulic connection based on a measured signal resulting from the first and second mechanical actions;
• (f) the first mechanical action comprising percussion of the outer wall of the tubing, and the natural frequency of the hydraulic connection is determined from an analysis of the measured signal in response to the first mechanical action;
• and
• (g) the second mechanical action comprising a series of sinusoidal stresses of variable frequency applied to the outer wall of the tubing, and the damping coefficient of the hydraulic connection is determined from an analysis of the measured signal in response to the second mechanical action.