Abstract
The present invention relates to an apparatus for monitoring a vascular access device, including at least one signal generator for generating vibrations in order to stimulate the vascular access device or a portion thereof to vibrate, at least one signal receiver for detecting vibrations of the vascular access device or of said portion thereof, and at least one evaluation device for evaluating the detected vibrations. Moreover a method for monitoring the vascular access device by using the apparatus of the invention is specified.
Claims
1. A method for monitoring a vascular access device, comprising: generating, via at least one signal generator, vibrations in order to stimulate the vascular access device or a portion thereof to vibrate; detecting, via at least one signal receiver, vibrations of the vascular access device or of said portion thereof; and evaluating, via at least one processor, the detected vibrations.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention will in the following be described by way of preferred embodiments with reference to the appended drawings, in which like reference numerals are used for designating like elements. In the drawings:
(2) FIG. 1 shows in a schematically simplified manner a possible arrangement of the apparatus of the invention;
(3) FIG. 2 shows in a schematically simplified manner an embodiment of the apparatus of the invention in enlarged view;
(4) FIG. 3 is an enlarged view of another embodiment of the apparatus of the invention; and
(5) FIG. 4 shows schematic graphs during monitoring of a vascular access device by using the apparatus of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
(6) FIG. 1 shows an arterial connection needle 1 and a venous connection needle 3 which serve as examples of vascular access devices being connected with a shunt 5 between an artery 7 and a vein 9 of the vascular system of a patient 11. An apparatus of the invention 13 is attached to the venous connection needle 3.
(7) FIG. 2 shows in an enlarged view an apparatus of the invention 13 wherein a signal generator/signal receiver 15 and an evaluation means 16 are fastened to a clip 17 and the latter is connected to the venous connection needle 3. Moreover a vascular access device 5 provided with a so-called punction or butterfly wing 14 is illustrated. The signal generator/signal receiver 15 is presently illustrated as a common means having the functions of both “transmitting” and “receiving.” The two functions may, however, also be realized with two separate means.
(8) FIG. 3 shows an enlarged view of the apparatus of the invention 13, wherein the signal generator/signal receiver 15 comprises an electrodynamic transducer 19. It is, for example, possible to record both the energy quantities absorbed by a signal generator and the vibratory signals received by a signal receiver. Acoustic signals received by the signal generator/signal receiver 15 may be converted into electric signals and evaluated by an evaluation means.
(9) FIG. 4 shows schematic graphs representing the monitoring of a vascular access device by using the present apparatus. The graphs do not depict actual measurements but show the measured results schematically. In the left-hand column of FIG. 4, the electronic signals emitted by the signal receiver 15 are represented as a voltage U per time unit t and/or as a frequency f per time unit t. The right-hand column shows the signals received by an evaluation means of the apparatus of the invention. The graphs are matched in lines, i.e., the left-hand graphs show the emitted signals (input signal), and the respective right-hand graphs show the corresponding received signals (output signals). The graphs represented in dashed lines each show signals of a needle about to slip out and/or having lost its optimum fixation.
(10) Line 1 of FIG. 4 illustrates the use of a transceiver, for example an electrodynamic transducer. The input signal is a step signal; the output signal is the associated step response.
(11) Line 2 of FIG. 4 illustrates the use of discrete transmitter and receiver, for example an electrodynamic transducer. The input signal is a pulse; the output signal is the associated pulse response.
(12) Line 3 of FIG. 4 illustrates the use of a transceiver, for example an electrodynamic transducer. The left-hand graph shows a so-called “frequency sweep” for the input signal. The right-hand graph shows the associated output signal as a function of the absorbed current in the case of a sweep with a constant voltage amplitude at the transceiver as a “signal to be evaluated.” The dashed signal 21 illustrates the slipping out of a connection needle 1, 3. The signal 23 drawn as a solid line illustrates a correct connection.
(13) The present invention is not restricted to the embodiments described in the foregoing; these merely serve for illustrative purposes.
