PL97404B1 - CARDIOTOCOGRAPH FOR RECORDING THE MOMENTARY FREQUENCY OF THE PLOD'S HEART ACTION AND THE STRENGTH OF THE UTERINE - Google Patents

Description

The invention relates to a cardiotocograph for recording the instantaneous heart rate the fetus and the force of contraction of the uterus during labor and instantaneous fetal heart rate before delivery dem.

The fetal heart rate signal is derived from the machine heart rate - vibration of the valves and muscle cardiac, is perceived on the surface of the belly cha mother. by means of an ultrasonic sensor or microphone.

So far, there are no cardiotocographs in the country.

Only Patent Specification No. 52929 to is found for the tokograph itself only.

Cardiotocographs produced by a few Western companies, such as Hewlett Packard, do not follow sit down such an efficient signal selection system lows. The essence of the invention is based on the use of the system of change of the constant time and the sale the feedback link between the comparators and the knock pre-selection demo by the verb and switch. The subject matter according to the invention is shown in the attached drawing, which shows a block diagram of the device.

Signal from fetal heart rate monitor 1, e.g. ultrasound pulse detector working on the principle of Doppler or a microphone picking up tones heart and cooperating with the amplifier or from the electrodes, the ECG is fed to the disc frequency min. 2. Followed by a signal from off taken - depending on the clinical situation - feel- nika is fed to an am ¬ discriminator plitude of 3 with variable discrimination threshold. Change on the threshold of discrimination, depending on the current re¬ measured by the fetal heart rate sensor, is obtained with an amplitude detector 4 and the system of changing the time constant 5, accelerates Jacego to establish a new threshold of discrimination after the signal amplitude has decreased.

The time constant shifting system 5 speeds up the process there is no threshold of discrimination, if the output of the disc amplitude criminator * 3 within 1.5 sec. not after the next impulse appears. After amplitude selection input signal in the form of standardized pulses obtained at the input of the discriminator is given to the system of preliminary time selection 6 limiting the maximum frequency of visits pulses according to the physiological barrier, i.e. to 420 pulses / min. (210 bpm). Then times are between successive pulses they are converted to na¬ five time-voltage converters with auxiliary whose memories 7.

The voltages corresponding to the three times tlt t2, t3 sa stored for the period until the next measurement and fed to the systems of comparators 8 checked or the times of arrival of mixed signals it is within physiological limits from 50 bpm. up to 210 bpm Additionally, it is checked regularly signal incoming within two circles consecutive cycles, i.e. whether the frequency change momentarily heats during two consecutive work cycles 97 4043 97 404 4 heart rate does not change more than ± 10%, sta the maximum change possible with a point view of physiology. In addition, 8 comparators determine whether there is one or two in the signal heart tones. If there are two tones in the signal heart to the outgoing memory 11 via switch the hyphen 10 is the time value tx. If there is one heart tone in the signal via the switch 10 to output memory 11 loaded is the value of time t3.

The contents of the auxiliary memory 7 via the computer ratory 8 (instantaneous fetal heart rate) via verb 9 and switch 13 regulate automatically timed pre-selection system 6, so that it did not pass the signal changes in two * consecutive cycles of heart beat unbelievable physiologically. Information from the output memory 11, it is fed to a time-frequency converter 43 ** The transmitter teS ° controls the dual channel recorder 14 recording in one channel instantaneous value of the fetal heart rate (contraction of the heart).

There is a register in the second recorder channel 14 important force of uterine contraction, signal of which was received is valid from the contraction force gauge 15. Additional output memory feedback 11 by switch 13 for time pre-selection system 6 causes a further frequency reduction w approximate to the value stored in memory outgoing 11.

At high noise level, i.e. when tests with 8 comparators gave negative result during a measurement longer than three seconds connectors 10 are open, recorder output 14 is closed with switch 13. Switch 13 disconnects the recorder input via verb 9 if in time not longer than 3 sec. at least two measurements will be recorded ry. Inputs of the recorder 14 are shorted by a switch 13 simultaneously disconnects the pre-circuit time select 6 from the output memory and increasing the transmitted frequency of pulses up to 420 / min.

P. vmm \ H OZGtraf. Order 792 circulation 105 + 17 copies

Price PLN 45

Claims (1)

1. Patent claim Cardiotocograph for recording the momentary frequency of the fetal heart rate and the force of uterine contraction, consisting of an ultrasound heart rate detector, or a microphone, or a fetal EKG input, frequency and amplitude discrimination system, amplitude detector, transducers and transducers Alternatively, it has a system of changing the time constant (5) and a feedback between comparators (8) and the system of preliminary time selection (6) through the verb (9) and a switch (13). \ T ~ o L 1 r ^^^ UTT * j ^ i po \ 5 M 7 ¥ 8 r 9 1 10 ll> 11 13 LLl i? U * - £ *