RU2604704C2 - Monitoring of postpartum bleeding - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: group of inventions refers to medical equipment, namely to monitoring technique using ultrasound. Device for evaluation of uterine muscle tone comprises first ultrasound transducer, focused on uterine muscles of patient, second ultrasound transducer of supplied and received reflected ultrasound energy, signal analysis unit, which presents received reflected ultrasound energy, in order to determine propagation velocity of shear waves in uterine muscles, and processor module for determining shear modulus and uterine muscle tone value, based on propagation velocity of shear waves. System for patient's monitoring additionally contains user interface for transmitting information, based on uterine muscle tone, to user. Method for assessing uterine muscle tone is performed by means of device.

EFFECT: using inventions provides early detection of PPH.

10 cl, 6 dwg

Description

FIELD OF THE INVENTION

This invention relates to the field of human monitoring in the General case. In particular, it relates to the field of non-invasive monitoring of a subject for bleeding after childbirth, in particular with the use of ultrasound.

BACKGROUND

Worldwide, the cause of many birth-related deaths is postpartum hemorrhage (PPH). Normally, soon after birth, the uterus contracts to a size close to normal. When the uterus is compressed, the blood vessels in the muscles of the uterus contract and the bleeding in the uterus stops. However, if there is a placenta residue in the uterus, or if the uterus muscles have lost their tone due to other reasons - a condition called uterine atony - then the bleeding does not stop. If this is not checked, then the mother experiences severe blood loss, and this can become fatal. Often when a baby is born, the attention of carers focuses on the newborn, and if the mother is left unattended even for a short period of time, and if she has bleeding, the consequences can be fatal.

US-2008/0139967 A1 sets forth an interface electrode system for connecting at least one electrode to a fetal monitor, the interface system converting electrical muscle activity captured by the electrode (s) into uterine activity data signals for use by the mother monitor fetus. The interface electrode system according to the invention preferably comprises conversion means for converting signals from the electrode (s) into signals similar to those provided by a current dynamometer. This provides a means to monitor uterine tone, providing early warning of atony and potential bleeding.

SUMMARY OF THE INVENTION

It is preferable to have a device for non-invasively assessing the tone of the uterine muscles and monitoring the subject during the period immediately after the birth of the baby in a more direct manner and providing an early warning of PPH to the user or carer. More preferred is a device that also determines the localization of bleeding in the uterus and its severity. It is also preferable to have a device that also provides decision support for caregivers to take action against PPH.

Such a device is disclosed in the present description. A device for assessing the tone of the uterine muscles contains a first ultrasound transducer for applying ultrasound energy focused on the area of the uterine muscles of the subject to generate acoustic radiation to generate a shear wave in the uterine muscles, a second ultrasound transducer for emitting ultrasonic energy in the subject and receiving reflected ultrasonic energy , an analysis unit for analyzing a signal representing the received reflected ultrasonic energy, in order to determine the shear wave propagation velocity in the uterine musculature, and a processor module for determining the tone value of the uterine musculature, for further use, based on the shear wave propagation velocity.

The described device can provide an advantage in that when using the tonus value of the uterine muscles, the subject can receive the required medical care required to prevent serious blood loss. The device may also allow monitoring of PPH in a subject without the need for a caregiver to be present in the immediate vicinity of the subject, and to ensure constant attention to the subject.

A system for monitoring a subject for postpartum hemorrhage is also described. The system for monitoring the subject for postpartum hemorrhage contains a first ultrasound transducer for applying ultrasound energy focused on the uterine musculature of the subject to generate acoustic radiation power to generate a shear wave in the uterine musculature, a second ultrasound transducer for emitting ultrasonic energy to the subject and receiving reflected ultrasonic energy, an analysis unit for analyzing a signal representing the received reflected ultrasonic energy, to determine the velocity of propagation of shear waves in the uterine muscle, the processing module for determining the value of the uterine muscle tone based on the velocity of propagation of shear waves and a user interface for transmitting information based on the value of the uterine muscle tone to the user.

Such a system may have the advantage that PPH can be fully controlled by the care provider.

It is also preferable to have a method for detecting postpartum hemorrhage and warning a caregiver about it. Such a method for assessing the tone of the uterine muscles includes the steps of: a stimulation step, which involves applying ultrasound energy focused on the area of the uterine muscles of the subject, to create acoustic radiation force to generate a shear wave in the uterine muscles, the radiation step is to emit ultrasonic energy in subject, the receiving phase, which consists in receiving the reflected ultrasonic energy, the analysis phase, which consists in analyzing the signal representing the received reflected ultrasound energy, in order to determine the speed of propagation of the shear wave in the uterine muscles, and the processing step, which consists in determining the tonus of the uterine muscles, for further use, based on the speed of propagation of the shear wave.

Such a method may have the advantage of allowing early detection of PPH so that the caregiver can monitor the PPH in order to ensure that the mother’s life is not at risk.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will be described in detail by way of example based on the following embodiments and implementations with reference to the accompanying drawings, among which

Fig. 1a is a schematic representation of an apparatus for monitoring a subject for postpartum hemorrhage;

Fig.1b is a schematic representation of an embodiment of the apparatus;

Figure 2 is a schematic representation of an embodiment of the apparatus;

Figure 3 is a schematic representation of an embodiment of a system for monitoring a subject for postpartum hemorrhage;

Figure 4 is a graphical representation of the apparatus for monitoring a subject for postpartum hemorrhage;

5 is a schematic representation of a method for monitoring a subject for postpartum hemorrhage; and

6 is a schematic representation of another implementation of the above method,

however, similar numerals refer to similar parts in various figures.

DETAILED DESCRIPTION OF EMBODIMENTS

The described device, system and method are described in detail below with reference to the figures.

Figure 1 is a schematic representation of an embodiment of the apparatus. The device comprises an ultrasonic transducer 101 for applying ultrasound energy focused on the uterine musculature of the subject to generate acoustic radiation power to generate a shear wave in the uterine musculature. The ultrasound transducer 101 is driven accordingly by the drive 105. The shear wave thus generated is radiated through the uterine muscles. Another ultrasound transducer 103 emits ultrasound into the abdominal cavity of the subject. The reflected ultrasound is received by the ultrasound transducer 103, and the analysis unit 107 analyzes the electrical signal generated by the ultrasonic transducer 103, and measures the shear wave propagation velocity in a known manner, and estimates the tone of the uterine muscles based on the propagation velocity. The analysis result is transmitted to the user via the corresponding user interface 111.

The ultrasound transducer 101 is a matrix of individual transducers placed and driven in such a way that the radiation emitted by the ultrasonic transducers of the matrix is focused on a small area inside the uterine muscles. Due to the strength of the acoustic radiation created by focused ultrasound, a shear wave occurs in the focal region, which is then radiated through the uterine muscles.

However, after the generation of the shear wave, the ultrasonic transducer 101 can be turned off, and the pulses of the ultrasound imaging can be emitted by the ultrasonic transducer 103 to track the propagation of the shear wave in the region surrounding the focal region. A signal representing the reflected signals received by the ultrasonic transducer 103 is then analyzed by the analysis unit 107 to evaluate the shear wave velocity. Since a shear wave propagates faster in a stiffer material than in a softer material, the measured shear wave velocity gives an estimate of the shear modulus of the musculature and, therefore, the tone of the uterine musculature. The muscle shear modulus can be calculated using generally accepted models.

Based on the calculated shear modulus, uterine tissue can be classified as soft, that is, having atony, or as hard or hard, that is, having adequate tone, based on threshold values for the shear modulus. It should be understood that the classification can have large classes covering the entire range of tones. Therefore, classification can also lead to the transfer of various information to the user.

After assessing the tone of the uterine muscles, the result can be transferred to the user accordingly. If the tone was rated as "mild" or the presence of atony was determined, then this means that there is the possibility of bleeding. After that, the device can proceed to determine the site of bleeding.

You can make it so that when the tone is classified in the middle or near the middle of the range, that is, it is neither hard nor soft, the device after a predetermined period of time can measure the tone again. If the tone remains the same or worsens, that is, it can be said that it is decreasing, the device can proceed to detect and determine the site of bleeding, if any.

The presence of bleeding in a vessel is characterized by changes in the spectral Doppler velocity profile and quantitative indicators, such as resistance index (RI), ripple index (PI), obtained by analyzing the spectral waveform. Reduced vascular resistance at the site of bleeding and downstream of it leads to an increase in the rate of diastolic flow in front of the supply vessel, causing a decrease in Doppler indices. Turbulence in the affected vessel can also be estimated by spectral Doppler signals as a measure of the severity of bleeding by assessing the variance of the velocity estimates. These Doppler parameters can be evaluated at various places in the uterus. A significant decrease in Doppler indices (RI, PI) or an increase in flow turbulence, or both, indicates the presence of bleeding in the uterus. By combining information on various characteristics of the flow profile by Doppler measurements and applying thresholds for each parameter, a decision is made on the presence of bleeding. The severity of bleeding can be quantified by comparing the quantitative Doppler indices in the affected vessels with the independently measured volume of bleeding at the calibration stage. If the uterus of the subject is soft and bleeding has been detected in the uterus, a danger signal is issued to alert the caregiver about possible PPH.

In addition, the analysis unit 109 may be configured to offer advice to the caregiver, for example, through the user interface 111, regarding the appropriate PPH control. This embodiment is described with reference to FIG. 2. Such a recommendation may be based on the severity of atony of the uterine muscles, the site of bleeding, the severity of bleeding and available clinical instructions. Various professional communities periodically publish such clinical guidelines. For example, the article “Prevention and Management of Postpartum Haemorrhage” published by the Canadian Society of Obstetricians and Gynecologists (SOGC), see document No. 88, dated April 2000 (available at http://www.sogc.org/guidelines/public/88E-CPG-April2000.pdf on October 8, 2010). The contents of one or more of these instructions may be appropriately stored in memory 213. The analysis unit 109, using appropriate software, evaluates various information stored in the memory and, based on the results of the analysis, determines or selects one or more appropriate actions for monitoring PPH from clinical instructions and displays the selection to the user on the user interface 111.

In the preceding description, focused pulse radiation, ultrasonic generation and reflected signal reception are described in such a way that although the various transducers 101 and 103 perform different functions, in order to simplify the description, it is also possible to combine all of these functions in the same transducer. This is shown in the form of a diagram in FIG. 1b.

Thus, the foregoing device 200 can help detect uterine atony, the presence and location of PPH and can also help control PPH.

The set forth system for monitoring a subject for PPH is described with reference to FIG. 3, which is a schematic representation of a system shown in a general view as 300. The system 300 comprises the set forth device 100 or 200 and a remote unit 315. The remote unit 315 comprises a user interface 311 ′ , which may be a copy of the user interface unit 111. It may also have additional elements. For example, while user interface 111 may be an alphanumeric display only, user interface 311 'may have additional elements, such as, for example, a blinking lamp and an audio device for emitting audible alarms. The remote unit 315 is in communication with the device 100 or 200, in particular with the processor module 109, wired or wireless. The system can be organized in such a way that the remote unit is located far from the subject being monitored, for example, at a nurse's post. In the case where the unit 100 or 200 detects atony, or bleeding, or both, the information is displayed on both user interfaces 111 and 311 '. If the system contains a unit 200, that is, it is able to offer recommendations to the caregiver for PPH control, then the recommendation is also displayed on the user interface 311 '. This allows the caregiver to prepare for the implementation of the recommendation, for example, by collecting the necessary materials and additional staff, if necessary.

Thus, system 300 allows monitoring of postpartum atony of the uterus without the presence of a carer in the immediate vicinity of the subject, and also helps in early care in the event of atony or bleeding, or both.

Figure 4 shows a possible implementation of the described device or system. It is shown that the subject wears a girdle device 402, which contains the necessary transducer or converters. The converter is electrically connected to the device. The electronics are enclosed in a block shown as 400. The combination of the transducer in 402 and 400 is the device described previously. Block 400 may be interconnected with a remote unit, such as a remote unit 315 described with reference to FIG. 3. This represents a possible implementation of the described device or system and may be something like a sketch.

The described method for monitoring a subject for PPH is described with reference to FIG. 5, which is a schematic representation of a method and in which the method is shown in general as 500.

At 517, the uterus is stimulated from the outer surface of the subject’s abdominal cavity. This stimulation is performed by applying acoustic radiation power to the uterus of the subject through focused ultrasound to create a shear wave in the uterine muscles. After the focused ultrasound has generated a shear wave, the focused ultrasound can be stopped, and the measurement ultrasound is emitted to the subject at radiation step 519. At a receiving step 521, the reflected ultrasound energy is received, and the received signals are analyzed at an analysis step 523 to determine a shear wave propagation velocity. At processing step 525, the tone of the uterine muscles is determined. The decision on the presence or absence of atony is made based on the analysis, and at step 525, information based on the decision is transmitted to the user. This transmission can be carried out on the device itself, or information can be transmitted by wire or wirelessly to a remote location.

A variant of the above method is described with reference to Fig.6. This implementation includes additional steps with respect to the steps described with reference to FIG. After analysis step 523, in an additional second analysis step 624, a signal representing the received reflected ultrasound signal is further analyzed to determine at least one of the presence of bleeding in the uterus of the subject, the severity of the bleeding, and the place of bleeding in the uterus. In the second processing step 626, which follows the processing step 535, one or more messages from a set of messages are selected based on the clinical instructions stored in the storage device for transmission to the user based on one or more of the presence of atony, the severity of the atony, the presence of bleeding, the severity bleeding and bleeding in the uterus. At step 527, in addition to information regarding the presence or absence of atony, additional information, such as the presence of bleeding, the severity of bleeding and the location of bleeding in the uterus, is transmitted to the user, while recommendations or suggestions to the user regarding PPH control are also transmitted.

Thus, such a method can provide comprehensive information to a caregiver to support treatment or control of PPH if it appears and when it appears.

Although embodiments and implementations have been described in detail in the drawings and in the description, such drawings and description should be considered as examples and are not limiting; The invention is not limited to the described embodiments. Variations and combinations will be understood by a practitioner, and all such variations are considered to be within the scope of the described methods.

Other variations of the described embodiments can be understood and carried out by specialists in the field of technology in the process of practical application of the claimed invention based on a study of the drawings, description and appended claims. In the claims, the word “comprising” does not exclude elements or steps other than those mentioned, and the singular does not exclude the plural. One processor or converter, or another unit can perform the functions of several elements specified in the claims. The mere fact that certain characteristics are set forth in mutually different dependent claims does not mean that a combination of these characteristics cannot be used to advantage. Any reference position in the claims should not be construed as limiting the scope of the claims.

Claims (10)

1. The device (100) for assessing the tone of the uterine muscles, containing:
a first ultrasonic transducer (101) for applying ultrasound energy focused on the uterine musculature of the subject to generate acoustic radiation to generate a shear wave in the uterine musculature;
a second ultrasonic transducer (103) for emitting ultrasonic energy in the subject and receiving reflected ultrasonic energy;
an analysis unit (107) for analyzing a signal representing the received reflected ultrasonic energy in order to determine a shear wave propagation velocity in the uterine muscles; and
a processor module (109) for determining the shear modulus and thus the tonus value of the uterine muscles, for further use, based on the shear wave propagation velocity. 2. The device (100) according to claim 1, wherein the analysis unit (107) is further configured to analyze signals representing the received reflected ultrasound energy in order to detect at least one of the presence of bleeding in the uterus of the subject, the severity of the bleeding and the place of bleeding in the uterus. 3. The device according to claim 1 or 2, in which the transducers are placed in a shingling structure (402) for carrying by the subject around the upper abdomen, and the transducers are in interaction with the upper abdomen, sufficient to emit ultrasound in the subject. 4. A system (300) for monitoring a subject for postpartum hemorrhage, comprising:
a first ultrasonic transducer (101) for applying ultrasound energy focused on the uterine musculature of the subject to generate acoustic radiation power to generate a shear wave in the uterine musculature;
a second ultrasonic transducer (103) for emitting ultrasonic energy in the subject and receiving reflected ultrasonic energy;
an analysis unit (107) for analyzing a signal representing the received reflected ultrasonic energy in order to determine a shear wave propagation velocity in the uterine muscles; and
a processor module (109) for determining a shear modulus and thus a tonus value of the uterine musculature based on the shear wave propagation velocity; and
a user interface (111) for transmitting information based on the tone value of the uterine muscles to the user. 5. The system of claim 4, wherein the user interface (111) comprises at least one of an audio alarm generating unit, an alphanumeric display, a visual display unit, and a visual alarm indicating unit. 6. The system of claim 4, wherein the processor module (109) is configured to select one or more messages from a set of messages based on clinical instructions stored in a storage device (213), for transmission to a user via a user interface (111), to based on one or more of the mean tonus, the presence of bleeding, the severity of the bleeding, and the location of the bleeding. 7. The system of claim 4, operably connected to a remote control unit (315) comprising a second user interface device (311 ′) substantially similar to the user interface (311) for duplicating the functions of the user interface (311) at a remote location. 8. The method (500) for assessing the tone of the uterine muscles, which includes the steps of:
a stimulation step (517), which consists in applying ultrasound energy focused on the uterine musculature of the subject to create acoustic radiation power to generate a shear wave in the uterine musculature;
a radiation step (519), comprising emitting ultrasonic energy in the subject;
a receiving step (521), comprising receiving the reflected ultrasonic energy;
an analysis step (523), which consists in analyzing a signal representing the received reflected ultrasonic energy, in order to determine the shear wave propagation velocity in the uterine muscles; and
a processing step (525), which consists in determining the shear modulus and thus the tonus value of the uterine muscles, for further use, based on the shear wave propagation velocity. 9. The method of claim 8, further comprising transmitting (527), the method of transmitting to the user at least one of the information based on the tonus value of the uterine muscles and the alarm. 10. The method according to p. 9, further comprising the steps of:
the second stage (624) of the analysis, which consists in analyzing the signals of the received reflected ultrasonic energy in order to detect at least one of the presence of bleeding in the uterus of the subject, the severity of bleeding and the place of bleeding in the uterus;
the second processing step (626), which consists of selecting a message from a set of messages based on clinical instructions stored in a memory device for transmission to a user through a user interface based on one or more of a tone, bleeding, bleeding severity and bleeding site; and
wherein, the transfer step (527) includes transmitting the selected message to the user.

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