Patent Application
20140073879
This invention relates to medical monitoring in general and more particularly to a system for monitoring pregnancy.
The birthing process in mammals has a normal or average duration, for example in humans gestation is normally 266 days while for horses it normally ranges between 335 and 345 days. For cattle gestation averages 283 days while for swine about 113 to 116 days and for sheep 144 to 151 days. The actual period for human gestation is variable but is considered full-term to conclude between 38-42 weeks post-conception. In humans, for example, labor and birth that commences earlier than 36 weeks as a result of a high risk pregnancy or other complications presents serious if not fatal problems for the newborn infant that can well continue on to adulthood. Delivery at 30-32 weeks normally necessitates considerable time in an NICU and delivery very early at around 23 weeks is considered almost uniformly fatal
For most domestic animals entering into labor and the birthing process occurs with little assistance. However, for humans in particular and certain valuable domestic animals, such as Thoroughbred horses, the gestation period in the final trimester is normally closely monitored for the beginning of labor and for complications such as preterm labor resulting in preterm birth.
For domestic animals a preterm birth will usually produce a still born or a weak and sickly animal requiring expensive attention. Especially in the case of Thoroughbred horses where stud fees may run up to six figures, a premature foal may not survive or perform to the expectations of the breeder resulting in a substantial financial loss.
For humans the societal burden of preterm births in the United States was estimated to be $26 billion in 2005 by the Committee on Understanding Premature Birth and Assuring Healthy Outcomes under the auspices of the US Institute of Medicine. These costs include medical care services at $16.9 billion; maternal delivery costs $1.9 billion; early intervention services $611 million; special education services associated with a high incidence of disabling conditions associated with premature infants added $1.1 billion. Finally, the committee estimated that lost household and labor market productivity associated with those disabling conditions contributed $5.7 billion.
High-risk pregnancies are not always detected early nor easily determined in advance so that preventative measures can be taken to avoid a preterm birth. Women pregnant for the first time or who may not have access to medical help can present a high-risk pregnancy without being aware of their condition. Early identification of high-risk pregnancies facilitates monitoring and prompt initiation of therapy. Early initiation of therapy has the potential to decrease the onset of labor, thus reducing the complications endured by the newborn as well as reducing the cost burden. However, monitoring of even normal pregnancies in the last trimester is also recommended if only to avoid unnecessary trips to the hospital because of false labor.
It is recommended that monitoring of a pregnancy, especially in the last half of the pregnancy, be conducted frequently so that complications can be identified as well as the onset of labor in its very early stages. In the case of domestic animals monitoring of the animal's pregnancy will normally require the on-site presence of a veterinarian which may not be convenient.
In the United States and other Western countries where medical services are more readily available, a pregnancy may be monitored at the doctor's office as an outpatient or in the hospital. However, this requires a visit to the doctor's office or the hospital every few days in order to monitor the patient's progress. In developing countries it may not be possible for a woman to see a doctor on a regular basis so that intervention to alleviate or treat a condition may be too late.
Various systems have been put forward to monitor the status of a pregnancy. For example U.S. Pat. No. 6,270,458 describes a system employing ultrasound to monitor the dilation of the cervix and descent of the presenting part during labor. This system employs small ultrasound reflectors disposed on either side of the cervical os and on the fetal presenting part to reflect ultrasound signals transmitted by an ultrasound interface unit located outside of the body.
Measurement of uterine electrical activity, electrohysterography, has been proposed as an alternative approach to the detection of labor. For example WO 94114373 (Garfield) records signals from embedded electrodes, WO 95/31932 and WO 96/39931 (Garfield) disclose a method which stores data and compares activity and U.S. Pat. No. 5,373,852 (Harrison) uses radiotelemetric transmission for sensing pressure, temperature and electrical activity. Rosenberg (WO 97/25922) discloses a further method for analysis of electromyographic data. These techniques relate exclusively to clinical settings, usually intrusive systems for data collection. U.S. Pat. No. 6,823,211 discloses a nonintrusive_device including recording electrodes, a digital converter and a display unit that can be_worn on the exterior of the abdomen or vaginal area of a body for the analysis of uterine electrical activity to monitor the progress of, and/or diagnose active labor and can be used to obtain an indication of uterine preparedness for labor in the initial phase of parturition before onset of active labor. Another system that relies on the measurement of uterine electrical activity is disclosed in U.S. Pat. No. 6,290,657 that, similar to the '211 patent, uses surface electrodes and a monitor to sense and analyze electrical signals that are transmitted by telephone to the physician's office.
The human birthing process is divided into four stages. Stage 1 occurs from the onset of labor to full cervical dilation. Stage 2 is from full cervical dilation to delivery; stage 3 from delivery to expulsion of placenta and stage 4 from expulsion of the placenta to afterbirth recovery. Thus, monitoring the physiological parameters of the cervix in humans and mammals allows the clinician to follow the progress of a pregnancy during stage 1 of the process where complications, particularly preterm labor, can be recognized and possibly treated. In that connection some successful work has been done in this area but the methods employed require the presence of the clinician and usually employ invasive procedures.
For example, in Patent Application Publication U.S. 2009/0137925 the pregnancy is monitored by attaching a clip carrying a pair of tetra-pole electrodes to the patient's cervix. The electrodes that are electrically connected to a transducer cable that supplies the signal to an interface unit and monitor. The transducer cable carries analog to digital conditioning hardware while the interface unit includes an algorithm for comparing typical impedance value with the impedance value of the cervix being measured. The resulting output can be a measure of time of labor vs. cervical stromal impedance (CSI) value or time in labor vs. cervical dilation and/or effacement for plotting a Friedman labor curve.
The prior art methods are inconvenient and are not suited for long term, continuous monitoring of the patient. In many cases monitoring involves the intervention of a clinician that requires the patient to visit the hospital or the clinician's office frequently to undergo the monitoring procedures. Placing sensors externally may introduce discrepancies in the data collected. For example, discrepancies due to variations in skin temperature and variations in contact pressure between the skin and the sensor. Other methods require that relatively large devices be placed in the patient that requires frequent removal to avoid odor and possible infection. Several methods require connection by wire to sensors at one end and to burdensome equipment at the output end that requires that the patient be non-ambulatory. In addition, many prior art systems are_concerned only with the measurement of vaginal contractions which can be an unreliable indicator of the onset of labor.
The physiological parameters of cervix effacement (length) and ripeness (thickness) and dilation are reliable indicators of the onset of labor. Data based on these parameters can be plotted to produce a curve having a slope that normally is relatively flat but which undergoes a significant change due to physiological changes of the cervix as labor becomes imminent. Such a curve can be used to determine if an individual is approaching actual labor as contrasted with false labor and is a reliable indicator of preterm labor. In addition other physiological parameters indicative of cervix condition and female health are pH and temperature.
The present invention relates to a system for long term, continuous, monitoring of pregnant mammals particularly to detect the onset of preterm labor. For example, the system enables communication between sensors and a collection unit for transmittal to a remote unit for display and monitoring of the collected data by a clinician. In accordance with the invention after an initial examination it is not ordinarily necessary for the individual being monitored to be in the presence of the clinician.
Accordingly, it is an object of the invention to monitor and record the physiological condition of the cervix from sensors immediately adjacent to and in contact with the cervix.
An object of the invention is to provide a system for continuous monitoring of the condition of the cervix while permitting the subject to be completely ambulatory and have complete freedom of action.
Another object of the invention is to provide a system wherein the monitoring of the cervix can be done remotely.
A further object of the invention is to continuously monitor changes in effacement, dilation and ripeness of the cervix to monitor the condition and/or the stage of pregnancy.
A further object of the invention is to continuously monitor pH and temperature as physiological parameters of the cervix and the genital health of the individual.
Another object of the invention is to provide a system that can be employed early in pregnancy to detect the early onset of conditions that indicate the likelihood of a preterm birth.
It is an object of the invention to provide a system m which data is wirelessly communicated to and recorded in an interface device”.
It is an object of the invention to provide a system that collects and analyses data and distinguishes between normal conditions of the cervix and relevant changes in effacement and ripeness that may indicate early stages of labor.
According to one aspect of the invention there is provided a method for monitoring the birth process of a mammal comprising the steps of:
In accordance with the method of the invention the data is developed and can be remotely monitored by a data collection center or by a clinician while the individual is completely unrestrained and ambulatory. Thus the need for frequent contacts with a clinician such as a doctor or veterinarian is unnecessary since the the condition of the cervix can be remotely monitored at the data collection center, the clinician's office or hospital.
The physiological parameters of the cervix including impedance, body temperature and pH can be measured by several relatively noninvasive technologies which permit the development of data while permitting the individual to be completely free to move around. For example, cervix effacement, dilation and ripeness can be measured using ultrasound, infrared or by measurement of impedance.
In one preferred mode the data includes impedance measurements and is conveniently processed to correlate to cervical stromal impedance (CSI) values stored in the database of the interface device. Typical values may be found in Gandhi, et al., “Comparison of Human Uterine Cervical Electrical Impedance Measurements Derived Using Two Tetrapolar Probes of Different Sizes,” European Journal of Obstetrics & Gynecology and Reproductive Biology, Vol. 129, Issue 2, December 2006, 145-149, which is incorporated herein by reference in its entirety.
Alternatively, in another embodiment the processed data is accumulated to generate baseline data for the individual being monitored. The baseline data can be displayed as a curve or displayed in textual form. In either case a significant change in the slope of the curve or an increase or decrease in data values is an indication that a significant change in the physiological condition of the cervix and that labor may be imminent. In the case of pH and temperature measurements the data is accumulated to generate a baseline of these parameters for the individual being monitored.
In another aspect of the invention the system comprises:
Depending on the technology employed to monitor the physiological parameters of the cervix the sensor may take several well understood forms. Thus, ultrasound and electrical measurements have been employed to measure contractions of the uterus to predict the onset of labor. These same techniques can be employed to monitor physiological parameters of the cervix. With ultrasound, for example, reflectors may be placed on either side of the cervical os that reflect ultrasound signals from an interface unit located outside of the body. Changes in physiological parameters of the cervix such as effacement, dilation or ripeness will produce changes in the reflected signals. In the case of electrical measurements, such as impedance, electrodes are positioned immediately adjacent to the cervix and the change in the output signal correlated with effacement, dilation and ripeness of the cervix. Likewise the sensing device can include one or more pH microelectrodes and temperature sensing electrodes. Temperature and pH are indicators of other systemic or gynecological problems that can be monitored to suggest that medical treatment is required.
In accordance with the invention these techniques can be employed early on in the pregnancy with no discomfort to the individual and without the necessity of restraining or otherwise preventing the free movement of the individual during the monitoring process.
To maintain freedom of movement for the individual being monitored all transmissions of data, i.e. from the sensor to the interface device which is external of the body and thence to the transmission unit is wireless. Since the transmission distance between the interface device and the transmission unit will be relatively short the choice of transmission means is not critical. Thus, blue tooth technology is applicable as it is easily adapted for the purpose and has low power requirements. For transmission from the interface unit to the remote unit a more robust system is required since the transmission distance can be long, on the order of a few miles to many miles depending on the location of the remote unit. Accordingly, transmission may be by telephone, landline or cellular, or by a radio frequency link (RF).
These and other objects and advantages will become apparent from the following description of the invention taken in conjunction with the drawings in which:
The system of the invention is suited for monitoring the pregnancy of mammals, however for ease of description the invention will be described in connection with monitoring the pregnancy of a human female. Although other systems employing infrared and ultrasound are within the scope of the invention, the preferred system described herein will be in connection with the utilization of impedance as an indicator of the physiological condition of the cervix.
Referring to
The sensing device 12 wirelessly communicates with an interface device 14 that receives the digital data from the sensing device. The interface device 14 will normally be worn by the individual outside of the body, such as by attachment to the individual's clothing or will otherwise be in close proximity to the individual's body.
The interface/telemetry device 14 includes a housing that contains electronics having software which is programed to compare the data as received to a data base consisting of values for the physiological parameters being monitored. The interface device 14 further includes memory containing the data base of values for the parameters or, as is often the case where typical values are not available, to accumulate the data as they are received to create a data base of parameters for the individual against which newly received data are compared. The software includes the corresponding algorithms for creating impedance, pH and temperature baseline data and for comparing the data of each parameter to the baseline data for the respective parameter. A significant change in received data from the baseline data will cause the software program to transmit a warning to the clinician that some action is required.
At predetermined time intervals the analyzed data that are received during a preceding interval may be transmitted to a transmitter 16 for transmission to a remote monitor 18 for read out of the analyzed data. The transmitter 16 may be any device capable of receiving the signal from the interface device 14 and transmitting it over relatively long distance. It may be a separate unit or may be integral with the interface device 14. Thus, good results are obtained when transmission is, for example, a telephone, either land line or cellular, or a radio receiver/transmitter. When the transmitter 16 is separate from the interface device 14 communication between the interface device 14 and the transmitter 16 preferably is wireless or, if the interface device is not being worn by the individual, the devices may be hardwired.
Because the sensing device 12 and the interface device 14 are normally in relatively close proximity communication between the sensing device 12 and the interface device 14 is most conveniently achieved using Zigbee, wifi, radio frequency or Bluetooth®.
As illustrated in
As more clearly shown in
Depending on the patient, under certain circumstances the sensing device 12 may tend to shift over time after being placed around the cervix 22. This can result in inaccurate data generated by the sensing device 12. As shown in
Yet another embodiment of the sensing device 12 is illustrated in
In another embodiment shown in
Although the system has been described thus far in connection with a sensing device in the form of annulus the surrounds the cervix good results can be achieved with a sensing device that can be positioned adjacent one side of the cervix and the facing vaginal wall. Such embodiment is convenient to place and can be readily removed for cleaning and repositioned by the patient or clinician.
Referring to
Depending on the individual being monitored, a bladder (not shown) containing a vaginally inert fluid, such saline solution, may be positioned between the body 64 and the adjacent vaginal wall to aid in maintaining the body in close contact with the cervix.
It will be understood that monitoring of the physiological parameters of a pregnancy requires that body temperature and pH may also be monitored and recorded. The various embodiments of the sensing devices described herein are provided with the appropriate sensors for detecting body temperature and pH. These sensing devices are well understood in the art and do not per se form a part of this invention. For example pH can be measured by ion sensitive field effect transistors (ISFET) and miniaturized electronic temperature sensors for converting pH and temperature signals to digital data and holding this data in separate packets for transmission to the interface device 14 for inclusion in a data base.
The interface device 14 receives and records the transmitted data in step 108 and compares the received data with previously recorded data at step 110. Data representing temperature, impedance and pH for each transmitted packet of data is analyzed by being compared either to a data base consisting of typical values or to a data base consisting of previously recorded data for the individual at step 110 to determine an increase, no change or decrease of the data values. The newly received data is stored in memory and, in the case where the data base consists of previously recorded data for the individual being monitored, is added to the data base.
After comparing the newly received packet of data with the baseline for any or all of the parameters of temperature, impedance and pH and there is no substantial change from the baseline, monitoring steps 104 through 110 will continue. In step 112 a change in the trend of the data values for any or all of the parameters of temperature, impedance and pH for each transmitted packet of data over a predetermined period, for example 8 hours, will trigger a signal 113 to the user and the clinician to more closely monitor data output or to personally examine the individual. In the meantime monitoring and recording of the parameters is continued at 114. Thus, for example, a decreasing trend of data for impedance may indicate a change in cervix effacement, ripeness or dilation indicating the onset of birth. In the case of impending preterm birth steps may be taken to delay the birthing process and thus allow for further development of the fetus. Likewise, a trend showing a change over time in pH and or temperature may indicate infection or other health issue that can be treated by the clinician.
In the event there are no substantial changes from the recorded data of a received data packet for a parameter, signal 115 issues and the data is reviewed at 112 for changes that have been recorded over the predetermined time. If changes have been recorded during this period signal 113 is issued and monitoring continues. If no changes in the trend of recorded data for the parameter are detected for the predetermined period a signal 117 will be issued instructing at 118 that all recorded data to be reviewed for data changes from the time the device was activated. If there has been no change of data, signal 119 displays on the interface device 14 and the remote monitor 18 notifying the patient and the clinician of a possible device malfunction. The sensing device 12, the interface device 14 and the patient can be checked to determine source of the problem.
Time periods for transmitting data packets to the interface device 14 are programmed m the sensing device 12 electronics. As mentioned above it is preferred to keep transmission of the packets of digital data to a minimum, particularly at the earlier stage of pregnancy, to preserve battery life. At a later stage or critical period during the pregnancy the period between data packet transmission may be shortened. Likewise the predetermined period for data review at 112 is programmed into the electronics of the interface device 14. Preferably this period can be programmed by the clinician and will be adjusted depending on the parameter being monitored and the stage of the pregnancy. For example, in the early stage of a pregnancy the predetermined period for impedance measurement may be as long as several months. In the later stages, however, change in impedance becomes more critical and the predetermined period may be a few hours.
The data can be displayed by the interface device 14 to provide a read out of any changes or lack thereof from the previously recorded data. Thus, those attending the individual being monitored, or in the case of a human, the patient herself, will receive immediate notification of a problem with the pregnancy or a possible device malfunction. The compared data and data base may be periodically wirelessly transmitted in step 111 through the transmitter 16 to the monitor 18 that may be remotely located for display and monitoring by the clinician. In addition the data can be plotted on a curve, along with the previously recorded data. Alternatively, only a signal indicating a significant change in one or all of the parameters being monitored or a problem with the sensing device 12 or the accumulation device 14 will be transmitted to the monitor 18 to alert the clinician to a potential problem that may require attention.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
