Surgery – Diagnostic testing – Detecting muscle electrical signal
Reexamination Certificate
2002-06-21
2004-11-23
Winakur, Eric F. (Department: 3736)
Surgery
Diagnostic testing
Detecting muscle electrical signal
C600S304000
Reexamination Certificate
active
06823211
ABSTRACT:
The present invention relates to a device for the prediction of the onset of labour in humans or animals, a method for predicting labour using the device and the use thereof. More specifically the invention relates to a device for predicting the onset of labour which may be premature, on time or delayed, a method thereof using the device, operated by the subject or another individual and the use thereof.
Measurement of uterine contractions to determine the state of pregnancy and diagnose real labour is well documented. For example U.S. Pat. No. 4,967,761 (Nathanielsz) discloses a method comprising sensing myometrial contractility, producing signals representing the sensed contractility, storing the signals and determining characteristic representative frequencies which are then classified as term or preterm labour. WO 94/13202 (Rosenberg) discloses a method and device as a diagnostic tool by means of assessing muscular contraction. Such clinical assessment by means of evaluating the mechanical activity in terms of strength, duration and frequency of palpated contractions do not however correlate with onset or progress of labour, and are liable to considerable inter-observer variation.
Measurement of electrical activity, electrohysterography, has been proposed as an alternative approach to the detection of labour. For example WO 94/14373 (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. WO 97/25922 (Rosenberg) discloses a further method for analysis of electromyographic data.
However such publications relate exclusively to clinical, usually intrusive techniques for data collection. Moreover, data analysis and/or diagnosis is generally also by complex methods requiring expert operation. These are therefore of limited application, inconvenient since they require the intervention of a clinician, and hence usually require the subject to attend a hospital, clinic or the like and are therefore limited in application since the likelihood of detecting abnormal pregnancies is low.
Moreover the disclosures all relate to methods for analysing data obtained by electrohysterography using various forms of frequency analysis which are limited and used for the diagnosis of contractile or true labour. The methods described, and in particular the analytical techniques employed, are not disclosed as predictive tools to determine the progress of the precontractile preparative phase of parturition prior to the onset of labour. Thus, the prior art discloses diagnostic tools which can give a measure as to whether a symptomatic patient is in labour only.
Accordingly there is a need for a device which non-intrusively predicts the onset of labour and/or which indicates the imminence of labour and which is suited for non clinical, i.e., home use. In particular, there is a desire for a device which can both be operated in a domiciliary environment and produce results which can be interpreted without the need for a clinician.
We have now surprisingly found that a device and method can be provided for non intrusive non clinical use which can enable the prediction of onset of labour and or indicate the imminence of labour and which can be operated by the subject or any observer without clinical knowledge, or specific expertise relating to the technique.
Since the device and method of the invention is predictive rather than merely diagnostic of labour it enables for the first time measures to be taken to provide medical assistance where necessary in the instance of premature labour, in advance of the event itself, thereby allowing for example preventative action, simplifying any remedial action and reducing loss of life or birth defects which might result from premature labour. The device and method also enable subjects to determine the expected onset of their labour with accuracy. This will help to avoid false alarms which are distressful and often dangerous for the subjects attempting to reach medical help, and are an undue burden on the medical services, but will also help to ensure that subjects remain within reasonable reach of medical assistance when onset of labour is close.
Accordingly in a first aspect of the invention there is provided a device for prediction of onset of labour comprising a portable assembly of a plurality of recording electrodes and optionally a reference electrode, a means for data acquisition, a means for conversion of analogue to digitised data and a display adapted to display this data in terms of one of a small number of discrete results indicative of the state of preparedness for labour, for example in terms of a positive or negative result indicating the preparedness for labour, wherein each electrode comprises a contact surface for application to a subject, and in particular to an abdominal and/or vaginal surface of a subject, the device further comprising data analysing means for analysing the digitised data with reference to pre-recorded reference data and/or predetermined reference parameters, the assembly being operatively associated in compact manner.
The device records uterine electrical activity, in particular by application to the abdominal or vaginal surface, in generally similar manner to that known in the art. That is to say, a plurality of recording electrodes for measuring action potential are provided which are applicable to an abdominal or vaginal surface of a patient under analysis; the analogue to digital convertor connected to the electrodes acts to convert electromyographic signals produced by the electrodes into digitised data indicative of the electromyographic signals and action potentials; and the digitised data is stored and analysed with reference to prerecorded reference data and/or predetermined reference parameters, the results being used to actuate a display adapted to display this data as indicating one of a small number of discrete conditions indicative of the measured uterine activity.
The invention differs from the prior art by exploiting the surprising result that analysis of uterine electrical activity can be used not merely to monitor the progress of, and/or diagnose active labour as in the prior art, but can be used to obtain an indication of uterine preparedness for labour in the initial phase of parturition before onset of active labour.
The display is adapted to work in conjunction with the pre-recorded reference data and/or pre-determined reference parameters to provide a simple display indicating one of a few discrete states of uterine preparedness for labour (for example a two-state model indicating a positive or negative result for preparedness; a three-state model indicating for example pre-parturition, early stage changes, and full preparedness etc.).
The present invention thus enables for the first time a prediction of the onset of labour and/or a monitoring of the pre-labour phase of parturition, as the uterus prepares for the contractile or labour phase of parturition. Moreover, the invention does this in a compact and portable manner, and by displaying only a small number of discrete results, provides a result which can be readily interpreted by a subject without the need for intervention by a clinician, and is thus particularly suited to home use.
The present invention provides highly reliable results based on the finding that certain parameters govern the production of uterine electrical signals. Specifically there is an increase in the number of intercell connections (gap junctions) which then facilitate the spread of electrical impulses from one part of the womb (uterus) to another, allowing for progressively synchronous and effective mechanical activity (contractions). These changes occur progressively throughout the pre-labour phase of parturition. We judge that the observed change in the rhythms governing electrical activity reflect these cellular changes.
This finding is highly significan
Simpson Nigel Alastair Buist
Walker James Johnston
Jacobson & Holman PLLC
Jopejo Limited
Winakur Eric F.
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