Patent Application
20080082024
Various embodiments of the present disclosure are described herein with reference to the drawings wherein:
Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.
In the discussion which follows, the term “cable” may incorporate a single conductor or may comprise an assembly of conductors arranged in any mode of operation known in the art. Connector refers to a single plug, receptacle, or other device capable of connecting to a cable, device or apparatus. A connector assembly refers to the connection between two connectors wherein the connectors facilitate connectivity between two cables, devices or apparatus, or any combination thereof. Connection or coupling between the two components may be mechanical, electro-mechanical or solely electrical without any mechanical means of connection. Such electrical coupling or connection may be infrared or incorporate electromagnetic wave principles. Thus, the term “connection” or “electrical connection” is to be construed as any electrical, mechanical connection or combination thereof known in the art.
Typically, monitoring device 40 is configured to receive a monitoring signal from a specific type of medical device with the monitoring signals having specific electrical characteristics. For example, first input connector 40a of monitoring device 40 is configured to receive a monitoring signal from an intrauterine pressure (IUP) catheter wherein the monitoring signal contains maternal intrauterine pressure medical signals. The electrical characteristics of a monitoring signal from an IUP catheter is typically an alternating current or direct current signal, as driven by the excitation voltage of the monitor to which it is connected, of amplitude less than 1 Volt. The amplitude of the IUP monitoring signal changes in response to changes in intrauterine pressure. Second input connector 40b of monitoring device 40 may be configured to receive a monitoring signal from a fetal scalp electrode wherein the monitoring signal contains a fetal electrocardiogram (FECG) medical signal. The electrical characteristics of a monitoring signal from a fetal scalp electrode is typically an electrical potential of less than 1 Volt which characterizes the periodic polarization and depolarization of the fetal heart muscle.
In the maternal and fetal monitoring system 10 of
Signal replication medical apparatus 100, as described herein, is used to resolve an incompatibility between any medical device and any monitoring device. Signal replication medical apparatus 100 consists of a housing 102 which houses a plurality of connectors 110, 111, output cables 151A, 151B, indicators I and user interface devices 112, 132, 134 described hereinbelow. Housing 102 may be sufficiently small and manufactured from lightweight materials, such as plastic, such that the signal replication medical apparatus 100 is a light-weight inline device.
Input connector 110 of the signal replication medical apparatus 100 is adapted to connect to a first end 50A of an electrical cable 50. Second end 50B of electrical cable 50 connects to a medical device, such as an electrode array 20. It is envisioned signal replication medical apparatus 100 described herein may have any number of inputs and may connect to any number of medical devices.
First and second output cables 151A, 151B of the signal replication medical apparatus 100 are adapted to connect to an electrical system, such as a monitoring device 40, capable of receiving a monitoring signal. It is envisioned signal replication medical apparatus 100 described herein may have any number of outputs, in the form of output cables or output connectors, and may connect to any number of electrical systems capable of receiving a monitoring signal from a medical device.
Electrodes 21 on electrode array 20 receive monitoring signals from the patient and fetus, including signals from maternal uterine muscle and from the maternal and fetal heart muscles. Monitoring signals from electrodes 21 on electrode array 20 are transmitted through electrical cable 50 to the signal replication medical apparatus 100. In this particular embodiment, electrical cable 50 transmits eight individual monitoring signals, one from each electrode 21 on electrode array 20, to signal replication medical apparatus 100 with each monitoring signal containing at least a portion of several maternal and fetal medical signals.
First and second output cables 151a, 151b of signal replication medical apparatus 100 connect to the first and second input connectors 40a, 40b, respectively, of monitoring device 40. Output signals from the signal replication medical apparatus 100 are transmitted on first and second output cables 51a, 51b to monitoring device 40.
Signal processing circuitry 160 may include an analog to digital (A/D) converter 160A, a digital signal processor (DSP) 160B, a signal generator 160C and a digital to analog (D/A) converter 160D. Signal processing circuitry 160 is adapted to receive at least one monitoring signal from a first medical device, such as an electrode array 120. A/D converter 160A converts the analog monitoring signal from a first medical device to a digital representation of the analog monitoring signal. DSP 160B, having a memory storing a set of programmable instructions capable of being executed by the DSP 160B for performing the functions described herein, processes the converted monitoring signal. Processing may include the extraction of a medical signal from a monitoring signal, extraction of one or more medical signals from a plurality of monitoring signals or determination if the signal is a valid signal. Signal generator 160C receives at least a portion of processed data from DSP 160B and generates replicated data indicative of a monitoring signal outputted by a second medical device. The replicated data is different than the monitoring signal from the first medical device and is compatible with monitoring device 140. D/A converter 160D converts the replicated data generated by the signal generator 160C to an analog signal and analog signal is outputted to an output cable 151A, 151B. Output cable 151A, 151B transmits replicated analog signal to monitoring device 140, and the medical signal is presented on display 141.
Signal processing circuitry 160 may be an application-specific integrated circuit (ASIC) customized for this particular use or may be a general purpose device adapted for this use. The functions performed by the various elements 160A-D of signal processing circuitry 160 may be performed in a variety of ways as known in the art
More specifically, first input connector 140A on monitoring device 140 is configured to receive an IUP catheter monitoring signal containing a maternal intrauterine pressure medical signal. Second input connector 140B is configured to receive a fetal scalp electrode monitoring signal, containing a FECG medical signal. Electrode Array 120 supplies eight monitoring signals to signal processing circuitry 160 with each monitoring signal containing at least a portion of several fetal and maternal medical signals (e.g. FECG medical signal, maternal ECG medical signal and maternal EHG medical signal). Electrode array 120 is therefore incompatible with monitoring device 140.
Signal replication medical apparatus 100 receives the plurality of monitoring signals from electrodes 121 on electrode array 120 through electrical cable 150. The A/D converter 160A converts the monitoring signals, DSP 160B extracts the EHG medical signal and the FECG medical signal from the monitoring signals. Signal generator 160C replicated an EHG monitoring signal and an FECG monitoring signal indicative of a monitoring signal from an IUP catheter and a fetal scalp electrode, respectively. A/D converter 160D converts the replicated IUP and FECG monitoring signals such that signals are compatible with first and second input connector 140A, 140B of monitoring device 140. The replicated monitoring signals are outputted through first and second output cable 151A, 151B, received by first and second input connector 140A 140B, respectively, of monitoring device 140 and the medical signals are presented on display 141.
In another embodiment of the present disclosure, the medical signal may be altered by signal processing circuitry 160. Alteration of the replicated signal may remove an incompatibility that exists between the signal and monitoring device 140, may increase compatibility of the signal with the monitoring device 140 or may aid a clinician in recognizing a characteristic of the signal. For example, a FECG from an electrode array 120 may need to be inverted in order for the signal to be indicative of a signal received from a second medical device and compatible with monitoring device 140. Alternatively, an offset may be added to the signal for the signal to be in a specific range (e.g. current or voltage range), or in order for a trigger or counting mechanism in the monitoring device 140 to recognize the signal. Low strength signals, or a portion of a low strength signal, may be amplified, re-scaled or otherwise altered. Alterations may be required to satisfy various criteria set by monitoring device 140 such as signal strength, signal quality, peak amplitude or signal energy.
In another embodiment of the present invention, signal replication medical apparatus 100 may replicate a signal indicative of a fault condition recognized by monitoring device 140. For example, monitoring device 140 may indicate a fault condition on display 141 when the input is either open or shorted. Signal replication medical apparatus 100 may simulate this fault condition by replicating a signal indicative of an open or shorted medical device when signal processing circuitry 160 is unable to extract a medical signal from the monitoring signals. Signal replication medical apparatus 100 may replicate any such fault signal recognized by monitoring device 140.
In another embodiment of the present disclosure, signal processing circuitry 160 performs at least one diagnostic check on electrical cable 150 as described in a U.S. Utility patent application titled Cable Monitoring Apparatus, Attorney Docket Number H-KN-00513 (1502-143), concurrently filed on Sep. 29, 2006 with the present application, the entire contents of which are incorporated herein by reference. Referring to
First connector 110 may interface with various medical devices including a medical electrode, a medical electrode array, an abdominal strain gage, a tocodynamometer, an intrauterine pressure catheter, an ultrasound transducer, a vacuum pressure sensor, a pulse oximeter, a pH sensor, a cervical dilation sensor, a cervical effacement sensor, a cervical length sensor and a fetal station sensor. Signal replication medical apparatus 100 may receive monitoring signals from any number of medical devices and supply replicated monitoring signals to any number of monitoring devices.
In yet another embodiment of the present disclosure first connector 110 and second connector 111 may receive medical signal from a first medical device 120 and second medical device (not shown). Signal processing circuitry 160 may select the source of the replicated signal from the first input connector 110 or from the second input connector 111. Selection may be performed automatically by the signal processing circuitry 160 or selection may be performed manually by a clinician. Signal processing circuitry 160 may use various criteria to automatically select an input, such as, for example, signal quality, signal strength and/or the functionality of the medical devices. Alternatively, clinician may select an input via the input selector switch 113.
A medical electrode and various medical uses are well know in the art. A medical electrode array is medical device containing a plurality of medical electrodes as described in U.S. Application No. 60/798,842 to Meyer, the contents of which are incorporated herein by reference. Abdominal strain gages, tocodynamometers, intrauterine pressure catheters and ultrasound transducers are also well know in the art.
Lesser known devices include a vacuum pressure sensor, a fetal pulse oximeter, a pH sensor, a cervical dilation sensor, a cervical effacement sensor, a cervical length sensor and a fetal station sensor. A vacuum pressure sensor measures the amount of vacuum applied to a fetal skull by a vacuum extractor, a device used to apply guiding pulls to a fetal scalp during delivery, and the vacuum measured by the vacuum pressure sensor is recorded by an external device. A fetal pulse oximeter measures the oxygen saturation of fetal blood during delivery. A measure of oxygen saturation, in conjunction with the fetal heart rate, can be used to detect abnormalities wherein a clinician may decide to proceed with a cesarean delivery. Similarly, fetal pH, measured with a fetal pH sensor, begins to decrease when oxygen saturation levels decrease. A cervical dilation sensor is used to measure the progress of labor by measuring and recording cervical dilation. A cervical effacement sensor measures the gradual softening or thinning of the cervix during the first stage of labor which may be used to predict the onset of delivery. Similarly, a cervical dilation sensor measures the dilation of the cervix during the first stage of labor. Finally, a fetal station sensor determines the relative positioning between the presenting part of the fetus, whether that be the head, shoulder, buttocks, or feet, and two parts of the maternal pelvis called the ischial spines.
An intrauterine pressure catheter is a common apparatus for measuring the fetal contractions of a maternal abdomen. Various pressure catheter components and systems are described in U.S. Pat. No. 5,566,680 to Urion et al., the contents of which are incorporated herein by reference. When using a monitoring device 140 configured to receive a monitoring signal from an IUP catheter it often becomes necessary or desirable to “zero” or “re-zero” the monitoring device 140. U.S. patent application Ser. No. 10/952,942 to Zaiken, titled Intrauterine Pressure Catheter Interface Cable System and filed on Sep. 29, 2004, the entire contents of which are incorporated herein by reference, describes use of a pressure catheter, a zero/re-zero apparatus and method of use.
In yet another embodiment of the present disclosure the zero/re-zero function as described in a U.S. Utility patent application titled Cable Monitoring Apparatus, Attorney Docket Number H-KN-00512 (1502-143), concurrently filed on Sep. 29, 2006 with the present application, may be incorporated into a signal replication medical apparatus 100. Referring to
In yet another embodiment of the present disclosure, indicators I may correspond to electrodes 121 on the electrode array 120 applied to the maternal abdomen A. With reference to
In yet another embodiment of the present disclosure, one or more of indicators I include a light driven by a signal from the signal processing circuitry 160 wherein the signal is indicative of the monitoring signal or the functionality of electrical cable 150. Indicator I may be driven with a signal proportional to the monitoring signal from the medical device, such as an electrode array 120. Clinicians can troubleshoot problems with an electrical cable 150 or medical device by observing indicator I on the signal replication medical apparatus 100.
Referring now to
In Step 202 an analog monitoring signal from one or more medical devices is converted from an analog format to a digital representation of the analog monitoring signal. As is known in the art, A/D conversion is not a single step but a real-time process.
In Step 204 the digital representation of the analog monitoring signal is processed. Processing may include extracting a medical signal from a monitoring signal, extracting a medical signal from a plurality of monitoring signals or determining if an extracted medical signal is a valid representation of the expected signal.
In Step 206 the format of replicated data is determined. The extracted medical signal may be replicated as a monitoring signal indicative of a signal having been outputted from a second medical device, wherein the monitoring signal from the second medical device is different that the monitoring signal converted in Step 202. The replicated data may be a zero-voltage signal, replicated for a predetermined period of time, supplied to the monitoring device 140 to perform a zero/re-zero of the monitoring device 140. The replicated data may also be indicative of a fault condition recognized by monitoring device 140.
In Step 208 the replicated data format determined in Step 206 is generated into a digital representation of a monitoring signal. Replicated data may be altered in order to remove an incompatibility between the signal and monitoring device 140, to increase compatibility of the signal with the monitoring device 140 or to aid a clinician in recognizing an element of the signal.
In Step 210 the replicated data generated in Step 208 is converted into a format recognized by the monitoring device 140. Format may be analog or digital and may be transmitted to the monitoring device 140 by a cable 151a, 151b or by any method of wireless transmission used to transmit a signal.
While several embodiments of the disclosure have been shown in the drawings and/or discussed herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
