Abstract: Various designs and features of an ambulatory transceiver and ECG lead set are disclosed for use in remote patient monitoring. One feature involves the use of unshielded, dual-conductor lead wires in which one conductor carries the patient's ECG signal and the other conductor provides an RF antenna element for the transceiver. The lead wires used in one embodiment provide improved flexibility, durability, and antenna performance over conventional lead sets with shielded wires. Another feature involves an antenna diversity scheme in which the transceiver switches between two or more ECG-lead antennas, each of which is formed from one or more ECG leads of the lead set. Another feature involves the use of a circuit within the transceiver to monitor, and dynamically compensate for changes in, the impedance of an ECG-lead antenna or a conductor thereof. Another feature is an improved circuit for protecting the transceiver from damage caused by defibrillation pulses.

Abstract: A method and system of encoding physiological data. In one embodiment of the invention, raw data is transformed into formatted images and then the formatted images are encoded. The data is transferred at full resolution once to a main server and then the superimposition of the data is encoded using a compression scheme. Preferably, the data is encoded using difference-based encoding, such as MPEG encoding. Encoding the data in this way makes it possible to perform data analysis on a wide variety of workstations, not just high-performance machines.

Abstract: A method and apparatus for monitoring and/or quantitatively measuring a patient's respiration using a flexible piezoelectric film sensor. The apparatus includes a piezoelectric film which converts acoustical waves generated by the patient's respiration into electrical signals. The piezoelectric film sensor can be used to monitor the respiration of a patient by correlating the sound generated in the patient's airway with respiratory activity. Further, the data generated by the sensor may be further analyzed by a patient monitor to diagnose respiratory conditions.

Abstract: A physiologic condition sensor comprises a sensor body including an optical assembly housed in a sensor housing. The optical assembly is configured to include a head portion, a tail portion, and an intermediate portion connecting the head portion and tail portion. The head and tail portions are wider than the intermediate portion to prevent longitudinal deformation of the sensor housing around the optical assembly.

Abstract: Blood pressure of an human being is read by a process that places a cuff around a portion of the human being's body. The cuff is inflated to a predefined pressure which occludes the flow of blood and then the cuff is deflated in a controlled manner. At a plurality of deflation pressure levels, pressure oscillations that occur in the cuff are measured to produce a series of measurements representing the waveform of the oscillations. The systolic pressure and mean arterial pressure are derived from the measurements in conventional manners. A portion of the waveform for one cardiac cycle is analyzed by locating points which correspond to the occurrence of the systolic and mean arterial pressures. The diastolic pressure, which occurs at the minimum point of the waveform, is derived from those points and the systolic and mean arterial pressures.

Abstract: A medical telemetry system includes a procedure alarm silence feature that enables a clinician to remotely disable a monitoring station alarm in order to perform a patient procedure that might cause inadvertent false alarms. To disable the alarm for a preprogrammed time interval, the clinician presses keys on the telemetry unit according to a predefined key sequence that is selected so as to reduce a likelihood of accidental alarm disablement. The monitoring system responds to the predefined sequence by disabling an audible alarm for all alarm conditions except class 1 arrhythmias. A corresponding visual alarm at the monitoring station is maintained active. While the alarm is disabled, the monitoring station displays an indication of the amount of time until expiration of the preprogrammed time interval.

Abstract: A method and system of distinguishing physiological pulses as measured by pulmonary artery catheterization. The method includes positioning two measurement devices in blood vessels of a subject, one in a major systemic artery and one in the pulmonary artery, and measuring blood pressure in the blood vessel with the measuring device to generate a pressure waveform. A phase difference between the two pressure waveforms is determined and used to create a warning or to display the phase difference on a display. The system includes an analysis module that determines phase differences based on the inputs from two or more physiological sensing modules.

Abstract: A method and apparatus for reducing noise and detecting electrode faults in a physiological activity acquisition system. The method includes the act of delivering a carrier signal through an electrode connected to a subject. Once the carrier signal is delivered, a combined signal having an electrical-activity portion and a carrier-signal portion is sensed by at least one signal sensing electrode attached to the subject. A low-pass, finite impulse response filter, having a first zero point frequency substantially the same as the carrier signal, separates the carrier signal portion from the electrical activity portion. An impedance value for the sensing electrode is calculated using the carrier signal portion. The calculated impedance value is compared against a known value to determine whether an electrode fault exists.

Abstract: A method and apparatus to detect irregular heart activity based upon a ventricular activity analysis, P wave activity, similarities in R wave to R wave intervals, and a state evaluation. The invention includes a beat classification module that receives ECG information as an input. The beat classification module determines whether the heart beat being analyzed falls within classifications that are suitable for use in analyzing whether an irregular condition exists. If the beat falls within a class suitable for analysis, the ECG information is fed to an interval calculator. The interval calculator determines the interval between successive R waves. The information from the interval calculator is provided to a probability engine and to a contextual analysis module. The probability engine is designed to detect atrial fibrillation based upon beat classification and RR interval values from the interval calculator.

Abstract: The invention relates to a system for and a method of establishing monitoring alarm limits based on physiological variables. Such a method can include the steps of receiving a plurality of physiological variable data where the physiological variable data is representative of physiological wellness variables, correlating alarm states of the physiological wellness variables with alarm states of physiological measurable variables, and providing a best clinical selection for the alarm limits.

Abstract: A system and apparatus for detecting electrode faults in a physiological activity acquisition system or device. The system includes at least one signal sensing electrode attached to the subject and a signal processor coupled to the at least one signal sensing electrode. The signal sensing electrode senses a combined signal from the subject. The combined signal has an activity portion and a carrier portion. The signal processor receives the combined signal from the electrode. The signal processor processes the combined signal and generates a noise-redeuced ECG and an electrode fault signal, if an electrode fault exists.

Abstract: An apparatus and method to connect to an electrode is claimed. The apparatus includes a first mating member and a second mating member having first and second openings. A resilient body portion connects the first and second mating members.

Abstract: An apparatus and a method for taking multiple physiological signals (e.g., ECG waveforms) from different sources as input, applying multiple algorithms in its core and generating results which are exported for use in clinical studies and research. The apparatus has a built-in database and a built-in spreadsheet to provide a unified platform for all clinical research in the medical field, including, but not limited to, clinical core laboratory work and high-end clinical research.

Abstract: A method and an apparatus for limiting the peak power consumed by a thermal recorder connected to portable battery-powered equipment. The battery-powered equipment is designed with a filter and an electronic circuit breaker. A circuit breaker current sense resistor and an output capacitor form an RC filter and provide a large current reservoir for the thermal recorder which averages the peak current demands seen at the circuit input. The electronic circuit breaker provides a current limit function and will not allow a current greater than a predetermined amperage level to be drawn. The thermal recorder has a CPU which provides pulses to a thermal print head in dependence on data incorporated in a pulse-width limit table. The values in the pulse-width limit table can be substituted for calculated pulse widths that would produce peak currents large enough to trip the circuit breaker.

Abstract: An electrocardiogram (ECG) electrode patch for attachment to a neonatal or infant patient. The ECG electrode patch includes a plurality of at least three electrodes coupled to a substrate. The plurality of at least three electrodes includes at least one electrode capable of measuring the electrical activity of the right side of the patient's heart. A plurality of electrical conductors are coupled to the plurality of electrodes and to the substrate.

Abstract: A method and system for identifying components of a waveform. The system includes an ECG acquisition module, a pressure waveform acquisition module to acquire a pressure waveform, and an analysis module coupled to the ECG acquisition module and the pressure waveform acquisition module. A monitor or similar display device is coupled to the analysis module. The analysis module is operable to determine three peaks in the pressure waveform corresponding to “a”, “c”, and “v” waves. Those “a”, “c”, or “v” waves that are identified by the analysis module are displayed on a monitor or similar device such that they are distinguished from each other and the remainder of the displayed waveform. The method involves displaying a waveform; identifying a number of peaks in a number of intervals of the waveform, and modifying the displayed waveform such that the identified peaks are distinguished from each other and the rest of the pressure waveform.

Abstract: A method and apparatus for evaluating the connection between the patient monitor and the patient. The apparatus is a compliance monitoring circuit that generates a constant current output to the isolation transformer of a patient monitoring device. Changes in the impedance of the patient connection cause changes in the output voltage of the constant current generator. This voltage can be measured and compared against a reference to generate a visible or audible compliance alarm.

Abstract: Blood pressure of an human being is read by a process that places a cuff around a portion of the human being's body. The cuff is inflated to a predefined pressure which occludes the flood of blood and then the cuff is deflated in a controlled manner. At a plurality of deflation pressure levels, pressure pulses that occur in the cuff are integrated to produce a plurality of integral values. A diastolic pressure of the human being is derived in response to the deflation pressure level at which occurred the integral value that is greatest in magnitude.

Abstract: A method and apparatus for detecting uterine contractions, determining the frequency of uterine contractions, trending the frequency data, and generating a real time graphical representation of the determined frequency. The invention employs commonly known methods of uterine activity detection. The uterine activity data is analyzed to determine the occurrence and frequency of contractions. The determined frequency of multiple time periods is displayed on a maternal/fetal monitor in real time over the course of labor.

Abstract: A method and apparatus for generating a signal representing uterine activity. The method including the acts of obtaining a uterine electromyography (EMG) signal, and processing the uterine EMG signal to produce a signal representative of uterine activity. The apparatus including a sensor for acquiring a uterine electromyography (EMG) signal, and a signal processor for generating a signal representative of uterine activity in response to the uterine EMG signal.