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: An Radiation detector employs one or more arrays of microphotonic light transmission devices to selectively control the flow of light from different detection sites in a scintillator into an optical conduit. For example the microphotonic light transmission devices may be microelectromechanical steerable mirrors or light gates. Instead of employing a separate detector element to convert the light from each site into an electrical signal that is then switched into a data acquisition system, the present detector assembly switches the light into the optical conduit to the data acquisition system.

Abstract: A method of switching the layout of an information monitoring system. Layouts are sets of graphical components that are associated with monitored or sensed activities. The invention provides a mechanism for switching the layout when conditions of the monitoring system change. The system determines the currently used components for the current layout, determines the currently used capabilities of the system, and determines a correspondence between the set of currently used components and currently used capabilities. The system reviews a group of layouts and determines a correspondence between the components in the layouts, in the group of layouts, and the set of currently used capabilities of the system. A layout switch occurs if one of the layouts in the group of layouts more closely corresponds to the currently used capabilities of the system than the current layout.

Abstract: A method and apparatus of correcting a data signal sampled at a first rate to a data signal displayed on a video monitor at a second rate is claimed. A data signal is received at a first rate. The data signal is separated into data windows. The minimum and maximum values and positions of data points in data windows are identified relative to a reference, and displayed on a video monitor.

Abstract: A method and apparatus for analyzing a physiological waveform. The apparatus comprising an input terminal for connection to a patient to acquire the physiological waveform from a patient, an instrumentation amplifier connected to the input terminal to filter the physiological waveform, and an analysis module including a processor and software for operating the processor to detect cyclic artifact in the physiological waveform. The method comprising the acts of obtaining the physiological waveform and determining whether there is more than one independent complex rhythm within the digital physiological waveform.

Abstract: A method and apparatus for determining A, C, and V waves in an atrial pressure waveform. The method includes the acts of establishing a time reference based on R waves in an ECG. A first interval in the an atrial pressure waveform between a first point offset ahead of a first R wave and a second point offset behind the first R wave is determined. The highest peak within the first interval is then identified. This peak is the A wave. Once the A wave is identified, a second R wave in the ECG, ahead of the first R wave, is identified. A second interval in the atrial pressure waveform that extends from the second point to a third point is established. The third point is positioned at a distance ahead of the second point equal to a percentage of the interval from the second point to a location behind the second R wave. The highest peak in the second interval is the V wave. After identifying the V wave, a third interval in the atrial pressure waveform is established.

Abstract: A computer site includes a data generating source. In one implementation, the source includes a device that can be manipulated by a patient to sense some function or condition of the patient. One example is a heart monitor that a patient can hold against his or her chest. The device outputs an audible signal responsive to the function or condition, such as the beating of the heart. A computer that can be operated by the patient or other initial user at the site runs a program that processes an electric signal generated in response to the audible signal as received through a microphone connected to the computer. The program is downloaded or otherwise accessed through a computer communication network, such as the Internet. The computer sends resulting data signals over the computer communication network.

Abstract: An electrocardiogram processing technique for measuring T-wave alternans by which the alternating electrocardiogram signals are aligned to a target cubic spline. The target cubic spline is calculated on base of three isoelectric points namely a point before the P-wave, a point before the QRS-complex and a point after the T-wave. The aligned signals may then be further analyzed for variations such as T-wave alternans which are only present in alternating beats and which have diagnostic significance.

Abstract: A method and apparatus for providing real-time support in interpreting a patient's ECG in order to assess the probability of perioperative cardiovascular risk associated with performing a non-cardiac surgery. The apparatus includes an acquisition unit for acquiring an ECG and a processor for determining whether the ECG has diagnostic statements of risk. From the diagnostic statements of risk, the processor determines the probability of cardiovascular risk associated with the non-cardiac surgery. The probability of cardiovascular risk is displayed on display in the form of an indicator of either major, intermediate, or minor cardiovascular risk. The method includes acquiring a patient's ECG, determining whether the ECG exhibits diagnostic statements of cardiovascular risk, and determining the probability of cardiovascular risk based on the diagnostic statements, and displaying the determined probability of cardiovascular risk.

Abstract: A wireless local area network (WLAN) system comprises multiple access points that are distributed throughout a medical facility to provide wireless access to a hardwired network. The access points implement multiple WLAN protocols, including a realtime protocol for realtime patient monitoring (telemetry) and a standard WLAN protocol (such as IEEE 802.11 within an ISM band) for providing general-purpose wireless access. Some or all of the access points preferably implement both WLAN protocols such that the different WLANs and wireless device types share network access resources. Some or all of the access points may also include RF location-tracking modules which may be used to track locations of patients, hospital personnel, capital equipment, and/or disposable medical supplies.

Abstract: Blood pressure is measured using the pulse transit time required for the blood volume pulse to propagate between two locations in an animal. Impedance plethysmography is employed to detect when the blood volume pulse occurs at one location. The plethysmograph may detect thoracic impedance to determine when the aortic heart valve opens or it may detect impedance at one location on a limb of the animal. Occurrence of the blood volume pulse at another location can be determined by impedance plethysmography or another technique, such as pulse oximetry. The calculation of cardiac stroke volume can be employed to compensate the derivation of the blood pressure for effects due to blood vessel compliance. A nonblood pressure monitor may periodically provide a reference blood pressure measurement that is used calibrate derivation of the blood pressure based on the pulse transit time.

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 apparatus for acquiring and processing electrical signals produced by a patient's heart. The apparatus includes fewer than ten electrodes for attachment to the patient. Each electrode is attached in a respective one of the standard ten-electrode, twelve-lead ECG positions. The device includes a signal processor connected to the electrodes for acquiring electrical signals from the electrodes and generating a twelve-lead ECG from the electrical signals. The signal processor generates less than twelve of the leads mathematically. For the method of the invention, a plurality of less than ten electrodes are attached to the patient. Each electrode is attached in a respective one of the standard ten-electrode, twelve-lead ECG positions. Electrical signals are acquired from the electrodes and a twelve-lead ECG is generated from the acquired electrical signals. Not all twelve leads are generated mathematically.

Abstract: An interface device receives data from a plurality of sensors and transmits the data over a communication network to one or more of a plurality of monitors. The interface device is capable of operating in both a peripheral mode of operation and a stand-alone mode of operation for the plurality of monitors. In another embodiment, a monitor is connected to a plurality of interface devices by way of a communication network. A separate visible physical communication link or other identification link is used to visually identify which of the interface devices is serving as a peripheral device for the monitor.

Abstract: A database is created that contains a plurality of data items gathered from many human beings wherein the data items affect the heart rate of a patient during a CT imaging procedure. Regression analysis is performed on the data in the database to derive an algorithm which defines an predicted heart rate value as a function of the plurality of data items. Specifically, values for the plurality of data items are obtained for the particular patient to be imaged and the algorithm is applied to those data items to predict the patient's heart rate which will occur during the CT imaging procedure. The predicted heart rate is employed to defined operating parameters of the CT procedure, such as the rate at which the x-ray source and detector rotate around a patient and the speed at which the patient moves through the imaging plane.

Abstract: An Radiation detector employs one or more arrays of microphotonic light transmission devices to selectively control the flow of light from different detection sites in a scintillator into an optical conduit. For example the microphotonic light transmission devices may be microelectromechanical steerable mirrors or light gates. Instead of employing a separate detector element to convert the light from each site into an electrical signal that is then switched into a data acquisition system, the present detector assembly switches the light into the optical conduit to the data acquisition system.

Abstract: Blood pressure is measured using the pulse transit time required for the blood volume pulse to propagate between two locations in an animal. Impedance plethysmography is employed to detect when the blood volume pulse occurs at one location. The plethysmograph may detect thoracic impedance to determine when the aortic heart valve opens or it may detect impedance at one location on a limb of the animal. Occurrence of the blood volume pulse at another location can be determined by impedance plethysmography or another technique, such as pulse oximetry. The calculation of cardiac stroke volume can be employed to compensate the derivation of the blood pressure for effects due to blood vessel compliance. A nonblood pressure monitor may periodically provide a reference blood pressure measurement that is used calibrate derivation of the blood pressure based on the pulse transit time.

Abstract: A method is provided for determining the presence of a condition of a patient's heart. The method includes the steps of reading at least one parameter value of a biomedical signal of a patient and determining the likelihood of the presence of a condition of a patient's heart based on the at least one parameter value. The step of determining includes the step of comparing the at least one parameter value of the biomedical signal with all corresponding parameter values stored in a database.

Abstract: An object location tracking system for tracking a movable object includes a plurality of beacons spatially distributed within a building, each beacon transmitting a respective ID signal, at least one transceiver device which receives the transmission of ID signals from the beacons and determines received signal strengths of such transmissions, the transceiver device adapted to be attached to the movable object, a motion detector coupled to the at least one transceiver device configured to provide information relating to a motion of the at least one transceiver device, and a processing module that uses information reflective of the received signal strengths of the transmissions received by the transceiver device, in combination with information reflective of the motion of the at least one transceiver device, to determine a current location of the transceiver device.

Abstract: A method and apparatus to detect irregular heart activity and estimate heart rate. In one embodiment, the heart rate estimation apparatus includes a group of six RR storage structures that receives an input of six successive RR interval values. The apparatus also includes a probability engine coupled to the group of RR storage structures, the probability engine is operable to calculate and output a mean value of the six RR interval values and a median value of the mean value and the six RR interval. In one embodiment, the apparatus carries out a method including the acts of determining a plurality of interval values between successive R waves; determining a mean of a group of six interval values; determining a median interval value for a group including the group of six interval values and the mean of the group of six interval values; and determining a running average of interval values between successive R waves using the median interval value.