Abstract: Techniques are provided for controlling therapy delivered in response to Cheyne-Stokes Respiration (CSR) or other forms of periodic breathing in an effort to reduce the likelihood of unnecessary therapy directed toward preventing sleep interruption. Following each burst of respiration during CSR, a prediction is made as to whether the amount of respiration achieved during the burst will be sufficient to sustain the patient through a period of apnea until the next respiration burst. If not, aggressive therapy, such as aggressive diaphragmatic pacing, is delivered to improve respiration and prevent the imminent sleep interruption. If, however, the amount of respiration achieved during the burst appears to be sufficient to sustain the patient until the next respiration burst, then relatively mild therapy is instead delivered.

Abstract: Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, utilizing pulsations of the brachial artery contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm proximate the brachial artery and two or more spaced apart voltage sensing electrodes positioned on the patient's arm proximate the brachial artery. The voltage sensing electrodes are positioned between the alternating current flow electrodes on the arm. An alternating current source is electrically connected to the alternating current flow electrodes and a voltmeter electrically is connected to the voltage sensing electrodes. A data input device is provided along with a processing unit in communication with the data input device, the alternating current source, alternating current flow electrodes, the voltmeter, and voltage sensing electrodes.

Abstract: Techniques are provided for detecting the circadian state of a patient using an implantable medical device based on selected blood carbon dioxide (CO2) parameters. In one example, the implantable device tracks changes in end tidal CO2 (etCO2) levels and changes in maximum variations of pCO2 levels per breathing cycle (?cycleCO2) over the course of the day and determines the circadian state based thereon. It has been found that average etCO2 levels are generally highest and average ?cycleCO2 levels are generally lowest while a patient is asleep and opposite while a patient is awake. Hence, by tracking changes in average etCO2 and ?cycleCO2 levels over the course of the day, circadian states can be detected. Minute ventilation and activity levels are used to assist in the determination of the circadian state. Additional techniques are directed to detecting the stage of sleep.

Abstract: The invention refers to a method for the regional determination of the alveolar opening and alveolar closing of the lung depending on the respiration pressure, wherein according to the method of electrical impedance tomography, an impedance signal is measured in at least one lung zone depending on the respiration pressure. The alveolar opening or closing of a lung zone is determined, in particular to enable an improved artificial respiration.

Abstract: A patient ambulation motion detector designed to be worn on the body. The detector incorporates a wireless transmitter, a motion sensor switch and a second call switch. It may be enclosed in a plastic case and attached most commonly to the upper anterior chest by a non-allergic double-backed tape.

Abstract: An active medical device to diagnose a patient respiratory profile. This device is able to measure respiratory activity and deliver a signal (26) representative of the periodicity and amplitude of the successive respiratory cycles of the patient, in particular, a of minute ventilation (MV) signal. The device is able to analyze the aforementioned signal and discriminate between various types of respiratory profiles, in particular, to diagnose a respiratory profile of the Cheyne-Stokes type. This is achieved by detecting an alternation of respiratory cycles of hyperventilation (20) separated by periods of respiratory pause (22) or periods of hypoventilation or normal ventilation (24) and, in the latter case, to discriminate between periods of respiratory pause, corresponding to a profile of the Cheyne-Stokes (CSR) type, and periods of hypoventilation or normal ventilation, corresponding to a profile of the periodic breathing (PB) type.

Abstract: An active medical device having an improved discrimination between an awake phase of a patient and a sleep phase of a patient. This device measures a physiological parameter of a patient, delivers a physiological signal with a slow time response variation, in particular a signal of minute-ventilation (signal MV), and detects whether the patient is in a phase of awakening or sleep. An average (VE) of the signal MV is calculated over a given number of respiratory cycle and compared with a predetermined threshold (Threshold MV), such that a first state of awakening is determined when the average is higher than the threshold, and a first state of sleep is determined in the contrary case. The device also measures patient activity (signal G), using a signal having a short response time.

Abstract: An implantable device having enhanced capabilities for monitoring a patient's heart rate and respiration trends over extended periods of time is disclosed. The information collected by the implantable device may be stored and telemetered to an associated external device such as a device programmer for display and analysis. Heart rates are measured by measuring the time intervals between sensed depolarizations of a chamber of the patient's heart and preceding sensed depolarizations or delivered pacing pulses. Intervals may be measured in the ventricle and/or atrium of the patient's heart. According to another aspect of the invention, an implanted impedance sensor is employed to monitor minute ventilation. The heart rate and minute ventilation data is used to develop long-term trend data used for diagnostic purposes. In one embodiment of the invention, heart interval and minute ventilation measurements are taken only during defined time periods of the night and/or day when the patient is at rest.

Abstract: An adapter for interfacing a pyro/piezo sensor to a polysomnograph machine comprises a differential input amplifier coupled to receive the raw transducer signals from a PVDF film transducer to provide a requisite gain while rejecting common mode noise. The resulting amplified signal is filtered to separate the pyro signal from the piezo signal and the piezo signal is further applied to half-wave rectifier stages that function to remove baseline noise from the piezo signal before its being applied to a microphone channel of an existing PSG machine.

Abstract: The present invention provides a method and apparatus for detecting and treating sleep respiratory events that includes a plurality of sensors gathering physiological data related to sleep respiratory events. A processor extracts an average cycle length and a frequency of at least one of Cheyne-Stokes respiration and periodic breathing based upon the physiological data, and determines whether therapy is required based on the average cycle length and the frequency.

Abstract: The present invention relates to the field of ambulatory and non-invasive monitoring of a plurality of physiological parameters of a monitored individual. The invention includes a physiological monitoring apparatus with an improved monitoring apparel worn by a monitored individual, the apparel having attached sensors for monitoring parameters reflecting pulmonary function, or parameters reflecting cardiac function, or parameters reflecting the function of other organ systems, and the apparel being designed and tailored to be comfortable during the individual's normal daily activities. The apparel is preferably also suitable for athletic activities. The sensors preferably include one or more ECG leads and one of more inductive plethysmographic sensor with conductive loops positioned closely to the individual to preferably monitor at least basic cardiac parameters, basic pulmonary parameters, or both.

Abstract: An improved method and apparatus for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one exemplary embodiment, the invention comprises a method of measuring cardiac output (CO) using impedance waveforms (and ECG waveforms) which are analyzed via discrete wavelet transforms. These transforms aid in identifying fiducial points within the waveforms, the fiducial points being used to calculate various parameters relating to cardiac stroke volume (such as LVET and dZ/dtmax), from which cardiac output may be determined. The use of wavelet transforms for fiducial point detection increases the accuracy of the CO determination by reducing cross-term artifact, and also significantly reduces the amount and complexity of processing required as compared to prior art time-frequency distribution or empirical techniques. Improved methods of QRS complex detection within the ECG waveform, and median filtering of an input waveform, are also disclosed.

Abstract: The present invention relates to the field of ambulatory and non-invasive monitoring of a plurality of physiological parameters of a monitored individual. The invention includes a physiological monitoring apparatus with an improved monitoring apparel worn by a monitored individual, the apparel having attached sensors for monitoring parameters reflecting pulmonary function, or parameters reflecting cardiac function, or parameters reflecting the function of other organ systems, and the apparel being designed and tailored to be comfortable during the individual's normal daily activities. The apparel is preferably also suitable for athletic activities. The sensors preferably include one or more ECG leads and one of more inductive plethysmographic sensor with conductive loops positioned closely to the individual to preferably monitor at least basic cardiac parameters, basic pulmonary parameters, or both.

Abstract: An intracardiac impedance-derived parameter, Half Cycle Activity (HCA) is used in sensing and controlling cardiac activities in implantable cardiac devices such as bradycardia pacemakers and cardioverter defibrillators. This impedance-derived parameter correlates closely with physical workload and at the same time provides hemodynamic feedback information. Thus, it allows a pacemaker system to implement accurately an increase in hemodynamically driven pacing rate, as well as to limit an inappropriate decrease of driven pacing rate advised by another sensor such as an accelerometer. In addition, it determines the maximum pacing rate for the pacemaker so as to prevent hemodynamic compromise. Therefore, the HCA parameter may be used to determine a Hemodynamic Upper Rate Limit and a Hemodynamic Lower Rate Limit, and thus define a Hemodynamic Pacing Range that is compatible with the range of physiological rate. This allows a closed-loop control of the pacing rate.

Abstract: The medical equipment warning device is employed in combination with a power operated medical treatment machine such as a sleep apnea treatment machine. The warning device includes a DC relay with contacts that are open when the relay is connected to an AC source. A signal generator is connected to a battery by the DC relay when the AC source is interrupted and contacts close the DC circuit. The signal generator produces an audible, visual or physical signal that warns a person that the AC power source has failed. Restoration of the AC power source activates the DC relay and opens the DC circuit thereby deactivating the signal generator.

Abstract: A cardiorespiratory monitor that generates bioimpedance sensing signals that produce substantially no interference with bioimpedance signals generated by implanted devices. The monitor detects the bioimpedance signal generated by the implanted device, using a voltage detector or a telemetry circuit, for example. The monitor analyzes this detected signal to generate a bioimpedance sensing signal that will not interfere with the sensed signal. For instance, if the monitor produces a pulsed sensing signal, the pulses are delivered in an interval of the detected signal where no pulses are present. Similarly, if the monitor produces a high frequency AC sensing signal, the zero crossings of the AC sensing signal are positioned during the delivery of a pulse by the implanted device.

Abstract: A cardiorespiratory monitor that generates bioimpedance sensing signals that produce substantially no interference with bioimpedance signals generated by implanted devices. The monitor detects the bioimpedance signal generated by the implanted device, using a voltage detector or a telemetry circuit, for example. The monitor analyzes this detected signal to generate a bioimpedance sensing signal that will not interfere with the sensed signal. For instance, if the monitor produces a pulsed sensing signal, the pulses are delivered in an interval of the detected signal where no pulses are present. Similarly, if the monitor produces a high frequency AC sensing signal, the zero crossings of the AC sensing signal are positioned during the delivery of a pulse by the implanted device.

Abstract: The present invention relates to the field of ambulatory and non-invasive monitoring of a plurality of physiological parameters of a monitored individual. The invention includes a physiological monitoring apparatus with an improved monitoring apparel worn by a monitored individual, the apparel having attached sensors for monitoring parameters reflecting pulmonary function, or parameters reflecting cardiac function, or parameters reflecting the function of other organ systems, and the apparel being designed and tailored to be comfortable during the individual's normal daily activities. The apparel is preferably also suitable for athletic activities. The sensors preferably include one or more ECG leads and one of more inductive plethysmographic sensor with conductive loops positioned closely to the individual to preferably monitor at least basic cardiac parameters, basic pulmonary parameters, or both.

Abstract: Disclosed is a wearable multifunctional examination apron for use in ECG and other medical tests. The apron includes a number of ECG electrodes for performing ECG tests, and a number of microphones for heart and lung auscultation. The ECG test signals and heart/lung sounds are transferred to a processing unit, and processed therein. Test results are then displayed on a built-in display device, and/or transmitted to external devices for evaluation. The ECG electrodes can also be used in chest wall movement tests. The apron further includes a temperature sensor and an inflatable cushion for body temperature and blood pressure measurements.

Abstract: In a lung therapy method, hyperpolarized gas is administered for one breath to a subject, and a magnetic resonance scan of at least one lung of the subject is conducted. The data obtained from the scan are evaluated, specifically to determine the extent and distribution of infusion of hyperpolarized gas in the lung, as an indication of the alveolae in the lung which are open. Based on the evaluation of the data obtained in the magnetic resonance scan, a determination is made as to whether administration of a surfactant is necessary in order to improve opening of the lung. If a surfactant is administered, the procedure can be repeated to obtain an updated dataset, which can be evaluated to determine whether the administered surfactant has been effective.

Abstract: A cardiorespiratory monitor that generates bioimpedance sensing signals that produce substantially no interference with bioimpedance signals generated by implanted devices. The monitor detects the bioimpedance signal generated by the implanted device, using a voltage detector or a telemetry circuit, for example. The monitor analyzes this detected signal to generate a bioimpedance sensing signal that will not interfere with the sensed signal. For instance, if the monitor produces a pulsed sensing signal, the pulses are delivered in an interval of the detected signal where no pulses are present. Similarly, if the monitor produces a high frequency AC sensing signal, the zero crossings of the AC sensing signal are positioned during the delivery of a pulse by the implanted device.

Abstract: The invention concerns a method and apparatus for monitoring respiratory condition by impedance pneumography.An electrical signal is applied at a plurality of frequencies to a human subject by way of a first pair of spaced electrodes applied to the trunk of the body, whilst the resulting electrical signal is monitored at the plurality of frequencies at different points on the body by way of a second pair of spaced electrodes. From the resulting electrical signal a measure of the impedance of a part of the body at the plurality of frequencies is obtained, and a difference signal representing the impedance change with frequency is calculated. The difference signal is normalized with respect to a signal representative of the impedance measure itself at one or more frequencies, thereby suppressing the effect of those impedance signal components--such as movement artifact--whose frequency dependent change is substantially proportional to the impedance signal value.

Abstract: An impedance monitor for discerning edema through evaluation of respiratory rate. Preferred embodiment includes edema monitor and trigger to initiate diagnostic reporting or corrective action when activated. Recording of Long Term Average and Short Term Average values for secondary edema measure based on DC signal level are described as are methods and apparatus for removing unwanted recurring noise.

Abstract: A process and a device for automatically detecting an abnormal respiratory ound permits a continuous and stress-free registration of abnormal respiratory sounds of a test person under normal life activities over a period of time. The respiratory sounds are detected, processed and evaluated in real time. From the detected frequency range, in the course of the evaluation consideration is given only to the previously determined characteristic frequencies at the position of which in the frequency spectrum of the respiratory sound of the test person an abnormal respiratory sound is to be recognized by a significant feature. The data detected at these frequency positions are compared with data which are individually determined for the test person for fulfillment of specific criteria for the occurrence of an abnormal respiratory sound, and the result of the comparison is made available as a signal.

Abstract: The present invention relates to a procedure for measuring a patient's impedance. Based on the impedance, it is possible to monitor the patient's respiration and/or blood circulation. In the procedure, a plurality of electrodes (1a, 1b; 1d, 2; 2a) are connected to be patient and the changes in the impedance relationships between the electrodes (1a, 1b, 2) are measured. The invention makes it possible to use the same measuring conductors and measuring electrodes for impedance measurement as are used in ECG measurement.

Abstract: A breathing monitor for detecting SIDS in infants caused by apnea or the like includes an enclosure which is applied to a baby's torso with a strap. The enclosure is supported by and isolated from the baby's torso in its entirety by a fluid filled bladder coupler such that there is no direct contact between the enclosure and the baby's torso. A detector including a piezoelectric element is connected to the opposite side of the fluid coupler and a battery powered electronic circuit contained within the enclosure flashes an LED as the baby breathes and sounds an alarm should the baby fail to exhale for a predetermined time period. An adjustable strap connector for the strap provides visual indication of the strap being correctly applied and a limited range of permissible motion between the strap and enclosure as the baby breathes.

Abstract: A portable apparatus for measuring the thoracic lung volume of a patient without enclosing the patient in a sealed chamber, comprising first and second impedance belts, a flow meter, shutter and a microprocessor-based controller. The flow meter includes pressure transducers for measuring the change in volume and pressure as the patient respires therethrough. The change in thoracic cage volume of the patient's lungs is directly correlated with the change of impedance in the belts. The thoracic lung volume is then determined from a measured barometric pressure, the measured change in pressure and the measured volume change in the thoracic cage volume utilizing a correction factor to determine the thoracic cage volume.

Abstract: An apparatus for and method of monitoring respiration of a patient using impedance changes of the body to indicate respiration events. The impedance changes are measured by applying a carrier signal across the thorax of the patient. The carrier is periodically interrupted to produce a quiet period. A first level detector assumes the presence of EMI if the signal present during the quiet period exceeds a predetermined threshold. A second level detector senses the presence of substantial high frequency EMI. At initial power up, a third level detector checks for presence of signal before the carrier drive is applied. A fourth test circuit checks for the hang up of the differential amplification circuit.