Abstract: A method of processing a raw acceleration signal, measured by an accelerometer-based compression monitor, to produce an accurate and precise estimated actual depth of chest compressions. The raw acceleration signal is filtered during integration and then a moving average of past starting points estimates the actual current starting point. An estimated actual peak of the compression is then determined in a similar fashion. The estimated actual starting point is subtracted from the estimated actual peak to calculate the estimated actual depth of chest compressions. In addition, one or more reference sensors (such as an ECG noise sensor) may be used to help establish the starting points of compressions. The reference sensors may be used, either alone or in combination with other signal processing techniques, to enhance the accuracy and precision of the estimated actual depth of compressions.

Abstract: A band stop filter is provided for a lead wire of an active medical device (AMD). The band stop filter includes a capacitor in parallel with an inductor. The parallel capacitor and inductor are placed in series with the lead wire of the AMD, wherein values of capacitance and inductance are selected such that the band stop filter is resonant at a selected frequency. The Q of the inductor may be relatively maximized and the Q of the capacitor may be relatively minimized to reduce the overall Q of the band stop filter to attenuate current flow through the lead wire along a range of selected frequencies. In a preferred form, the band stop filter is integrated into a TIP and/or RING electrode for an active implantable medical device.

Abstract: Chest compressions are measured and prompted to facilitate the effective administration of CPR. A displacement detector produces a displacement indicative signal indicative of the displacement of the CPR recipient's chest toward the recipient's spine. A signaling mechanism provides chest compression indication signals directing a chest compression force being applied to the chest and a frequency of such compressions. An automated controller and an automated constricting device may be provided for applying CPR to the recipient in an automated fashion. The automated controller receives the chest compression indication signals from the signaling mechanism, and, in accordance with the chest compression indication signals, controls the force and frequency of constrictions.

Abstract: A system applies cardiopulmonary resuscitation (CPR) to a recipient. An automated controller is provided together with a compression device which periodically applies a force to a recipient's thorax under control of the automated controller. A band is adapted to be placed around a portion of the torso of the recipient corresponding to the recipient's thorax. A driver mechanism shortens and lengthens the circumference of the band. By shortening the circumference of the band, radial forces are created acting on at least lateral and anterior portions of the thorax. A translating mechanism may be provided for translating the radial forces to increase the concentration of anterior radial forces acting on the anterior portion of the thorax. The driver mechanism may comprise a tension device for applying a circumference tensile force to the band. The driver mechanism may comprise an electric motor, a pneumatic linear actuator, or a contracting mechanism defining certain portions of the circumference of the band.

Abstract: Devices and methods for substantially closing the airway of a patient during cardiopulmonary resuscitation. A chest compression device designed to compress substantially the entire chest of a patient is used to perform chest compression on the patient. As the chest of the patient is compressed, the airway of the patient is substantially closed, thereby preventing the flow of gasses through the airway. Because gasses cannot flow through the airway of the patient, intrathoracic pressure increases during chest compressions relative to manual chest compressions or other point chest compressions.

Abstract: A system and method for using magnetic resonance imaging to increase the accuracy of electrophysiologic procedures includes an invasive combined electrophysiology and imaging antenna catheter which includes an RF antenna for receiving magnetic resonance signals and diagnostic electrodes for receiving electrical potentials. The combined electrophysiology and imaging antenna catheter is used in combination with a magnetic resonance imaging scanner to guide and provide visualization during electrophysiologic diagnostic or therapeutic procedures, such as ablation of cardiac arrhythmias. The combined electrophysiology and imaging antenna catheter may further include an ablation tip, and be used as an intracardiac device to deliver energy to selected areas of tissue and visualize the resulting ablation lesions. The antenna utilized in the combined electrophysiology and imaging catheter for receiving MR signals is preferably of the coaxial or “loopless” type.

Abstract: A system for rapid induction of indication of hypothermia especially of the heart and brain during cardiac arrest and normal circulation. The device recirculates blood through an extracorporeal circuit using a single venous access. The blood can be cooled and/or treated before reentry to the vascular system. The device maximizes the cooling rate by optimizing the blood withdrawal rate. Cooling of the brain is achieved by flow of cooled blood from the thorax to the head. During cardiac arrest, the blood flow is generated by cardiopulmonary resuscitation.

Abstract: Chest compressions are measured and prompted to facilitate the effective administration of CPR. A displacement detector determines a displacement indicative signal indicative of the displacement of the CPR recipient's chest toward the recipient's spine. A signaling mechanism provides chest compression indication signals directing a chest compression force being applied to the chest and a frequency of such compressions. An automated controller and an automated constricting device may be provided for applying CPR to the recipient in an automated fashion. The automated controller receives the chest compression indication signals from the signaling mechanism, and, in accordance with the chest compression indication signals, controls the force and frequency of constrictions.

Abstract: The systems and methods of the present invention provide for MRI probes adapted for insertion into a plurality of body orifices, in order to evaluate the anatomy of proximate anatomic structures, to diagnose abnormalities thereof and to treat the diagnosed abnormalities. MRI probes are described that are suitable for use in the mediastinum, in the pancreaticohepaticobiliary system, in the tracheobronchopulmonary system, in the head and neck, in the genitourinary system, the gastrointestinal system, the vascular system, and in the evaluation, diagnosis and treatment of internal fluid collections.

Abstract: An improved vest design for cardiopulmonary resuscitation is disclosed. The vest includes an inflatable bladder capable of radial expansion to first conform to a patient's chest dimensions and then to apply circumferential pressure. The improved vest design affords ease of placement on a patient without concern for how tightly the vest is initially applied. Also disclosed are various vest designs that reduce the amount of compressed air that must be used for each compression/decompression cycle of the vest. These improvements lower the energy consumption and make smaller and portable cardiopulmonary resuscitation systems possible.

Abstract: A device for monitoring a patient or pacing a patient is disclosed which can safely operate in a MRI system. The device uses unique RF filtering and shielding to attenuate voltages on the leads resulting from the high frequency RF signals produced in the MRI. The device is uniquely shielded to prevent induced currents from disrupting the amplifying and processing electronics. The device uses an optional secondary low pass or band reject filter to eliminate interference from the MRI's gradient magnetic field. The device uses optional inductors placed close to electrodes to limit RF currents through the electrodes. Several embodiments of the RF filter are taught which depend on the number of sensing leads, whether the leads are shielded, whether the RF filter is contained in the electronic shielded housing or whether single or multistage filtering is employed. The device may operate as an extended ECG monitor or may be an implantable MRI safe pacemaker.

Abstract: An electronic, miniaturized, pocket-size device having a multiplicity of tri-electrode sets (note FIGS. 3 and 6A) for monitoring and storing EKG or EEG signals, one being positive and the other negative, with the third being a possible signal opposite to the signal received sent in the opposite direction (to the electrode), lessening background noise. Each is connected to one or more amplifiers joined in a central amplifier which breaks up the signals into two separate, related signals, one being the difference in the bias voltages of the positive and negative voltages and the second being the amplified difference of the signals. The first is sent to a voltage sensitive detector, which sends a signal out when this difference becomes sufficient, the detector being set for triggering when an electrode becomes detached or otherwise defective, as in even an abnormal EKG or EEG the voltages will not be greatly different.

Abstract: An electronic miniaturized, pocket-sized device for monitoring EKG and/or EEG signals and storing such signals. First, second and third electrodes are adapted for connection to a human body and first and second voltage amplifiers are electrically connected to respective ones of the first and second electrodes for producing first and second output signals having low noise content. A third amplifier is connected to both the first and second voltage amplifier for producing two output signals, one being the difference in voltage of the two voltage amplifiers as amplified and the second output being the difference of the bias voltages of the first and second voltage amplifiers. A lead fail detector includes voltage sensing device electrically connected to the second output of the third voltage amplifier and outputting a signal only when the difference of the bias voltages of the electrodes through the respective first and second voltage amplifiers is above a preselected level.

Abstract: A vest system for generating cyclic fluctuations in intrathoracic pressure for use in cardiopulmonary resuscitation and non-invasive circulatory assistance. The vest is preferably provided with a two bladder inflation system. A high pressure bladder contacts the chest wall while a bias bladder is disposed between the high pressure bladder and the vest material. The bias bladder is pressurized to press the high-pressure bladder tightly against the chest wall so that cyclic inflation of the high-pressure bladder can generate large changes in intrathoracic pressure. The bias bladder is released periodically to allow the chest to expand for adequate ventilation. Air flow into and out of each bladder is controlled by sequencing large bore 3-way and 2-way solenoid valves and the rate of air flow into the high-pressure bladder is controlled by a variable resistor.