406 results about "Cardiac output" patented technology

A heart retractor links lifting of the heart and regional immobilization which stops one part of the heart from moving to allow expeditious suturing while permitting other parts of the heart to continue to function whereby coronary surgery can be performed on a beating heart while maintaining cardiac output unabated and uninterrupted. Circumflex coronary artery surgery can be performed using the heart retractor of the present invention. The retractor includes a plurality of flexible arms and a plurality of rigid arms as well as a surgery target immobilizing element. One form of the retractor can be used in minimally invasive surgery, while other forms of the retractor can accommodate variations in heart size and paracardial spacing.

Systems, methods and devices are provided for treating heart failure patients suffering from various levels of heart dilation. Heart dilation treated by reshaping the heart anatomy with the use of magnetic forces. Such reshaping changes the geometry of portions of the heart, particularly the right or left ventricles, to increase contractibility of the ventricles thereby increasing the stroke volume which in turn increases the cardiac output of the heart. The magnetic forces are applied with the use of one or more magnetic elements which are implanted within the heart tissue or attached externally and/or internally to a surface of the heart. The various charges of the magnetic forces interact causing the associated heart tissue areas to readjust position, such as to decrease the width of the ventricles. Such repositioning is maintained over time by the force of the magnetic elements, allowing the damaging effects of heart dilation to slow in progression or reverse.

Excessive dilation of the annulus of a mitral valve may lead to regurgitation of blood during ventricular contraction. This regurgitation may lead to a reduction in cardiac output. Disclosed are systems and methods relating to an implant configured for reshaping a mitral valve. The implant comprises a plurality of struts with anchors for tissue engagement. The implant is compressible to a first, reduced diameter for transluminal navigation and delivery to the left atrium of a heart. The implant may then expand to a second, enlarged diameter to embed its anchors to the tissue surrounding and/or including the mitral valve. The implant may then contract to a third, intermediate diameter, pulling the tissue radially inwardly, thereby reducing the mitral valve and lessening any of the associated symptoms including mitral regurgitation.

Described are devices and methods for treating degenerative, congestive heart disease and related valvular dysfunction. Percutaneous and minimally invasive surgical tensioning structures offer devices that mitigate changes in the ventricular structure (i.e., remodeling) and deterioration of global left ventricular performance related to tissue damage precipitating from ischemia, acute myocardial infarction (AMI) or other abnormalities. These tensioning structures can be implanted within various major coronary blood-carrying conduit structures (arteries, veins and branching vessels), into or through myocardium, or into engagement with other anatomic structures that impact cardiac output to provide tensile support to the heart muscle wall which resists diastolic filling pressure while simultaneously providing a compressive force to the muscle wall to limit, compensate or provide therapeutic treatment for congestive heart failure and/or to reverse the remodeling that produces an enlarged heart.

Systems and methods for determining a physiological parameter in a patient are provided. In certain embodiments, a system can include an analyte detection system configured to measure first analyte data in a fluid sample received from a patient, a medical sensor configured to measure second analyte data in the patient, and a processor configured to receive the first analyte data and the second analyte data and to determine a physiological parameter based at least in part on the first analyte data and the second analyte data. In certain such embodiments, the medical sensor may be a pulse oximeter, and the physiological parameter may include a cardiovascular parameter including, for example, cardiac output.

The present disclosure relates, in some embodiments, to devices, systems, and/or methods for collecting, processing, and/or displaying stroke volume and/or cardiac output data. For example, a device for assessing changes in cardiac output and/or stroke volume of a subject receiving airway support may comprise a processor; an airway sensor in communication with the processor, wherein the airway sensor is configured and arranged to sense pressure in the subject's airway, lungs, and/or intrapleural space over time; a blood volume sensor in communication with the processor, wherein the blood volume sensor is configured and arranged to sense pulsatile volume of blood in a tissue of the subject over time; and a display configured and arranged to display a representative of an airway pressure, a pulsatile blood volume, a photoplethysmogram, a photoplethysmogram ratio, the determined cardiac output and/or stroke volume, or combinations thereof. A method of assessing changes in cardiac output or stroke volume of a subject receiving airway support from a breathing assistance system may comprise sensing pressure in the subject's airway as a function of time, sensing pulsatile volume of blood in a tissue of the subject as a function of time, producing a photoplethysmogram from the sensed pulsatile volume, determining the ratio of the amplitude of the photoplethysmogram during inhalation to the amplitude of the photoplethysmogram during exhalation, and determining the change in cardiac output or stroke volume of the subject using the determined ratio.

A depolarization waveform classifier based on the Modified lifting line wavelet Transform is described. Overcomes problems in existing rate-based event classifiers. A task for pacemaker/defibrillators is the accurate identification of rhythm categories so correct electrotherapy can be administered. Because some rhythms cause rapid dangerous drop in cardiac output, it's desirable to categorize depolarization waveforms on a beat-to-beat basis to accomplish rhythm classification as rapidly as possible. Although rate based methods of event categorization have served well in implanted devices, these methods suffer in sensitivity and specificity when atrial/ventricular rates are similar. Human experts differentiate rhythms by morphological features of strip chart electrocardiograms. The wavelet transform approximates human expert analysis function because it correlates distinct morphological features at multiple scales. The accuracy of implanted rhythm determination can then be improved by using human-appreciable time domain features enhanced by time scale decomposition of depolarization waveforms.

Medical diagnostic system, apparatus and methods are disclosed. Optical transmitters generate radiation-containing photons having a specific interaction with at least one target chromophore in a target structure, preferably a blood vessel such as the interior jugular vein. The optical transmitters transmit the radiation into at least a first area including a substantial portion of the target structure and into a second area not including a substantial portion of the target structure. Optical receivers detect a portion radiation scattered from at least the first area and the second area. A processor estimates oxygenation, pH or cardiac output based on the scattered radiation detected from the first area, and the scattered radiation from the second area.

Heat exchanger-equipped catheters and related methods that are useable for changing or maintaining at least a portion of the body of a human or veterinary patient at a desired temperature and for the measurement of cardiac output or blood flow rate within a blood vessel, without the need for introduction of saline solution or any other foreign substance into the patient's blood.

An extracardiac pumping for supplementing the circulation of blood, including the cardiac output, in a patient without any component thereof being connected to the patient's heart, and methods of using same. One embodiment provides a vascular graft that has a first end that is sized and configured to couple to a non-primary blood vessel and a second end that is fluidly coupled to a pump to conduct blood between the pump and the non-primary blood vessel. An outflow conduit is also provided that has a first end sized and configured to be positioned within the same or different blood vessel, whether primary or non-primary, through the vascular graft. The outflow conduit is fluidly coupled to the pump to conduct blood between the pump and the patient. The vascular graft may be connected to the blood vessel subcutaneously to permit application of the extracardiac pumping system in a minimally-invasive procedure.

The present invention relates to a method and apparatus for monitoring haemodynamic function in animals and humans during anaesthesia and surgery. During anaesthesia and surgery the subject's haemodynamic, respiratory, neuromuscular and neurological functions are monitored as indicators of the condition of the health of the subject. Commonly, variations in blood pressure are used to imply corresponding variations in cardiac output, i.e. good blood pressure equals good cardiac output. The present invention utilizes a device to monitor changes of blood flow in peripheral blood vessels of the subject as an indicator of cardiac output. This is believed to provide a much more accurate indicator.

A device for regulating blood pressure between a patient's left atrium and right atrium comprises an hourglass-shaped stent comprising a neck region and first and second flared end regions, the neck region disposed between the first and second end regions and configured to engage the fossa ovalis of the patient's atrial septum; and a one-way tissue valve coupled to the first flared end region and configured to shunt blood from the left atrium to the right atrium when blood pressure in the left atrium exceeds blood pressure in the right atrium. The inventive devices may reduce left atrial pressure and left ventricular end diastolic pressure, and may increase cardiac output, increase ejection fraction, relieve pulmonary congestion, and lower pulmonary artery pressure, among other benefits. The inventive devices may be used, for example, to treat subjects having heart failure, pulmonary congestion, or myocardial infarction, among other pathologies.

A method and apparatus for ultrafiltration of blood operating by removing blood from a peripheral blood vessel at a rate of less than two percent of total cardiac output of a patient, extracting fluid at a rate of 0.1 liter to 1.0 liters per hour while retaining cells and proteins in the blood, and returning the concentrated blood to a secondary blood vessel is disclosed. Blood is removed and returned using small gage needles. As a pump circulates blood from the patient, a filter removes ultrafiltrate from the blood using duty cycle or pump control, and a transparent container collects the removed fluid.

An extracardiac pumping for supplementing the circulation of blood, including the cardiac output, in a patient without any component thereof being connected to the patient's heart, and methods of using same. One embodiment of the intravascular extracardiac system comprises a pump with inflow and outflow conduits that are sized and configured to be implantable intravascularly through a non-primary vessel, whereby it may positioned where desired within the patient's vasculature. The system comprises a subcardiac pump that may be driven directly or electromagnetically from within or without the patient. The pump is configured to be operated continuously or in a pulsatile fashion, synchronous with the patient's heart, thereby potentially reducing the afterload of the heart. In another embodiment, the system is positioned extracorporeally, with the inflow conduit and outflow conduit applied percutaneously to a non-primary vessel for circulating blood to and from the non-primary vessel or between the non-primary vessel and another blood vessel within the patient's vasculature.

An apparatus to measure cardiac output (Q) and other parameters such as alveolar ventilation (VA), minute CO₂ elimination from the lung (VCO₂ ), minute oxygen consumption (VO₂), oxygenated mixed venous partial pressure of CO₂, (PvCO₂-oxy), true mixed venous partial pressure of CO₂(PvCO₂), PaCO₂, mixed venous oxygen saturation (SvO₂), pulmonary shunt, and anatomical dead space, consisting of: a) a breathing circuit with characteristics that: i. on exhalation, exhaled gas is kept substantially separate from inhaled gas; ii. oninhalation, when V_E is greater than FGS flow, the subject inhales FGS first and then inhales a gas that is substantially SGS, for the balance of inhalation; b) gas sensor means for monitoring gas concentrations at the patient-circuit interface c) a first gas set (FGS), and a second gas set (SGS), said second gas set which may comprise previously exhaled gases or exogenous gases or both d) a gas flow control means for controlling the rate of FGS flow into the breathing circuit e) means to identify phase of breathing, said means may consist of pressure sensors or analysis of signal generated by gas sensors or other means known to those skilled in the art; f) machine intelligence consisting of a computer or logic circuit capable of controlling the gas flow control means, receiving the output of the gas sensor means and means to identify phased of breathing, and performing the calculations for measuring cardiac output and other parameters as outlined in the disclosure.