摘要:
Cardiac output is measured utilizing a catheter in conjunction with the indicator dilution technique. Non-thermal analyte-containing fluid is used as the injectate. This fluid is biocompatible with and metabolizable within the body of the patient. An analyte concentration sensor is mounted upon the catheter and located downstream within the bloodstream from the port from which the analyte-containing fluid is expressed. Because of the matching of rapid concentration sensor response with an analyte-containing fluid which is metabolizable, the measurement of cardiac output may be carried out as often as about one to three minutes in conjunction with an infusion interval substantially less than the measurement frequency interval. The analyte-containing fluids are selected from a group consisting of ammoniacal fluid, heparin, ethanol, a carbon dioxide releasing fluid, glucose, and anesthesia agent. The system performs in conjunction with a microprocessor-driven controller which automates the measurement procedure and provides a display of cardiac output and various cardiovascular parameters.
摘要:
Total ammoniacal concentration (TAC) in blood is measured and displayed on a repetitive basis by a controller driven sensor arrangement which may be utilized either with a catheter structure or with a bypass system. The catheter based sensors may be employed with a peripheral region of the vascular system of the body. Repetitive measurements are carried out and these measurements are subjected to a moving average filtering procedure, whereupon the filtered TAC values are displayed numerically and graphically. The controller functions to compute the rate-of-rise of TAC and compares that value with a threshold rate-of-rise valuation which is inputted by the practitioner. Threshold values for TAC also may be inputted and the system not only provides alarm warnings for threshold excursions in TAC above threshold or excursions in rate-of-rise of TAC above threshold but also provides a visual cuing as a warning that TAC is elevating from one filtered measurement to the next.
摘要:
A scan completeness auditing system for screening a volume of tissue comprising a manual image scanning device having an imaging probe, a position tracking system configured to track and record the position of the imaging probe during use, and a controller in communication with the recording system and the manual image scanning device, the controller configured to electronically receive and record the scanned images from the manual image scanning device, and to measure an image-to-image spacing and a scan-to-scan spacing between the scanned images within scan sequence and between scan sequences respectively. The scan completeness auditing system is further adapted to provide an alert to the operator if the image-to-image or scan-to-scan spacing exceeds an acceptable value.
摘要:
A system, and apparatus for detecting and quantifying circulatory anomalies, including right-to-left cardiac shunts. The apparatus implements a sensor system useful in connection with a circulatory indicator delivery system. The sensor apparatus is preferably configured with a series of emitter/detector pairs to optimize the sensitivity of detection of the circulating indicator. Sensing of the indicator concentration takes place at an arterial vasculature, for example, the pinna of the human ear. A monitor/controller calculates and displays a indicator/dye dilution curve to assess for the presence of a cardiac shunt. The monitor/controller further corrects the indicator/dilution curve displayed for any recirculation phenomena and can quantify any right-to-left shunt calculated conductance associated with detected shunts.
摘要:
A hemostatic surgical blade is described which is formed of five symmetrically disposed layers. A martensitic stainless steel core is provided with oppositely disposed faces which are bonded to hard pure copper thermal transfer layers which, in turn, are supported by buttressing layers of austenitic stainless steel. The blade is heated by a blade heater circuit which is provided as a flexible circuit carrying one or more resistor heaters and associated leads supported by a polyimide substrate. A thermally conductive and electrically insulative adhesive is used to bond the flexible circuit to a blade blank. The system employs a multi-lead cable which is removable from an instrument handle. One blade embodiment involves an elongate stem for accessing body cavities and another embodiment incorporates a controller function within an instrument handle.
摘要:
Method, system and apparatus for monitoring target tissue temperatures wherein temperature sensors are configured as passive resonant circuits each with a unique resonating signature at monitoring temperatures extending below a select temperature setpoint. The resonant circuits are configured with an inductor component formed of windings about a ferrite core having a Curie temperature characteristic corresponding with a desired temperature setpoint. By selecting inductor winding turns and capacitance values, unique resonant center frequencies are detectable. Temperature monitoring can be carried out with implants at lower threshold and upper limit temperature responses. Additionally, the lower threshold sensors may be combined with auto-regulated heater implants having Curie transitions at upper temperature limits.
摘要:
Systems and methods are provided for applying a high frequency voltage in the presence of an electrically conductive fluid to create a relatively low-temperature plasma for ablation of tissue adjacent to, or in contact with, the plasma. In one embodiment, an electrosurgical probe or catheter is positioned adjacent the target site so that one or more active electrode(s) are brought into contact with, or close proximity to, a target tissue in the presence of electrically conductive fluid. High frequency voltage is then applied between the active electrode(s) and one or more return electrode(s) to non-thermally generate a plasma adjacent to the active electrode(s), and to volumetrically remove or ablate at least a portion of the target tissue. The high frequency voltage generates electric fields around the active electrode(s) with sufficient energy to ionize the conductive fluid adjacent to the active electrode(s). Within the ionized gas or plasma, free electrons are accelerated, and electron-atoms collisions liberate more electrons, and the process cascades until the plasma contains sufficient energy to break apart the tissue molecules, causing molecular dissociation and ablation of the target tissue.
摘要:
Method, system and apparatus for carrying out accurate electrosurgical cutting. A thin resilient electrode is utilized at the forward end region of an instrument that is deployable from a longitudinally disposed slot positioned rearwardly of the tip of the instrument. Lateral sides of the slot extend between a forward location adjacent the tip and a rearward location. The electrode is deployed by urging it forwardly in compression to form an arch profile supported by the abutting slot sides adjacent the forward and rearward locations. Electrosurgically excitable with a cutting output, the electrode may carry out a cutting action both during its deployment and retraction into the noted slot. This permits a pivoting maneuver effective for circumscribing a volume of targeted tissue.