Abstract: A probe for use with a catheter in an electrophysiological procedure to map and to ablate any of several tissue sites without repositioning the probe includes a metallic tip and a plurality of metallic rings, each tip and ring having a first work function and energized by a source of RF energy. The RF energy return path is through a further electrode of a metallic material having a second work function and disposed at a tissue location removed from the ablation site. After the sites have been mapped and one or more sites are selected for ablation, the selected site(s) is ablated prior to any repositioning of the probe. Regulation of the temperature at the ablation site(s) is achieved by sensing the temperature dependent current of a galvanic cell created by the tissue between the energized tip/ring and the further electrode due to their different work functions.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A catheter for use in an electrophysiological procedure to ablate a site includes a metallic tip having a first work function and energized by a source of RF energy. The RF energy return path is through a relatively large plate of a metallic material having a second work function and disposed at a location removed from the ablation site. The difference in work functions of the tip and the plate, operating in the presence of an electrolyte represented by the intermediate tissue, produces an exchange of electrical charges through chemical reaction to create a galvanic cell. By loading the galvanic cell with a shunt resistor, it becomes a current source providing a current linear with and highly dependent on the tissue temperature at the ablation site. This accurate representation of the tissue temperature at the ablation site is used to regulate the RF energy applied to maintain the tissue at the ablation site at a predetermined temperature during the ablation procedure.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A hollow core coaxial catheter supporting a heatable probe or balloon transmits electrical power, such as RF energy, to the ohmically resistive probe or balloon. The hollow core may accommodate passage of a guide wire, fiber optics for imaging or laser, fluid flow for perfusion and/or a lumen for fluid inflation and pressurization of a balloon. Inner and outer electrical conductors are disposed on radially opposed sides of dielectric tubing with an outer covering of dielectric material mechanically shielding and electrically insulating the outer conductor. A similar inner covering of dielectric material may be disposed radially inwardly of the inner conductor to mechanically and electrically insulate the inner conductor. An ohmically resistive load, in the event RF energy is the power source, interconnects the inner and outer conductors to form the probe.

Abstract: A source of radio frequency energy is applied to a low thermal inertia heating element with high thermal conductivity, such as a spool, for rapidly heating the heating element to settable predetermined temperature, which temperature is maintained essentially constant. The heating element is detachably attached about the die of a mold for transferring heat to the die to form, mold, weld or extrude thermoplastic material placed within the mold. Thermal chokes restrict heat transfer from the die to the remainder of the mold. One or more heat sinks draws and dissipates heat from the thermal chokes to maintain cool zones of the mold. Following the heating cycle, upon termination of application of radio frequency energy to the spool, cooling may be accelerated by directing a stream of gas upon the heating element.

Abstract: Radio frequency power for melting, sealing and welding plastic tubing compressed between a pair of manually or automatically actuated electrically conducting jaws of a hand held or fixed base tubing sealer is regulated by a pulse width modulator controlling the duty cycle of applied constant voltage pulses. A predetermined change of impedance of the tubing during compression and melting is detected to regulate the power applied and to ensure a weld of predetermined physical parameters. On completion of the weld, a first timer is reset and a further weld may be made. In the event of impedance mismatch, a second timer inhibits further application of power and resetting of the first timer. The use of the pulse width modulator enhances conservation of power and accommodates portability of the tubing sealer through use of rechargeable batteries as the power source.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: A hollow core coaxial catheter supporting a heatable probe or balloon transmits electrical power, such as RF energy, to the ohmically resistive probe or balloon. The hollow core may accommodate passage of a guide wire, fiber optics for imaging or laser, fluid flow for perfusion and/or a lumen for fluid inflation and pressurization of a balloon. Inner and outer electrical conductors are disposed on radially opposed sides of dielectric tubing with an outer covering of dielectric material mechanically shielding and electrically insulating the outer conductor. A similar inner covering of dielectric material may be disposed radially inwardly of the inner conductor to mechanically and electrically insulate the inner conductor. An ohmically resistive load, in the event RF energy is the power source, interconnects the inner and outer conductors to form the probe.

Abstract: A radially compressible heating element is located about concentric overlapped heat fusible elements temporarily mounted upon a mandrel to form an annular seal between the heat fusible elements upon energization of the heating element.

Abstract: A bridge is attachable to and mountable upon the upper edge of a centrifuge cup for suspending a blood collection bag within the cavity of the centrifuge cup during centrifugation of the collected blood. The bridge includes structure for supporting the bridge upon an expressor to permit expressing the centrifuged blood from the bridge suspended blood collection bag.

Abstract: Isolation of a quantity of blood within a fold of a blood collection bag is prevented during centrifugation by applying a laterally oriented force against the blood collection bag to pressurize it and encourage unfolding of any folds. The laterally oriented force is generated by the apparent weight increase of the blood collection bag during centrifugation.

Abstract: A blood bag support system is described which is very useful for supporting a blood bag in a centrifuge. The support system includes two upright support members and horizontal connecting means extending between the upright supports. A blood bag is suspended from the connecting means. The support system is balanced so as to avoid vortexing or mixing inside the blood bag during centrifuging. The support system holds up the ports at the top of the bag, enabling red blood cells in the ports to be forced downwardly during centrifuging. This prevents contamination of blood components with red blood cells.

Abstract: A weight monitor includes a first part for attachment to a pedestal or other support member and a second part for suspending a blood collection bag to be filled by a flow of blood from a donor. A trough shaped spring interconnects the first and second parts and retains the second part in fixed positional relationship to the first part until the bending force imposed upon the spring by the filling blood collection bag exceeds a predetermined value at which point the spring flexes abruptly and the second part becomes positionally reoriented with respect to the first part. A clamp, associated with the fill tube of the blood collection bag, is actuated by the reorientation of the second part to terminate further flow of blood through the fill tube into the blood collection bag.

Abstract: A solenoid operated moveable jaw cooperates with a fixed jaw protruding from a blood tubing sealing unit and formed as part of a relatively massive heat sink to effect seals on liquid filled plastic tubing upon transmission of RF energy timed to coincide with a degree of initial mechanical compression of the tubing by the jaws after the movement of the moveable jaw has been triggered by the tubing intercepting and reflecting a beam of light. Dissipation of heat from the exposed part of the fixed jaw is by convection. Dissipation of heat from the enclosed part of the fixed and moveable jaws and that produced by the circuitry generating the RF energy internal to the sealer unit is effected by channeling the heat by conduction from all internal heat sources to the bottom and rear plates of the unit and dissipating the heat from the bottom and rear plates to the atmosphere by convection.

Abstract: A pair of jaws moveable with respect to one another whether mounted in a hand held sealer or desk mounted sealer, compresses, heats, elongates, spreads and welds liquid filled tubing placed therebetween. Variants of the pair of jaws provide means for serially or simultaneously segmenting the tubing into a plurality of sealed compartments. The pair of jaws are electrically connected to a source of RF energy as the plates of a variable capacitor in an RF resonant circuit. The flow of RF energy across the pair of jaws, which energy heats the tubing and, in conjunction with mechanical pressure, makes the weld, is a function of timing and of the spacing between the jaws which spacing affects the degree of resonance of the RF resonant circuit.