Abstract: Disclosed is a method of compensating any of a plurality of different pressure transducers for their characteristic pressure sensitivity, zero pressure offset, and self-heating error. The method comprises selecting a gain resistor that adjusts the gain of an output signal of the pressure transducer in use so that the pressure transducer appears as an ideal pressure transducer to a pressure monitor. The self-heating error is compensated by measuring an initial bridge voltage that drives the transducer and an initial output signal of the pressure transducer when the transducer is first energized. After a period of time a second bridge voltage and a second output signal are determined. The self-heating error is determined as a function of the difference between the initial and second values. The zero pressure offset is compensated by determining the output signal of the pressure transducer at zero gauge pressure after the pressure has been compensated for the self-heating error.

Abstract: A pressure transducer compensation system for compensating an offset and adjusting the sensitivity of the pressure transducer to a predetermined level. A reusable cable (160) connected to a pressure monitor (14) is intended for use with a plurality of disposable pressure transducers (12). In one embodiment, a connector (150) of the reusable cable includes a CPU (70), which determines the offset and self-heating errors of the pressure transducer during the first 30 seconds it is energized, stores the corrections in its internal memory and compensates the output signal produced by the pressure transducer for those errors and for variations in ambient temperature. A gain-set resistor (56) is included in a male modular phone plug (202) of a disposable cable that is integrally connected to the pressure transducer, and is used by the compensation circuit to control the signal produced by the pressure transducer, compensating for the characteristic sensitivity of the device.

Abstract: Apparatus for monitoring fluid pressure and controlling fluid flow in a fluid line. The apparatus (10) includes a base (36) and a cover (38), between which is captured a membrane (42). The base includes an inlet port (18), a first outlet port (20), and a second outlet port (34). Channels formed within the base and covered by the membrane connect the inlet and outlet ports in fluid communication. The apparatus includes a flushing flow control valve (30) formed by a flow control projection (70), which projects outwardly from the base through the cover, and separates an inlet channel (62) from an outlet channel (64). A capillary flow passage 88 for restricting flow through the apparatus is disposed between the inlet channel and outlet channel comprises a capillary groove (86), formed across the flow control projection, adjacent the overlying membrane.

Abstract: A valve for selectively controlling flow within a fluid line between a relatively low capillary flow rate and a flushing flow. A flush valve (10) comprises a base (14) and a cover (16) that secures an elastomeric membrane (18) in place over a flow path (32) formed in the base. The flow path includes an inlet passage (34) connected in fluid communication to an outlet passage (50) by a capillary groove (38). The membrane seals over the capillary groove to define a capillary passage (48), which restricts fluid flow through the flush valve to the capillary flow rate. A user may selectively enable the relatively greater fluid flow through the device by deforming the membrane away from the capillary groove, thereby creating a relatively larger flushing flow passage (66). The flushing flow of fluid through the region of the capillary groove serves to carry away any obstruction that may be present in the groove or downstream of the flush valve.

Abstract: An apparatus and method for providing a blood pressure transducer suitable for use in a catheter line, for monitoring blood pressure. Two embodiments of the blood pressure transducer (20, 120) are disclosed, both of which include connectors (24) suitable for connection to a catheter line. A flow-through passage (22) extends between the two connectors, in fluid communication with a solid-state pressure transducer chip (36), which is mounted on a chip carrier (34) inside a rectangular-shaped plastic housing (30/130, 32). The chip carrier includes a plurality of formed flat leads (38) connected to the pressure transducer chip, and an extending nib (62) having a passage (66) filled with a silicon gel (64), which couples fluid pressure in the flow-through passage to a pressure sensitive diaphragm (106) on the solid-state pressure transducer chip.

Abstract: A compact, inexpensive, and lightweight pressure calibrator and a method for calibrating pressure monitoring devices. The pressure calibrator (10) comprises a plunger (14) sized to slide snugly within a hypodermic syringe barrel (12). Included within the plunger are pressure transducer (56), a microprocessor (54) and other electronic components (62). A digital display (30) disposed within the side of the plunger is operative to display the pressure developed within the syringe barrel (12) as the operator moves the plunger. "O" rings (28) provide a hermetic seal between the plunger and the internal bore (16) of the syringe barrel. A tube (22) is connected to the output port (20) of the syringe and provides fluid communication between the syringe and a pressure monitoring device (26) being calibrated.

Abstract: An optical module for coupling a fiberoptic catheter to a catheter oximeter processing apparatus. The optical module includes a plurality of light emitting diodes, each of which is mounted on a flat surface at the free end portion of a respective bracket. A plurality of optical fibers, which are adapted to be optically connected to the catheter, have their free ends secured to a mounting substrate in spaced positions and in closely spaced alignment with the diodes. The diodes are each individually provided with electrical connections that can be selectively actuated by the processing apparatus. The brackets, which are fixed at one end, are constructed of thin flexible material so that the diodes can each be adjusted generally in the plane of the receiving end faces of the optical fibers so as to obtain maximum light energy transfer therebetween.

Abstract: A surgical instrument includes a handle and a disposable assembly which can be readily replaced after each operation or as necessary. The disposable assembly includes both an electrically heated scalpel blade and an electrosurgical active electrode which are mounted in a spaced parallel arrangement so that they can be used alternately by rotating the instrument by 180 degrees. The mounted ends of both the blade and the electrode are adapted to be received by separate terminals in the instrument handle so that the appropriate external power sources can be selectively connected thereto.

Abstract: The cutting instrument of this invention is made by threading a heater assembly through a hollow cutting instrument body. A blade having a shank and a blade body including a cutting edge is secured within the hollow cutting instrument body at its shank portion such that the blade body extends from the hollow cutting instrument body. The heating assembly is secured to the blade body and to the cutting instrument body. The blade body is coated with a non-stick means.

Abstract: A portable infusion device includes a disposable syringe which is located in a removable section of a compact package that comprises the device. In order to conserve space, a flexible piston rod assembly is provided wherein the syringe plunger head is connected to a thin flexible plunger stem which is reversely bent about the upstream end of the syringe body so that the outer end of the stem lies directly adjacent and parallel to the syringe body. A small motor located in the non-removable portion of the package drives the plunger through a screw which sequentially engages closely spaced teeth on the face of the plunger stem as it moves along the outer surface of the syringe. When the syringe contents have been discharged, the removable section, including the syringe and plunger stem assembly, can be readily removed and replaced.

Abstract: The cutting instrument of this invention is made by threading a heater assembly through a hollow cutting instrument body. A blade having a shank and a blade body including a cutting edge is secured within the hollow cutting instrument body at its shank portion such that the blade body extends from the hollow cutting instrument body. The heating assembly is secured to the blade body and to the cutting instrument body. The blade body is coated with a non-stick means.