Abstract: An apparatus adapted to be inflated and deflated in response to selective communication with a source of pressurized fluid includes a bladder having a semi-rigid shell body portion and a relatively thin membrane portion defining an inflatable chamber. The elongate semi-rigid shell body preferably includes a contoured, concave inner surface terminating at a peripheral side edge. At least one passage extends through the shell body defining an opening in the inner surface of the shell body. The flexible membrane is continuously bonded to the shell body adjacent the peripheral side edge to define the enclosed inflatable chamber in communication with the passage. The membrane has a reduced waist portion defining a membrane tension zone adjacent the opening of the passage into the chamber to reduce the probability of occluding the entrance while deflating the chamber.

Abstract: A percutaneous access device implantable beneath the skin of a patient includes a turret assembly containing current limiters, electrical contacts and fluid couplings and includes a sealing device having a small screw fastener at the bottom of the turret assembly. A screwdriver is provided configured to have access through a required air inlet passage to provide rapid removal and replacement of a new turret. The screwdriver includes a shaft having an eccentric drive socket. A handle has a roller clutch bearing pressed in place to allow the handle to freely turn clockwise to tighten the screw but locks the handle to the shaft for screw extraction in the counterclockwise direction. A driver captively engages a fastener for assembling a first part having a shoulder to a mating fitting having an aperture.

Abstract: An apparatus for assisting cardiac function of a patient includes an inflatable chamber operably positionable with respect to an aorta of the patient, a percutaneous access device implantable with respect to a hypogastric region of the patient and connectible in fluid communication with the inflatable chamber, and a drive unit connectible through the percutaneous access device for selectively inflating and deflating the inflatable chamber in accordance with a control program stored in memory. The control program controls the drive unit in response to a periodically scheduled patient monitoring routine for measuring values of the physiology of the patient. The control program uses measured values as modified in accordance with the control program and physician programmable parameters for assisting cardiac function of the patient.

Abstract: A trephine device for preparing apertures through a flexible material, such as skin of a patient, including a base plate having an upper surface and an opposed lower surface, where the upper surface has at least one upwardly protruding skin deforming contoured surface. The base plate is adapted to be removably inserted into a pocket surgically prepared in tissue of the patient. The device can include a handle member mounted on and projecting upwardly from the upper surface of the base plate. A clamping member is connected to the trephine device in overlying relationship to the upper surface of the base plate. The clamping member facilitates deformable, clamping, sandwiched engagement of the flexible material between the upper surface of the base plate and the clamping member. When the base plate is inserted into the pocket surgically prepared in the tissue of the patient, the skin of the patient is engageable between the base plate and the clamping member.

Abstract: A control system for an inflatable chamber operably positionable with respect to an aorta of a patient monitors an actual flow duration time for inflating and/or deflating the inflatable chamber with a predetermined volume of pressurized fluid and compares the actual flow duration time to a target flow duration time. The system controls the fluid pressure in a high pressure reservoir, and/or in a vacuum reservoir, based on the results of the comparison. If the actual time for inflation is too short compared to the target time, the fluid pressure in the high pressure reservoir is reduced. If the actual time for inflation is too long compared with the target time, the fluid pressure in the high pressure reservoir is increased. If the actual time for deflation is too short compared to the target time, the vacuum in the vacuum reservoir is decreased. If the actual time for deflation is too long compared with the target time, the vacuum in the vacuum reservoir is increased.

Abstract: An apparatus for measuring flow rate and controlling delivered volume of fluid flow in a fluid conduit is disclosed including a valve having a fixed aperture disposed in the fluid conduit for selectively opening and closing the aperture between an open position and a closed position. The valve is selectively closed when a predetermined volume has passed through the valve. Differential pressure is measured across the valve and the differential pressure is accumulated with respect to time to provide a value corresponding to volume of fluid flow passing through the valve when in the open position.

Abstract: An apparatus and method for measuring the blood pressure of a patient with a permanent or temporary cardiac assist device throughout an entire cardiac cycle by partially filling the inflatable chamber of the cardiac assist device operatively disposed with respect to an aorta with pressurized fluid and using the partially filled chamber as a transducer. An external pressure sensor is located in a drive unit connected to the inflatable chamber. The drive unit controls, monitors and stores the fluid pressure with respect to the inflatable chamber. When isolated from a pressurized fluid reservoir, the pressure within the inflatable chamber corresponds to the current blood pressure of the patient throughout the cardiac cycle. The inflatable chamber preferably is defined at least in part by a flexible membrane. The inflatable chamber is partially inflated with a predetermined volume of pressurized fluid from the reservoir.

Abstract: A percutaneous access device implantable beneath the skin of a patient which includes a housing having a flange positionable beneath the skin and neck projecting outward through the skin. The percutaneous access device includes electrical communication through the flange and fluid access through the flange. The components providing fluid access and electrical communication are removable through the neck portion of the implant for testing and service as required without the need for further surgery on the patient. A turret body is received within the hollow interior of the neck having a fluid channel extending therethrough and containing current limiting devices securely disposed within the turret body.

Abstract: A medical current limiter protects medical electrodes and associated diagnostic apparatus from overcurrents. The medical current limiter includes first and second external terminal connections and first and second cascade circuits, each formed of a pair of n-channel field effect transistors and a p-channel field effect transistor consecutively connected in series between one of the first and second external terminals and a low value resistor. The p-channel field effect transistor and one of the n-channel field effect transistors connected thereto in each cascade circuit have a pinch-off voltage of less than 0.7 volts.

Abstract: A percutaneous access device includes a body having a horizontal disc-like base flange and a frusto conical projection extending centrally upwardly from one side of the base flange. An elongate flexible tube extends loosely through a bore through the projection and base flange and is sealingly bonded to the body adjacent the bottom of the bore. A coating of a silicone-polycarbonate is applied to the outer surface of the projection and is formed with a multiplicity of microscopic pores to facilitate the bonding of dermal cells to the device upon implantation. The body is of a relatively soft, flexible, biocompatible material so that the device absorbs forces tending to displace the implanted device.

Abstract: A surgical tool for forming a circular opening through the skin which is of smaller diameter at the outer skin surface than at the inner surface of the skin employs a trephine having a circular cutting edge. The trephine is inserted into a pocket surgically formed beneath the skin with its cutting surface facing the skin. A rod member is then inserted through the skin and threaded into the trephine. The rod member is attached to a spring biassed plunger within a tool housing which is released from a ready position by withdrawal of a locking pin. Upon release of the plunger, the spring drives the plunger to drive the cutting edge of the trephine outwardly through the skin.

Abstract: A culture and transport assembly for enclosing a percutaneous access device within a sealed outer container to maintain the device under sterile conditions during transport while accommodating culturing of a coating of dermal cells on a portion of the device while the device is retained within the container. The container has a removable cap to which a culture well body is attached. The percutaneous access device is releasably clamped between the bottom of the body and an underlying platform with a portion of the device projecting into a bore in the body. When the device is so clamped, the bore constituted a sealed culture chamber in which the dermal cell culturing procedure may be performed by introducing cells and culturing solutions into the chamber via fluid passages extending from the chamber to connectors accessible at the exterior of the cap.

Abstract: A combination is provided of a percutaneous lead designed for implantation in the human body, which lead has a surface which is adapted to pass through and be exposed to the dermis of a patient when the device is implanted. Said surface is adapted to receive the growth of a cultured autogenous fibroblast coating on an etched, nanoporous surface. A liquid tight sealed removable, disposable chamber encloses said surface, said chamber being provided with openings for introduction therein of finely divided living dermal tissue suspended in a liquid carrier, thus providing a means for formation of the cultured surfaces which can be easily handled. The disposable chamber is removed and discarded at the time of surgery.