Abstract: Apparatus for collecting a sample of liquid, such as blood, having a plurality of phases of differing densities. Disclosed is an apparatus for collecting a sample in an enclosed chamber, wherein said apparatus can be used with a separating means which rotates the chamber about either a longitudinal axis of the chamber, or about an axis perpendicular to the longitudinal axis of the chamber and not passing through the chamber. In addition, said apparatus facilitates automated manipulation of the sample by providing formed features for: decreasing the gas permeability of said apparatus; clot activation of a blood sample contained within said apparatus; interconnection of a multiplicity of said apparatus; automated manipulation of said apparatus; protecting markings upon said apparatus; layering the construction of said apparatus; and, encoding of information upon said apparatus in both a tactile and visual manner. Also disclosed is an apparatus for dispensing fluid from said enclosed chamber.

Abstract: Apparatus useful in surgery for holding a patient's lower limb in a number of different positions required by a surgeon for the performance of a surgical procedure, and for eastablishing a sterile barrier between a surgical site and a patient's lower limb while the limb is being grasped by such positioning apparatus.

Abstract: A biomedical transducer which is useful for interposing between a tissue and apparatus or another tissue or organ which is applying pressure to the tissue, in order to estimate the pressure applied to a selected area of the tissue. The biomedical pressure transducer comprises: a first flexible layer carrying at least one electrical contact; a second flexible layer carrying at least one electrical contact and cooperating with the first flexible layer to define a pressurizable chamber wherein the contacts are normally touching when the chamber is not pressurized; and pressure estimation means for selectably pressurizing the pressurizing chamber so as to move at least one of said flexible layers sufficiently to separate the electrical contacts, and for indicating the lowest selected pressure at which the contacts are separated.

Abstract: Method and apparatus for partitioning a pre-selected phase of a sample of liquid, such as blood, having a plurality of phases of differing densities the method comprising the steps of introducing a sample into a chamber of constant cross-sectional shape and a volume greater than that of the sample, ordering the phases of the sample concentrically by rotating the chamber about its longitudinal axis, reducing the volume of the chamber in response to a separation control signal, removing a portion of the separated sample in order of phase, deriving information about the portion of the sample being removed from the chamber and modifying the separation control signal in response to the derived information.

Abstract: Apparatus useful in surgery for holding part of a patient's body such as a limb, portion of a limb, extremity organ or tissue in a number of different positions required by a surgeon for the performance of a surgical procedure, and for establishing a sterile barrier between a surgical site and a patient's limb or body part while the limb or body part is being grasped by a such positioning apparatus.

Abstract: Apparatus useful in surgery for holding part of a patient's body such as a limb, portion of a limb, extremity organ or tissue in a number of different positions required by a surgeon for the performance of a surgical procedure, and for establishing a sterile barrier between a surgical site and a patient's limb while the limb is being grasped by a limb positioning apparatus.

Abstract: An occlusive cuff which is useful for safety occluding blood flow into the digit of a human subject distal to the cuff for the duration of a surgical procedure.

Abstract: A visual stimulator for light stimulation of a subject's eyes to obtain electroretinogram, electro-oculogram or visually evoked potential responses. The stimulator comprises a light directing means for directing light from a light source into the subject's eyes, attenuator means for selectably attenuating the light source, photodetector means for producing an output signal representative of the radiant energy directed into the subject's eyes and signal processing means for receiving and processing the output signal to derive therefrom further output signals representative of the radiometric or photometric characteristics of said radiant energy. A light shutter comprising first and second shutter leaves affixed to the shafts of first and second galvanometers is also provided. The shutter leaves are positioned for pivotal movement with the galvanometer shafts to attenuate light passing between the shutter leaves.

Abstract: A cuff which is useful for accurately, reliably and remotely determining the circumference of a limb which the cuff encircles. The cuff comprises a laminate consisting of a low-impedance conductor that does not vary significantly as a result of bending or flexing, and a high-impedance electrically conductive strip which is in electrical contact with the low-impedance conductor along its length, and which is comprised of a material that is sufficiently flexible to remain in electrical contact with the low-impedance conductor along its length while the conductor is bent or flexed; an electrically conductive contact; and, an elongated strip of flexible material to which the laminate and electrically conductive contact are attached, such that a voltage-dividing circuit may be formed when the cuff encircles the limb, the ratio of voltages being relative to the circumference of the limb and being insensitive to the impedance between the laminate and the electrically conductive contact.

Abstract: A method for detecting an interruption in the supply of breathing gas to a patient, and apparatus adapted to carry out the method by:(a) during a reference time period, sensing the pressure in the patient's breathing gas;(b) storing, in memory apparatus, reference breathing information derived from the pressure sensed during the reference time period;(c) after the reference time period, sensing the pressure in the patient's breathing gas;(d) comparing active breathing information derived from the pressure sensed after the reference time period with the reference breathing information; and,(e) producing an alarm signal upon detection, during the comparing step, of predetermined variations between the reference breathing information and the active breathing information.

Abstract: A pneumatic tourniquet for maintaining occluded or restricted blood flow into a patient's limb includes an inflatable cuff, a pressurizing mechanism for pressurizing the cuff, a pressure relief mechanism for depressurizing the cuff, a blook pressure sensing mechanism for sensing the patient's systolic blood pressure and for producing a blood pressure output signal representative thereof, and a pressure regulator mechanism responsive to the blood pressure output signal for selectably activating the pressurizing mechanism and the pressure relief mechanism to maintain a substantially constant pressure difference between the cuff pressure and the patient's systolic blood pressure.Thus, the cuff pressure may be varied "adaptively" in response to changes in the patient's intra-operative systolic blood pressure to pressurize the cuff close to the minimum level required to maintain a bloodless surgical field, thereby minimizing the risk of patient injury due to over-pressurization of the cuff.

Abstract: A pneumatic tourniquet includes an inflatable cuff, a pressurizing mechanism for pressurizing the cuff, a pressure relief mechanism for depressurizing the cuff, a pressure sensing mechanism for sensing the pressure to which the cuff is pressurized and a pressure regulator mechanism for selectably activating the pressurizing mechanism and the pressure relief means to maintain the cuff pressure near a selected pressure. Visual and audible alarm signals are triggered if the cuff pressure exceeds a cuff pressurization limit, if the cuff pressure falls below a cuff depressurization limit, or if the cuff has remained pressurized for, or in excess of a selected time period.A computer may be used to sense the cuff pressure and pressurized or depressurized the cuff as required to maintain the cuff pressure within upper and lower cuff pressure limits.

Abstract: A composite electrode especially suitable for electrowinning processes comprising an electrically conductive substrate having on at least a part of its surface a multilayer coating, said coating comprising:(a) a barrier layer directly on the substrate;(b) a ruthenium dioxide-containing non-electrodeposited surface layer; and(c) between the barrier layer and the surface layer, an intermediate layer consisting of an electroplated ruthenium-iridium deposit, said ruthenium-iridium deposit being at least partially in an oxidized state.