Abstract: A sensor for measuring the oxygen saturation of blood flow within the skull is described. In a first embodiment the sensor comprises a photodetector and a pair of light emitting diodes surface mounted near the end of a length of flexible printed wiring. The sensor is hermetically sealed by a coating of rubber or polymeric material which has an optical window over the photodetector and light emitting diodes. The sensor is inserted through a burr hole drilled in the skull and slides between the skull and the dura of the brain. The light emitting diodes are pulsed to illuminate blood within the dura and brain with light, and light reflected by the blood is received by the photodetector and converted to electrical signals. The signals are processed by a pulse oximeter to provide an indication of blood saturation. In a second embodiment the photodetector and light emitting diodes are mounted at the end of a core of compressible foam extending from the end of a hollow bone screw.

Abstract: An over-the-needle catheter assembly in which a restriction of the inner diameter of the catheter tube is formed in the proximity of the needle hub. The restriction is formed by heating a portion of the catheter tube to the softening point of the catheter material, stretching the catheter tube to cause the heated portion of the catheter tube to tighten about an inner needle or mandrel, then releasing the stretching force to allow the stretched portion to relax, leaving a small gap between the inner wall of the catheter tube and the outer diameter of the insertion needle. The small gap is preferably sized to be on the order of the size of the diameter of blood cells to restrict the flow of liquids past the restriction and into the catheter hub.

Abstract: A catheter device is disclosed which contains a catheter in an insertion needle. The insertion needle is attached to a needle hub which contains a flash chamber. Within the flash chamber the proximal end of the needle is connected to a clear plastic tube so that flash is initially determined in this tube; overflow flash is then caused to flow into the larger flash chamber from the flash tube.

Abstract: A catheter device is described with a safety needle guard that covers and protects the needle after use of the device. The device includes a semi-tubular needle housing containing a flash chamber with a hollow needle extending from the distal end of the flash chamber. A tubular needle guard concentrically fits and slides within the needle housing. The needle guard has a longitudinal slot through which the mounting base of the flash chamber passes as the guard slides within the housing. The top of the semi-tubular housing is open so that a user may access the top of the tubular needle guard with a finger to urge the needle guard to an extended position from the distal end of the housing and in a surrounding position about the needle. The proximal end or hose of the needle guard detaches for the needle housing and has a luer fitting for an infusion set. The catheter hub contains a lever capable of occluding the catheter to inhibit fluid flow.

Abstract: A method and apparatus are described for determining characteristics of peripheral arterial volume and compliane. A blood pressure cuff is inflated and deflated around a limb of the body and pressure measurements are taken. The volume of air removed from the cuff is determined in a quantifiable manner, such as by expelling air through an orifice of known characteristics or by means of a volume of know characteristics. The detected pressures and volume of air removed are used to compute oscillation volume, which in turn is used to display arterial capacity and compliance as a function of transmural pressure and time. Arterial capacity may be displayed in terms of arterial radius, arterial cross-sectional area, or arterial volume. A display of these characteristics as a function of pre and post anesthetic administration is particularly useful to the anesthesiologist and surgeon.

Abstract: Methods and apparatus for constructing optically stabilized, shutterless infrared capnographs are disclosed. The capnographs of the present invention provide the absolute concentration of the constituents of the respiratory airstream of a patient, without the thermal drift problems normally associated with thermopile detectors, thereby providing a device with a high degree of accuracy. The present invention eliminates the need for a mechanical shutter to modulate the incident infrared beam and the need for a modulated source, thereby increasing the reliability and response time of the devices disclosed. Capnographs which are substantially unaffected by changes in the ambient temperature at which they operate are provided by connecting pairs of optically filtered thermopiles in series and processing the resulting differential pair.

Abstract: A catheter assembly is provided with a needle guard that slides along the needle to shield the distal tip of the needle after the needle is withdrawn from a patient. The needle passes through an aperture at the distal end of the needle guard. To prevent the backflow of blood through the aperture and into the needle guard, a gasket is formed in the aperture about the needle. The gasket is formed with the needle in place by filling the aperture around the needle with adhesive. After the adhesive has substantially cured but before the adhesive has tightly bonded to the needle the needle guard is moved along the needle to prevent bonding of the adhesive to the needle. The needle guard will thereafter slide along the needle with the needle passing through the formed-in-place gasket.

Abstract: A catheter with a double membrane gasket and a locking needle guard is disclosed. The gasket prevents blood from seeping through the catheter hub. The locking needle guard prevents the user from inadvertent needle sticks.

Abstract: Improved infrared detectors for use in device such as capnographs are provided. A preferred embodiment of an infrared detector of the invention is comprised of paired thermopiles, connect in opposed relation to each other, which are preceded by an analytical or reference filter for passing a desired wavelength and a neutral density filter in the optical path of one of the thermopiles in the pair. The difference between the outputs can be used to eliminate the effects of background thermal noise, thereby improving performance of the detector. Preferably, a reference channel and an analytical channel are provided so that the respective differences between the detectors in each pair can be used to further cancel the effects of background thermal noise.

Abstract: An over-the-needle catheter assembly is provided in which a restriction of the inner diameter of the catheter tube is formed in the proximity of the needle hub. The restriction is formed by heating a portion of the catheter tube to the softening point of the catheter material, stretching the catheter tube to cause the heated portion of the catheter tube to tighten about an inner needle or mandril, then releasing the stretching force to allow the stretched portion to relax, leaving a small gap between the inner wall of the catheter tube and the outer diameter of the insertion needle. The small gap is preferably sized to be on the order of the size of the diameter of blood cells to restrict the flow of liquids past the restriction and into the catheter hub.

Abstract: A disposable endotracheal airway adapter for use in proximity of a patient's mouth in the measurement of the concentraton of respiratory gases. The disposable airway adapter of the invention provides a conduit for patient respiratory gases and allows the passage of infrared radiation through the gases for measuring the constituent concentration of the respiratory gases while keeping the patient gases from coming in contact with the analyzer mechanism. The body of the airway adapter is designed to connect in series with the airway tubing which connects a patient to a mechanical respirator or anesthesia breathing circuit. The body of the airway adapter is very light in weight and is formed of inexpensive material such as polyethylene or polypropylene so that it may be manufactured inexpensively and discarded after each use. An inexpensive optical window in the adapter is also formed of material such as polyethylene or polypropylene so that the gas analyzer can pass light into the sample for analysis.

Abstract: A catheter hub assembly is disclosed wherein the assembly contains a membrane useful in preventing backflow of blood into the flash chamber. The hub assembly contains a membrane opener which operates upon the insertion of a luer locking mechanism into the catheter hub. This membrane opener allows flow of nutritional fluid into the body by causing the opening of the membrane during use of the catheter after removal of the catheter needle.

Abstract: The deflation of the inflatable and deflatable cuff worn by a subject during automatic sphygmomanometric measurement is accomplished in unequal size decrements and principally in larger steps than 7 Torr. Each step after detection of the initial oscillations is determined in the first instance by reference to a look-up table or an equation as a function of prevailing cuff pressure. This Base Step dimension is augmented by a factor proportional to the last oscillation amplitude, the factor being increased after detection of the maximum oscillation amplitude. A valve mechanism with at least two different effective orifice sizes is used for deflation, the smaller size effective orifice being used first, to maintain control over the decrement step rate while holding the time for decrement within a predetermined limit of 8 mSec. per Torr, i.e., maintaining the rate above 125 Torr per second.

Abstract: A catheter is provided which deters the backflow of blood between the insertion needle and the catheter cannula by forming the distal end of the catheter hub so as to restrict the inner diameter of the catheter cannula to a wiping fit with the engaged insertion needle. In a first embodiment the distal end of the catheter hub is pre-formed to its desired final inner dimension. The distal end of the hub is stretched to an oversize condition, the catheter cannula is attached to the hub, and the distal end of the catheter hub is heated, causing a stress relief of the previously stretched hub. The distal end of the catheter hub returns to its pre-formed dimension which will mechanically restrict the diameter of the catheter cannula at that point to form the wiping fit with the engaged needle.

Abstract: A sensor for measuring the oxygen availability of blood flow within the skull is described. In a first embodiment the sensor comprises a photodetector and a pair of light emitting diodes surface mounted near the end of a length of flexible printed wiring. The sensor is sealed by a coating of rubber or polymeric material which has an optical window over the photodetector and light emitting diodes. The sensor is inserted through a burr hole drilled in the skull and slides between the skull and the dura of the drain. The light emitting diodes are pulsed to illuminate blood flow in the brain beneath the dura with light, and light reflected by the blood is received by the photodetector and converted to electrical signals. The signals are processed by a pulse oximeter to provide an indication of blood availability. In a second embodiment the photodetector and light emitting diodes are mounted at the end of a core of compressible foam extending from the end of a hollow bone screw.

Abstract: A catheter device is described with a safety needle guard that covers and protects the needle after use of the device. The device includes a semi-tubular needle housing containing a flash chamber with a hollow needle extending from the distal end of the flash chamber. A tubular needle guard concentrically fits and slides within the needle housing. The needle guard has a longitudinal slot through which the mounting base of the flash chamber passes as the guard slides within the housing. The top of the semi-tubular housing is open so that a user may access the top of the tubular needle guard with a finger to urge the needle guard to an extended position from the distal end of the housing and in a surrounding position about the needle. As the needle guard attains its fully extended position about the needle, it locks in place in the needle housing.

Abstract: A through the needle catheter device is described which includes apparatus for threading a catheter into a blood vessel. The apparatus is irreversible during the threading process. The catheter device also includes means for irreversibly withdrawing and splitting the needle. A technique is provided for inserting the needle, threading the catheter, and withdrawing the needle from a patient.

Abstract: A looseleaf notebook is provided for retaining bar code listings which denote conditions of a patient in a hospital. The notebok includes a strap which encircles the binding of the notebook. Preferably this strap is fixed in place between the notebook ring mechanism and the inside of the binding panel of the notebook. The strap is also preferably adjustable or resiliently stretchable. The strap permits the notebook to be held open and manipulated by a user who slides a hand between the strap and the binding panel while supporting the opened covers of the notebook with the thumb and fingers of the hand. With the notebook being held in one hand in this manner, the user's other hand is free to manipulate a bar code reader over the patient condition bar codes, or to perform other information-gathering or medical functions.

Abstract: A through the needle catheter device is described in which a catheter is located inside a splittable needle for insertion into the body. Means are provided for preventing rearward motion of the catheter relative to the needle as the needle and catheter are inserted into the body. As the needle is withdrawn from the body, a splitting mechanism splits the needle, releasing the enclosed catheter. Means are provided for preventing forward motion of the needle relative to the catheter as the needle is withdrawn, thereby preventing inadvertent perforation of the catheter during withdrawal. After the needle has been withdrawn and split, the catheter assembly, including a catheter cannula, a section of extension tubing and a luer, fall away from the patient-facing side of the device. In a preferred embodiment a taping wing is provided at the proximal end of the catheter cannula.

Abstract: A through the needle catheter device is described which includes apparatus for threading a catheter into a blood vessel. The apparatus is irreversible during the threading process. The catheter device also includes means for irreversibly withdrawing and splitting the needle. A technique is provided for inserting the needle, threading the catheter, and withdrawing the needle from a patient.