Abstract: An automated sphygmomanometer which automatically determines when a blood pressure determination needs to be made. During a "guard mode" determination, a cuff on an appendage of the patient is frequently inflated to a check pressure, which is preferably below the patient's mean arterial pressure ("MAP"), and the signature (shape, amplitude, pulse period, etc.) of the measured oscillometric signal is compared to a stored signature of a portion of an oscillometric signal at a corresponding portion of the oscillometric envelope determined during a previous blood pressure determination. If these signals differ by some predetermined amount, it is determined that the patient's blood pressure has changed significantly and that a new blood pressure determination needs to be conducted immediately. These guard mode determinations are made in addition to the normal blood pressure determinations made at predetermined intervals typically selected by the user.

Abstract: A series of blood pressure cuffs is provided having two indications of size thereon. The first indication of size is preferably a sequential system of numbers numbering the size of the cuffs from smallest to largest. The second system of size indication is a caricature depiction of animals of increasing size on each of the respective increasing cuff sizes. For example, five cuffs may be sized from smallest to largest having depicted thereon a goldfish, a rabbit, a duck, a dog and a dinosaur.

Abstract: A catheter needle having surface indication thereon and process for forming such catheter by laser marking of the needle with a visual surface indicator of the terminus of the catheter tube.

Abstract: A method and apparatus are described for determining characteristics of peripheral arterial volume and compliance. 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 using a volume of known 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: A process and product and apparatus are disclosed wherein a laser is used to form a conical tapered tip on a catheter product. The catheter is placed on an insertion needle prior to the formation process, thus eliminating the problems associated with wearing out forming tooling. The process and product further call for the use of the laser to create a surface effect on the cannula to indicate the terminus of the catheter.

Abstract: A new catheter stick protector is described having a metal flap clip which snaps down into place to prevent return of the needle through the protector device once withdrawn. The device is small and received over the needle to provide an interface between the needle hub and the hub of a catheter like product. A sleeve of hydrophobic or fluid impermeable material is provided and attached at one end to the needle hub and at a second end to the tip protector. The length of the material is selected to hold the tip protector in a position just extending beyond the tip of the needle of a catheter inserter.

Abstract: A method and apparatus are described for determining characteristics of peripheral arterial volume and compliance. 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. Also, systolic and pulse pressures are determined using only these determined values.

Abstract: A process is provided wherein a laser is used to shape and/or trim a polymer tubular catheter material while in situ on a metal insertion needle or cannula. The laser process seals the interface between the polymer catheter material and the metal cannula to prevent the flow of blood between the tubular catheter and the introducing cannula during insertion into a patient. The interface is of sufficient strength to resist such blood flow, but still sufficiently weak to prevent the removal of the cannula needle after insertion into a patient.

Abstract: A method for determining a dominant heart rate from a series of beat triggers representative of a mixed series of normal heart beats and non-arrhythmic activities, with the beat triggers being determined at a specific sampling rate defining sample intervals, comprising the steps of: framing a window to include a portion of the series of beat triggers and to be beat-aligned with a first beat trigger and a last beat trigger, the window thereby defining a plurality of trigger intervals for respective adjacent beat triggers, with each trigger interval containing a plurality of the sample intervals existing between the respective adjacent beat triggers; summing the windowed sample intervals; for each of the trigger intervals, computing a weight factor based upon the ratio of the summed windowed sample intervals to the number of sample intervals within that trigger interval; grouping the trigger intervals according to the weight factors; computing the percentage of the window that each group of weight factors const

Abstract: A method and apparatus are described for determining characteristics of peripheral arterial volume and compliance. 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: This invention relates to a novel needle for expeditiously determining proper insertion of the needle into a patient. A transparent shaft is positioned behind the tip of the needle. Upon insertion of the needle into the vein of a patient, blood is observed in the transparent shaft of the needle. Preferably, the shaft is formed of polyurethane or polycarbonate the needle can be used with an over-the-needle catheter.

Abstract: A patient monitoring system includes a pulse oximeter sensor and an audible alarm which is not produced when a blood pressure module is taking measurements, but only during that portion of the cycle that affects the pulse oximeter reading. During such measurements, the pulses detected by the oximeter decrease below a threshold T.sub.oxim. An audible alarm is caused to receive a logic level of zero by an AND gate through the detection of measurements exceeding a minimum pressure P.sub.min on the blood pressure module. The audible alarm continues to receive such a logic level until the measurements exceed a threshold P.sub.thr. After that time, the audible alarm AND gate logic level is reset to one, so as to permit reporting of pulses missing at the oximeter. None of the other alarms, such as the actual SPO.sub.2 reading, are affected by the AND gate. Accordingly, the present invention does not affect the taking of important SpO.sub.

Abstract: An anesthetic agent analyzer having six or more independent analytical channels, where each channel comprises a first thermopile which receives incident infrared radiation and a second thermopile behind the first thermopile which is blocked from the incident infrared radiation and thus serves as a reference for detecting ambient temperature variations. The first and second thermopiles are connected in a "parallel opposed" fashion so that the effects of ambient temperature variations automatically cancel and the detectors may be readily configured in a detector package. The anesthetic agent analyzer of the invention is designed for use with a wideband infrared radiation source so that anesthetic agents having characteristic absorption bands in the far infrared wavelength range (6-15 microns) may be more readily detected and discriminated.

Abstract: An infrared gas analyzer implementing an optically stabilized detector in a sidestream configuration. In order to reduce the pneumatic sampling volume, an "optical funnel" or collimator is used to resize the optical aperture of a multi-channel optically stabilized detector without compromising signal strength. The smaller pneumatic volume is desirable in order to minimize the time required for a gas wavefront from the sample cell to traverse the optical aperture, thereby minimizing pneumatic response time. The geometry of the sample cell of the invention is also streamlined so that sharp corners or transitions which might induce turbulent gas flow are eliminated. The sample cell of the invention thus promotes smooth, laminar flow of aspirated respiratory gases through the optical aperture so as to preserve the temporal relationship of gas concentration wavefronts within the gas stream and to thereby allow the analyzer to exhibit a faster pneumatic response.

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. In addition, techniques are provided for selecting overlapping optical filters for use with thermopiles with a minimum level of cross-talk.

Abstract: An I.V. catheter is described, including a catheter and hub assembly and a needle and hub assembly. A needle guard, including a tubular distal portion and a split proximal flange, is located about the needle at the distal end of the needle hub. The needle includes a slot near the needle tip. As the needle assembly is withdrawn from the catheter, the needle guard slides along the needle until the split flange engages the needle slot, which locks the tubular distal portion of the guard over the needle tip.