Abstract: A linear phase high pass filter having a linear phase low pass filter in parallel with an electronic delay means is disclosed to remove baseline wander from an ECG signal. The linear phase low pass filter is preferably a digital Infinite Impulse Response (IIR) filter. An input ECG signal is simultaneously presented to an IIR low pass filter and an electronic delay. The low pass filter passes the low frequency baseline signal while blocking the ECG signal comprised of higher frequency components than the cutoff frequency of the low pass filter. Thereafter, the outputs from the IIR low pass filter and delay are passed to a summer that subtracts the output of the low pass filter from the output of the delay to produce the output of the filter. The combination of the output of a low pass filter being subtracted from a delayed input signal produces a high pass filter. The resulting high pass filter has a -0.3 dB cutoff frequency of about 0.

Abstract: A catheter is disclosed having an outer sheath made of a porous polymer material such as expanded polytetrafluoroethylene (ePTFE). The sheath has a porosity to allow anti-microbial or anti-bacterial medicament or other medicaments or liquids to pass through the sheath. A medicament lumen is provided passing through the elongated tube of the catheter from the catheter's proximal or out of patient end to openings along the catheter tube wall. Medicament is passed from the proximal end of the catheter through the medicament lumen and expelled through the openings into the area between the sheath and the catheter's main tube. There, the medicament or other liquid passes through the sheath into contact with the patient's body lumen. In the preferred embodiment, the catheter is a Foley urinary catheter.

Abstract: A chart recorder (10) is disclosed having an automatic paper loading system, an automatic tensioning system and an "odometer" system for determining the amount of paper moved through the chart recorder. The chart recorder (10) includes a print roller (34) and a feed roller (22), both in frictional contact with the paper in the recorder and both connected to and rotated by a motor. The feed roller (22) is connected to the motor through a one way clutch that allows the feed roller (22) to "free wheel" when the feed roller (22) is rotated at a faster rate, due to frictional contact with the paper, than the roller would be rotated by the motor (56). Dissipative forces in the one way clutch (68) and bearings (24) of the feed roller (22) cause it to resist being rotated which imparts tension to the paper and draws it into contact with a paper guide (14).

Abstract: A filter system for removing small amplitude, high frequency signals such as muscle artifact signals from an ECG signal is provided. The filter system includes a low pass filter with variable cutoff frequencies, an electronic delay and a system for detecting the R wave in the ECG signal and determining the variable cutoff frequency in response to the detection of the R wave. A digitized input ECG signal is simultaneously presented to the electronic delay and the system for detecting the R wave. During the portion of the ECG signal exclusive of the QRS complex, the filter is operated at a low cutoff frequency to filter the muscle artifact signals for a maximum smoothing effect. At a time slightly prior to the on set of the QRS complex, the cutoff frequency is rapidly incrementally increased to a higher cutoff frequency to pass the QRS complex with a minimum reduction of amplitude of the QRS signal.

Abstract: A drop detector circuit and method are provided for a drop detector of the type including a drop chamber and an electro-optical sensor. A photodiode detects drops passing through its optical sensing path, and a capacitor is connected between the photodiode and an amplifier to block the DC component of the diode signal. After amplification, the signal is passed through a low pass filter to further block signals caused by undesirable factors. The cutoff frequency of the low pass filter is controlled by a microprocessor that controls the pump that pumps liquid from the drop chamber.

Abstract: A relatively flexible, dual-lumen enteral feeding tube for delivery of fluid through a patient's esophagus to the patient's digestive system, the enteral feeding tube having proximal and distal ends. The tube comprises an enteral feeding lumen having a feeding lumen inlet opening adjacent the proximal end of the tube and a feeding lumen outlet opening adjacent the distal end of the tube. Additionally, a relatively small stylet lumen is provided separate from said enteral feeding lumen, the stylet lumen having a stylet lumen inlet opening adjacent the proximal end of the tube and being longitudinally co-extensive with a substantial length of the enteral feeding lumen. A relatively stiff stylet having a tapered annealed distal portion is removably positioned in the stylet lumen and extends from the stylet inlet lumen opening to adjacent to the feeding lumen outlet opening.

Abstract: A device having a rechargeable power source with an associated battery charger base having a quick charge current output and a trickle charge current output. A control circuit within the device is also provided that monitors if and for how long the device is attached to the base and determines the present capacity of the power source. Based on these signals, the control circuit selects an appropriate charge current output. The control circuit also includes timer circuits and circuits to measure the battery voltage during charging to allow for maximum but safe quick charging to protect the power source from long-term damage.

Abstract: A chest drainage apparatus (CDU) and method is disclosed for accurately measuring gas flow or leakage from a patient's chest cavity even at very low or near zero flow rates. The CDU has a collection chamber for receiving fluid and gas to be drained from a pleural cavity of a patient, a vacuum source for applying suction to the collection chamber and a valve for connecting the CDU to the vacuum source. A pressure transducer measures the gas pressure in the collection chamber. A microcomputer controller, responsive to the pressure measured by the pressure transducer, causes the valve to disconnect the vacuum source from the CDU when the gas pressure in the collection chamber is less than a first predetermined threshold and connects the CDU to the vacuum source when the gas pressure in the collection chamber exceeds a second predetermined threshold. The time period during which the vacuum source is disconnected from the CDU is measured as an indication of the rate of gas flow into the CDU.

Abstract: A biopsy device is disclosed having a tubular cannula through which a stylet having a stylet cavity near the distal end is placed. The stylet is attached to a stylet actuator and the cannula is attached to a cannula actuator. Both actuators are constrained by a housing to relative proximal and distal movement. In use, the stylet and stylet cavity are positioned in the cannula. The cannula and stylet are then inserted into the patient's tissue. When a sample is to be taken, the stylet is moved farther into the patient's tissue thereby exposing the stylet cavity. The patient's tissue then falls into the stylet cavity. Thereafter, the cannula actuator moves the cannula forward over the stylet cavity thereby cutting the tissue so that a sample of the tissue remains in the stylet cavity which becomes encased by the cannula as the cannula is moved forward.

Abstract: An improved pulmonary function tester provides for dynamic calibration during patient testing of various modes such as Forced Vital Capacity (FVC), Resting Ventilation (RV), Negative Inspiratory Force (NIF) and Maximum Voluntary Ventilation (MVV). The improved tester senses the ambient atmospheric pressure prior to and after sensing the pressure created by a patient's pulmonary function. The pressure created by a patient's pulmonary function is calibrated in view of the difference between the ambient atmospheric pressure sensed prior to and after sensing the pressure created by a patient's pulmonary function.

Abstract: A hemostasis valve membrane for use with a catheter introducer having a cover and a frame is disclosed. The valve membrane is inserted between the cover and the frame of the catheter introducer body. The valve membrane is a disc made of a soft elastic material. The disc has opposed faces, at least one of which has a concave shape extending into the disc. A plurality of slits extend into the disc from the faces so that slits extending into the disc from one face do not touch slits extending into the disc from the opposed face. A needle hole connects the slits extending into the disc from one face with the slits extending into the disc from the opposed face.

Abstract: The present invention relates to an angiographic catheter package consisting of a sterilizable envelope pouch, an elongate tray and a catheter tip restraint which releasably retains the catheter tip therein in the desired performed shape. The tip restraint securely holds the catheter tip in the desired shape during sterilization and storage of the catheter and yet readily releases the catheter tip from the tip restraint when the user desires to remove the catheter from the sterile package.

Abstract: A disposable sharps container having an insert mounted in the secondary opening located on the top cover of the sharps container to allow for the repeated removal of needles from medical devices such that the needle hub of the needle is insertable into a secondary opening in the sharps container to allow the needle to be removed from the medical device and the medical device may be subsequently inserted into the sharps container through a primary opening which is surrounded by a plurality of flexible flaps.

Abstract: A stopper for medical containers such as blood collection tubes having integral flange and plug portions, the flange portion being substantially larger in diameter than the plug portion, which plug portion is sized to sealably close the container. The stopper has opposed wells formed in the flange and plug portions, the well in the flange portion having a relatively flat bottom surface at least as large in diameter as the diameter of the opposed well in the plug portion. The flange portion is constructed to be guided into a tube holder into which it is inserted such that one end of a needle projecting into the interior of the tube holder will penetrate the stopper in the area of the opposed wells so as to avoid otherwise contacting the stopper. The enlarged flange portion also serves to facilitate removal of the stopper from the container without contaminating a handler.

Abstract: An improved pulmonary function tester provides for dynamic calibration during patient testing of various modes such as Forced Vital Capacity (FVC), Resting Ventilation (RV), Negative Inspiratory Force (NIF) and Maximum Voluntary Ventilation (MVV). During testing in the modes, when the airflow is detected to be below a selected value indicating minimal or substantially no airflow, the pressure transducer which is used to detect mouthpiece airflow is vented to atmosphere, and data representing the output of the pressure transducer are taken and stored for calibration of later readings during testing.