Apparatus for facilitating the performance of medical procedures involving the vascular system of a patient, especially in a critical care environment, such as withdrawal of blood for analysis and infusion of medication. In the taking of a blood sample, blood flows through an arterial catheter connected to an artery of the patient, past a sample station, and then through a venous catheter that brings the blood back to the patient, the various mechanisms being connected by transparent plastic tubes. After a sample is taken, the tubes are flushed through the sample station, arterial catheter, and the venous catheter. Calibration of all pressure transducers requires application of high and low pressures to them, the high pressure being obtained by applying a high pressure (e.g. 200 mm Hg) to a bottle of saline solution which is also utilized to flush the tubes and which is connected to all of the transducers.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation application of application Ser. No. 830,847 filed Sept. 6, 1977 now U.S. Pat. No. 4,258,717 issued Mar. 31, 1981.
A method and device for testing artificial or natural venous valves. The device comprises (a) a fixture for mounting a sample valve on a liquid flow path, (b) a muscle pump component and/or (o) respiratory pump component and/or (d) capacitance reservoir component and/or (e) vertical hydrostatic column component, all of the components being fluidly connected to the flow path to mimic the muscle pump, respiratory pump, capacitance and hydrostatic impedance effects of actual in situ venous circulation in the mammalian body. The invention includes methods of testing venous valves by mimicking known hemodynamic flow conditions within a mammalian body.
Apparatus for monitoring fluid pressure and controlling fluid flow in a fluid line. The apparatus (10) includes a base (36) and a cover (38), between which is captured a membrane (42). The base includes an inlet port (18), a first outlet port (20), and a second outlet port (34). Channels formed within the base and covered by the membrane connect the inlet and outlet ports in fluid communication. The apparatus includes a flushing flow control valve (30) formed by a flow control projection (70), which projects outwardly from the base through the cover, and separates an inlet channel (62) from an outlet channel (64). A capillary flow passage 88 for restricting flow through the apparatus is disposed between the inlet channel and outlet channel comprises a capillary groove (86), formed across the flow control projection, adjacent the overlying membrane. Flushing fluid flow through the apparatus is obtained by pulling upwardly on a grip (90) to deform the membrane away from the flow control projection, thereby enlarging the capillary flow passage. A pressure sensing assembly (28) is mounted on the apparatus in fluid communication with the outlet channel for continuous monitoring of fluid pressure. A flow direction valve is formed by a generally "T"-shaped flow direction channel (122) formed in the base and overlying the membrane, with an actuator button (128) being slidably secured to the cover above the flow direction channel providing for selection of the flow path. An inwardly extending valve projection (130) included on the actuator button bears on and deforms the membrane into the flow direction channel. Sliding the actuator button between three positions causes the membrane to selectively block one of the inlet or outlet ports, preventing fluid flow through that port, but allowing fluid flow between the other two ports.
A blood pressure monitor kit suitable for use in emergency scenarios such as cardiopulmonary arrest situations. The kit includes a catheter for insertion in the femoral artery of the patient, a transducer arranged to receive blood pressure signals from the catheter and operative to convert the blood pressure signals into electric signals; a housing; a monitor mounted in the housing and including electric circuitry arranged to receive the electric signals from the transducer and operative to generate at least one display indicative of a condition of the patient's blood pressure; a battery positioned within the housing and operative to power the electric circuitry; a switch associated with the housing for connecting the battery into the electrical circuitry to power the circuitry; and a securement device on the housing operative to secure the housing to a patient's body at a location proximate the location of the catheter insertion. The entire kit is packaged in a container which totally envelops the catheter, transducer, and monitor and forms a sealed, sterile package which may be opened upon demand. The kit is intended for one time use and is suitably disposed of after the single use.
A system for delivering oxygen to a gas permeable membrane oxygenator is disclosed. The system may include an integral source of gas under pressure and a source of vacuum. A first mass flow controller is connected to the source of gas upstream in the gas flow from the gas exchange device. A pressure valve is positioned in the gas flow between the first mass flow controller and the membrane oxygenator. An atmospheric vent is positioned between the pressure valve and the first mass flow controller. A second mass flow controller is positioned downstream from the gas exchange device and is connected to the source of vacuum. A central controller commands the pressure valve to maintain the pressure at the inlet of the gas exchange device at a subatmospheric pressure. The second mass flow controller is commanded to maintain a rate of flow which is desired through the gas exchange device. The first mass flow controller is commanded to maintain a rate of flow higher than the second mass flow controller to ensure that a sufficient flow of gas is available through the pressure valve and the gas exchange device. The excess gas is exhausted through the vent. The present invention ensures sufficient gas flow at the gas permeable membrane to provide transfer of gases with the blood. Also, the pressure of the gas within the membrane oxygenator is low enough that outgassing through the membrane of bubbles into the blood is avoided.
An optical system for positioning a pressure transducer relative to a patient to provide for accurate measurement of bodily fluids within the patient. A light source such as a laser is used to direct light onto a specified location on the human body to accurately identify the elevation of the transducer relative to the specified location to provide an absolute measurement of fluid pressure.
