Abstract: Methods for the sterile transfer of a solution are disclosed, including sterilizing the inlet to a connector by flowing a sterilizing fluid around the connector inlet, sterilizing a penetrating element for the connector by flowing a sterilizing solution around the penetrating element, and penetrating the sterilized inlet by the sterilized penetrating element in order to transfer the solution through the penetrating element on the connector. Apparatus for such sterile transfer of a solution is also provided.

Abstract: Apparatus for the preparation of fluids intended for medical use is disclosed, including a water source and at least one cartridge or other vessel containing a solid such as a powder which is to be dissolved in the water for preparation of the desired fluid. The apparatus includes a container such that the water and a powder can be mixed and a concentrate provided in the container, and a recirculation circuit for recirculation of the water or concentrate solution into the container for further mixing of the water and powder to prepare a concentrate having a predetermined concentration.

Abstract: Methods and apparatus are disclosed for monitoring an infusion pump utilized in a dialysis machine for hemodiafiltration or hemofiltration. The apparatus includes a first flow circuit for a dialysis solution, including a flow meter, a second flow circuit for blood, the dialysis apparatus including a first chamber connected to the first flow circuit, a second chamber connected to the second flow circuit, and a semipermeable membrane separating the first and second chambers, a third flow circuit for withdrawing an infusion solution from the first flow circuit and delivering the infusion solution to the second flow circuit, the third flow circuit including the infusion pump, and a first valve for disconnecting the dialysis apparatus from the first flow circuit and connecting the infusion pump in series with the flow meter in the first flow circuit whereby the expected flow through the infusion pump can be compared with the measured flow through the flow meter.

Abstract: Catheters are disclosed for insertion into a body cavity. The catheters include a region near the distal end of the catheter which includes a number of apertures as well as a reduced diameter portion which has a diameter less than the diameter of the rest of the catheter region so that the flow of a fluid through the reduced diameter portion is reduced thereby.

Abstract: Methods and apparatus for measuring the concentration of decomposable substances, such as urea, are disclosed. The disclosed methods include adding a gaseous buffer, such as CO.sub.2, to the solution containing the decomposable compound, measuring the conductivity of the solution, decomposing the decomposable compound, measuring the conductivity of the thus-decomposed compound solution, and calculating the differential conductivities between the two measured solutions. The apparatus for carrying out these methods are also disclosed.

Abstract: Methods for the central preparation and distribution of a concentrate to a plurality of medical treatment devices are disclosed comprising supplying a stream of substantially only water to a central container which includes a single salt composition at least partially in solid form, producing a substantially saturated solution of the salt composition in the central container, and distributing the salt solution to a distribution conduit which includes a plurality of concentrate connectors whereby the salt solution can be distributed to the plurality of medical treatment devices. Methods for disinfecting this apparatus, the apparatus itself, and containers for use in the apparatus are also disclosed.

Abstract: A method is disclosed for determining a parameter (D, K, Kt/v, Cbin) indicative of the effectiveness of an extracorporeal blood treatment carried out using a membrane exchanger. The method includes the steps of flowing through the exchanger a treatment liquid having a concentration characteristic (Cd) and of varying the value of the characteristic (Cd) upstream of the exchanger for a time at the end of which the characteristic (Cd) is returned to a nominal value. A plurality of values adopted by the characteristic (Cd) downstream of the exchanger in response to the upstream variation is measured and stored in memory. The area (Sout) of a downstream perturbation region is determined, which is bounded by a baseline and a curve representing the variation of the measured values with respect to time. Then, the parameter (D, K, Kt/v, Cbin) indicative of the effectiveness of the treatment is calculated using the area (Sin) beneath the upstream curve and an area beneath an upstream curve.

Abstract: Methods for detecting the condition of a catheter providing access to a patient's blood vessel are disclosed in which the blood is supplied to an extracorporeal blood flow circuit. The method includes generating a pressure wave on one side of one of the access points for supplying blood to the extracorporeal blood flow circuit or returning the blood to the patient, then sensing the pressure wave on the other side of the access points. Apparatus for detecting the condition of the catheter are also provided.

Abstract: A container for enclosing a sterile medical solution and method for mixing the same, such as a peritoneal dialysis solution. The container comprises a first compartment comprising the major part of the solution, such as an electrolyte solution comprising NaCl, CaCl.sub.2, etc., and two separate compartments, each comprising glucose in a high concentration. The entire container is autoclaved including the solutions as separated, thereby minimizing the formation of toxic products. During preparation for use, the second compartment or the third compartment, or both, are connected to the first compartment by breaking pins in a connection tube for each compartment. Depending upon the compartments connected to the first compartment, a different concentration of glucose results. Thus, all three of the usually employed glucose concentrations may be provided in a single container.

Abstract: A container for a sterile medical solution comprises an upper surface, a lower surface, and a rigid top border having a central portion and peripheral portions. At least one separation line joints the upper and lower surfaces of the container to form first and second compartments. The top border of the container includes lines of weakness in the central portion thereof to form a hinged connection between the peripheral portions of the top border so that solutions in the first and second compartments are more quickly mixed when openable connectors between the compartments are broken.

Abstract: Methods for the central preparation and distribution of a concentrate to a plurality of medical treatment devices are disclosed comprising supplying a stream of substantially only water to a central container which includes a single salt composition at least partially in solid form, producing a substantially saturated solution of the salt composition in the central container, and distributing the salt solution to a distribution conduit which includes a plurality of concentrate connectors whereby the salt solution can be distributed to the plurality of medical treatment devices. Methods for disinfecting this apparatus, the apparatus itself, and containers for use in the apparatus are also disclosed.

Abstract: Apparatus for disinfecting dialysis devices are disclosed including a first circulation conduit for circulating a first fluid through at least a portion of the supply conduit to a dialyzer in order to disinfect that portion of the supply conduit and a second circulation conduit for circulating a second fluid through at least a portion of the removal conduit from the dialyzer for disinfecting that portion of the removal conduit.

Abstract: Removable inserts are disclosed for positioning within a dialysis machine in order to connect a pressure transducer to external apparatus such as a drip chamber. The removable insert comprises a cup-shaped container adapted to be disposed within the dialysis machine with its open end aligned with the front face of the dialysis machine, a cover to cover the open end of the container, the cover including an orifice, a tube extending from the closed end of the cup-shaped container for communication with the pressure transducer, a filter positioned within the container, and a coupler for coupling the tube with the orifice in the cover with the filter interposed therebetween so that the pressure associated with the drip chamber can be monitored by the pressure transducer.

Abstract: Methods for the sterile transfer of a solution are disclosed, including sterilizing the inlet to a connector by flowing a sterilizing fluid around the connector inlet, sterilizing a penetrating element for the connector by flowing a sterilizing solution around the penetrating element, and penetrating the sterilized inlet by the sterilized penetrating element in order to transfer the solution through the penetrating element on the connector. Apparatus for such sterile transfer of a solution is also provided.

Abstract: Methods for measuring the flow differential through a dialysis machine are disclosed in which the dialysis machine includes a heat exchanger having a primary side and a secondary side for exchanging heat therebetween. The method includes measuring the temperature differences across the primary and secondary sides of the heat exchanger and calculating the flow differential based upon these measured temperature differences. Apparatus for measuring such a flow differential is also disclosed, as are methods for calibrating that apparatus.

Abstract: Drip chamber heads are disclosed for attachment to drip chambers in which the drip chamber head includes a vertical body, a first connector for connecting the body to a blood supply, and a drip tube disposed within the body including a depending lower portion, the upper portion of the drip tube being in communication with the first connector so that blood may be supplied to the drip chamber through the first connector and the drip tube, thereby providing the blood at an adjustable level within the drip chamber with an air filled region thereabove, a second connector disposed at the upper portion of the body for communicating with the air filled region of the drip chamber, and an air permeable filter disposed at the upper portion of the body between the second connector and the adjustable level of blood within the drip chamber whereby the air pressure within the air filter region of the drip chamber can be sensed through the second connector.

Abstract: A method for preparation of a medical solution from water and a plurality of concentrates, including at least one acid in gaseous form, comprises the steps of transporting the water from a source through a main conduit and successively adding the plurality of concentrates to the water in the main conduit at a plurality of predetermined points positioned along the main conduit.

Abstract: Apparatus for monitoring flow of a dialysis fluid through a dialyzer is disclosed including a computer for calculating the flow rate of the dialysis fluid into and out of the dialyzer based on the formula P-P.sub.O =k*Q.sup.n in which P is the pressure in the dialysis fluid between a throttle and a pump either upstream or downstream of the dialyzer, P.sub.O is the pressure in the dialysis fluid on the opposite side of the throttles from the pump, k is a characteristic coefficient for the throttle, Q is the flow of the dialysis fluid through the throttle, and N is a characteristic exponent for the throttle, and the apparatus includes microprocessor for calculating the values of k and P.sub.O prior to use and for calculating the value of P.sub.O during use of the dialyzer. Methods for carrying out such monitoring are also disclosed.

Abstract: Methods for measuring the effect of dialysis treatments are disclosed in which a fraction of the used dialysis fluid is extracted downstream of the dialyzer for analysis of at least one substance such as urea, and in which the fraction of dialysis fluid is extracted through a branch conduit containing a pump. In accordance with this method, the total amount of used dialysis fluid is measured and the concentration of that substance in the extracted fraction is measured, and the total amount of that substance removed from the patient can then be calculated from these values. This invention is preferably intended for use in connection with hemodialysis, hemofiltration and hemodiafiltration.