Abstract: Calibration apparatus is described for use in a calibratable analytical system wherein a continuously flowing liquid sample, either alone or in admixture with other liquids, is normally caused to contact a sensor. The novel calibration apparatus enables diversion of said continuously flowing sample out of contact with the sensor and alternate contact of a calibration reference liquid or other calibration sample with the sensor. The calibration apparatus of the present invention is particularly useful in a system for analytical monitoring of a continuously flowing liquid blood sample obtained through a double lumen cannula inserted into a blood vessel of a human or animal subject. This apparatus permits the analytical system to be calibrated without the necessity of removing any portion of the cannula from the subject thereby avoiding the risk of loss of sterility inherent in such removal.

Abstract: An improved apparatus is described wherein a semi-permeable membrane is supported against a convex surface and wherein the likelihood of damage to such membrane during mounting and use is minimized. In the apparatus the membrane is stretched over the convex surface of a first member in a manner allowing, during assembly of the apparatus, any fluid located between the membrane and the convex surface to escape therefrom around the edges of the membrane. The membrane is clamped between the convex surface of said first member and a complemental concave surface of a second member such that the membrane is held in stretched relationship against and in close contact with the convex surface. Means is provided to form a fluid-tight seal between said membrane and said second member.In a preferred embodiment, the membrane is used in a polarographic electrode apparatus used to detect specific components of a fluid sample.

Abstract: Double lumen cannula apparatus for blood sampling is described having the improvements of apparatus features for obtaining controlled dilution of the blood sample with an anti-coagulant and a minimal volume for a chamber introducing the anti-coagulant to the cannula.

Abstract: Apparatus is described for controlling blood glucose concentration in a subject by selected infusion of insulin and/or glucose, depending upon the general blood glucose concentration. This apparatus comprises in combination sensor means for measuring the blood glucose concentration and for providing computer input signals based on such measurement, computer means for receiving such input signals and being programmed to provide output signals based upon such input signals, and pump means responsive to such computer output signals to supply insulin and/or glucose to such subject at a rate determined by such output signals. The computer derives the output signals in accordance with specific quadratic and biquadratic equations employing certain independently selected values relating to basal blood glucose concentrations and basal insulin and glucose infusion rates at such basal blood glucose concentrations.

Abstract: An improved peristaltic pump is described wherein the basic configurations of movable pump rollers, a base member and pump tubing compressed by the pump rollers against the spring loaded movable base member is improved by the addition of at least one actuating member capable of movement toward and away from an actuating position with respect to the base member. When the actuating members move toward their actuating positions, they compress the pump tubing against the base member and prevent fluid flow along the pump tubing. During such movement the actuating members also contact the base member and push it away from the pump rollers toward a non-pumping position so that movement of the pump rollers is no longer effective to cause pumping fluid along the pump tubing. When the actuating members are retracted from their actuating positions they allow the pump tubing to open for fluid flow therealong and allow the base member to return to a pumping position. A multiple channel pump assembly is also described.