Abstract: An apparatus for producing a tube having a round cross-section over a major portion of its length and intermediate its ends having a flattened oval cross-section. The apparatus includes an extrusion head with an extrusion die through which the tube is extruded. A pinching device, which includes opposed pinching elements, is arranged at the extrusion head so as to be selectively moveable together to press on and pinch the tube to produce the oval cross-section of the tube. The rollers are selectively moveable apart to not pinch the tube to enable the tube to be extruded round, whereby a round tube with an intermediate flattened oval shaped portion is produced.

Abstract: A multipurpose drain has at least first and second lumens for selectively supplying medical material into a surgical site and removing the medical material and bodily fluids from the surgical site. The first and second lumens are extruded from suitable surgically compatible material to be detachably coupled to one another. The first and second lumens have a first open distal end and a second open distal end, respectively. The first and second distal ends are displaceable relative to one another to prevent the medical material from directly passing between the first and second open distal ends without first passing through the surgical site.

Abstract: This invention is directed to an improved impedance sensing system to measure blood flow and particularly cardiac output which comprise an elongated flexible catheter having two spaced apart sensing electrodes disposed on the surface thereof formed from a conductive fabric such as metallic screen. Preferably, a pair of current transmitting electrodes are also positioned on the catheter each being outside of the pair of sensing electrodes.