Abstract: A hemodialysis conductivity meter apparatus is provided for measuring dialysate concentration using a self contained syringe. The meter includes a syringe body having a needle attached thereto with a syringe plunger coacting with the body to draw fluid into the body. A pair of electrodes are positioned for contact with the fluid in the syringe body while a power source located on the syringe generates an electric current reading across the electrodes responsive to the fluid in the syringe body. An output meter attached to the syringe gives an immediate reading of the conductivity of the fluid. The plunger of the syringe may be used to keep the electrodes clean and an alternate embodiment allows the syringe plunger to switch the meter on when drawing fluid thereinto and to switch the meter off when removing the plunger or pushing the liquid out of the syringe body.

Abstract: A drainage control valve apparatus utilizes a pressure relief valve for opening upon a predetermined fluid pressure being applied thereto and a liquid column is used for holding the pressure relief valve open by the weight of the liquid column escaping past the pressure relief valve to apply a negative pressure to the back of a pressure relief valve element. A small opening or a check valve releases the suction column when drainage is complete to allow the pressure relief valve to close. The pressure relief valve may be a spring biased valve and may be adjusted by varying the compression on the spring. The unit may be attached to a patient's leg with a strap. A method of draining a bladder is provided having the steps of opening a pressure relief valve under bladder pressure in a catheter, holding the pressure relief valve open with the suction of a column of liquid formed by the liquid passing the opened pressure relief valve and releasing the pressure relief valve when drainage is substantially complete.