A coronary artery graft flow-meter apparatus for insertion into a delivery line for solution to be perfused through a graft after the graft is anastomosed to a coronary artery is disclosed. The apparatus comprises a flow-meter chamber having an upper end and a lower end, the upper end having an inflow port and the lower end having an outflow port. The chamber includes a plastic bag positioned therein which is adapted to communicate with a volumetric container containing the solution. The solution flows from the volumetric container to the plastic bag thereby providing a measurement of the flow rate of the solution through the graft.
A non-invasive technique and system is provided for measuring flow of liquid driven by a flexible diaphragm of a membrane pump (18). Flow, pressure and/or temperature of a gas, such as air, used to drive the pump (18) is continuously monitored. Instantaneous volume of liquid being pulled into or out of a chamber of the pump (18) can be calculated from measured values of the gas used to drive the pump (18). Sensors (10, 12 and/or 14) are used to measure values relating to the gas. The sensed parameters are concurrently monitored and continuously determine the amount of gas flowing to and from the diaphragm of the membrane pump (18) utilized to move liquid within a liquid pathway. The measurements may then be used to calculate the instantaneous flow rate of the liquid.
A method and apparatus for preparing a cardioplegia mixture is provided which allows an increased level of control over the flow rate, dilution ration and concentration of cardioplegia inducing components in cardioplegia mixture during cardiovascular surgery. The method for preparing the cardioplegia mixture includes the steps of combining first and second crystalloid solutions of different concentrations to establish a total volume flow rate of combined solutions. The flow rate of the first crystalloid solution is self adjusted to equal the established total volume flow rate minus the established volume flow rate of the second crystalloid solution. The apparatus for preparing a cardioplegia mixture includes first and second crystalloid solutions containing a cardioplegia inducing component at different concentrations, and means for flowing and combining the solutions and establishing a total volume flow rate of the combined solution. The apparatus further includes means for self-adjustment of the flow rate of the first crystalloid solution to equal total the volume flow rate minus the established volume flow rate of the second crystalloid solution. The apparatus preferably includes a disposable tubing set for flowing, combining, and interconnecting the crystalloid solutions.
