Abstract: A piggyback IV administration system uses a solenoid actuated sequence valve to control the flow of fluid from a pair of IV fluid sources to the inlet of an IV pump or controller. The sequence valve pinches off a first tube while allowing fluid to flow through the second tube and then, in response to a control signal, changes state so that the second tube is pinched off and fluid can flow through the first tube unimpeded.

Abstract: A piggyback IV administration system uses a solenoid actuated sequence valve to control the flow of fluid from a pair of IV fluid sources to the inlet of an IV pump or controller. The sequence valve pinches off a first tube while allowing fluid to flow through the second tube and then, in response to a control signal, changes state so that the second tube is pinched off and fluid can flow through the first tube unimpeded. The sequence valve automatically senses conditions which indicate a failure of the sequence valve to occlude the second tube when the valve changes state.

Abstract: An IV fluid control system having an IV set and a control device (such as an IV controller or fusion pump) includes a flow sensor which senses the flow of fluid through the IV set. Fluid runaway is prevented by an interlock which prevents removal of the IV set from the control device unless the fluid flow through the IV set is stopped. As a result, the medical personnel must clamp the outlet tubing of the IV set to stop fluid flow before removing the IV set from the control device.

Abstract: An electrosurgery safety monitor senses a parameter indicative of the area of contact between the return electrode of an electrosurgery system and the body of the patient. An alarm is provided if the area of contact between the return electrode and the body is less than a predetermined amount.

Abstract: A small, accurate, reliable and economical pump which is particularly useful in intravenous (IV) feeding includes a disposable pump chamber and a pump housing. The disposable pump chamber has an inlet, an outlet, and first and second flexible rolling diaphragm pumping chambers. First and second cylinders in the pump housing are positioned to eceive the first and second flexible rolling diaphragms of the disposable pump chamber. First and second pistons are movable in the first and second cylinders, respectively. In addition, first and second valves are provided in the pump housing. The first valve controls fluid flow between the inlet and the first flexible rolling diaphragm pump chamber, while the second valve controls fluid flow between the first flexible rolling diaphragm pumping chamber and the second flexible rolling diaphragm pumping chamber. A motor and cam shaft drive the first and second pistons and the first and second valves.

Abstract: A small, accurate, reliable and economical pump which is particularly useful in intravenous (IV) feeding includes a disposable pump chamber and a pump housing. The disposable pump chamber has an inlet, an outlet, and first and second flexible rolling diaphragm pumping chambers. First and second cylinders in the pump housing are positioned to receive the first and second flexible rolling diaphragms of the disposable pump chamber. First and second pistons are movable in the first and second cylinders, respectively. In addition, first and second valves are provided in the pump housing. The first valve controls fluid flow between the inlet and the first flexible rolling diaphragm pump chamber, while the second valve controls fluid flow between the first flexible rolling diaphragm pumping chamber and the second flexible rolling diaphragm pumping chamber. A motor and cam shaft drive the first and second pistons and the first and second valves.

Abstract: A small, accurate, reliable and economical pump which is particularly useful in intravenous (IV) feeding includes a disposable pump chamber and a pump housing. The disposable pump chamber has an inlet, an outlet, and first and second flexible rolling diaphragm pumping chambers. First and second cylinders in the pump housing are positioned to receive the first and second flexible rolling diaphragms of the disposable pump chamber. First and second pistons are movable in the first and second cylinders, respectively. In addition, first and second valves are provided in the pump housing. The first valve controls fluid flow between the inlet and the first flexible rolling diaphragm pump chamber, while the second valve controls fluid flow between the first flexible rolling diaphragm pumping chamber and the second flexible rolling diaphragm pumping chamber. A motor and cam shaft drive the first and second pistons and the first and second valves.

Abstract: A volumetric infusion pump of the type having a rolling diaphragm pumping chamber includes a back pressure sensor between the rolling diaphragm pumping chamber and the pump outlet for sensing back pressure. A valve is positioned between the back pressure sensor and the pump outlet for controlling fluid flow to the pump outlet in order to control back pressure supplied to the rolling diaphragm pumping chamber. Back pressure is maintained within the rolling diaphragm pump chamber so that the rolling diaphragm maintains close contact with the piston even in the event of a negative head pressure at the pump outlet. The valve and the back pressure sensor are preferably linked so that the valve restricts fluid flow to the pump outlet only when the sensed back pressure is less than a predetermined level.

Abstract: An electrosurgery safety monitor senses a parameter indicative of the area of contact between the return electrode of an electrosurgery system and the body of the patient. An alarm is provided if the area of contact between the return electrode and the body is less than a predetermined amount.

Abstract: A volumetric infusion pump useful in intravenous feeding includes a detector which provides an alarm when the supply bag or reservoir becomes empty or an occlusion occurs between the supply bag and the pump. The pump includes a first pumping chamber having a cylinder, a piston, a first flexible diaphragm and first and second valves. The piston is driven by a first cam through a first cam follower which is connected to the piston. The empty supply bag detector senses contact between the first cam and the first cam follower. During normal operation, when the first valve opens and the second valve closes the first pumping chamber fills due to the head pressure of fluid from the bag, and the cam follower remains in contact with the cam.

Abstract: A small, accurate, reliable and economical pump which is particularly useful in intravenous (IV) feeding includes a disposable pump chamber and a pump housing. The disposable pump chamber has an inlet, an outlet, and first and second flexible rolling diaphragm pumping chambers. First and second cylinders in the pump housing are positioned to receive the first and second flexible rolling diaphragms of the disposable pump chamber. First and second pistons are movable in the first and second cylinders, respectively. In addition, first and second valves are provided in the pump housing. The first valve controls fluid flow between the inlet and the first flexible rolling diaphragm pump chamber, while the second valve controls fluid flow between the first flexible rolling diaphragm pumping chamber and the second flexible rolling diaphragm pumping chamber. A motor and cam shaft drive the first and second pistons and the first and second valves.

Abstract: An electrosurgical unit having a feedback control circuit for providing control of the power amplifier of the unit so power delivered to tissue presented between the active and return electrodes of the unit will be substantially constant over the range of impedance presented by various tissues that are encountered. The feedback signal to the power amplifier is determined from a comparison of a power level reference signal and the mathematical product of two signals which are derived from a sensed current in the unit that is directly related to current delivered to tissue and a sensed voltage that is directly related to voltage delivered to tissue. A non-linear compensation circuit is also disclosed for use in the feedback circuit.

Abstract: A transistorized electrosurgical unit for selectively providing high fequency, high voltage level, cutting or coagulation currents to electrosurgical patient electrodes and including a plurality of parallel connected power stages actuatable by a control signal to supply power to an output transformer connected to the electrodes, which power stages each include a power transistor biased in a nonsaturated condition and connected in series with a constant current transistor, and a signal source transistor connected to such power transistor to supply a switching signal thereto and to serve as a current flow path whenever current flow through the power transistor is interrupted.