Cincinnati Children's Hospital Medical Center

George Benzing, Iii

John J Bissler

Nat Hemasilpin

Yuli Kitaevich

Paul T McEnery

J Gabriel Marchevsky

Rumult Iltis

A multipurpose hemofiltration system and method are disclosed for the removal of fluid and/or soluble waste from the blood of a patient. The system and method are equally applicable to adult, pediatric and neonatal patients. In one embodiment, the system continuously monitors the weight of infusate in a first reservoir and drained fluid in a second reservoir and compares those weights to corresponding predetermined computed weights. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted in order to achieve a preselected amount of fluid removal from the patient's blood in a preselected time period. Application of this system and method provide repeatable and highly precise results. Alternatively, predetermined patient parameters can be monitored and the adjustment of pumping rates may be responsive to these monitored parameters. Suitable patient parameters are arterial pressure, central venous pressure, pulmonary arterial pressure, mean arterial pressure, capillary wedge pressure, systemic vascular resistance, cardiac output, mixed venous O saturation, arterial O saturation, blood pressure, heart rate, patient weight, and hematocrit.

Hemofiltration system and method based on monitored patient parameters

A multipurpose hemofiltration system and method are disclosed for the removal of fluid and/or soluble waste from the blood of a patient. The system and method are equally applicable to adult, pediatric and neonatal patients. In one embodiment, the system continuously monitors the weight of infusate in a first reservoir and drained fluid in a second reservoir and compares those weights to corresponding predetermined computed weights. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted in order to achieve a preselected amount of fluid removal from the patient's blood in a preselected time period. Application of this system and method provide repeatable and highly precise results. Alternatively, predetermined patient parameters can be monitored and the adjustment of pumping rates may be responsive to these monitored parameters. Suitable patient parameters are arterial pressure, central venous pressure, pulmonary arterial pressure, mean arterial pressure, capillary wedge pressure, systemic vascular resistance, cardiac output, mixed venous O,saturation, arterial O,saturation, blood pressure, heart rate, patient weight, and hematocrit.

Hemofiltration system and method

A multipurpose hemofiltration system and method are disclosed for the removal of fluid and/or soluble waste from the blood of a patient. The system and method are equally applicable to adult, pediatric and neonatal patients. The system continuously monitors the weight of infusate in a first reservoir and drained fluid in a second reservoir and compares those weights to corresponding predetermined computed weights. When necessary, the pumping rates of the infusate, drained fluid and blood are adjusted in order to achieve a preselected amount of fluid removal from the patient's blood in a preselected time period. Application of this system and method provide repeatable and highly precise results.

A method and apparatus are disclosed for measuring the ohmic, that is, purely d-c, resistance at the area of contact between cardiac tissue and a pacemaker electrode surgically implanted in the heart of a patient requiring a pacemaker. The contact resistance is measured by apparatus connected across the electrical circuit formed by the electrode and heart. The apparatus includes circuitry for sampling and holding the instantaneous voltage across the electrical circuit formed by the electrode and heart at the onset of a pulse generated by the pacemaker pulse generator, at which time the effect of a parallel capacitance in the electrical circuit formed by the pulse generator, electrode wire, electrode, heart, and return path through the body to the pulse generator is such that the current initially produced is determined only by the voltage and equivalent output impedance of the pulse generator, the resistance of the electrode wire, and the resistance at the area of contact between cardiac tissue and the electrode. The apparatus further includes analog signal processing circuitry for deriving the contact resistance from the instantaneous voltage based on an equivalent circuit model for the electrical circuit formed by the pacemaker and the heart taking into account the effect of the parallel capacitance at the onset of a pulse. The apparatus also includes a device for displaying the measured contact resistance. The disclosed method and apparatus are also applicable for measuring the ohmic contact resistance of an electrode attached to other body tissue.

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Cincinnati, OH, United States of America

George Benzing, Iii