Blood volume controller during fluid removal

A blood volume control method comprising:

• repeatedly monitoring and measuring a hematocrit (Hct) level of blood of a patient;
• repeatedly determining a difference between the measured Hct level and a predetermined Hct level;
• in response to a determination that the difference exceeds a predetermined value, automatically infusing an infusion solution into the patient,
• continuing to automatically infuse the infusion solution while the difference exceeds the predetermined value,
• automatically ceasing or reducing a rate of the infusion of the infusion solution in response to the difference being no greater than the predetermined value;
• monitoring urine output of the patient, and
• reducing or ceasing the infusion of the infusion solution if the monitored urine output is less than a predetermined threshold level of urine output.

A blood volume control system comprising:

• a Hct sensor connected to a patient measuring a Hct of blood of the patient;
• a urine flow sensor monitoring urine output by the patient;
• an infusion pump connectable to a fluid tube providing an infusion solution from a source of the infusion solution to a venous system of a patient;
• a controller receiving a Hct signal indicating a Hct level of the blood from the Hct sensor and a urine signal from the urine flow sensor indicating a urine output rate, the controller:
• repeatedly determines a Hct difference between the Hct level indicated by the Hct signal and a threshold Hct level;
• while the Hct difference exceeds a predetermined value, automatically actuating the pump to infuse an infusion solution into the patient to reduce the Hct level by increasing blood volume in the patient,
• reducing a rate of infusion or stopping the infusion in response to the Hct difference being no greater than the predetermined value, and
• monitoring urine output of the patient, and actuating the pump to stop or reduce the infusion of the infusion solution if the urine output is above a predetermined threshold urine output.

A method for controlling a Hct level of blood in a patient using a Hct sensor and an infusion pump, said method comprising:

• repeatedly sensing current Hct level of blood of a vascular system of the patient;
• repeatedly determining a difference between the sensed Hct level and a predetermined threshold Hct level;
• monitoring urine output of the patient and determining whether the monitored urine output is above a predetermined threshold urine output;
• automatically increasing an infusion rate of an infusion solution to the patient while the difference between the sensed Hct level and the threshold Hct level is above a predetermined difference value;
• automatically reducing the infusion rate or ceasing the infusion of the infusion solution while the difference is less than a predetermined value;
• automatically reducing the infusion rate or ceasing the infusion of the infusion solution while the monitored urine output is above a threshold urine output.

A method of preventing vascular volume depletion using a Hct sensor and an infusion pump, said method comprising:

• repeatedly determining a Hct of blood of a patient;
• repeatedly comparing the Hct to a predetermined desired Hct value;
• monitoring urine output of the patient;
• infusing an infusion solution to a venous system of the patient while the Hct is above the desired Hct target value and the monitored urine output is below a threshold urine output level;
• reducing the infusion rate or stopping the infusion in response to the Hct becoming less than the Hct target value, and
• reducing the infusion rate or stopping the infusion in response to the urine output becoming greater the threshold urine output.

A method of preventing vascular volume depletion during diuretic delivery using a Hct sensor, an infusion solution, an infusion pump and catheter, said method comprising:

• repeatedly sensing a current Hct level of blood of a patient;
• comparing each of the sensed current Hct levels to a target Hct level,
• repeatedly sensing current urine output level of the patient;
• comparing each of the sensed current urine output levels to a target urine output level, and
• actuating the infusion pump to infuse a solution into the vascular space while the sensed current Hct level is above the target Hct level;
• stopping the infusion pump or reducing a rate of infusion of the solution in response to the current Hct level falling below the target Hct level, and
• stopping the infusion pump or reducing a rate of infusion of the solution in response to the current urine output level exceeding a target urine output level.