Aspiration control via flow or impedance

1. A method of controlling aspiration in a microsurgical system, comprising the steps of:

providing a pump speed to a peristaltic pump with a computer;

determining an actual level of fluid in an aspiration chamber with a fluid level sensor;

determining a suction pressure in said aspiration chamber with a pressure transducer;

calculating a suction flow rate with said computer in response to said actual level of fluid, said pump speed and said suction pressure;

maintaining a desired suction flow rate in said aspiration chamber with said computer by providing a first signal to a proportional valve fluidly coupled to a pressurized gas source and a second signal to a second proportional valve fluidly coupled to a venturi vacuum generator, said first and second signals responsive to said calculated suction flow rate;

aspirating fluid from a surgical device into said aspiration chamber; and

monitoring a change in said calculated suction flow rate with said computer to detect an occlusion.

2. The method of claim 1 further comprising the step of adjusting a surgical parameter of said system with said computer in response to said monitoring step.

3. The method of claim 2 wherein said surgical parameter is selected from the group consisting of ultrasound energy, desired suction flow rate, desired suction pressure, infusion pressure, cut rate, and port open duty cycle.

4. The method of claim 1 further comprising the step of adjusting a surgical parameter of said device in response to said monitoring step.

5. A method of controlling aspiration in a microsurgical system, comprising the steps of:

providing a pump speed to a peristaltic pump with a computer;

determining an actual level of fluid in an aspiration chamber with a fluid level sensor;

determining a suction pressure in said aspiration chamber with a pressure transducer;

calculating a suction flow rate with said computer in response to said actual level of fluid, said pump speed, and said suction pressure;

maintaining a desired suction flow rate in said aspiration chamber with said computer by providing a first signal to a proportional valve fluidly coupled to a pressurized gas source and a second signal to a second proportional valve fluidly coupled to a venturi vacuum generator said first and second signals responsive to said calculated suction flow rate;

aspirating fluid from a surgical device into said aspiration chamber;

calculating a suction impedance with said computer in response to said calculated suction flow rate; and

monitoring a change in said suction impedance with said computer to detect an occlusion.

6. The method of claim 5 further comprising the step of adjusting a surgical parameter of said system with said computer in response to said monitoring step.

7. The method of claim 6 wherein said surgical parameter is selected from the group consisting of ultrasound energy, desired suction flow rate, desired suction pressure, infusion pressure, cut rate, and port open duty cycle.

8. The method of claim 5 further comprising the step of adjusting a surgical parameter of said device in response to said monitoring step.

9. The method of claim 5 further comprising the step of communicating a fluid property to a surgeon in response to said suction impedance.