MEDICAL TREATMENT SYSTEM AND METHOD USING A PLURALITY OF FLUID LINES

There is disclosed herein a system for adjusting a negative pressure used to withdraw fluid from a cavity of a patient, the system comprising: a pump configured to provide negative or positive pressure to a fluid line connected to the cavity; a controller configured to measure and control the pressure provided by the pump; the controller (61100) also configured to measure a flow rate of fluid from the fluid line to the pump; wherein the controller (61100) is arranged to control the pump by providing negative pressure to the fluid line, measuring the rate of fluid flow, and control the pump by providing a positive pressure to the fluid line if the measured rate of fluid flow is less than a pre-determined value; and wherein the controller (61100) is arranged to re-apply negative pressure to the fluid line if a measured fluid flow upon application of the positive pressure is greater than a pre-determined amount.