Flow control system and method for endoscopic surgeries

In a fluid flow system for endoscopic surgery comprising a probe having an aspirating tip for engagement at a surgical site coupled by probe tubing to at least one collection canister, and a negative pressure source coupled to the at least one collection canister, a method for controlling the relation between the fluid flows from the surgical site during an endoscopic surgery to assure that suction at the probe tip is not lost, comprising the steps of:

• aspirating fluid and organic debris form the surgical site through the probe and probe tubing into the at least one collection canister;
• collecting overflow fluid from a body orifice in gravity communication with the drain receptacle and flowing through the drain tubing and into the at least one collection canister;
• holding the at least one collection canister under negative pressure and producing a suction force through the probe tubing and drain tubing by operation of the negative pressure source;
• and
• increasing the flow impedance of the drain tubing as compared to the flow impedance of the probe tubing to a level where the suction force acting on the fluid in the drain tubing provides restricted flow such that the fluid in the drain tubing is not completely withdrawn and that suction remains at the probe tip.

In a fluid flow system endoscopic surgery comprising a probe having an aspirating tip coupled by probe tubing to at least one collection canister, an overflow drain receptacle coupled by drain tubing to at least one collection canister, and a negative pressure source coupled to the at least one collection canister, a method for maintaining suction at the aspirating tip substantially constant at a level to withdraw the majority of the fluid flow from a surgical site into which the aspirating tip is inserted in endoscopic surgery, comprising the steps of:

• aspirating fluid and organic debris from the surgical site through the probe and probe tubing into the at least one collection canister;
• collecting overflow from a body orifice in communication via the overflow drain receptacle with the surgical site into the drain receptacle through the drain tubing and into the at least one collection canister;
• holding the at least one collection canister under negative pressure and producing a suction force through the probe tubing and drain tubing by operation of the negative pressure source;
• and
• increasing the flow impedance of the drain tubing as compared to the flow impedance of the probe tubing to a level where the suction force in the probe tubing is larger than the suction force in the drain tubing, such that a majority of irrigation fluid at the surgical site is removed through the probe to minimize absorption of fluid within the patient and reduce overflow.

A method of assuring proper flows of irrigation fluid in performing a surgical procedure in a body cavity in which irrigation fluid flowing into the cavity is to be aspirated to a collection chamber to minimize absorption in the body while overflow under gravity to a drain receptacle from the cavity is also to be collected under suction in the collection chamber, comprising the steps of:

• drawing the aspirated fluid toward the collection chamber via a first path having a first flow impedance,
• drawing the overflow toward the collection chamber from the drain receptacle via a second path having a second flow impedance higher than the first,
• combining the first and second paths to a common third path leading to the collection chamber, and
• establishing a suction level in the collection chamber sufficient to provide a desired suction level for aspiration in the body cavity.

A method of providing desired flow relationships between an aspiration path from the interior of a body cavity that is being irrigated with a fluid while overflow of fluid from the cavity drains initially under gravity into a collector, to reduce absorption of fluid within the body, comprising the steps of:

• establishing a negative pressure collection volume;
• providing a single negative pressure path from the collection volume;
• splitting the single path into two subsequent paths, the first subsequent path being in communication with the collector and the second subsequent path being in communication with the aspiration path in the interior of the body cavity, and
• adjusting the flow of impedance of the first and second subsequent paths such that the impedance of the first path is selectively greater than the impedance of the second path.