Procedures Never Explained in Textbooks: How to Correctly Convert a Closed-Suction Drain to a Closed-Gravity Drain, and How to Correctly Remove a Closed-Suction Drain Off Suction.

Objective: To describe a novel method to convert a closed-system suction drain to a highly efficient closed-system gravity-dependent drain and demonstrate its efficacy in an ex-vivo model.

Methods: We reviewed the 5 top-selling urology and surgery text/reference books for information on drainage systems. An ex-vivo model was designed with a reservoir of fluid connected to a Jackson-Pratt bulb drain. We measured the volume of fluid drained from the reservoir into the bulb while on-suction and off-suction. This was repeated using a novel modified bulb, where the bulb's outflow stopper was replaced with a one-way valve oriented to allow release of pressure from the bulb.

Results: With the bulb on-suction, drainage was maintained regardless of the height of the drain relative to the reservoir. With the bulb off-suction, closed passive gravity-dependent drainage occurred only when the drain was below the fluid reservoir; drainage ceased at minimal volumes. With addition of a one-way valve and maintenance of the bulb below the level of the reservoir, drainage proceeded to completion.

Conclusion: How surgical drains work is not described in the leading urology and general surgery textbooks/reference books. Closed-system suction drains cannot be used to achieve passive gravity-dependent drainage without allowing release of displaced air from the bulb-lumen. The novel modified drain we describe affords reversible closed-system suction and passive drainage.