STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

BACKGROUND OF THE INVENTION

Drainage of bodily fluids is necessary in various contexts. For example, urinary catheters are intended to provide continuous drainage of the bladder and chest tubes are intended to provide continuous drainage of and suction to the thoracic cavity, respectively. Systems such as the Foley urinary catheter and standard chest tube systems are widely used to implement such drainage. However, these systems are prone to problems that impede efficient and continuous drainage, with negative consequences for patients. Furthermore, such systems can become physically obstructed (clogged) with tissue (e.g. blood clots) and/or debris (e.g. stones, pus).

A major issue in drainage systems is the presence of a dependent loop or air-lock. This occurs when air bubbles in the tubing form in advance of draining fluid, for example when the tubing is coiled or bent such that drainage must occur against gravity. The presence of a dependent loop in the tubing will substantially increase resistance to flow, requiring additional driving pressure to overcome that resistance and allow air and fluid to flow through the tubing and completely out of the drainage system. Pressure in excess of the vertical height of the fluid within the dependent loop is required to restore flow, leading to backup of fluid and potentially dangerous back-pressures.

For example, in urinary drainage systems, standard catheter and drainage tube systems are prone to frequent air-locks and discontinuous flows, for example, as quantified in Garcia et al., 2007, Traditional Foley Drainage Systems: Do They Drain the Bladder?, J Urology, 177:203-207. The failure of conventional urinary drainage systems to provide effective and continuous drainage presents various problems. One problem is that blockages and back pressures can result in the back-up of urine into the bladder, which increases patient discomfort, potentially causes injury, and presents a serious risk of infection.

Another major problem with discontinuous flow in urinary drainage systems is that this compromises the ability to accurately monitor patient urine output and composition. In some contexts, it would be advantageous to monitor a patient's real-time urinary output, however, discontinuities in flow negate accurate volumetric measurements, as pooled urine within drainage tubes will flow intermittently and not in real time. Additionally, in some contexts it is desired to measure metabolites and other biomarkers in urine in real time as assessments of patient health, by sampling urine from bladder drainage systems at regular intervals or continuously. When air-locks and other factors create discontinuous flows, real time monitoring of biomarkers is compromised, because urine is not flowing to sampling devices as produced, but is pooling and flowing intermittently and/or is admixed with older urine which has pooled. Accordingly, there is a need in the art for systems that effectively empty the bladder and which create an uninterrupted conduit to sampling vessels or detectors.

Pumps have been utilized to apply suction, which aids in the clearing of air-locks. However this solution is less than optimal due to the bulk and expense of complicated pumping devices.

Accordingly, there is a need in the art for medical drainage systems which efficiently prevent air-locks or which can overcome the resistance created within dependent loops in drainage tubing. The inventions described herein provide the art with such solutions, which are inexpensive, low profile, and effective.

Effective drainage also becomes an issue in other contexts as well, for example in space travel. In the absence of normal gravitational forces, fluid and/or semi-solid material to be drained forth from the body is currently often moved by air-suction, but this requires subsequent filtering of air used for this purpose, which is complicated and costly. Accordingly, there is a need in the art for gravity independent drainage systems that can be employed in low gravity environments.

SUMMARY OF THE INVENTION

Disclosed herein are novel devices that employ an Archemedian screw element to mechanically prevent obstructions and airlocks in drainage tubing. The devices described herein allow for drainage of fluid to be achieved independent of gravity. The devices of the invention may be utilized in catheter systems for the drainage of urine, in chest tube systems, and in other contexts. The inventions herein are also directed to the need for unobstructed continuous drainage of materials in a weightless environment, such as at extremely high altitudes and/or in space. Instead, human wastes and other fluids and solids requiring transport in space can be moved by mechanical force using the devices and methods described herein.

