Traditional Foley Drainage Systems—Do They Drain the Bladder?

Garcia, Maurice M.; Gulati, Shelly; Liepmann, Dorian; Stackhouse, G. Bennett; Greene, Kirsten; Stoller, Marshall L.

doi:10.1016/j.juro.2006.08.101

« Previous Next »The Journal of Urology
Volume 177, Issue 1 , Pages 203-207, January 2007

Traditional Foley Drainage Systems—Do They Drain the Bladder?

Maurice M. Garcia
- Department of Urology, University of California, San Francisco, California
Shelly Gulati
- University of California, Berkeley Joint Graduate Group in Bioengineering, Berkeley, California
Dorian Liepmann
- University of California, Berkeley Joint Graduate Group in Bioengineering, Berkeley, California
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
G. Bennett Stackhouse
- Department of Urology, University of California, San Francisco, California
Kirsten Greene
- Department of Urology, University of California, San Francisco, California
Marshall L. Stoller
- Department of Urology, University of California, San Francisco, California
- Correspondence and requests for reprints: 400 Parnassus Ave., Box A633, San Francisco, California 94143 (telephone: 415-353-2200; FAX: 415-476-8849).

Received 13 February 2006

Purpose

Foley catheters are assumed to drain the bladder to completion. Drainage characteristics of Foley catheter systems are poorly understood. To investigate unrecognized retained urine with Foley catheter drainage systems, bladder volumes of hospitalized patients were measured with bladder scan ultrasound volumetrics. Additionally, an in vitro bench top mock bladder and urinary catheter system was developed to understand the etiology of such residual volumes. A novel drainage tube design that optimizes indwelling catheter drainage was also designed.

Materials and Methods

Bedside bladder ultrasound volumetric studies were performed on patients hospitalized in ward and intensive care unit. If residual urine was identified the drainage tubing was manipulated to facilitate drainage. An ex vivo bladder-urinary catheter model was designed to measure flow rates and pressures within the drainage tubing of a traditional and a novel drainage tube system.

Results

A total of 75 patients in the intensive care unit underwent bladder ultrasound volumetrics. Mean residual volume was 96 ml (range 4 to 290). In 75 patients on the hospital ward mean residual volume was 136 ml (range 22 to 647). In the experimental model we found that for every 1 cm in curl height, obstruction pressure increased by 1 cm H₂O within the artificial bladder. In contrast, the novel spiral-shaped drainage tube demonstrated rapid (0.5 cc per second), continuous and complete (100%) reservoir drainage in all trials.

Conclusions

Traditional Foley catheter drainage systems evacuate the bladder suboptimally. Outflow obstruction is caused by air-locks that develop within curled redundant drainage tubing segments. The novel drainage tubing design eliminates gravity dependent curls and associated air-locks, optimizes flow, and minimizes residual bladder urine.

Key Words: balloon dilatation, urinary tract infections, catheterization, drainage

Abbreviations and Acronyms: ICU, intensive care unit, UTI, urinary tract infection