Closed versus open systems:

Current opinion holds that a closed urinary drain system is superior to an open system because it reduces catheter associated urinary tract infection (CAUTI) risk. While this is the case when looking at drainage of Foley catheters into an open jar, this is actually not true in modern urinary drain systems. The likely explanation for this persistent myth is a good marketing campaign conducted by the major manufacturer of urinary catheters based on outdated literature (over 25 –40 years old) that supports their claim and their product. In fact, the CDC guidelines that are the basis for the concept of closed system were published in 1981 and base this recommendation on literature from the 1950’s and 1960’s.[1, 2] The source article supporting closed system drainage in the CDC’s guideline was published in the New England Journal of Medicine in 1966.[3] In this study the “closed” system consisted of a drain tube and bag attached to the Foley (no tamper seals, no maintaining closure, etc). Using this “closed” system the authors found a CAUTI rate of 23%. Because this was simply an observational study of a new device, there was no randomization and no direct comparison to prior methods of drainage. However previous investigations conducted in the 1950’s and early 1960’s had demonstrated CAUTI rates of 95% within 4 days when the traditional open system (end of Foley in glass bottle full of old urine) was used.[4-6] This study did not claim nor demonstrate that strict maintenance of continuos closed drainage reduced CAUTI. In fact, the drain tube was not attached until after the Foley was established, and the authors allowed drain bag replacement for clinical reasons such as bacterial colonization detected within the bag.

The findings of this 1966 nonrandomized uncontrolled observational case series have grown into a perceived “standard” pushed by industry anxious to get you to buy their newest drain systems despite failure of future studies to support these recommendations. In fact, Dr. Kunin, the doctor whose article launched the concept of closed system drainage, specifically lamented that the “proliferation of gimmicks on drain bags” and systems are “more fiction that science” warning that very little is absolutely certain in medicine, that the current recommendations are soft, based to a large degree on expert opinion and not research, and that they will need to be changed as new knowledge becomes available.[7] These warnings did not stop industry from using this guideline as an effective marketing tool and driving this point deep into the minds of medical practitioners as fact rather than hypothesis or guideline. Products were soon developed which had tamper resistant seals connecting the Foley to the drain tube and were advertised as infection reducing urinary drain systems, referencing the CDC guidelines as “proof”. 

While observational studies and expert opinions provided in guidelines are often the best level of evidence available at the time of publication, one must be careful when using opinions that are 25 years old as “fact.” Since the 1981 CDC guideline was published, six prospective randomized controlled clinical trials and one prospective observational study have been conducted specifically with the intent to compare pre-connected, sealed tamper resistant closed systems to standard down drain systems which are connected to the catheter after insertion.[8-14] None of these publications – conducted on over 4000 patients - found any difference in the rate of CAUTI in patients with continuously closed system drainage versus patients who had drain systems that were aseptically opened when clinically indicated. These prospective randomized trails constitute what is truly “higher level of evidence” compared to the CDC expert opinion piece of 1981. The results clearly demonstrate that pre-connected urinary catheters with tamper resistant seals have at best very little if any impact on the risk of CAUTI compared to non-pre-connected drainage systems that are aseptically disconnected for proper clinical indications.

If a closed system does not reduce UTI risk, what risk factors do lead to catheter associated UTI’s? Recent research concludes that UTI risk is not actually related to open versus closed systems, but primarily related to patient factors such as diabetes malnutrition and female gender.[15-19] However, these studies do note several modifiable factors related to catheter associated UTI: Length of time the catheter is inserted (i.e. take it out as soon as possible), hospital site where the catheter was inserted (insertion in the sterile area of the operating room reduces UTI risk) and drain tube manipulation to measure urine output with improper positioning of the drain tube (large loops of tubing below the drain bag, or lifting the drain tube above the level of the bladder increase UTI risk).

While there is no difference in UTI risk in a closed versus open urinary drain system, this data should not be interpreted to imply that care and protection of the urinary drain system is unimportant. These studies did not purposely expose the internal aspects of the drain tube to contaminants, they did not reopen the system repeatedly and they all provided standard catheter care. The urinary drain system should be treated with respect by using sterile technique at insertion, eliminating manipulation of the drain tube while it is in place and removal of the catheter as soon as it is unnecessary for patient care.  Brief tubing disconnection done using sterile technique, on the other hand, is not dangerous.

Intra-abdominal pressure monitoring:

So how does this data apply to intra-abdominal pressure (IAP) monitoring?  First of all, the current reference standard for IAP monitoring is the bladder pressure.[20] Since intra-abdominal pressure monitoring requires access to the urinary drain system to obtain bladder pressure data, there is an obvious concern as to whether this measurement leads to an increase in UTI risk. Based on 1960’s data the major manufacturers of Foley catheter would suggest that this is the case – basing this opinion on no data what so ever. However, if one carefully reviews the material referenced above one can surmise that careful access of the urinary catheter should not increase UTI risk, whether this access is via the urinary sampling port or if it involves brief disconnection of the drain tubing. (There is actually some concern that the needleless urinary drain access port provides higher risk for infectious complications based on literature from needless access in vascular systems – but this would also need confirmation in a research study before it could be reliably concluded.)[21] Fortunately we have a number of published studies that provide evidence that bladder pressure monitoring does NOT lead to a higher incidence of CAUTI. Cheatham et al investigated the UTI risk in 122 patients undergoing IAP monitoring and compared it to 2986 other patients in their ICU.[22] There were no differences in UTI risk between the two groups.  Ejike compared baseline CAUTI risk in patients undergoing routine bladder pressure monitoring to historical controls – noting a CAUTI rate of 0.22/1000 catheter days in those being monitored and a 5.4/1000 in historical controls.[23] Malbrain  also failed to find an association between bladder pressure  monitoring and CAUTI in a large ICU cohort.[24] All these authors conclude that IAP monitoring is safe and does not increase the risk of UTI. 

Summary:

Risk Factor for CAUTI:

References:

1. 1.            Wong, E.S., Guideline for prevention of catheter-associated urinary tract infections. Am J Infect Control, 1983. 11(1): p. 28-36.

   2.            Wong, E.S. and T.M. Hooton. Guideline for prevention of catheter-associated urinary tract infections.  1981  [cited 2008 December 1]; Available from: http://www.cdc.gov/ncidod/dhqp/gl_catheter_assoc.html.

   3.            Kunin, C.M. and R.C. McCormack, Prevention of catheter-induced urinary-tract infections by sterile closed drainage. N Engl J Med, 1966. 274(21): p. 1155-61.

   4.            Kass, E.H., Asymptomatic infections of the urinary tract. Trans Assoc Am Physicians, 1956. 69: p. 56-64.

   5.            Gillespie, W.A., et al., Prevention of catheter infection of urine in female patients. Br Med J, 1962. 2(5296): p. 13-6.

   6.            Gillespie, W.A., et al., Prevention of Urinary Infection in Gynaecology. Br Med J, 1964. 2(5406): p. 423-5.

   7.            Kunin, C.M., A.J. Yost, and L.P. Christel, Guideline for prevention of catheter-associated urinary tract infections - Comments. Am J Infect Control, 1983. 11(1): p. 33-36.

   8.            DeGroot-Kosolcharoen, J., R. Guse, and J.M. Jones, Evaluation of a urinary catheter with a preconnected closed drainage bag. Infect Control Hosp Epidemiol, 1988. 9(2): p. 72-6.

   9.            Leone, M., et al., Comparison of effectiveness of two urinary drainage systems in intensive care unit: a prospective, randomized clinical trial. Intensive Care Med, 2003. 29(4): p. 551-4.

   10.           Wille, J.C., A. Blusse van Oud Alblas, and E.A. Thewessen, Nosocomial catheter-associated bacteriuria: a clinical trial comparing two closed urinary drainage systems. J Hosp Infect, 1993. 25(3): p. 191-8.

   11.           Huth, T.S., et al., Clinical trial of junction seals for the prevention of urinary catheter-associated bacteriuria. Arch Intern Med, 1992. 152(4): p. 807-12.

   12.           Platt, R., et al., Reduction of mortality associated with nosocomial urinary tract infection. Lancet, 1983. 1(8330): p. 893-7.

   13.               Keerasuntonpong, A., et al., Incidence of urinary tract infections in patients with short-term indwelling urethral catheters: a comparison between a 3-day urinary drainage bag change and no change regimens. Am J Infect Control, 2003. 31(1): p. 9-12.

   14.           Leone, M., et al., Prevention of nosocomial urinary tract infection in ICU patients: comparison of effectiveness of two urinary drainage systems. Chest, 2001. 120(1): p. 220-4.

   15.           Leone, M., et al., Catheter-associated urinary tract infections in intensive care units. Microbes Infect, 2004. 6(11): p. 1026-32.

   16.           Maki, D.G. and P.A. Tambyah, Engineering out the risk for infection with urinary catheters. Emerg Infect Dis, 2001. 7(2): p. 342-7.

   17.           Platt, R., et al., Risk factors for nosocomial urinary tract infection. Am J Epidemiol, 1986. 124(6): p. 977-85.

   18.           Maki, D.G., V. Knasinski, and P.A. Tambyah, Risk factors for catheter-associated urinary tract infection: a prospective study showing the minimal effects of catheter care violations on the risk of CAUTI (Abstract). . Infect Control Hosp Epidemiol, 2000. 21: p. 165.

   19.           Garcia, M.M., et al., Traditional Foley drainage systems--do they drain the bladder? J Urol, 2007. 177(1): p. 203-7.

   20.               Cheatham, M.L., et al., Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. II. Recommendations. Intensive Care Med, 2007. 33(6): p. 951-62.

   21.           Rupp, M.E., et al., Outbreak of bloodstream infection temporally associated with the use of an intravascular needleless valve. Clin Infect Dis, 2007. 44(11): p. 1408-14.

   22.               Cheatham, M.L., et al., Intravesicular pressure monitoring does not cause urinary tract infection. Intensive Care Med, 2006. 32(10): p. 1640-3.

   23.           Ejike, J.C., K. Bahjri, and M. Mathur, What is the normal intra-abdominal pressure in critically ill children and how should we measure it? Crit Care Med, 2008. 36(7): p. 2157-62.

   24.           Malbrain, M., et al., Intra-abdominal pressure measurement with the Foleymanometer does not increase urinary tract infection. Acta Clinica Belgica, 2009. 64(3): p. 274 (Abstract 119).