Diagnostic Precision: Exchanging Urinary Catheters Before Urine Specimen Collection to Reduce Catheter-Associated Urinary Tract Infection

In 2020, amid the COVID-19 pandemic, an inpatient critical care unit at an oncology health care institution noted a 7-fold increase in CAUTI rates. At that time, the step-down unit had been converted into a pop-up COVID intensive care unit (ICU). This change in patient population resulted in a dramatic increase in indwelling urinary catheter use and placement duration, as patients’ care plans necessitated catheters to support adequate bladder emptying in the context of chemical paralysis, sedation, vasopressor support, and mechanical ventilation. These new interventions, not previously supported by the step-down unit, challenged the unit’s typical workflow to support prompt catheter removal with nurse-driven removal orders. This situation prompted the clinical nurses serving on the quality assurance shared governance council to question whether the current standard of care encompassed all CAUTI prevention opportunities.

Further prompting the nurses’ spirit of inquiry was a CAUTI case reviewed during a quality assurance council meeting. A patient receiving mechanical ventilation who had tested positive for COVID was noted to have 2 differing urine culture results 1 day apart. The first urine specimen was collected via the sample port of a 10-day-old urinary catheter and yielded a positive result on microbiological analysis. The second specimen, collected the following day from a newly placed urinary catheter, yielded a negative result. Except for replacement of the catheter, there had been no changes in the patient’s plan of care or interventions between the first and second cultures. This case review increased the nurses’ concern that the organization’s current urine culture practices did not distinguish between CA-ASB and CAUTI. Without appropriate urine culture stewardship programs to support the distinction between CA-ASB and CAUTI, patients were at risk for potential misdiagnosis, leading to poor antibiotic stewardship, increased health care costs, patient discomfort, prolonged length of stay, and higher mortality.² 

The goal of this quality improvement (QI) initiative was to improve urine culture practices for patients with suspected CAUTI in the ICU and the mixed medical/ surgical and step-down unit. We hypothesized that implementation of an evidence-based protocol for urine specimen collection would result in a decrease in CAUTI rates. We hoped to demonstrate a 25% reduction in the incidence of CAUTI over a 3-month pilot period.

An interprofessional task force was formed to plan the QI project. The task force was composed of frontline clinical nurses, clinical nurse specialists, quality assurance nurses, nursing leaders, and microbiology services personnel. This QI project was deemed exempt from the need for approval by the institutional review board.

The frontline clinical nurses performed a literature review to gather evidence on best practices for urine culture specimen collection in the critical care areas and collaborated with clinical nurse specialists to critically appraise the findings. Databases used for the literature search were MEDLINE, the Cochrane Library, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and the Web of Science. In addition to research articles, professional organizations’ published papers, such as white papers of the American Urological Association, were considered. The following search terms were used alone and in combination: CAUTI, critical care patients, best practices, CAUTI prevention, Foley catheter exchange, catheter replacement, CA-ASB v. CAUTI, and urine cultures. Eleven articles were identified for analysis based on relevancy and publication date within 5 years of the time of the literature search, except for organizational white papers.⁴ 

The strongest and most consistent theme that emerged from the literature review was the importance of distinguishing between CA-ASB and CAUTI.^5–8  The relationship between the duration of catheterization and the risk of bacterial colonization was consistently highlighted with respect to the development of CA-ASB or CAUTI.^5–9  Moreover, the presence of patient symptoms was recommended to determine the need for urine cultures.⁵  A major reported finding was the need to exchange the urinary catheter before urine specimen collection in patients with long-term urinary catheters to ensure that the specimen accurately represented the bladder rather than the catheter biofilm.^5,10,11  Numerous studies reviewed the optimal timing of replacing urinary catheters before specimen collection, with proposed times ranging from 24 hours to 7 days from initial catheter insertion to replacement.^6,10,11  For our intervention, we adopted the shortest proposed time frame, 24 hours after initial urinary catheter insertion, as supported by biofilm growth time and the clinical CAUTI diagnostic criteria requiring catheter placement duration of 2 days, to inform our urinary catheter replacement workflow. In addition, opportunities to collect urine via a midstream specimen were encouraged throughout this workflow, as supported by evidence.^9,11 

After synthesis and review of the evidence, we noted inadequacy in our institution’s standard of care for patients who required urine culture specimens to be obtained from indwelling urinary catheters. We hypothesized that previously reported CAUTIs could be related to the method of specimen collection, as long-term urinary catheters (those in place for more than 24 hours) were used to obtain samples for microbiological evaluation. In 1 instance, samples were obtained from a urinary catheter that had been in place for 52 days, thus making the presence of biofilm a clinical certainty, with a great likelihood of biofilm colonization, or CA-ASB, versus CAUTI. Because the patient was delirious, the need for culture could not be determined by the presence of symptoms. Thus, the task force sought to establish a better workflow to ensure distinction of CA-ASB and CAUTI in the setting of unclear patient symptoms as well as for overall optimization of care.

A new evidence-based workflow was established for urine culture practices for patients with indwelling urinary catheters (Figure 1). The workflow began with a collaboration between frontline nurses and physicians or advanced practice providers to determine whether patients met criteria for initial urinalysis. If so, staff members were guided to use the existing urinary catheter and aseptic technique to collect a urine sample via the sample port. If urinalysis showed the presence of nitrates, leukocytes, or bacteria, the nurse and physician or advanced practice provider would collaborate to determine the feasibility and safety of exchanging the urinary catheter.¹⁰  Once catheter exchange was deemed safe and clinically appropriate, the physician or advanced practice provider would enter a new urinary catheter insertion order. The nurse would then remove the old urinary catheter and immediately replace it with a new urinary catheter. Once the catheter was replaced, the urine sample could be immediately obtained from the new urinary catheter sample port and sent for microbiological examination.

The task force nurses identified strategies to help educate staff members on the new urinary catheter exchange workflow. These included in-person point-of-care education, dissemination of a recorded presentation, and meetings with service chiefs of the ICU and step-down unit as well as nursing director stakeholders within the quality assurance and critical care units. Unit champions were recruited to embed unit-based support for navigating the new workflows. The clinical nurse specialists and frontline nurses commonly advocated for adherence to the new workflow or contributed to urinalysis interpretation.

On April 12, 2021, the catheter exchange pilot program was initiated on 2 critical care inpatient units, an 18-bed ICU and a 36-bed mixed medical/surgical and step-down unit, which previously functioned as a pop-up COVID ICU. These units were targeted on the basis of urinary catheter use rates and CAUTI rates, which pointed to opportunities for improvement. Additionally, in targeting 2 critical care units, the task force hoped to capture patient populations that required urinary catheters for safe care and did not meet criteria for prompt removal through nurse-driven removal orders.

To support nurses navigating this pilot workflow, a visual aid was created (Figure 1). This tool helped nurses determine whether a patient was a candidate for a catheter exchange before the collection of culture specimens. Additionally, the algorithm helped to inform ordering physicians and advanced practice providers of the appropriate steps to support the urinary catheter exchange workflow. Documentation by the nurse included an event note. Data collection and examination of urinary catheter exchanges were supported via partnerships with nursing quality assurance representatives. These representatives and the frontline nurses performed monthly medical record reviews for all patients who had urinary cultures obtained. A final data review was performed upon conclusion of the pilot program on December 31, 2021.

The catheter exchange pilot program ran over 3 consecutive quarters (the second to fourth quarters of 2021). Workflow adherence was strong in the step-down unit but was poor in the ICU; therefore, data from the ICU were excluded from the final review. During the pilot program, the CAUTI rate in the step-down unit decreased to zero in both the second and third quarters. Seven patients followed the full catheter exchange workflow; all 7 had positive urinalysis results from existing urinary catheters (in place for more than 24 hours), and negative urine culture results after urinary catheter exchange. Without the catheter exchange workflow, all 7 patients could have had false-positive urine cultures, as all of the catheters were likely colonized as evidenced by preliminary positive urinalysis from existing (old) catheters.

Improving diagnostic accuracy enables good clinical decisions, with a profound impact on patient care. Patients diagnosed with CAUTI face numerous health risks, including sepsis and potential death, and typically have their length of stay prolonged by 2 to 4 days.³  Common issues that arise from CAUTI include discomfort, mental status changes in the elderly, and complications related to urosepsis. Once CAUTI is diagnosed, treating it can require frequent venipuncture to ascertain periodic laboratory values and long-term intravenous access for antibiotic administration, further increasing the patient’s risk of infection. Administration of antibiotics creates the possibility for the development of multidrug-resistant bacteria and can put patients at higher risk for opportunistic infections and adverse drug effects.^10,11 

After 2 consecutive quarters of no CAUTIs, the step-down unit team had 1 reported CAUTI in the fourth quarter of the pilot program, as shown in Figure 2. A review of this CAUTI is provided in the SBAR (situation, background, assessment, recommendation) case study documented in Figure 3. This case was reviewed by an interprofessional group, which identified clinical inexperience and unawareness of the pilot program as root causes. After final review, the group hypothesized that the initial specimen, from a 5-day-old catheter, was likely contaminated and that the case represents a potential false-positive CAUTI result. Therefore, the results of this pilot program can be viewed as 1 CAUTI diagnosis that is potentially inaccurate because of failure to adhere to the pilot workflow and further supported by the negative culture results of the same patient when the pilot workflow was followed.

With rules associated with value-based payment programs of the Centers for Medicare & Medicaid Services, institutions face direct financial burdens resulting from CAUTI diagnosis; in addition, patients are both directly and indirectly affected financially through increased pharmaceutical costs and a potentially prolonged length of stay.^10,11  Financial penalties faced by organizations for HAIs are of particular concern in the setting of potential misdiagnoses. Additionally, HAIs are organizational priorities not only for bioethical reasons but also because they have a major impact on professional reputation and eligibility for Magnet designation.

Avoidance of possible misdiagnosis in the 7 patients in this pilot program represents an estimated institutional cost savings of $4522 to $75 222.¹  Ultimately, allowing institutions to better report and represent outcomes allows consumers and future patients to make more informed health care decisions. Additionally, with improved financial health, institutions can better allocate resources, which has become of particular interest in the financial aftermath of the pandemic. The potential patient and institutional financial benefits are immense, especially given the low cost associated with the catheter exchange workflow, which requires only routine urinalysis, an indwelling urinary catheter tray, and a urine culture.

This QI project highlights the importance of implementing evidence-based interventions to enhance patient outcomes. This project also illuminated the value of having frontline staff members drive change. This was a nurse-driven initiative that leveraged transformational leadership to promote clinical buy-in.

To prevent CAUTI, institutions and clinicians must identify and dismantle barriers and systems that allow CAUTI proliferation. At this institution, the catheter exchange workflow dismantled barriers for critical care patients who require long-term use of urinary catheters and thus cannot have them promptly removed. The catheter exchange workflow has since been formally approved by the institution’s medical board, which governs clinical guidelines that span nursing and medical scope. The workflow is now considered a guideline for all adult inpatients with indwelling urinary catheters. The decision to define a long-term catheter as a catheter that has been in place for more than 24 hours was based on the definition of CAUTI set forth by the Centers for Disease Control and Prevention, which requires the presence of a urinary catheter for 2 calendar days, as well as the fact that the incidence of bacteriuria increases by 3% to 7% per day.⁴  Additionally, evidence sources that demonstrated decreased CAUTI rates used 24 hours as the specified time to exchange the urinary catheter.¹⁰ 

Although this pilot program was intended to focus on critical care patients, nurses on the task force noted that introduction of the new workflow prompted increased vigilance with regard to all patients’ urinary catheter care. Unprompted, staff members advocated for the collection of urine culture specimens upon insertion of a new urinary catheter, citing the evidence that informed the catheter exchange workflow. Additionally, the clinical nurse specialist on the task force noted increased vigilance with regard to urinalysis interpretation and was increasingly consulted for expert input during and after the pilot phase. This increased vigilance with regard to urine culture stewardship could lead to a decrease in urine culture orders. Well-established evidence supports the utility of urinalysis results in determining needs for urine culture evaluation.⁹ 

The 3 most influential sources of evidence used to inform the new workflow evaluated the impacts of exchanging catheters at 7 days, 24 hours, and more than 48 hours, respectively.^5,10,11  One study was unique in that the primary outcome was not CAUTI itself but antibiotic use, as antibiotics were ordered to treat CAUTI.⁵  The study demonstrated a statistically significant decrease in antibiotic use with the implementation of a clinical decision support (CDS) tool.⁵  The CDS tool took a bundled approach, with multimodal interventions that mirrored this work group’s process improvement.⁵ 

Another study evaluated a protocol requiring the removal of catheters in place for more than 24 hours and obtaining urine cultures through intermittent catheterization or replacing the old catheter with the new catheter, directly mirroring our own workflow.¹⁰  Implementation of the new protocol resulted in a 77% reduction in the CAUTI rate per 1000 patients, a significant difference (P < .001). Another study examined implementation of a CDS tree, with 1 intervention arm introducing catheter exchanges for patients with urinary catheters in place for more than 48 hours.¹¹  This decision tree also prompts clinicians to test for CAUTI in the presence of appropriate symptoms, which was supported by our organization, a specialized oncology organization focused on urinary stewardship driven by nurses versus clinical decision trees. Outcome measures included catheter use rates, number of urine specimens, and number of CAUTIs. There was no change in total CAUTI rates from before to after the intervention.

After completion of this pilot program, the step-down unit team strove to adhere to the new workflow while awaiting hospital-wide implementation, which finally occurred in April 2023. The frontline nurses championed this project from inception to hospital-wide rollout. Since the program’s formal adoption in 2023, the step-down unit and ICU team have witnessed 10 consecutive months of no incidences of CAUTI, indicating the profound impact of the new workflow on patient safety.

One limitation of this pilot program was the small number of patient cases. This small size was expected given the limited population of critically ill patients who could not have urinary catheters removed. Additionally, the pilot program was intended to encompass 2 inpatient critical care units, but poor workflow adherence in the ICU prevented its data from being integrated into the final review. A possible driver of this poor adherence was the lack of a consistent presence of project champions on the ICU team as compared with the step-down unit team. Another possible factor was the higher turnover rate in the ICU due to staff travel work contracts.

This QI pilot program was highly successful and met its goals. During implementation and the second and third quarters, the step-down unit experienced no CAUTIs, a metric not seen in more than a year. In addition, the single CAUTI diagnosis that occurred during the pilot program is believed to be inaccurate, as detailed in Figure 3, strengthening the hypothesis that previous workflows may have contributed to false-positive CAUTI findings. Notably, the step-down unit team experienced a positive CAUTI result in the first quarter of 2022. The medical records are unclear as to whether the patient’s indwelling urinary catheter was exchanged. If it was not, the catheter was in place for 193 days.

Adopting catheter exchange workflows in adult patients helps improve diagnostic distinction between CA-ASB and CAUTI, thereby improving patient care and safety. Any organization not currently using such workflows should evaluate the safety and feasibility of their integration. Our organization currently employs numerous evidence-based CAUTI prevention strategies, such as education, nurse-driven removal protocols, maintenance and insertion bundles, and the use of alternative devices. Institutions seeking to implement catheter exchange workflows should ensure that foundational CAUTI prevention strategies such as nurse-driven removal algorithms are in place. Without infrastructure supporting prompt catheter removal, institutions may struggle to reduce the largest risk factor for CAUTI, duration of catheter placement.

Catheter exchange workflows are generalizable to the broader health care context. Although our organization is an oncology center, all organizations seeking to reduce CAUTI rates can implement these practices, as biofilm development and colonization of urinary catheters are universal. Additionally, the overarching benefits of improved antibiotic stewardship and proper CAUTI diagnosis can have an immense positive impact on patients and health care organizations alike.

To the incredible, resilient critical care nurses that despite the chaos in the workplace jumped into this work with pride and eagerness; we hope you always remember that you perform tremendous, life-changing acts daily. This work would not have been possible without you.