Transitioning from heparin to saline locks for central venous access devices in oncology: An evidence-based practice approach

Abstract

Central vascular access devices (CVADs) are often essential to the care of patients undergoing long-term cancer treatment. CVAD maintenance is an essential oncology nurse competency. Evidence-based practice (EBP) in flushing and locking help to prevent intraluminal occlusion, a common complication. Heparinized saline (HS) has been the standard locking solution for CVADs. However, research indicates no superiority of HS over normal saline (NS). The objectives of this EBP project were 1) to evaluate whether a significant difference in intraluminal occlusion was associated with the change from HS to NS use for locking CVADs in ambulatory oncology care, and 2) to evaluate the effects of peer nurse mentoring on nurses’ and patients’ perspectives about the practice change. Analysis of data revealed decreases in alteplase usage after transitioning to NS locking. Patient and nurse surveys indicated that peer nurse mentoring increased nurse and patient confidence and competence in making the practice transition.

INTRODUCTION

Central vascular access devices (CVADs) are an essential aspect of the care of many patients undergoing long-term treatment for cancer (Schiffer et al., 2013). With effective maintenance, CVADs provide venous access for many months to years (da Costa et al., 2019). Maintenance is a fundamental responsibility of oncology nurses, and of vital importance to patients whose treatment depends on reliable, safe venous access (Camp-Sorrell & Matey, 2017).

Occlusion and central line-associated blood stream infection (CLABSI) are two common complications (Akhtar & Lee, 2021; Ullman et al., 2015). Occlusion due to catheter-associated venous thrombosis (CAVT) occurs in up to 66% of CVADs and is a risk factor for CLABSI (Gerçeker et al., 2018; Schiffer et al., 2013).

Evidence-based practices in flushing and locking help to prevent occlusions (Goossens, 2015; Gorski et al., 2021). Heparin was historically the standard locking solution used for CVADs. However, research findings that include sampling from oncology populations have not demonstrated superiority of heparin over saline locks for maintaining patency (Bertoglio et al., 2012; Brito et al., 2018; Dal Molin et al., 2015; Goossens et al., 2013; Klein et al., 2018; López-Briz et al., 2018; Zhong et al., 2017). Transitioning long-standing practices that requires complex research appraisal can present challenges for oncology clinical settings. Although oncology nurses feel competent to question clinical practice, they may lack confidence and skills in evidence-based practice (EBP) implementation (Ginex et al., 2021).

BACKGROUND

The longstanding policy of a National Cancer Institute (NCI)-designated comprehensive cancer centre located in the northeastern United States specified a 1,000 units/mL of catheter volume of heparinized saline (HS) lock be placed in all CVADs at the time of de-access or discharge unless contraindicated (e.g., with heparin-induced thrombocytopenia). Clinical specialists led a review and appraisal of the literature that revealed several, rigorously designed recent studies comparing use of heparin to saline for locking CVADs. Studies that included oncology population sampling found no superiority of heparin (HS) over normal saline (NS) locks for maintaining CVAD patency (Bertoglio et al., 2012; Brito et al., 2018; Dal Molin et al., 2015; Goossens et al., 2013; Klein et al., 2018; López-Briz et al., 2018; Zhong et al., 2017). When benchmarking practice with other institutions, nurses discovered that the majority were using HS locks. Nevertheless, the Policy and Procedure Committee enacted a policy change from HS to NS use for locking CVADs. With a weekly volume of 1,500–1,700 patients seen with CVADs, nurses anticipated an influx of questions and concerns from both nurses and patients.

With consideration of the tenets of evidence-based practice (EBP; best scientific evidence, clinical expertise, and patient values and preferences), nurses designed a project to address concerns about the clinical practice transition. The project team adopted principles from the Innovation for Nursing-Sensitive Practice in a Research Environment (INSPIRE) model to guide the project. The INSPIRE model provides a framework for implementing EBP, quality improvement (QI) and research within an organization (Wallen, 2014). The model directed the team in differentiating EBP and QI elements of the project, as well as understanding how the processes intersect.

REVIEW OF THE LITERATURE

EBP is the responsibility of all health care professionals within an organization, and a commitment to provide resources and develop a supportive infrastructure for EBP are essential. However, barriers to EBP in clinical practice are common, and nurses may lack both confidence and competence in implementation (Melnyk et al., 2018). To achieve successful EBP implementation, assessment of organizational barriers and facilitators is needed at the onset. Measures to overcome barriers include mentoring, journal clubs, library resource access, education, and support for research appraisal and practice implementation (Boswell et al., 2020). An organizational climate supportive of a spirit of nurse-led inquiry and innovation leads to sustainable EBP transitions (Geerligs, et al., 2018).

Historically, HS has been the standard locking solution used for maintaining CVAD patency after a NS flush. Current evidence indicates no superiority of HS over NS for avoiding intraluminal occlusions, particularly in populations such as oncology, where long term central catheter use is predominant (Bertoglio et al., 2012; Brito et al., 2018; Dal Molin et al., 2015; Egnatios & Gloria, 2021; Goossens et al., 2013; Klein et al., 2018; López-Briz et al., 2018; Sharma et al., 2019; Zhong et al., 2017). The use of NS eliminates the risks of heparin overdose, hypersensitivity, drug incompatibilities, and heparin-induced thrombocytopenia (HIT) and reduces the potential for staphylococcal biofilm formation (Goossens, 2015). Published standards and guidelines agree there is insufficient evidence to recommend heparin over saline locks for CVADs (Camp- Sorrell & Matey, 2017; Gorski et al., 2021; Schiffer et al., 2013). Alteplase, a thrombolytic, is recommended to restore patency to a non-functioning CVAD, determined by difficulty or inability to flush or obtain an adequate blood return. (Gorski et al., 2021; Schiffer et al., 2013).

Flushing technique is as important as the solution itself for maintaining catheter patency. Pulsatile flushing (i.e., brief, 1mL boluses interrupted by short pauses that cause turbulence in the catheter) has shown superiority to laminar flow flushing (i.e., continuous push that causes smooth, regular, non-turbulent flow in the catheter) for maintaining CVAD patency (Boord, 2019). Much of this research was conducted in vitro (Ferroni et al., 2014; Royon et al., 2012; Vigier et al., 2005), yet one small in vivo study conducted in an ambulatory oncology setting, corroborates these findings (Chong et al., 2013). Professional nursing organizations recommend pulsatile flushing using a 10mL syringe or larger in diameter to reduce the risk for pressure-related damage to the catheter, and stress that manual force should not be applied to overcome resistance (Camp-Sorrell & Matey, 2017; Goossens, 2015; Gorski et al., 2021).

OBJECTIVES

The objectives of this EBP project were 1) to evaluate whether a significant difference in CVAD intraluminal occlusion was associated with the change from HS to NS use for locking CVADs in patients receiving ambulatory oncology care and 2) to evaluate the effects of a peer nurse mentoring intervention on oncology nurses’ and patients’ perspectives about the transition from HS to NS use for locking CVADs.

METHODS

Participants were recruited from two ambulatory clinics on the main campus of an ambulatory cancer centre, Y2 and Y9. Y2 provides initial care for most patients, including lab work and IV access services in preparation for infusions. Y2 nurses see 200–300 patients with CVADs per day. Y9 provides infusion therapies for a variety of cancer diagnoses. Y9 nurses see between 10 and 20 patients with CVADs per day.

Nurse Mentoring Intervention

The project team developed a peer nurse mentoring intervention to promote implementation of the practice change. Five nurses were trained to conduct the intervention consisting of 1) a 2-minute instructional video demonstration (viewed on a smart device) of flushing and locking CVADs according to the updated policy, 2) individualized mentor support including practice and discussion, 3) a nurse information card (Figure 1) and patient information card (Figure 2), and 4) posted full texts of the referenced literature for easy access by nurses. These peer mentors championed evidence-based CVAD management on their units throughout the project.

Figure 1.

Institution-developed nurse information card

Figure 2.

Institution-developed patient information card based on current policy

Evaluation Indicators

To address the first objective, the use of alteplase (an existing quality metric) prior to the policy change was compared with usage after the policy change. Individual patients who received alteplase during a clinic visit were counted as a single CVAD occlusion, whether one or more doses were administered. Cumulative rates of alteplase use were calculated monthly. Percentages of cumulative alteplase administrations associated with HS and NS usage were compared using two proportion z-tests.

To address the second objective, the project team developed and administered surveys to describe changes in nurse and patient perspectives specific to the policy change. Mean aggregate scores regarding the perspectives from patient and nurse participants were calculated at three time points: baseline, three months, and six months post-intervention. The differences between aggregate change scores for each group were described.

Participation was voluntary and anonymous. The project was approved by the Institutional Review Board (IRB) of the cancer centre prior to commencement.

RESULTS

Differences in cumulative alteplase usage are displayed in Figure 3. Data were aggregated and analyzed for six months before and then 10 months after the policy change to NS locks. Three months of interim data were excluded, when HS stock remained accessible to nurses after the policy change. There were significant decreases in alteplase usage in the Y2 clinic (Lab Services; p = 0.048) and in all areas combined (p = 0.003). Non-significant decrease in alteplase usage was observed in the satellite clinics (p = 0.172), while main campus infusion clinics had comparable alteplase usage despite the locking solution change (p = 0.818).

Figure 3.

Comparison of monthly alteplase (tPA) usage in CVADs

A total of 79 nurse surveys were completed: 34 at baseline, 23 at three months post-intervention, and 22 at six months post-intervention. A total of 358 patient surveys were completed: 120 at baseline, 113 at three months post-intervention, and 125 at six months post-intervention. Types of CVADs reported were: 95% implanted ports, 4% peripherally inserted central catheters (PICCs), and 1% others. Additional survey results are displayed in Figures 4 and 5.

Figure 4.

Survey results for three time points: Baseline, 3 months, 6 months post-intervention

Figure 5.

Survey results for three time points: Baseline, 3 months, 6 months post-intervention

Frequently asked questions (FAQs) and answers were posted in nurses’ stations during each phase of the project based on open-ended survey responses. FAQs from nurse participants most often related to literature appraisal, such as: 1) “Can I be confident that the evidence is accurate when my practice experience differs?” and 2) “Why is there a discrepancy between the port manufacturer lock solution recommendation and our policy?” Patient participant survey data reflected patients’ reliance on the expertise of their nurses in CVAD care. A few patients reported that their physicians expressed no preferences in CVAD management, referring them to Nursing. Nurses and patients alike reported that the patient information card prompted discussion. Many patients expressed appreciation for being included in decision-making processes about their care.

DISCUSSION

Consistent with other studies (Brito et al., 2018; Egnatios & Gloria, 2021; López-Briz et al., 2018; Zhong et al., 2017), findings from this project indicated that NS was as effective as HS in preventing CVAD intraluminal occlusion in ambulatory oncology patients. Among occlusions that occurred, classification by CVAD type was as follows: 92% implanted ports, 6.9% PICCs, and 1.2% others. Data reflected significant decreases in intraluminal occlusion overall and in the Y2 clinic, where most intravenous (IV) device management occurs. The majority of participants in the study were recruited from Y2, the lab services clinic of the institute. Of note, all Y2 nurses received the mentoring intervention, while only one out of 10 infusion nurse clinics participated in the project. Interestingly, data from Y2 revealed significant decreases in alteplase use, while data from the other areas revealed no significant differences. The team surmised that peer mentoring reinforced best practices in flushing and locking techniques overall, which had a positive effect on prevention of occlusion. Additionally, Y2 nurses were considered to have the most expertise overall with IV device management within the institute, as this is the focus of their practice and where the largest volume of patients is seen for IV issues. Their cumulative experience, perhaps, contributed to this finding. Finally, many nurses, including those on Y2, reported being unsure of performing the pulsatile flushing technique until viewing the video demonstration. Future in vivo studies are needed to differentiate the impact of distinct factors, such as pulsatile flushing, on CVAD outcomes.

Nurse survey data indicated a steady increase across data collection points in the belief that NS is an effective lock solution, and an overall decrease in the belief that HS is more effective. Nurses’ confidence in implementing the practice change increased steadily, as did their confidence in impacting patients’ attitudes. Nurses’ awareness of current evidence had the greatest increase of all survey items measured, reaching almost 100% at the final data collection point. Studies indicate that the presence of mentors increases nurses’ knowledge, confidence, and skills in practice, as well as self-efficacy in promulgating EBP (Abdullah et al., 2014; Boswell et al., 2020; Spiva et al., 2017).

Nurses raised thoughtful questions related to discrepancies between research, personal practice experience, and manufacturer flushing recommendations. In response to FAQs, information about the evidence pyramid was provided to reinforce the level of confidence in research findings related to study methods used. Randomized controlled trials, systematic reviews and meta-analyses were provided as exemplars of high-level evidence. Mentors led discussions about reconciling personal practice experience and research using critical thinking. Unlike pharmaceuticals, medical devices are not often evaluated in clinical trials research after they have completed initial testing and obtained approval to market (Van Norman, 2016). Thus, clinical research can provide important evidence to guide practice that may conflict with product inserts.

As reflected in previous literature, the team noted the importance of fostering partnerships in decision-making between nurses and patients to positively impact trust, as well as the quality and safety of care (Sharma et al., 2018; Shay & Lafata, 2015). Like nurse surveys, patient surveys showed a consistent increase in support for the use of NS locks. These similar trajectories may indicate that nurse and patient perspectives mirror each other in environments where EBP is championed. Data also showed an increase in NS use and a decrease in HS use for flushing and locking CVADs at home. There was no collaboration with home care agencies during the project. Many oncology patients flush their own CVAD at home with the help of a caregiver with minimal oversight from home care nurses after initial education. These data may reflect increased patient autonomy with CVAD home management. Survey data also revealed that patients predominately leave decisions about CVAD management to the nurses caring for them; however, this metric consistently decreased over time. Research has emphasized that patient knowledge and engagement in care results in positive health outcomes (Sharma et al., 2018). Like nurses, patients’ confidence in EBP may increase with knowledge and support. Oncology patients commonly seek out information about their care and according to one study, approximately half trust online information (Lange et al., 2019). However, health information on the internet targeted to the general public is often inaccurate (Daraz et al., 2019). Further study of how to improve patients’ EBP knowledge and skills are essential in this information age.

Patient participants reported that their physicians did not have knowledge or preferences about CVAD flushing methods. In hospital settings, physicians are often unaware that their patients have CVADs (Chopra et al., 2014). While our findings are specific to ambulatory oncology, provider awareness and communication about vascular access issues may be suboptimal in some settings. The team recognized the need to prioritize interdisciplinary team communication of practice changes. In addition, as a result of the project, the team collaborated with health care organizations in the community to collaborate in this work.

Oncology nurses expressed uncertainty about EBP implementation for two primary reasons: 1) a lack of confidence in conducting evidence appraisal; and 2) personal practice experiences that conflicted with evidence. Patients questioned differences in practice between healthcare organizations. Consistent with other studies (Middlebrooks, Carter-Templeton, & Mund, 2016; Williams, Perillo, & Brown, 2015), EBP implementation can be enhanced when barriers such as lack of time, access to resources, and assistance in appraising literature are addressed. Consistent with other studies, nurses were empowered by participating in the EBP project (Fridman & Frederickson, 2014). The need to closely monitor emerging research and internal QI data were commitments that all organizational stakeholders agreed upon. As previously demonstrated, organizational support and engagement are essential to promoting EBP (Boswell et al., 2020). Finally, the project team estimated a $2 million annual savings in direct costs related to the change to NS use. Cost inevitably influences clinical decision-making in healthcare. Cost analysis, combined with safety and quality measures, can influence EBP implementation. In this project, the practice change resulted in a significant cost savings.

LIMITATIONS

Although the mentoring intervention changed both nurse and patient perspectives about CVAD management, the most influential aspects of the intervention were not ascertained. A cost savings related to a change from HS to NS CVAD locks was estimated. However, a full cost analysis would require a more in-depth examination. Finally, as an EBP project, findings are not generalizable.

CONCLUSION

Assessment and prevention of CVAD intraluminal occlusion is an essential competency for oncology nurses. Despite long-standing use of heparin for CVAD locking, current evidence indicates no clear superiority of heparin over saline. This study’s findings suggest a clinically meaningful benefit of using saline alone as a locking solution, along with a pulsatile flushing technique to maintain CVAD catheter patency. More randomized controlled trials are needed to further evaluate factors impacting CVAD-related patient outcomes. Meanwhile, practice and policy should reflect current evidence and ongoing appraisal of emerging research with related QI monitoring of oncology patient outcomes to inform best practices. Data from this project suggest that peer nurse mentoring can promote confidence and competence in EBP among nurses and patients, particularly during practice transitions. EBP and QI are inextricably related in addressing complex and challenging clinical issues such as transitioning from heparin to saline CVAD locks. Exploration of the best approaches for promulgating EBP is critical in a constantly changing oncology care environment.