A Preprocedural Hydration Protocol for Prevention of Contrast-Induced Nephropathy

The focus on quality care metrics has sparked a cultural change in healthcare, increasing quality improvement (QI) programs over the past ten years. These programs are often facilitated by advanced practice nurses, who continue to practice in a variety of settings, and possess the training and experience to facilitate practice change based on quality metrics. 

Launching a QI Project

A unit-based nurse practitioner in a large interventional cardiology lab identified a high rate of contrast-induced nephropathy (CIN) based on the lab’s participation in the National Cardiology Data Registry (NCDR), which reports the percutaneous coronary intervention (PCI) acute kidney injury (AKI) rate as one of its quality metrics. The lab performs an average of 400 inpatient and outpatient cardiac catheterizations monthly. At the time, the CIN rate was at less than the 50th percentile nationally and no structured facility QI program existed. 

A QI project was launched in order to develop and implement a preprocedural hydration protocol, with the goal of lowering the lab’s CIN rate. Quarterly aggregate NCDR PCI-AKI rates were used as the baseline and outcome data. The purpose of the QI project was to examine whether a preprocedural hydration protocol reduced the incidence of CIN in patients undergoing cardiac catheterization with PCI. The expected outcome was a decrease in the rate of CIN for patients undergoing PCI. Benefits include decreased length of stay, decreased health care delivery costs, and a decrease in patient complications, which improve quality scores and reimbursement margins. Additionally, best practices can be carried over into other areas of the hospital that also administer contrast media and then on to other facilities within the healthcare system. The benefits to the patient population include a decrease in complications, shorter hospital length of stay, and lower cost of care.

The Importance of Contrast-Induced Nephropathy (CIN)

CIN is the third leading cause of renal failure in the acute care setting. Reduction of CIN is an objective for the National Quality Forum (NQF) and NCDR.¹ CIN has become an area of QI focus because it is a complication with an important impact on mortality and morbidity. No specific treatment is available after CIN has occurred, so management is focused on prevention.² Evidence supports adequate parenteral volume repletion (PVR) as the most important factor in reducing the incidence of CIN in both the high and low risk patients. Patients with an estimated glomerular filtration rate (eGFR) <60 ml/min are considered high risk.² Additional risk factors for CIN include diabetes, hypovolemia or hypotension, age >75 years, and advanced heart failure.^3,4 The NCDR national benchmark CIN rate is 7.24%.⁵ The Society for Cardiovascular Angiography and Interventions (SCAI) recommendations for prevention of CIN consist of pre-procedural risk scoring, evaluation of renal function, avoidance of nephrotoxic medications, adequate hydration, and judicious contrast use.^6,7 

Hydration as a Prevention Strategy for CIN

Hydration recommendations advise providers to begin parenteral hydration three to four hours prior to contrast administration and to continue six to eight hours after completion of the procedure.² A prospective cohort studied the effect of 1000 ml normal saline hydration before and after contrast administration in patients with risk factors for CIN. Only 2% of patients developed CIN after hydrating with this approach.⁸ Low-risk patients have an eGFR ≥60 ml/min and high-risk patients have an eGFR ≤60 ml/min. For low-risk patients, hydration status should be optimized, and preprocedural hydration is more important than intraprocedural or postprocedural hydration. A reasonable volume for optimization of hydration status is 1-1.5 ml/kg per hour for three hours, or 3-4.5 ml/kg prior to contrast administration. High-risk patients may need to be hydrated gently over a longer period of time, and if needed, the procedure start time should be delayed to accommodate adequate hydration. Some patients may need to be admitted overnight prior to cardiac catheterization to allow for overnight hydration.² 

The prior workflow for hydration orders was dependent on awareness of the risk of CIN by the ordering provider and patient-specific preprocedural hydration orders. This lab has four interventional cardiologists; however, the ordering provider may be a hospitalist, internal medicine, general cardiologist, or a physician assistant or nurse practitioner from these respective areas. Preprocedural hydration orders varied widely and included no preprocedural hydration, a saline bolus for creatinine above 1.5, a standard rate and volume for each patient, or hydration orders individualized to that patient’s history and clinical status. 

Facilitating Best Practice Guidelines

In order to adhere to clinical guidelines recommended for prevention of CIN, a standardized preprocedural hydration order set was needed to provide clarity and establish consistency of preprocedural hydration practices among providers. The QI project facilitated the adoption of best practice guidelines, and increased monitoring and communication of performance. The objective was the development and implementation of a preprocedural hydration protocol for patients undergoing cardiac catheterization in order to decrease the rate of CIN. Additional objectives included establishment of a tracking mechanism for CIN and increased awareness of the importance of adherence to preprocedural hydration through the education of clinical staff. A preprocedural hydration protocol was selected by the unit-based nurse practitioner because it was a factor over which they had influence and is the easiest of the SCAI recommended best practices with which to begin.

A challenge to the development and implementation of a comprehensive CIN protocol is the physician-centric environment. An advanced practice nurse, the unit-based nurse practitioner who is not the physician performing the procedure, is not the final decision maker for process and policy change, but can work as a change agent to advocate for QI. The barrier was moderated by performing a review of the current research and involving the physicians as key stakeholders during the planning stage. In this cardiac catheterization lab, four interventional cardiologists with extensive knowledge, proficiency, and anecdotal evidence were asked to review and approve the proposed hydration protocol that was developed by the unit-based nurse practitioner. A multidisciplinary meeting involving key stakeholders was convened in fourth quarter 2017 to review and approve the proposed hydration protocol and timeframes. Baseline data on the current CIN rate was reviewed, along with current literature findings and evidence-based practice recommendations. Preprocedural hydration orders were finalized as 3 ml/kg over three hours prior to contrast administration. Other aspects of the protocol included an updated clinical weight, and close clinical monitoring for changes in respiratory status or signs of fluid overload. A preprocedural hydration protocol rollout plan was composed and disseminated. Education was provided to all impacted staff and providers including medical staff, advanced practice nurses and physician assistants, nursing, pharmacy, and the executive leadership team. The education included the background of CIN, purpose of the QI project, methodology, and preprocedural hydration protocol. Education was conducted using PowerPoint presentations, and a question-and-answer session followed the education. Preprocedural electronic medical record order sets were changed to reflect the hydration protocol changes and the standardized hospital preprocedural hydration protocol commenced. Manual audits and chart reviews were performed by the unit-based nurse practitioner. Real-time feedback regarding opportunities for improvement was given. Data was manually abstracted by a contracted third-party vendor and input into the NCDR. Daily adherence rates were tracked on graphs and reasons hydration was not administered were tracked on run charts. The adherence graphs and reasons patients were not hydrated per protocol were posted on the unit quality improvement board. The CIN rate was calculated by the NCDR and tracked monthly. Issues identified on the run chart were investigated utilizing the root-cause-analysis approach and addressed in a timely manner with appropriate parties. Cases were discussed in a monthly meeting with the cardiology physicians, nurse practitioners, cardiology leadership, and executive leadership along with the QI team. The details of the root-cause-analysis review were included along with the CIN rates. Suggestions for improvement were discussed by the team.  

QI Project Results

The CIN rate was calculated by a denominator population of all inpatients undergoing cardiac catheterization with PCI, and a numerator of all patients that experienced a 0.3 rise in creatinine or dialysis 48 hours after the procedure. The hydration protocol was implemented in January 2018. The baseline group consisted of 285 patients, with 298 patients in the measurement group. A total of 1098 patients were audited for preprocedural hydration protocol adherence. The baseline aggregate CIN PCI rate for third quarter 2017 was 6.7%. The measurement period aggregate CIN PCI rate for first quarter 2018 was 10.9%. The difference was an increase in CIN rate for PCI patients of 4.2%.

Preprocedural hydration rates were not previously tracked; therefore, baseline data for preprocedural hydration was not available. Monthly preprocedural hydration adherence rates were 71% in January 2018, 79% in February 2018, and 77% in March 2018. The adherence rates increased by 8% over the quarter. Of patients audited for preprocedural hydration adherence, 22% did not receive hydration per protocol. Of this 22%:

• 86 patients did not have a hydration order, including both emergent and nonemergent cases; 
• 33 patients were hydrated at less than 3 ml/kg; 
• 66 patients were not hydrated due to a medical contraindication; 
• 49 patients had a hydration order, but no documentation indicated the hydration was administered.

QI project objectives review. The objective of establishing and implementing a standardized facility preprocedural hydration protocol for patients undergoing cardiac catheterization was met. The literature was reviewed and the agreed-upon reasonable standard quantity and duration of PVR was 3 ml/kg of normal saline over three hours prior to contrast administration, with close clinical monitoring for signs of intolerance with patients with heart failure, cardiomyopathies, and severe valvular heart disease. The additional objective of educating providers and nurses during the process was met. Education included the definition and cause of CIN, the facility rate compared to the benchmark rate, and its impact on the patient and health system, as well as recommended methods for prevention. The objective to reduce the incidence of CIN in patients undergoing PCI was not met. The baseline measurement period had an aggregate rate of 6.7% for the quarter that increased by 4.2% in the measurement period, with an aggregate rate of 10.9% for the first quarter of 2018. Both facility and unit-specific tracking mechanisms were established. The facility tracking is conducted by data entry into NCDR and dissemination of the monthly rate, along with details of missed opportunities through email and at a monthly cardiology QI meeting. The unit-specific tracking is for CIN rate and adherence to preprocedural hydration protocol. The review of adherence to protocol is conducted by the unit-based nurse practitioner and updated on a daily basis. Cases which are not adherent to the hydration protocol are discoursed between the unit-based nurse practitioner, and involved parties and solutions are discussed.

The literature review indicated adequate PVR is clearly the most significant intervention in the prevention of CIN and its sequelae, if not corrected. Additionally, a hydration protocol was the SCAI recommended best practice with which the nurse practitioner could implement extensive physician involvement. The development and implementation of the preprocedural hydration protocol was well received by clinical and administrative team members. The suggested hydration solution, duration, and amount, along with other protocol details, were agreed upon by the interventional cardiologists with minimal suggestions for changes. The education and implementation were executed as expected, with the exception of the electronic medical record changes. The goal was to have to fluid volume automatically calculated based on the patient’s clinic weight; however, informatics issues prevented the final order from being released on time and it was not completed until March. The hydration orders were calculated manually until March. Adherence rates improved as the team adjusted to the hydration protocol. Although the plan was executed without significant issue and adherence rates gradually improved, the CIN PCI rate did not decrease, and in fact, increased by 4.2% in the measurement period. 

Multifactorial Causes for the Rise in CIN PCI

The researcher deduced the elevation in CIN rate to be multifactorial. The cases provided by the NCDR were reviewed and several trends were noticed. First, patients were given IV diuretics in the procedural timeframe, perhaps when another clinical alternative would have been suitable, such as giving an additional dose of an oral diuretic. Second, in some cases, contrast amounts appeared to be higher than recommended. Some of the procedures with higher contrast amounts included more than one intervention during the same case. Third, emergency PCI cases are included in the NCDR sample. Patients who undergo emergency PCI often have a medically complex case, possibly even cardiogenic shock. Patients in shock are independently at risk for an AKI, even without undergoing a contrast study. ST-segment elevation myocardial infarction (STEMI) patients are rushed directly to the cath lab without delay, which leaves no opportunity for preprocedural hydration. Lastly, patients with acute heart failure exacerbation were labeled as having CIN, although it might not have truly been an AKI directly related to contrast administration. A patient admitted with acute heart failure cannot clinically tolerate IV hydration. The issue is compounded by the treatment for acute heart failure, which is diuresis. Also noted was that the use of concordant nephrotoxic medications was not addressed. 

Continuing and Future Actions

The results were disseminated through email and presented at the monthly cardiology section QI meeting. The run charts were reviewed to discuss areas for improvement. The trends identified in the review of missed opportunities were also discussed. The run chart highlighted that nursing leadership needed to discuss with staff the importance of ensuring preprocedural hydration was started and properly documented. The team was receptive and a plan was developed for continued process evaluation, with a focus on monitoring contrast use. A special device designed to reduce dye usage was suggested by one team member. The run chart also identified situations that were unavoidable, such as patients with cardiogenic shock, STEMI, or acute heart failure exacerbation. 

Discussion

CIN and its potential complications are compelling indicators for further investigation into the most effective methods of QI to reduce CIN in patients undergoing procedures with the use of contrast media in the cardiac cath lab. The results of this project led the researcher to recommend a three-pronged approach to reducing CIN in PCI. The first element is a hydration protocol, as discussed in this project. The second element is a reduction in contrast use. The third essential element is staging procedures. 

The mechanism of injury in CIN is tubular cell necrosis due to apoptosis, which is related to the viscosity of the contrast. Due to its rapid onset of action, preprocedural hydration is imperative to reduce the concentration of contrast in the vascular system. Therefore, preprocedural hydration remains a key element, despite this project’s failure to validate the hypothesis. The second most important element of reducing CIN in the literature review was reduction of contrast use. The concentration of contrast will be reduced if less contrast is used overall. Recommendations on the maximum contrast amount exist for both patients with normal renal function and reduced renal function. The researcher suggests incorporating the maximum allowable contrast amount into the QI project. A second measure to reduce contrast use is to limit the interventions performed during the procedure to only the necessary intervention. If one intervention is performed, and a second intervention is recommended but not critical to fix the same day, it can be scheduled to be performed in two weeks. 

Despite the failure to reduce the CIN PCI rate in this facility, the unit-based nurse practitioner identified an area over which an advanced nurse practitioner could influence clinical change by applying research to improve quality care. A literature review clearly identified the individual components that impact CIN and the individual case reviews suggest the three-pronged approach would be most beneficial in reducing facility CIN PCI. Sharing this QI project, results, and recommendations with other cardiac cath labs will ideally provoke further conversation and positive results. The hydration protocol and tracking mechanisms will continue to be a part of the practice at this facility, and the next topic to be addressed will be judicious contrast use.

References

1. Brown JR, Robb JF, Block CA, et al. Does safe dosing of iodinated contrast prevent contrast-induced acute kidney injury? Circ Cardiovasc Interv. 2010 Aug; 3(4): 346-350. doi: 10.1161/CIRCINTERVENTIONS.109.910638.
2. Brar SS, Aharonian V, Mansukhani P, et al. Haemodynamic-guided fluid administration for the prevention of contrast-induced acute kidney injury: The POSEIDON randomised controlled trial. Lancet. 2014; 383(9931): 1814-1823. doi: 10.1016/S0140-6736(14)60689-9.
3. Mehran R, Aymong E, Nikolsky E, et al. A simple risk score for prediction of contrast-induced nephropathy after percutaneous coronary intervention: Development and initial validation. J Am Coll Cardiol. 2004 Oct 6; 44(7): 1393-1399.
4. Schweiger MJ, Chambers CE, Davidson CJ, et al. Prevention of contrast induced nephropathy: Recommendations for the high risk patient undergoing cardiovascular procedures. Catheter Cardiovasc Interv. 2007 Jan; 69(1): 135-140.
5. National Cardiovascular Data Registry. Cath PCI registry. Available online at https://cvquality.acc.org/NCDR-Home/registries/hospital-registries/cathpci-registry. Accessed October 17, 2018.
6. Seeliger E, Sendeski M, Rihal CS, Persson PB. Contrast-induced kidney injury: Mechanisms, risk factors, and prevention. Eur Heart J. 2012 Aug; 33(16): 2007-2015. doi: 10.1093/eurheartj/ehr494.
7. Sadat U, Usman A, Boyle JR, et al. Contrast medium-induced acute kidney injury. Cardiorenal Med. 2015 Jun; 5(3): 219-228. doi: 10.1159/000430770.
8. Balemans CEA, Reichert LJM, Schelven BIH, et al. Epidemiology of contrast material-induced nephropathy inthe era of hydration. Radiology. 2012; 263(3): 706-713.

Leighanne Meade, DNP, ARNP, FNP-BC, CCRN, can be contacted at leighanne.meade@gmail.com.