BACKGROUND AND OBJECTIVE: Decreasing practice variation and following clinical guidelines improve patient outcomes and reduce costs. Inhaled nitric oxide (iNO) is an effective but expensive treatment of pulmonary hypertension and right heart failure in patients with congenital or acquired heart disease. Our objective was to implement standardized initiation and weaning guidelines for iNO usage in the cardiothoracic ICU (CTICU) to reduce variation in use while maintaining quality patient care.
METHODS: All CTICU patients who received iNO from January 2011 to December 2012 were retrospectively reviewed. Standardized iNO initiation and weaning guidelines were implemented in January 2012. Variables before and after guideline implementation were compared.
RESULTS: From January to December 2011, there were 36 separate iNO events (6% of CTICU admissions; n = 547). Mean ± SD iNO usage per event was 159 ± 177 hours (median: 63 hours; range: 27–661 hours). From January to December 2012, there were 47 separate iNO events (8% of CTICU admissions; n = 554). Mean iNO usage per event was 125 ± 134 hours (median: 72 hours; range: 2–557 hours). Initiation guideline compliance improved from 83% to 86% (P = .9); weaning guideline compliance improved from 17% to 79% (P < .001). Although mean iNO usage per event decreased, there was no significant reduction in utilization of iNO (P = .09).
CONCLUSIONS: Implementation of standardized iNO initiation and weaning guidelines in the CTICU was successful in reducing practice variation supported by increasing guideline compliance. However, decreasing practice variation did not significantly reduce iNO utilization and does not necessarily reduce cost.
- congenital heart disease
- inhaled nitric oxide
- pulmonary hypertension
- quality improvement
- CTICU —
- cardiothoracic ICU
- IHI —
- Institute of Healthcare Improvement
- iNO —
- inhaled nitric oxide
- SMART —
- specific, measurable, achievable, realistic, timely
Clinical practice guidelines have been touted as methods to reduce practice variation, improve quality of care, and contain cost. 1 Guidelines require redesign of work processes, communication strategies, and infrastructure, as well as sustained measurement and vigilance. According to the Institute of Healthcare Improvement (IHI) strategy for designing systems, the first step is to create a simple, standardized approach or guideline that is minimally controversial. 2 The second step is to evaluate adherence to the guideline. The next steps use strategies of standard order sets, checklists, education, and training. Once the standardized process is in place, compliance is reviewed to identify failures to use the process to help identify barriers and understand the failures. This process leads to improvement of the guidelines.
Inhaled nitric oxide (iNO) is an effective but expensive treatment of pulmonary hypertension and right heart failure in patients with congenital or acquired heart disease. Pulmonary hypertension may be due to increased flow, increased resistance, or a combination of the 2 factors. 3 Examples of congenital cardiac defects associated with pulmonary hypertension after cardiac surgery include atrioventricular canal defects, total anomalous pulmonary venous return, truncus arteriosus, aortopulmonary window, and double outlet right ventricle. Pulmonary hypertension is a process of pathologic changes to the pulmonary vascular bed, including vasoconstriction, vascular remodeling, endothelial dysfunction, and thrombus formation. Postoperative pulmonary hypertension has been associated with longer duration of mechanical ventilation, ICU stay, and hospital stay.
iNO is a selective pulmonary vasodilator that diffuses across the alveolar-capillary membrane into the pulmonary artery smooth muscle, resulting in local vasodilation. 3 , 4 It reduces vascular tone by activating soluble guanylate cyclase, which converts guanosine triphosphate into cyclic guanosine monophosphate. Increased intracellular concentrations of cyclic guanosine monophosphate relax the smooth muscle of the pulmonary vessels. iNO has few effects on the systemic vasculature.
Review of iNO utilization in the cardiothoracic ICU (CTICU) of our institution revealed inconsistency in the starting dose of iNO, inconsistency in the timely discontinuation of iNO when not clinically effective, and inconsistency in the method of weaning of iNO. These issues led to a quality initiative to create standardized guidelines for iNO initiation and weaning. We used the IHI strategy to develop experience-based guidelines for initiation and weaning of iNO in the CTICU. Our objective was to implement standardized initiation and weaning guidelines for iNO usage in the CTICU to reduce variation in use while maintaining quality patient care.
This quality improvement work involved development of experience-based guidelines for initiation and weaning of iNO in the CTICU. No interventions involved comparison of multiple devices or therapies, and patients were not subjected to randomization. Medical records were accessed by quality improvement team members as part of their normal responsibilities. No personal health information was shared outside of our institution. Therefore, a waiver for consent for this study was provided by the institutional review board at our institution.
Nationwide Children’s Hospital is an academic, nonprofit, freestanding children’s hospital located in Columbus, Ohio. The CTICU is a 20-bed unit with >500 admissions per year. Its current electronic medical record system (Epic Systems Incorporated, Verona, WI) and computerized practitioner order entry system are fully integrated with clinical decision support.
Planning the Intervention
Retrospective review of all patients in the CTICU who received iNO therapy in 2011 revealed inconsistencies in the following: the starting dose of iNO, the timely discontinuation of iNO when not clinically effective, and the method of weaning iNO. These issues led to a quality initiative to develop and implement standardized guidelines for iNO initiation and weaning.
We began by creating a SMART (specific, measurable, achievable, realistic, timely)-specific objective statement and key driver diagram 2 (Fig 1). Patient factors, lack of guidelines, staff education, staff accountability, and measurable outcome were identified as our key drivers.
The interventions or process changes that were introduced included establishment of patient criteria for iNO initiation that were simple and minimally controversial; development of standardized initiation and weaning guidelines for iNO that were also simple and minimally controversial; creation of electronic medical record SMART phrases for the initiation and weaning guidelines to simplify use; education and training of the CTICU staff regarding the guidelines and goals; obtaining CTICU staff buy-in and accountability; and development of outcome and compliance measures. Standardized initiation and weaning guidelines were implemented in January 2012 (Table 1).
Method of Evaluation and Analysis
Data on guideline usage compliance and effect on iNO utilization were tracked. We used a Plan-Do-Study-Act cycle to review guideline compliance. Compliance was initially measured by searching for physician documentation of iNO initiation and weaning in the physician progress notes in the electronic medical record. After the first quarter following implementation, we found that physician documentation in the medical record was lacking with respect to justification for weaning or not weaning. iNO weaning remained inconsistent and difficult to track. Therefore, we shared these findings with the CTICU staff and reeducated them on the importance of the guidelines and the SMART phrases developed for our electronic medical record system to facilitate usage of the guidelines.
We also altered the way we tracked compliance. Instead of measuring documentation of iNO initiation and weaning justification or plan in the physician progress notes, we elected to track the usage of the iNO initiation and weaning SMART phrases in our electronic medical record. This method was a more consistent and easily obtainable plan of tracking compliance with initiation and weaning guidelines.
Retrospective review of iNO usage and outcome variables was performed with comparison of patients from 2011 (before the standardization guidelines) and from 2012 (after the standardization guidelines). Data are expressed as mean ± SDs; median and interquartile ranges are also supplied where appropriate. Statistical analysis was performed by using Fisher’s exact test or χ2 tests where appropriate. Statistical significance was defined as a P value <.05.
Overall trend in iNO utilization over time is displayed as a run chart in Figure 2. Shortly after guideline implementation, our baseline mean iNO hours per event decreased, although this change was not statistically significant (P = .09). There were still outliers; however, they were less frequent postguideline implementation. We were able to sustain our new baseline with continued staff engagement and routine e-mails updating progress and outcomes.
Patient characteristics were similar before and after guideline implementation and are shown in Table 2. Overall, more than one-half of our patients who underwent ventricular assist device placement were treated with iNO therapy postprocedure to decrease right ventricular afterload and improve right ventricular function. Twenty-five percent of our patients were treated with iNO after comprehensive stage II palliation (bidirectional Glenn shunt and Norwood arch reconstruction) for cyanosis. One-third of our patients with atrioventricular septal defects were treated with iNO therapy postoperatively. In 2012, seven patients with human rhinovirus were treated with iNO. (Of note, the test for human rhinovirus only became available in our institution in 2012.)
Initiation guideline compliance improved from 83% to 86%. This change was not a significant increase because most of the CTICU staff already had indicated buy-in regarding patient and clinical scenarios in which iNO may be useful. Once the literature was reviewed, there was also a buy-in regarding the recommended starting dose of iNO (20 ppm). Weaning guideline compliance improved from 17% to 79% after the Plan-Do-Study-Act cycle, staff reengagement, education, and alteration of the compliance tracking method. CTICU practitioners were more apt to use the SMART phrases developed for our electronic medical record once the practitioners were shown the inconsistency in the timely discontinuation of iNO when not clinically effective and the inconsistency in the method of weaning iNO. In-depth review of fourth quarter weaning compliance data demonstrates that the most frequent reason for noncompliance was weaning faster than guidelines would indicate.
High health care costs, practice variation, and demands for quality medical care have stimulated health professionals to develop practice guidelines. 5 Practice guidelines are systematically developed statements intended to assist with decisions regarding appropriate care for certain medical situations. 6 These guidelines are intended to improve decision-making and optimize patient outcomes while reducing costs. 1 iNO is an effective but expensive treatment of pulmonary hypertension and right heart failure in patients with congenital or acquired heart disease. Our objective was to implement standardized initiation and weaning guidelines for iNO usage in the CTICU to reduce variation in use while maintaining quality patient care.
Our initiation and weaning guidelines were based on evidence from the literature. iNO therapy in pediatric patients after surgery for congenital heart disease has been reported in a variety of clinical trials, including case reports, pilot studies, prospective and retrospective investigations, randomized controlled clinical studies, and crossover studies. 3 , 7 – 18 The recommended dose of iNO is 20 ppm for the approved indication of hypoxic respiratory failure associated with pulmonary hypertension in term and near-term neonates. 3 , 19 iNO may also be beneficial in patients with right ventricular dysfunction because it selectively decreases right ventricular afterload and improves right ventricular function. 20 Abrupt withdrawal from iNO may lead to rebound pulmonary hypertension, secondary to down-regulation of endogenous nitric oxide production and increased levels of endothelin-1, a potent vasoconstrictor. 21 , 22 In pediatric patients who failed to be weaned from iNO after surgery for congenital heart disease, sildenafil has been shown to facilitate weaning. 23
Our first step toward obtaining CTICU staff buy-in for iNO initiation and weaning guidelines was review of the patients and iNO usage from the previous year. The inconsistent initiation and weaning (or not weaning) was obvious. The awareness of CTICU practitioner variation in usage of iNO, coupled with a hospital-wide initiative to reduce variation of iNO usage in all units, improved individual practitioner buy-in and accountability. This improvement was reinforced by periodic review of usage, patient outcomes, and compliance throughout the year at staff meetings and via e-mail communications. With 8 CTICU physicians, it became obvious who was and was not using the guidelines consistently, and individual coaching was at times necessary.
The patients who received iNO in 2011 and 2012 were similar in terms of overall number (percentage of total CTICU admissions), number of postoperative patients, categorization according to underlying heart disease, and mortality to hospital discharge. We believe this similarity supports our continued delivery of quality patient care despite reducing variation and utilization. The 2 major differences in the patients who received iNO in 2011 and 2012 were age and human rhinovirus infection. The patients in 2012 were older than the patients in 2011. We surmise this is secondary to our case mix, with increasing numbers of heart and lung transplant patients and our screening process for human rhinovirus in which high-risk patients, defined as those with single-ventricle physiology or atrioventricular septal defects, were screened preoperatively and cardiac surgery postponed if positive for human rhinovirus.
Average nitric oxide utilization (in hours) per event decreased in 2012. Initiation of iNO was not a significant issue after review of the literature and agreement that 20 ppm was the recommended starting dosage. Most practitioners agreed up front with the clinical indications for therapy. Indications for continued treatment and weaning guidelines provided a consistent method of defining response to iNO and providing a consistent method of weaning for both responders and nonresponders, as well as accountability for weaning when meeting criteria, thus eliminating past issues that may have slowed down the weaning process. In fact, the most common cause for noncompliance with the weaning guidelines at the end of 2012 was weaning too fast rather than not weaning.
This study did have some limitations. They included a small patient population and patient heterogeneity. Only 6% of our total CTICU patient population received iNO therapy. This quality initiative involves only a single, freestanding children’s hospital system. Limitations also include those inherent to any retrospective data review.
Key components that we believe contributed to our successful process include involving a multidisciplinary team to question and explore our current practice variability; developing and implementing simple guidelines to reduce variation and change the practice pattern; holding appropriate staff accountable for implementation and outcomes; monitoring to ensure the intervention was successful; and sharing the results with the staff of the CTICU.
Based on our compliance data, one of the reasons for noncompliance with the guidelines is the physician desire to wean faster than the guideline recommendations. Therefore, our next step is to reevaluate our weaning guidelines and adjust our weaning frequency to allow for a more flexible weaning strategy if warranted.
Implementation of standardized initiation and weaning guidelines for iNO in the CTICU was successful in reducing variation in iNO usage and overall CTICU iNO utilization (from a mean of 159 ± 177 hours per event to 126 ± 136 hours per event) while maintaining quality patient care.
- Accepted January 29, 2014.
- Address correspondence to Janet M. Simsic, MD, The Heart Center, T2292, Nationwide Children’s Hospital, 700 Children’s Dr, Columbus, OH 43205. E-mail:
Dr Simsic contributed to the concept and design, supported the quality initiative, conducted the initial and continued analyses, and wrote the first draft and all revisions; Ms Harrison and Dr McClead conceptualized, designed, and instituted the quality initiative, conducted the initial and continued analyses, and reviewed and revised the manuscript; Ms Evans conceptualized, designed, and instituted the quality initiative, conducted the initial analysis, and reviewed and revised the manuscript; Dr Teske contributed to the concept and design as well as supported the quality initiative, conducted the initial and continued analyses, and reviewed and revised the manuscript; and all authors approved the final manuscript as submitted.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
FUNDING: No external funding.
POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.
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