Quality improvement in imaging strategies for pediatric appendicitis

Appendicitis is the most common abdominal surgical procedure in the pediatric population, yet diagnosis can prove challenging in many cases.1 Standard diagnostic approaches include history and physical exam, white blood cell count, and diagnostic imaging. Both ultrasound (US) and computed tomography (CT) scans have been reported to improve diagnostic accuracy in appendicitis. Although CT has a higher sensitivity for diagnosing appendicitis than US, ongoing concerns have been raised about the radiation exposure and increased costs associated with CT scans.2

The American College of Radiology (ACR) has published guidelines that state, “In children, US is the preferred initial examination as it is nearly as accurate as CT for diagnosis of appendicitis but is without ionizing radiation exposure.”3 Without diagnostic imaging, misdiagnosis of appendicitis can carry significant consequences, including progression to perforated disease in a case of missed appendicitis; and in a case of a “negative appendectomy,” the considerable cost and morbidity of undergoing an unnecessary operation. Although the goal of evaluating patients with suspected appendicitis is timely diagnosis with minimal CT use and risk of removing a normal appendix, there exists a great variation among children’s hospitals in US and CT use and negative appendectomy rates.4 This variance remains a critical problem in pediatric surgery, in light of extensive literature detailing the adverse effects of increased CT scan usage, such as exposure to ionizing radiation, and risk of future malignancies in the pediatric population.5

The local problem: Overuse of CT scans

Children’s of Alabama, Birmingham, is a tertiary care, freestanding children’s hospital. It is a 380-bed facility, which provides services to all pediatric patients in the state of Alabama, resulting in approximately 15,000 annual overall admissions and 6,200 annual surgical admissions. Approximately 75 percent of surgical admissions present directly to the children’s hospital, whereas 25 percent are transferred from other facilities in the state.

In a recent comparative analysis of 29 children’s hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program Pediatric (ACS NSQIP® Pediatric), Children’s of Alabama was noted to be a high outlier for preoperative CT scan use for appendicitis and a low outlier for compliance with the ACR guidelines. The rate of preoperative CT scan use at Children’s of Alabama was 70 percent of all appendicitis admissions, which is well above the aggregate cohort rate of approximately 25 percent. Similarly, only 30 percent of appendicitis admissions at Children’s of Alabama had preoperative US scans in contrast to an aggregate cohort rate of approximately 85 percent.

How was the QI activity put in place?

To address the overuse of CT scans, Children’s of Alabama created a multidisciplinary focus group comprising senior members of the department of pediatric surgery, pediatric emergency medicine, and pediatric radiology. This group was charged with establishing the best clinical and radiological approach to evaluating pediatric appendicitis. The group met three times over the period of several months in order to direct its focus to specific issues.

The first meeting centered on initial exploration. Group members discussed and described current methods of evaluating a child with suspected appendicitis. Specific topics of focus were perceived barriers for use of US in suspected appendicitis, perceived radiological challenges, and specific populations that may need to forgo imaging or need CT imaging. As part of this meeting, the workgroup created a standard template for the reporting of US findings in children with appendicitis to aid the physician in making a decision about whether to operate or perform additional diagnostic imaging.

At the second meeting, the group focused on the development of an evidence-based algorithm for the initial evaluation of children with suspected appendicitis, incorporating the barriers discussed in the previous meeting. Following this meeting, the workgroup created an algorithm based on the Pediatric Appendicitis Score (PAS) as described later in this column.

During the third meeting, the group met with the members of each department to gather feedback from all clinicians, house staff, nurses, and radiology technicians prior to implementation. At the final meeting, which occurred mid-implementation, the group addressed challenges with implementation of the algorithm, adherence to the algorithm, and suggested changes to improve the algorithm. This meeting occurred four months after initiation of the algorithm-based approach.

Description of the QI activity

Children’s Hospital of Alabama sought to improve the imaging strategies for pediatric appendicitis by concentrating on the following three actionable goals:

  • Develop an algorithm based on best practices in the literature, which health care professionals can use when faced with diagnosis of a child with appendicitis
  • Create a standard template for reporting of US findings in children with appendicitis to aid the physician in deciding whether to pursue surgery or additional diagnostic imaging
  • Attempt to achieve a significant reduction in the baseline rate of CT scan use for children with suspected appendicitis while improving the US utilization rate

To develop the algorithm, a comprehensive literature search was performed to determine the most appropriate clinical risk stratification tool. We opted to use the PAS developed by Samuel, considering its validation in the literature.2 The PAS allowed for initial patient risk-stratification into low, moderate, or high risk for appendicitis. Based on this initial classification, imaging modalities and other diagnostic interventions were determined according to the algorithm outlined in Figure 1. This algorithm was further linked with a web-based order set in the electronic health record for emergency medicine providers to enable a “point and click” interface.

Figure 1. Clinical decision algorithm based on the PAS

Figure 1. Clinical decision algorithm based on the PAS

Based on a classification system developed by Nielsen and colleagues, all patients were grouped into the following categories:6

  • Normal appendix
  • Appendix not visualized or partially visualized without secondary signs of appendicitis
  • Appendix not visualized or partially visualized with secondary signs of appendicitis
  • Acute appendicitis

Patients in the first two categories were considered negative for appendicitis, while those matching the description in the latter two categories were considered positive.

All data were evaluated on a quarterly basis to follow trends in use of US and CT, thus monitoring both the implementation and success of the QI program.

Necessary resources and skills

Engagement of all pediatric surgeons, radiologists, and emergency physicians was crucial to the success of this initiative. For that purpose, specific department-level meetings were held in each of the specialties involved. During those meetings, members of the department were encouraged to contribute to the formation of the pathway and were queried regarding the obstacles or difficulties they could foresee in its implementation. Consequently, when the pathway was implemented, those individuals were vested in its successful launch.

No additional direct clinical costs were incurred. The only additional expenses for this project were in the employment of a statistician and data entry personnel for the quarterly evaluations of US and CT use rates.

Results

The PAS algorithm and radiological reporting template were implemented September 1, 2016. For the next eight months, all appendicitis admissions were evaluated for demographics, clinical characteristics, use of diagnostic imaging, and rates of negative appendectomies. Those variables were then compared with all appendicitis admissions in the eight months prior to implementation.

The changes in imaging modality rates before and after protocol implementation are illustrated in Figure 2. Since initiation of the PAS-based protocol, the rates of CT scans among appendicitis admissions almost halved to 35 percent of admission, while the rates of US studies more than doubled to 65 percent of admission.

Figure 2. Imaging modality use pre- and post-protocol implementation

Figure 2. Imaging modality use pre- and post-protocol implementation

Concurrently, no differences were noted in length of hospital stay; postoperative complication rates; rates of intraoperative findings of complicated appendicitis (perforation, abscess, and so on); or rates of negative appendectomy between the pre-protocol and the post-protocol cohorts.

Approximately 25 percent of appendicitis admissions presented to our institution as transfers from other hospitals throughout the state. Those patients overwhelmingly underwent CT imaging in the referring facilities. To address this problem, Children’s is presenting its protocol and data at local, regional, and state meetings in an effort to increase the rate of US evaluations in referring facilities.

Another setback that Children’s of Alabama faced in implementing this algorithm is that US scans are not performed overnight at the facility. Following a meeting with the pediatric radiology department, the exact timing of US availability was determined. That information was then disseminated to the house staff in pediatric surgery and pediatric emergency medicine. If individuals with PAS score >3 are evaluated at times when US is unavailable, they are admitted overnight for imaging in the morning.

Assuming an approximate cost of $697 for a limited abdominal US and an approximate cost of $3,889 for a CT scan of abdomen/pelvis with intravenous contrast, the hospital’s pre-protocol imaging costs for the monitored period was $201,309. Post-protocol the cost was $133,176, yielding a net cost savings of $68,133, or a 33.8 percent decrease in imaging costs.

Lessons learned

Institutions considering undertaking a similar QI activity should evaluate the rates of different imaging modalities used in the appendicitis admissions in their facility and compare them with the ACS NSQIP Pediatric cohort to determine the extent of deviation from the national standard. Involve collaborators from radiology and emergency medicine departments at an early stage of planning and create a standardized protocol for clinical evaluation of right lower quadrant pain, which takes into account history, physical findings, and lab values. Furthermore, evaluate the radiological capabilities of your institution when establishing your clinical pathway.

To ensure successful implementation, the authors recommend interval audits of US and CT rates. Arrange a mid-implementation meeting to discuss any concerns or complications, as well as receive feedback on the pathway. Conduct individual meetings as necessary to address identified barriers created by system process changes.

As final words of advice, Children’s of Alabama found that a multidisciplinary effort and collaboration between surgical, radiological, and emergency medicine specialists is absolutely necessary for such a program to be implemented and maintained. And lastly, create posters of the clinical pathway to be displayed in physician work areas of the surgical and emergency house-staff. Those materials can be useful in facilitating calculation of the PAS score and improving compliance with the pathway.


References

  1. Miglioretti DL, Johnson E, Williams A, et al. The use of computed tomography in pediatrics and the associated radiation exposure and estimated cancer risk. JAMA Pediatr. 2013;167(8):700-707.
  2. Samuel M. Pediatric appendicitis score. J Pediatr Surg. 2002;37(6):877-881.
  3. American College of Radiology, ACR appropriateness criteria. Expert panel on gastrointestinal imaging. 2013. Available at: https://acsearch.acr.org/docs/69357/Narrative/. Accessed October 3, 2017.
  4. Quigley AJ, Stafrace S. Ultrasound assessment of acute appendicitis in paediatric patients: Methodology and pictorial overview of findings seen. Insights Imaging. 2013;4(6):741-751.
  5. Lee JH, Jeong YK, Park KB, et al. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. Am J Roentgenol. 2005;184(1):91-97.
  6. Nielsen JW, Boomer L, Kurtovic K, et al. Reducing computed tomography scans for appendicitis by introduction of a standardized and validated ultrasonography report template. J Pediatr Surg. 2015;50(1):144-148.

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