Comparing Proposed Algorithm and Current Practice in the Evaluation of Suspected Appendicitis
Comparing Proposed Algorithm and Current Practice in the Evaluation of Suspected Appendicitis
Acute appendicitis is one of the most common causes of acute abdominal pain requiring
 surgical intervention. In the current era, with diagnostic imaging technique like Computed
 Tomography (CT), negative appendectomy rates have been greatly reduced. However, the
 radiation risk with CT poses as a concern. Rules for clinical decision guiding CT utilization
 is thus essential to minimize unnecessary CT scans, which not only poses a radiation risk but
 also contributes to increased healthcare costs.

 Through the development of an algorithm based on Alvarado Score for the management of acute
 appendicitis, investigators hope to reduce CT utilization with an acceptable negative
 appendectomy rate, and hence reducing unnecessary radiation and the healthcare costs
 involved.
Acute appendicitis is one of the most common causes of acute abdominal pain requiring
 surgical intervention, with a lifetime risk of 8.6% for males and 6.7% for females.
 Historically, negative appendectomy rates of more than 20% were considered the norm. This is
 no longer acceptable in the current era, as despite low complication rates in the setting of
 negative appendectomy, conditions such as incisional hernias, intestinal obstruction
 secondary to adhesions and stump leakages can still result in significant morbidity.

 Computed Tomography (CT) scan has emerged as the dominant imaging modality for evaluation of
 suspected appendicitis in adults. It has decreased negative appendectomy rates to fewer than
 10%. However, the radiation exposure with CT poses a concern, particularly in appendicitis,
 which occurs predominantly in young patients most susceptible to the adverse effects of
 radiation. Available literature has estimated that at least 25% of CT scans are not
 clinically warranted and may pose more harm than benefits. Rules for clinical decision
 guiding CT utilization is thus essential to minimize unnecessary CT scans, which not only
 poses a radiation risk but also contributes to increased healthcare costs.

 Currently, the management of suspected appendicitis is surgeon dependent. Accuracy of
 diagnosis is dependent on individual's clinical acumen, preference for CT scan and threshold
 for offering surgery. There is also a recent trend towards indiscriminate CT utilization with
 an estimated 1 in 4 CT scans ordered found to be clinically unwarranted. The Alvarado Score
 (AS) is a 10 point clinical scoring system for acute appendicitis that has been extensively
 validated. AS on a prospective database of 500 consecutive cases of suspected appendicitis
 admitted to Singapore General Hospital, Department of General Surgery from August 2013 to
 July 2014, was validated. A comparison was then made between diagnostic performance measures
 of CT scan and AS to identify ranges of AS where patients are unlikely to benefit from CT
 evaluation. From these findings, an objective algorithm for the management of suspected
 appendicitis guided by AS was formulated. Ideally, the algorithm will streamline CT
 utilization and reduce the number of CT scans ordered with an acceptable negative
 appendectomy rate. Thus, investigators hope to validate this proposed algorithm through a
 randomized control trial.

 The trial will recruit 160 eligible patients over 2 years. Eligible patients who consented to
 participate in the trial will be subjected to randomization into one of the two trial groups
 - Usual Care Arm or Intervention Arm - in equal numbers (n=80). Patients randomized to Usual
 Care Arm will be managed according to individual's doctor discretion. On the other hand,
 patients randomized to Intervention Arm will have their Alvarado Score tabulated and managed
 as per proposed algorithm.

 The primary objective of the trial is to show that the proposed management algorithm is
 effective in reducing the percentage of CT utilization as compared to current best practice
 for patients with suspected appendicitis seen at Singapore General Hospital and Sengkang
 Health. The hypothesis is that the proposed management algorithm will reduce the percentage
 of CT scans from 80%, which is the CT utilization rate when current best practice is used, to
 60%. The study will be powered to detect this decrease with a 5% type I error rate.

 The secondary objective of the trial is to estimate the proportion of negative appendectomy
 and missed diagnosis in each of the study arm. In addition, the total length of stay in days
 and overall cost of stay would also be estimated and compared between the two study arms.
 These secondary objectives are purely descriptive and no hypothesis testing is planned for
 these objectives.

 Randomization schedule will be generated using standard statistical software by a
 statistician who is not going to be involved in data analysis. Envelopes containing the
 treatment instructions will be marked according to that schedule. Randomization will be
 performed in blocks of six subjects, three for intervention and three for control arm, to
 ensure balanced groups.

 If the proposed algorithm is validated and found to be of value, it can potentially be
 implemented nationwide as a standard protocol for the evaluation of suspected appendicitis.
 This may reduce the number of unwarranted CT scans performed and reduce health care costs. In
 addition, the reduction of unnecessary CT scans helps to minimize unwarranted radiation
 exposure which is not insignificant. A single CT Abdomen Pelvis for evaluation of suspected
 appendicitis exposes one to 14 mSv of ionizing radiation which adds an additional cancer risk
 of up to 0.2% for an individual who is 30 years of age. The cumulative effects of such
 radiation exposure may prove significant and a management algorithm guiding sensible CT
 utilization will help ease the burden of radiation induced complications in the future.
Inclusion Criteria:

 -  Patients between the ages of 21 to 80 who are admitted to Singapore General Hospital
 and Sengkang Health for suspected appendicitis based on admission diagnosis from the
 Emergency Department

 Exclusion Criteria:

 -  Patients who are pregnant

 -  Patients below 21 or above 80 years of age

 -  Patients with generalized peritonitis on presentation

 -  Patients with palpable right iliac fossa mass on presentation

 -  Patients with evidence of acute confusional state/dementia

 -  Patients at high risk of surgery (ASA>4) from the study

 -  Patients who are immunocompromised (on chemotherapy, steroids etc.)