Evaluating the effectiveness of a discharge protocol for children with advanced appendicitis

In 2006, an evidence-based protocol for the management of children with appendicitis was established at our institution. Discharge criteria for patients with advanced appendicitis were based on a combination of clinical parameters and laboratory values. The purpose of this study is to evaluate the utility of laboratory values in guiding patient management with a discharge protocol for advanced appendicitis.

We reviewed charts of patients with advanced appendicitis as defined by the surgeon intraoperatively from 2008-2009. We evaluated the sensitivity and specificity of the laboratory values at discharge for predicting postoperative intra-abdominal abscess (IAA) formation using a receiver operator curve. A logistic regression analysis was performed to identify predictors of IAA formation.

We identified 450 patients (mean age 8.9 ± 3.9 y). The postoperative IAA rate was 25%. The sensitivity and specificity for developing an abscess with a white blood cell count >12,000/UL were 52% and 82%, respectively (AUC 0.72, 95% CI 0.67-0.78, P < 0.001). The sensitivity and specificity for bands >3% were 47% and 70% (AUC 0.60, 95% CI 0.53-0.67, P = 0.002), respectively. On logistic regression analysis, an elevated white blood cell count was independently associated with an increased likelihood of a postoperative IAA (OR 1.27, 95% CI 1.19-1.35, P < 0.001).

The absence of leukocytosis is useful for identifying children with a decreased risk of postappendectomy IAA formation who otherwise meet clinical discharge parameters. A band count is not as predictive of risk. The use of laboratory evaluation as a component of discharge criteria in advanced appendicitis can stratify a subset of patients who are at increased IAA risk and may benefit from continued antibiotic therapy.