Using shock index, pediatric age adjusted (SIPA) to predict prolonged length of stay in perforated appendicitis: a retrospective review.

Purpose: Hospital length of stay (LOS) following admission for appendicitis is difficult to predict. Shock index, pediatric age adjusted (SIPA) accurately identifies severely injured trauma patients and predicts mortality among children admitted to the ICU. Our aim was to determine if elevated SIPA at presentation, and time to normalization of SIPA, can identify children with perforated appendicitis and predict hospital LOS.

Methods: This was a retrospective cohort study of children 1-17 years admitted to a quaternary care referral center with appendicitis after appendectomy in 2021. The primary outcomes were presence of perforated appendicitis and hospital LOS. Generalized linear regressions were performed. Covariates included in all models were age, sex, fecalith, initial temperature, and time from diagnosis to OR.

Results: We included 169 patients; 53 (31.4%) had perforated appendicitis. After adjustment, elevated SIPA was associated with presence of perforated appendicitis (p = 0.0002) and longer LOS (p < 0.0001). A patient presenting with appendicitis and elevated SIPA had 5.447 times higher odds of having perforated appendicitis (95% CI: 2.262, 13.826), a mean hospital LOS 2.047 times longer (95% CI: 1.564, 2.683), a mean time to toleration of regular diet 4.995 times longer (95% CI: 2.914, 8.918), and a mean duration of antibiotics that is 1.761 times longer (95% CI: 1.383, 2.243) than a patient with normal SIPA.

Conclusion: In children with appendicitis, elevated SIPA at presentation is associated with higher risk of perforation. These findings support the incorporation of SIPA during triage of patients with appendicitis and counseling families after surgery.

Level of evidence: Level 3.