Acute appendicitis is the most common surgical emergency in children. Despite the widespread adoption of laparoscopic appendectomy, postoperative care still varies widely between institutions, with prolonged fasting, opioid-based analgesia, delayed feeding, and routine drain placement being common. Enhanced Recovery After Surgery (ERAS) is an evidence-based, multidisciplinary care pathway that has been shown in adults - and increasingly in children - to reduce length of stay, opioid consumption, and postoperative complications.

This single-center, prospective, single-arm cohort feasibility study (IDEAL Stage 2a) tests whether a comprehensive 20-item pediatric ERAS protocol, adapted for minimally invasive appendectomy in children aged 5-18 with non-complicated acute appendicitis (ASA I-II), can be implemented with high fidelity and acceptable safety in a tertiary academic pediatric surgery department. We aim to enroll 100 patients to obtain ~80 evaluable cases. The primary endpoint is the global ERAS compliance rate (target ≥80%, with the lower bound of the 95% confidence interval staying above 70%). Co-primary safety endpoints include Clavien-Dindo ≥III complications and 30-day unplanned readmission rates, both targeted at <5%. Secondary endpoints include time to medical readiness for discharge, actual length of stay, opioid sparing, and parent-reported outcomes.

The study includes a structured run-in phase (first 5 patients) with explicit decision logic to either continue with the protocol unchanged or revise it before full enrollment. Audit-and-feedback cycles every 20 patients monitor compliance drift. The findings will inform a definitive institutional clinical guideline and provide hypothesis-generating data for future multi-center trials.

Background and Rationale Acute appendicitis affects roughly 1 in 10 children in their lifetime and remains the leading cause of emergency abdominal surgery in pediatric populations. Although laparoscopic appendectomy has become the standard of care for non-complicated cases, perioperative practice patterns vary substantially. Routine prolonged preoperative fasting, opioid-based postoperative analgesia, delayed enteral feeding, and the prophylactic use of nasogastric tubes, abdominal drains, and urinary catheters persist in many institutions despite evidence to the contrary. This unwarranted clinical variation prolongs recovery, increases adverse events, and exposes children to avoidable opioid exposure.

Enhanced Recovery After Surgery (ERAS) protocols package multiple evidence-based perioperative interventions into a coordinated multidisciplinary care pathway. Adult ERAS programs have consistently demonstrated reductions in complications, length of stay, and resource utilization. Pediatric ERAS adoption has lagged but is accelerating, particularly in colorectal, urological, and now general surgical contexts. Most pediatric ERAS reports to date, however, focus on elective procedures - applying ERAS to a time-pressured, emergent context like acute appendicitis introduces operational challenges (limited preoperative optimization window, variable family preparation, fluctuating staffing) that must be tested locally before adoption.

Conceptual Framework This study follows the IDEAL Framework Stage 2a (Development) for surgical innovation: a structured, prospective evaluation of a defined protocol in a single center, with explicit revision logic and transparent reporting. Implementation science elements are integrated through (a) Knowledge-Attitudes-Practice (KAP) surveys before and after the pilot, (b) a CFIR 2.0-informed barriers assessment, and (c) NoMAD-based normalization process measures. The study is registered as interventional (single-group assignment, open-label; Health Services Research) because all enrolled patients are prospectively and uniformly exposed to the institutional ERAS protocol as a defined health-services intervention. There is no randomization and no experimental drug or device assignment; the protocol is applied to consecutive eligible patients.

The 20-Item ERAS Protocol

The protocol spans the perioperative pathway in three blocks:

Preoperative (5 items): ERAS counseling and family education; avoidance of prolonged fasting (clear fluids permitted up to 2 hours; solids ≥6 hours); no oral carbohydrate loading (acute appendicitis context); no mechanical bowel preparation; restricted sedative premedication.

Intraoperative (9 items): timely prophylactic antibiotics (within 30-60 min of incision); regional analgesia with 0.25% bupivacaine port-site infiltration; short-acting anesthetic agents; restricted intraoperative opioid (<0.1 mg/kg morphine equivalent); active normothermia (core temp >36 °C); goal-directed euvolemic fluid therapy (3-7 mL/kg/h crystalloid, zero balance target); minimally invasive surgical approach; avoidance of routine drains/tubes; universal PONV prophylaxis (ondansetron + dexamethasone 0.15 mg/kg, max 8 mg).

Postoperative (6 items): early NG tube removal; early oral feeding (clear fluids within 2-4 hours; staged advancement to age-appropriate diet); early IV fluid discontinuation (saline lock once 100 mL tolerated orally); early mobilization (out of bed by hour 4, corridor walk by hour 6); multimodal scheduled "zigzag" oral analgesia (paracetamol 15 mg/kg PO q6h alternating with ibuprofen 10 mg/kg PO q6h, every 3 hours); criterion-based discharge planning.

Decision Algorithms

Three algorithms standardize bedside decisions:

• PONV cascade (3 levels: nausea → 30-min pause; first emesis → rescue antiemetic from a different receptor class with 1-hour wait then re-challenge from clear fluids; clinically significant emesis → suspend ERAS feeding goals, restart IV maintenance, surgical reassessment for ileus/mechanical/leak);
• Rescue analgesia (triggered by VAS ≥5 in patients ≥7 years or FLACC ≥5 in <7 years on two consecutive measurements 30 minutes apart, despite scheduled paracetamol+ibuprofen; managed with low-dose IV opioid recorded as rescue, not as a protocol deviation);
• Medical Readiness for Discharge (MRD): a six-criterion checklist (tolerating ≥Phase 2 diet without vomiting; oral analgesia adequate VAS/FLACC <4; age-appropriate ambulation; spontaneous urine output; family preparedness; physiologic stability with SpO2 >95% on room air, temperature <38 °C in last 4 hours, vital signs within PALS limits). Notably, gas/stool passage is explicitly NOT an MRD criterion. After MRD, patients enter a brief "in-hospital home simulation" phase before actual discharge to measure the institutional/cultural delay (Δ time = T-discharge - T-MRD).

Run-in Phase and Decision Gate

Per IDEAL Stage 2a methodology, the first 5 enrolled patients constitute a Run-in (Vanguard) phase. After the 5th patient, the leadership team conducts an Early Safety and Compliance Audit:

• Decision A (Protocol Stable): if ≥70% compliance and no Clavien-Dindo ≥III complications, the patients are included in the main analysis and enrollment continues.
• Decision B (Protocol Revision): if a systemic implementability barrier is identified, the first 5 patients are excluded from primary feasibility analysis, the protocol is revised to Version 2.0, ethics committee notification/approval is obtained, and the screening target is increased to N=105 to preserve statistical power. A pre-specified sensitivity analysis includes the original 5 patients in an "all-enrolled" set for transparency.

Audit and Feedback Compliance scorecard data are reviewed every 20 patients (h20, h40, h60, h80) by the leadership team. Compliance items are dichotomously coded (1=achieved, 0=not). Up to 3 items may be voided due to medical contraindication; ≥4 voided items classify the patient as "complex" and exclude them from the primary compliance analysis. Rescue analgesia use does NOT affect compliance scoring of the multimodal oral analgesia item but is reported as a secondary metric (total opioid consumption in mg/kg morphine equivalents).

Stopping Rules (3-tier) Level 1 (Immediate report): Any Clavien-Dindo ≥III complication is reported to the IRB within 24 hours as a Serious Adverse Event.

Level 2 (Temporary halt): Triggered by (a) any Grade IV/V complication, OR (b) cumulative Clavien-Dindo ≥III rate exceeding 10% in any consecutive 10-patient window, OR (c) unplanned true readmission rate exceeding 10% in any consecutive 10-patient window. Enrollment pauses; the leadership team holds an emergency safety meeting with at least one independent senior clinician (department chair or hospital quality/safety representative) as observer.

Level 3 (Permanent halt): If post-pause review concludes the complications are protocol-attributable, the study is permanently terminated and the IRB is notified with a detailed report.

Mixed Methods and Implementation Science The study uses a Concurrent Embedded mixed-methods design. Quantitative implementation outcomes (compliance, MRD time, length of stay, complications, opioid use) are integrated with provider surveys (KAP pre/post, CFIR Barriers, NoMAD post-pilot) and parent-reported outcomes (study-specific PROMs CRF: VAS for parental anxiety/satisfaction, categorical Yes/No items for quality of recovery). Qualitative content analysis of an open-ended PROMs question uses two-coder blinded review with Cohen's κ ≥0.70 threshold and third-coder consensus arbitration.

Statistical Analysis Sample size: precision-based, single-proportion formula yields n=80 evaluable patients to estimate compliance at 80% with a 95% CI half-width of ±8.7% (lower bound 71.3%, upper 88.7%) - verified in G*Power 3.1 ('Proportion: Confidence Interval Width' module). Allowing for ~20% cumulative attrition (10-15% intraoperative reclassification, 2-5% laparoscopic-to-open conversion, 3-5% follow-up loss), 100 patients are enrolled.

The primary endpoint compliance rate is reported as a point estimate with Wilson 95% CI. Co-primary safety endpoints (Clavien-Dindo ≥III, 30-day readmission) are similarly reported. Critical-item compliance is reported per item with 95% CIs. Survey modules: KAP pre vs post - Wilcoxon signed-rank if paired n ≥15, otherwise descriptive only; KAP/CFIR Cronbach α ≥0.70 threshold reported (gating); NoMAD α reported but non-gating. Subgroup analyses are exploratory/hypothesis-generating. Missing data: pre-specified multiple imputation thresholds. Reporting follows CONSORT-Pilot.

Anticipated Outcomes If feasibility is demonstrated (compliance ≥80% with CI lower bound >70%, safety endpoints below 5%), the protocol will be formalized as the institutional standard for non-complicated pediatric appendectomy and will inform a planned multi-center IDEAL Stage 3 trial. If feasibility is not demonstrated, the audit data will identify specific implementability barriers for targeted revision before any further deployment.

Inclusion Criteria:

1. Pediatric patients aged 5 to 18 years (preschool, school-age, and adolescent).
2. Acute appendicitis without preoperative radiologic or clinical evidence of complication/perforation, who are candidates for and accept laparoscopic surgery.
3. ASA Physical Status I (healthy) or ASA II (mild systemic disease).
4. Family/legal guardians literate in Turkish (or the institution's primary service language) and able to comprehend the educational materials.
5. Written informed consent from parents/legal guardians; for children of sufficient developmental maturity (generally ≥7 years), age-appropriate written assent.

Exclusion Criteria:

1. Preoperative imaging or clinical evidence of complicated appendicitis (perforation, generalized peritonitis, intra-abdominal abscess) anticipated to require an extended procedure (anastomosis, resection, or extensive peritoneal irrigation).
2. History of chronic pain syndrome or regular/sustained opioid use within the past 3 months.
3. Therapeutic preoperative antibiotic treatment for an active infection (other than surgical prophylaxis).
4. ASA III or higher; immunosuppression, progressive neurological disease, chronic inflammatory bowel disease, or other significant comorbidities likely to interfere with postoperative recovery/mobilization.
5. Anatomic/mechanical contraindications to laparoscopy or pneumoperitoneum (e.g., prior major open abdominal surgery with suspected adhesions, abdominal wall defects).

De-identified individual participant data underlying the published results, the full study protocol, the statistical analysis plan, and the informed consent forms will be made available upon reasonable request following primary publication. Access will be granted to investigators with a methodologically sound proposal for individual participant data meta-analyses or hypothesis-confirming research. Requests will be reviewed by the principal investigator and the study steering committee. Data will be transferred via encrypted email or institutional secure repository following execution of a data sharing agreement.

Beginning 6 months and ending 5 years following primary publication.

Investigators with a methodologically sound proposal for individual participant data meta-analyses or hypothesis-confirming research. Requests will be reviewed by the principal investigator and the study steering committee. Data will be transferred via encrypted email or institutional secure repository following execution of a data sharing agreement.