This handout is for infantile hypertrophic pyloric stenosis (ihps). Your care team identified this based on: infant 2-8 wk old with progressive non-bilious projectile vomiting, hungry-after-vomit, weight loss or poor weight gain — classic ihps entry signal (apsa + aap infant-vomiting guidance; hernanz-schulman *radiology* 2003 us criteria).
Other reasons your team may use this plan: palpable "olive" in ruq / epigastrium during/after a feed when the infant is relaxed — lr+ ~ 25 when present (sensitivity ~ 50% in experienced operator hands); visible peristaltic waves moving left-to-right across the upper abdomen after a feed — lr+ ~ 5 for ihps; cl < 100 meq/l + k+ < 3.5 meq/l + hco3 > 30 meq/l in an infant 2-8 wk old with persistent vomiting — classic ihps pattern; severe alkalosis is an or contraindication until corrected (pediatric anesthesia society).
Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.
| Medication | Starting dose | How | When | What it does |
|---|---|---|---|---|
| normal saline / lactated Ringer's | 20 mL/kg IV bolus over 30-60 min, repeat × 1-2 PRN; max ~ 60 mL/kg total before reassessing for fluid overload | IV | bolus PRN with reassessment | AAP pediatric resuscitation principles; only for shock physiology in IHPS (most cases require slower correction with D5 1/2NS + KCl maintenance, not boluses) |
| D5 0.45% NaCl + 20 mEq/L KCl maintenance | 1.5 × maintenance rate with measured deficit replacement after first void documented | IV | continuous | Pre-op IVF posture for IHPS metabolic correction; targets Cl > 100, K+ > 3.5, HCO3 < 30 over 12-48 h before OR (APSA + pediatric anesthesia society) |
| potassium_chloride | Add 20-40 mEq/L to maintenance IVF; titrate to serum K+ > 3.5; hold if K+ > 5.0 | IV | continuous | Replace hypokalemia (K+ < 3.5) targeting pre-op K+ > 3.5; do NOT exceed peripheral concentration 40 mEq/L without central access; OR contraindicated until corrected (pediatric anesthesia society) |
| cefazolin | 25-30 mg/kg IV single dose at induction | IV | pre-op single dose | Pre-op single-dose antimicrobial prophylaxis for clean/clean-contaminated pyloromyotomy; no prolonged course for uncomplicated cases (Cantey SCOUT Lancet Infect Dis 2016 PMID 27452782 stewardship principles) |
| ondansetron | 0.1-0.15 mg/kg IV single dose intraoperative or post-op PRN (sparingly in infant cohort) | IV | PRN | Sparingly used in infant cohort; post-op emesis is typically self-limited and resolves spontaneously; reserve for prolonged or severe; FDA pediatric label considerations |
| acetaminophen | 10-15 mg/kg PO/PR q4-6h PRN (max 60 mg/kg/day in infants; lower than older pediatric ceiling) | PO/PR | q4-6h PRN | First-line post-op analgesic in infants; avoid opioids in infant cohort when possible; safe at infant-appropriate dose |
| morphine | 0.025-0.05 mg/kg IV PRN (HALVED infant doses vs older pediatric); monitor respiratory depression carefully | IV | PRN with monitoring | Reserve for severe post-op pain; infant respiratory depression risk is elevated; use HALVED doses + capnography monitoring |
| piperacillin-tazobactam | 80-100 mg/kg IV q6-8h (piperacillin component) × 5-7 d for confirmed intraoperative mucosal perforation | IV | q6-8h | Broad Gram-positive + Gram-negative + anaerobe single-agent backbone for intra-abdominal contamination per Solomkin IDSA intra-abdominal 2010 (peds-adapted PMID 20583865); rare scenario (< 1% IHPS perforation rate) |
| metronidazole | 10 mg/kg IV q8h (max 500 mg/dose); add to ceftriaxone (or cefotaxime if < 28 d) for anaerobic cover when pip-tazo not available | IV | q8h | Anaerobic cover adjunct; alternative to single-agent pip-tazo (Solomkin IDSA 2010 peds-adapted) |
Plan: Pediatric IHPS pre-op IVF + electrolyte correction + perioperative antibiotics + analgesia (APSA + pediatric anesthesia society + Solomkin IDSA intra-abdominal 2010 peds-adapted)
Contact your care team if any of the following happen:
Call 911 or go to the nearest emergency room right away if you have:
Post-op pediatric surgical follow-up at 2-4 weeks for wound check + scar inspection + weight-gain review; pediatrician follow-up within 1-2 weeks for routine well-baby care including weight-gain trajectory + feeding tolerance + family education on macrolide-avoidance principle in neonates < 6 weeks (CDC + AAP advisory); long-term outcomes excellent (most infants recover completely with no long-term sequelae); recurrence after pyloromyotomy < 1-2% (incomplete myotomy). Atypical / preterm / older infant cases: ongoing pediatric GI follow-up for differential broader workup if persistent symptoms (eosinophilic gastroenteritis, gastroparesis, pyloric dysfunction without classical hypertrophy). Jaundice cases: pediatric hepatology follow-up for biliary atresia workup if applicable (< 60 d Kasai window) OR Gilbert-related management.
Guideline: APSA (American Pediatric Surgical Association) pediatric surgical-emergency guidance for IHPS + AAP infant-vomiting guidance + macrolide-in-neonates advisory + NASPGHAN pediatric GI differential consensus for the persistently vomiting infant + ACR Appropriateness Criteria — Vomiting in Infants Up to 3 Months of Age + Hernanz-Schulman M *Radiology* 2003 (pyloric US diagnostic criteria — pyloric muscle thickness ≥ 3 mm + channel length ≥ 14-17 mm) + CDC + AAP macrolide-in-neonates advisory (erythromycin > azithromycin association with IHPS) + Pediatric anesthesia society consensus (operate only on corrected metabolic state) + Solomkin IDSA Complicated Intra-Abdominal Infection 2010 PMID 20583865 (peds-adapted for the < 1% intraoperative mucosal perforation) + SSC peds 2020 (for shock physiology if severe dehydration in IHPS precipitates sepsis)