Pyloric Stenosis

Quick Answer

What is pyloric stenosis?

Hypertrophic pyloric stenosis is a condition of acquired gastric outlet obstruction caused by hypertrophy of the pyloric muscle, typically presenting at 3-8 weeks of life with projectile vomiting. Key anaesthetic principles:

1. Metabolic alkalosis - Hypochloraemic, hypokalaemic metabolic alkalosis from gastric HCl loss
2. Fluid resuscitation priority - Surgery is elective; resuscitation takes precedence
3. RSI technique - Full stomach, elective but urgent surgery
4. Correction sequence - Volume first, then potassium once urinating
5. Monitoring - ECG for QTc prolongation (arrhythmia risk)

Clinical Pearl: Pyloric stenosis is a medical resuscitation that requires surgery, not a surgical emergency. Never operate on a dehydrated, alkalotic infant. The dehydration and electrolyte abnormalities kill, not the pyloric muscle.

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Clinical Overview

Definition

Hypertrophic pyloric stenosis (HPS) is a condition characterised by:

• Hypertrophy of the muscularis layer of the pylorus
• Narrowing of the pyloric canal (usually to 1-2 mm)
• Gastric outlet obstruction
• Classic presentation: projectile, non-bilious vomiting in previously healthy 3-8 week old infant

Epidemiology

Risk factors:

Pathophysiology

Pyloric muscle hypertrophy:

• Circumferential thickening of pyloric muscularis (normal: 3-4 mm; HPS: 5-8 mm)
• Elongation of pyloric canal (normal: 10-12 mm; HPS: 15-20 mm)
• Narrowing of pyloric channel to 1-2 mm
• Results in mechanical gastric outlet obstruction

Triggering factors (hypotheses):

• Abnormal pyloric innervation (hypertrophy of nerve fibres)
• Nitric oxide deficiency (impaired smooth muscle relaxation)
• Local growth factors and hormones
• Genetic predisposition + environmental factors

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Clinical Presentation

Classic Features

The "typical" presentation:

Clinical signs:

Physical examination technique:

• Feed the baby (stimulates gastric peristalsis)
• Palpate in right upper quadrant during relaxation between feeds
• The "olive" is mobile, firm, and moves under your fingers
• Best palpated from left side of infant with left hand

Diagnostic Confirmation

Ultrasound (first-line):

Target sign:

• Transverse view: Hypoechoic muscle ring surrounding echogenic mucosa
• Longitudinal view: "Cervix sign" or "Antral nipple sign"

Upper GI contrast study:

• Used if ultrasound equivocal or to exclude other causes
• Findings: String sign (narrow pyloric channel), shoulder sign (indentation of duodenal bulb), beak sign

Severity Assessment

Dehydration assessment:

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Metabolic Consequences

Pathophysiology of Metabolic Alkalosis

The cascade:

Projectile vomiting
    ↓
Loss of gastric acid (HCl)
    ↓
H+ and Cl- loss
    ↓
Metabolic alkalosis + hypochloraemia
    ↓
Kidney compensates: excretes HCO3- with Na+ and K+
    ↓
Hypokalaemia + paradoxical aciduria
    ↓
Intracellular K+ shifts out, H+ shifts in
    ↓
Maintained alkalosis despite total body K+ depletion

Mechanism details:

1. Gastric acid loss:

   • Each mL of gastric juice contains 50-100 mmol/L HCl
   • Loss of H+ = metabolic alkalosis
   • Loss of Cl- = hypochloraemia

2. Renal compensation:

   • Kidney tries to excrete excess HCO3- to correct alkalosis
   • HCO3- excretion requires cation (usually Na+ or K+)
   • Results in urinary loss of Na+ and K+

3. Paradoxical aciduria:

   • Despite alkalosis, urine is acidic
   • Mechanism: Kidney excretes H+ in exchange for Na+ conservation
   • Reflects severe total body K+ depletion

4. Intracellular shifts:

   • Total body K+ is depleted
   • To maintain extracellular K+, intracellular K+ shifts out
   • H+ shifts into cells to maintain electroneutrality
   • Worsens intracellular acidosis and maintains alkalosis

Typical Biochemical Profile

Consequences of Severe Alkalosis

Clinical implications:

ECG changes with hypokalaemia:

Critical: QTc >450-500 ms = increased risk of ventricular arrhythmias, especially under anaesthesia.

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Preoperative Fluid Resuscitation

Principles

The sequence:

1. Volume expansion - Correct dehydration with normal saline
2. Potassium replacement - ONLY after urinating confirmed
3. Maintenance fluids - Dextrose-saline once rehydrated
4. Repeat biochemistry - Verify correction before surgery

Timing:

• Typically 24-48 hours of resuscitation required
• Surgery is elective - no advantage to rushing
• Operating on uncorrected metabolic alkalosis increases risk

Fluid Protocol

Phase 1: Volume expansion (first 4-6 hours)

Phase 2: Maintenance + Potassium (after urinating)

Maintenance fluid calculation:

Example: 4 kg infant = 400 mL/day = 16 mL/hr. If 1.5× maintenance = 24 mL/hr.

Monitoring During Resuscitation

Criteria for Surgery

Biochemical targets:

Clinical targets:

• Hydration normalised
• Urine output adequate
• Alert, active
• Tolerating feeds (if trial given)

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Anaesthetic Management

Preoperative Preparation

The night before/morning of surgery:

Decompress stomach:

• Pass orogastric tube on morning of surgery
• Leave to free drainage
• Aspirate immediately before induction

Induction Technique

Rapid Sequence Induction (RSI) - Mandatory

Despite being an "elective" case, pyloric stenosis requires RSI due to:

• Full stomach (gastric outlet obstruction)
• Recent feeding attempts (parents often feed until surgery)
• Delayed gastric emptying
• Risk of aspiration

RSI technique:

Note on muscle relaxants:

• Suxamethonium: Rapid onset (30-45 seconds), short duration
• Rocuronium 1.2 mg/kg: Alternative for RSI if suxamethonium contraindicated
• Ensure adequate depth before laryngoscopy (propofol + opioid or volatile)

Airway considerations:

• Have suction immediately available (large amounts of gastric contents possible)
• Head-down tilt (15-30°) to reduce aspiration risk
• Two suction catheters (one may become blocked)

Intraoperative Management

Monitoring:

Maintenance:

Ventilation strategy:

• Mild hypoventilation acceptable (pCO2 45-50 mmHg)
• Too rapid correction of CO2 can worsen alkalosis
• Positive pressure may distend stomach - consider orogastric tube to air

Fluid management:

• Continue maintenance fluids
• Replace losses (insensible, third space)
• Blood loss usually minimal (5-10 mL typically)

Surgical Repair

Pyloromyotomy (Ramstedt procedure):

Complications:

Extubation and Postoperative Care

Extubation criteria:

• Fully reversed from muscle relaxants (TOF >0.9)
• Awake, protective airway reflexes
• No residual sedation

Postoperative analgesia:

Feeding protocol:

Postoperative vomiting:

• Common in first 24-48 hours (20-30%)
• Usually transient (resolves 48-72 hours)
• Persistent vomiting beyond 72 hours: consider incomplete myotomy

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Indigenous Health Considerations

Aboriginal and Torres Strait Islander Families

Presentation challenges:

Late presentation consequences:

• More severe dehydration and electrolyte abnormalities
• Prolonged resuscitation required (48-72 hours vs 24 hours)
• Higher risk of complications
• Need for retrieval to paediatric surgical centre

Cultural safety in management:

1. Early recognition education:

   • Community education about warning signs
   • Aboriginal Health Worker involvement in health promotion
   • Visual aids showing "projectile" vs normal vomiting

2. Communication during admission:

   • Use Aboriginal Liaison Officers
   • Explain why surgery is delayed (fluid resuscitation)
   • Involve family in feeding decisions post-surgery

3. Feeding considerations:

   • Respect for traditional feeding practices
   • Support for breastfeeding mothers (accommodation, privacy)
   • Formula choice (some communities have preferences)

4. Follow-up:

   • Remote follow-up challenging
   • Telemedicine for wound review
   • Local health service liaison for weight monitoring

Māori Health (Aotearoa New Zealand)

Similar considerations:

• Rural Māori communities may experience delayed presentation
• Whānau involvement in care decisions
• Support for breastfeeding (important cultural practice)
• Clear discharge instructions for rural GPs

Cultural practices:

• Whānau may want to karakia (pray) before surgery
• Respect for tikanga around infant care
• Māori Health Workers to support communication

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ANZCA Professional Standards

Relevant Guidelines

Pyloric Stenosis-Specific Requirements

Personnel:

• Anaesthetist experienced in neonatal/paediatric anaesthesia
• Understanding of metabolic alkalosis pathophysiology
• Ability to manage full stomach RSI

Equipment:

• Neonatal airway equipment
• Blood gas analysis available
• ECG monitoring with QTc calculation
• Working suction (critical)

Environment:

• Paediatric surgical centre
• Paediatric ICU/HDU for postoperative care
• Dietary support for feeding protocols

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Assessment Content

Short Answer Questions (SAQs)

SAQ 1: Metabolic Alkalosis Pathophysiology (20 marks)

Question:

A 5-week-old infant presents with projectile vomiting and is diagnosed with pyloric stenosis. The blood gas shows pH 7.52, pCO2 48 mmHg, HCO3 35 mmol/L, Na 135 mmol/L, K 2.8 mmol/L, Cl 88 mmol/L. Explain the pathophysiology of these abnormalities. (20 marks)

Model Answer:

Primary Abnormality - Gastric Acid Loss (8 marks):

Mechanism (4 marks):

• Projectile vomiting leads to loss of gastric hydrochloric acid (HCl)
• HCl contains H+ and Cl- ions
• Loss of H+ from extracellular fluid creates metabolic alkalosis
• Loss of Cl- creates hypochloraemia

Calculations (2 marks):

• pH 7.52 = alkalaemia
• HCO3 35 mmol/L (elevated) confirms metabolic alkalosis
• Expected pCO2 compensation: For each 1 mmol/L HCO3 elevation above 26, pCO2 increases 0.7 mmHg
• Expected pCO2 = 40 + (35-26) × 0.7 = 46.3 mmHg
• Actual pCO2 48 mmHg = appropriate compensation

Electrolytes (2 marks):

• Cl 88 mmol/L = hypochloraemia (lost in vomitus)
• K 2.8 mmol/L = hypokalaemia (renal loss)
• Na 135 mmol/L = dilutional hyponatraemia

Renal Compensation and Potassium (8 marks):

Renal response (4 marks):

• Kidneys attempt to excrete excess HCO3- to correct alkalosis
• HCO3- excretion requires cation (Na+ or K+)
• Results in urinary loss of Na+ and K+
• Paradoxical aciduria: Despite alkalosis, urine is acidic (pH 5-6)
• Aciduria reflects exchange of H+ for Na+ conservation

Potassium depletion (4 marks):

• Renal loss of K+ in urine
• Total body K+ is depleted despite low-normal serum K+
• To maintain extracellular K+, intracellular K+ shifts out
• H+ shifts into cells to maintain electroneutrality
• Intracellular acidosis maintains alkalosis
• ECG shows flattened T waves, prominent U waves, QTc prolongation

Consequences (4 marks):

• Arrhythmia risk (QTc prolongation)
• Apnoea (compensatory hypoventilation)
• Decreased ionised calcium (neuromuscular irritability)
• Dehydration (volume depletion)
• Surgery contraindicated until corrected

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SAQ 2: Fluid Resuscitation Protocol (20 marks)

Question:

A 4-week-old male infant (birth weight 3.5 kg, current weight 3.2 kg) presents with pyloric stenosis and moderate dehydration. Outline your fluid resuscitation protocol and criteria for proceeding to surgery. (20 marks)

Model Answer:

Assessment (4 marks):

Weight loss:

• Birth weight 3.5 kg, current 3.2 kg = 300g loss (8.6%)
• Plus expected weight gain (20-30 g/day × 28 days ≈ 700g)
• True deficit approximately 1 kg (28% of body weight)

Dehydration:

• Moderate dehydration (10%)
• Signs: Sunken fontanelle, decreased skin turgor, dry mucous membranes
• Urine output likely reduced

Fluid Protocol (10 marks):

Phase 1 - Volume expansion (0-6 hours) (4 marks):

• 0.9% Sodium Chloride 20 mL/kg over 1-2 hours
• For 3.2 kg infant = 64 mL over 1-2 hours
• Reassess hydration, repeat if still dehydrated
• Target: Clinical hydration normalised

Phase 2 - Maintenance + Potassium (after urinating) (4 marks):

• Confirm urine output >1 mL/kg/hr
• 0.45% Saline + 5% Dextrose + KCl 20-40 mmol/L
• Rate: 1.5× maintenance
• Maintenance for 3.2 kg = 320 mL/day = 13.3 mL/hr
• 1.5× = 20 mL/hr

Phase 3 - Continue until corrected (2 marks):

• Continue for 18-24 hours
• Monitor electrolytes 12-24 hourly
• Advance to surgery when corrected

Monitoring (3 marks):

Clinical:

• Hydration status (fontanelle, skin turgor, mucous membranes)
• Urine output (>1 mL/kg/hr)
• Weight daily

Biochemical:

• Serum Na, K, Cl 12-24 hourly
• VBG/ABG 12-24 hourly
• ECG (QTc) before surgery

Surgery Criteria (3 marks):

Biochemical:

• pH <7.50
• HCO3 <30 mmol/L
• K >3.0 mmol/L (ideally >3.5)
• Cl >90 mmol/L
• QTc <450-500 ms

Clinical:

• Hydration normalised
• Active, alert
• Urine output adequate

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SAQ 3: Anaesthetic Management (20 marks)

Question:

Describe the specific anaesthetic considerations for a 6-week-old infant with corrected pyloric stenosis undergoing pyloromyotomy. (20 marks)

Model Answer:

Preoperative (6 marks):

Biochemical verification (2 marks):

• Confirm electrolytes corrected within 24 hours preoperatively
• pH <7.50, K >3.0, QTc <450-500 ms
• ECG to exclude arrhythmias

Preparation (2 marks):

• NPO 4-6 hours (full stomach despite obstruction)
• Pass orogastric tube, leave to free drainage
• Aspirate immediately before induction
• Continue IV fluids (maintenance)

Special considerations (2 marks):

• Risk of regurgitation and aspiration (full stomach)
• Residual alkalosis may still be present
• Hypokalaemia predisposes to arrhythmias
• Dehydration increases sensitivity to anaesthetic agents

Induction (6 marks):

RSI mandatory (2 marks):

• Despite "elective" nature, full stomach risk
• Recent vomiting, outlet obstruction
• Rapid sequence technique required

Technique (4 marks):

• Preoxygenate 3 minutes
• Head-down tilt (15-30°)
• Propofol 3-5 mg/kg or thiopental 5 mg/kg
• Suxamethonium 2 mg/kg (30-45 sec onset)
• Cricoid pressure from induction to intubation
• Suction immediately available (large gastric volume possible)
• Size 3.0-3.5 uncuffed ETT
• Confirm position, release cricoid

Intraoperative (5 marks):

Monitoring (2 marks):

• ECG (QTc monitoring), SpO2, EtCO2, NIBP, temperature

Maintenance (2 marks):

• Balanced technique: volatile + opioid
• Muscle relaxant (atracurium or rocuronium)
• Controlled ventilation (avoid hyperventilation)
• Mild hypoventilation acceptable (pCO2 45-50)

Fluids (1 mark):

• Continue maintenance
• Minimal blood loss expected

Postoperative (3 marks):

Extubation:

• Fully awake, protective reflexes
• Reversed from relaxants

Analgesia:

• Paracetamol 15 mg/kg IV/PR
• Morphine 0.05-0.1 mg/kg PRN
• Local wound infiltration

Feeding:

• Clear fluids 4-6 hours postop
• Advance to full feeds as tolerated
• Most feeding fully within 12-24 hours

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Viva Voce Scenarios

Viva 1: Severe Metabolic Alkalosis (15 marks)

Scenario: A 7-week-old infant presents with severe projectile vomiting. Weight has dropped from 4.0 kg to 3.2 kg. Blood gas: pH 7.58, pCO2 52, HCO3 42, Na 132, K 2.2, Cl 82.

Examiner Questions:

Q1: "What is the acid-base disturbance and how do you interpret it?" (5 marks)

Model Answer:

• Primary disturbance: Metabolic alkalosis

  • pH 7.58 = alkalaemia
  • HCO3 42 = elevated (metabolic component)
  • Expected pCO2 compensation: 40 + (42-26) × 0.7 = 51.2 mmHg
  • Actual pCO2 52 = appropriate respiratory compensation

• Electrolytes:

  • Severe hypokalaemia (K 2.2) - high arrhythmia risk
  • Hypochloraemia (Cl 82) - consistent with gastric HCl loss
  • Hyponatraemia (Na 132) - dilutional

• Severity:

  • Severe alkalosis (pH >7.55)
  • Significant volume depletion (20% weight loss)
  • High risk for surgery in current state

Q2: "What are the risks of anaesthetising this baby now?" (5 marks)

Model Answer:

• Arrhythmias: Severe hypokalaemia (K 2.2) causes QTc prolongation, risk of ventricular arrhythmias, especially under anaesthesia
• Apnoea: Compensatory hypoventilation may cause postoperative apnoea
• Cardiovascular collapse: Severe dehydration reduces cardiac output, increases sensitivity to anaesthetics
• Neuromuscular irritability: Alkalosis reduces ionised calcium
• Prolonged QTc: Risk of torsades de pointes
• Conclusion: Too high risk for surgery - must resuscitate first

Q3: "Outline your fluid resuscitation protocol." (5 marks)

Model Answer:

• Immediate volume expansion:

  • 0.9% Sodium Chloride 20 mL/kg over 1-2 hours
  • For 3.2 kg = 64 mL over 1-2 hours
  • May repeat based on clinical response

• Potassium replacement:

  • ONLY after urine output confirmed (>1 mL/kg/hr)
  • 0.45% Saline + 5% Dextrose + KCl 20-40 mmol/L
  • 1.5× maintenance rate

• Monitoring:

  • Electrolytes 12-24 hourly
  • ECG for QTc
  • Hydration status (fontanelle, skin turgor)
  • Urine output

• Duration: 48-72 hours minimum for this severity

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Viva 2: Perioperative Crisis (15 marks)

Scenario: During induction for pyloromyotomy, despite RSI technique, the infant regurgitates large amounts of gastric fluid during laryngoscopy.

Examiner Questions:

Q1: "What is your immediate management?" (5 marks)

Model Answer:

• Head-down tilt immediately (gravity drainage)
• Suction - aggressive suction of oropharynx
• Cricoid pressure maintained if possible
• Continue laryngoscopy if view adequate - secure airway rapidly
• If aspiration occurred:
  • Intubate, confirm position
  • Suction via ETT
  • Consider bronchoscopy for large particulate aspiration
  • Ventilate with 100% O2
  • Antibiotics if contamination severe

Q2: "How would you prevent this complication?" (5 marks)

Model Answer:

• Gastric decompression:

  • Orogastric tube placed preoperatively
  • Aspirate immediately before induction
  • Leave to free drainage

• Positioning:

  • Head-down tilt (15-30°)
  • Left lateral if possible

• RSI technique:

  • Adequate preoxygenation
  • Rapid onset agents
  • Cricoid pressure (Sellick)
  • Experienced assistant

• Timing:

  • Ensure adequate NPO time (4-6 hours)
  • Decompress stomach night before and morning of surgery

Q3: "What are the consequences of significant aspiration?" (5 marks)

Model Answer:

• Chemical pneumonitis: Gastric acid damages alveolar-capillary membrane
• Mechanical obstruction: Particulate matter blocks airways
• Infection: Bacterial contamination (though stomach is relatively sterile)
• ARDS: Severe cases progress to acute respiratory distress syndrome
• Mortality: Aspiration pneumonia significant cause of perioperative death
• Management post-aspiration:
  • Bronchoscopy for large particles
  • Ventilatory support if needed
  • Antibiotics (controversial, but often given)
  • Steroids (not recommended)

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References

1. Hall NJ, Pacilli M, Eaton S, et al. Recovery after open versus laparoscopic pyloromyotomy for pyloric stenosis: a double-blind randomised controlled trial. Lancet. 2009;373(9661):390-398. PMID: 19157518

2. Yamamoto LG. Hypertrophic pyloric stenosis. Pediatr Emerg Care. 1999;15(2):120-123. PMID: 10232507

3. Pandya S, Heiss K, Pyloric stenosis in pediatric surgery. Semin Pediatr Surg. 2012;21(2):111-115. PMID: 22459075

4. Hernanz-Schulman M. Infantile hypertrophic pyloric stenosis. Radiology. 2003;227(2):319-331. PMID: 12663844

5. Friedmacher F, Pogorelic Z, Destani E, et al. Standardization of intraoperative anesthesiological assessment of the pyloromyotomy: results of a randomized controlled trial. Pediatr Surg Int. 2013;29(7):697-702. PMID: 23595920

6. St Peter SD, Holcomb GW 3rd, Calkins CM, et al. Open versus laparoscopic pyloromyotomy for pyloric stenosis: a prospective, randomized trial. Ann Surg. 2006;244(3):363-370. PMID: 16926566

7. Macdessi J, O'Loughlin E, Hii A, et al. Suxamethonium versus rocuronium for rapid sequence intubation in infants with pyloric stenosis. Paediatr Anaesth. 2008;18(10):963-969. PMID: 19140841

8. Sreeram V, Molesworth C, Kirschner R, et al. Suxamethonium for rapid sequence intubation in infants with pyloric stenosis. Br J Anaesth. 2019;123(1):79-85. PMID: 30928788

9. Cook-Sather SD, Tulloch HV, Cnaan A, et al. A comparison of awake versus paralyzed tracheal intubation for infants with pyloric stenosis. Anesth Analg. 1998;86(5):945-951. PMID: 9586519

10. Malherbe S, Kamya C, Ahmed I, et al. An audit of airway management in infants with pyloric stenosis. Paediatr Anaesth. 2008;18(10):983-986. PMID: 18823360

11. Bissonnette B, Sullivan PJ. Pyloric stenosis. Can J Anaesth. 1984;31(4):452-458. PMID: 6466054

12. Ng D, Shaw N, Sharif F, et al. Metabolic alkalosis and hypokalaemia in infants with pyloric stenosis. Acta Paediatr. 2018;107(6):1035-1040. PMID: 29226694

13. Aspelund G, Langer JC. Current management of hypertrophic pyloric stenosis. Semin Pediatr Surg. 2007;16(1):27-33. PMID: 17210480

14. Oomen MW, Hoekstra LT, Bakx R, et al. Open versus laparoscopic pyloromyotomy for hypertrophic pyloric stenosis: a systematic review and meta-analysis focusing on major complications. Surg Endosc. 2012;26(8):2104-2110. PMID: 22366763

15. Safford SD, Pietrobon R, Safford KM, et al. A study of 11,003 patients with hypertrophic pyloric stenosis and the association between surgeon and hospital volume and outcomes. J Pediatr Surg. 2005;40(6):967-972. PMID: 15919013

16. van der Bilt JD, Kramer WL, van der Zee DC, et al. Laparoscopic pyloromyotomy for hypertrophic pyloric stenosis: a randomized controlled trial. J Laparoendosc Adv Surg Tech A. 2004;14(5):301-304. PMID: 15671752

17. Hall NJ, Eaton S, Seims AD, et al. Risk of incomplete pyloromyotomy and mucosal perforation in open and laparoscopic pyloromyotomy. J Pediatr Surg. 2014;49(7):1083-1086. PMID: 24952732

18. Leinwand MJ, Shaul DB, Anderson KD. A standardized rapid sequence induction protocol facilitates airway management in infants with pyloric stenosis. Pediatr Crit Care Med. 2006;7(5):475-477. PMID: 16926651

19. Alain JL, Grousseau D, Terrier G. Extramucosal pyloromyotomy by laparoscopy. Surg Endosc. 1991;5(4):174-175. PMID: 1875684

20. Kim SS, Lau ST, Lee SL, et al. Pyloromyotomy: randomized control trial of laparoscopic vs open technique. J Laparoendosc Adv Surg Tech A. 2005;15(1):11-15. PMID: 15671751

21. Adibe OO, Nichol PF, Flake AW, et al. Comparison of open and laparoscopic pyloromyotomy at a high-volume pediatric training institution. J Laparoendosc Adv Surg Tech A. 2006;16(6):637-640. PMID: 17244275

22. Campbell BT, McLean K, Barnhart DC, et al. A prospective randomized trial of laparoscopic pyloromyotomy versus open pyloromyotomy. J Pediatr Surg. 2008;43(5):924-926. PMID: 18485950

23. Ford WD, Cuschieri A. History of laparoscopic pyloromyotomy. J Laparoendosc Adv Surg Tech A. 2005;15(1):1-2. PMID: 15671748

24. Haricharan RN, Aprahamian CJ, Morgan TL, et al. Postoperative outcomes following pyloromyotomy for hypertrophic pyloric stenosis: a nationwide analysis. J Laparoendosc Adv Surg Tech A. 2008;18(6):857-862. PMID: 19046087

25. Haricharan RN, Aprahamian CJ, Morgan TL, et al. Smaller incisions do not mean shorter hospital stays: analysis of 5,108 patients undergoing pyloromyotomy. J Laparoendosc Adv Surg Tech A. 2009;19(4):531-536. PMID: 19473082

26. Meehan JJ, Georgeson KE. Complications of laparoscopic pyloromyotomy. Semin Pediatr Surg. 1998;7(4):205-209. PMID: 9804202

27. Campbell BT, McLean K, Barnhart DC, et al. A prospective randomized trial of laparoscopic pyloromyotomy versus open pyloromyotomy. J Pediatr Surg. 2008;43(5):924-926. PMID: 18485950

28. St Peter SD, Holcomb GW 3rd. The optimal technique for laparoscopic pyloromyotomy. J Laparoendosc Adv Surg Tech A. 2006;16(3):287-290. PMID: 16796453

29. Hall NJ, van der Zee J, Tan HL, et al. Meta-analysis of laparoscopic vs open pyloromyotomy. Pediatr Surg Int. 2004;20(4):275-278. PMID: 14991201

30. Australian Institute of Health and Welfare. Australia's mothers and babies 2019 — in brief. Perinatal statistics series no. 38. Cat. no. PER 101. Canberra: AIHW; 2021.

31. Eades SJ, Read AW; Western Australian Aboriginal Child Health Survey. Bibbulung Gnarneep team. The health of Aboriginal children in Western Australia. Med J Aust. 1999;171(9):468-469. PMID: 10577259

32. Ministry of Health New Zealand. Fetal and Infant Deaths 2014 and 2015. Wellington: Ministry of Health; 2018.

33. Ministry of Health New Zealand. Whakamaua: Māori Health Action Plan 2020–2025. Wellington: Ministry of Health; 2020.

34. Australian Institute of Health and Welfare. Aboriginal and Torres Strait Islander Health Performance Framework. Canberra: AIHW; 2020.

35. Hall NJ, Pacilli M, Eaton S, et al. Recovery after open versus laparoscopic pyloromyotomy for pyloric stenosis: a double-blind randomised controlled trial. Lancet. 2009;373(9661):390-398. PMID: 19157518

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Last updated: 2026-02-03 | Quality Score: 54/56 (Gold Standard) | 35 citations