Pyloric Stenosis


Pyloric Stenosis is a medial emergency that requires urgent fluid resuscitation and resolution of biochemical abnormalities. Definitive surgical treatment can then be undertaken to restore enteral nutrition.


  • commoner in first born males
  • 80% males
  • 10% are premature
  • projectile vomiting in neonate (not billous)
  • 2-8 weeks
  • dehydration
  • weight loss
  • hyperaldosteronism with paradoxical aciduria
  • visible peristalsis and olive sized mass in epigastrium
  • confirmed on US
  • associated pathology: cleft palate, GORD



  1. hypochloraemia
  2. metabolic alkalosis
  3. hyponatraemia
  4. hypokalaemia
  5. initially, alkaline urine -> later, acidic urine
  6. dehydration
  • hypochloraemia
    – loss of chloride in vomitus
  • metabolic alkalosis
    – loss of H+ in vomitus
    – decreased secretion of pancreatic HCO3-
    – increased HCO3- presented to distal tubule and eliminated producing an alkaline urine
  • hyponatraemia
    – loss of Na+ in vomitus
    – decreased absorption of Na+
    – loss of Na+ in urine until kidney adjusts to increased HCO3- load
    – activation of renin-AG-ALD system to off set this and restore Na+ and H2O
  • hypokalaemia
    – K+ loss in vomitus
    – activation of rennin-AG-ALD system with produces loss of K+ in urine
    – with extreme K+ loss in urine -> it gets reabsorbed in distal tubule with loss of H+ worsening metabolic alkalosis and producing and acidic urine
  • initially, alkaline urine -> later, paradoxical aciduria
    – in order to prevent hypokalaemia
  • dehydration
    – inability to absorb enteral fluid and vomiting
    – activation of rennin-AG-ALD system + ADH


Fluid resuscitation — determined by weight and degree of dehydration assessed clinically (tissue turgor, pulse, fontanelle, CR centrally, peripheral perfusion, respiratory rate)

  • IV boluses of normal saline or colloid (4% albumin) – 10-20mL/kg to restore circulating volume
  • maintenance @ 4mL/kg/hr with 5% dextrose with 0.45% normal saline and 20mmoL KCl
  • fluid therapy should be titrated to clinical variable including urine output (2mL/kg/hr)
  • need a lot of K+ once they pee

Laboratory criteria by which patient is sufficiently resuscitated for surgery — ideally biochemical abnormalities would be normal before surgery however, variable associated with adequate resuscitation and resolution of metabolic alkalosis include:

  • serum Cl- of at least 105mmol/L
  • serum HCO3- (normal)
  • urinary Cl- of >20mmol/L
  • urinary K+
  • urinary Na+


  • operation = splitting of the pylorus muscle longitudinally down to the mucosa (myomectomy)
  • risk of pulmonary aspiration from gastric outflow obstruction
  • aspirate N/G and don’t remove as will help to decompress stomach from vigorous ventilation
  • RSI or use of NDNMBD
  • fentanyl 1mcg/kg
  • paracetamol suppository 30-40mg/kg
  • bupivacaine infiltration
  • extubate awake and in left lateral position


  • remove N/G
  • feed within 6 hours
  • give maintenance IVF until feeding established
  • use apnoea alarm overnight

CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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