Pyloromyotomy

 

Main thing:

·        The emergency is medical

·        The cure is surgical

 

Pathophysiology:

Causes

·      Gastric losses

·      Starvation

Problems

1.    ↓Volume -> lactic acidosis

2.    ↑Tonicity -> not sure

3.    ↑pH -> respiratory depression

4.    Electrolyte disturbance -> arrhythmia

Priorities

1.    Volume

2.    Tonicity

3.    pH

4.    Electrolytes

Metabolic profile

Plasma:

·      ↑↓pH

·      ↑↓pCO2

·      ↓Na

·      ↓Cl

·      ↓K

·      ↓BSL

Urine:

·      Paradoxical aciduria

i.e. sacrifice pH for the sake of volume

Hormonal profile

·      ↑Renin-angiotensin-aldosterone

·      ↑ADH

 

Fluid assessment:

Most reliable

·      Weight

·      Wet nappies

Mild (1-5%)

·      Thirsty

·      Dry mouth

Moderate (5-10%)

·      Grumpy

·      Oliguria

·      Slow cap refill

·      Tachypnoea, mild tachycardia

Severe (≥10%+)

·      Rag doll

·      Anuric

·      Very slow cap refill

·      Cold, pale, mottled

·      Sunken fontanelle

·      Tachypnoea, tachycardia, hypotension

 

Anaesthesia: pyloric stenosis

Resuscitation

Treatment:

·      Boluses: 10mL/kg 0.9% NaCl over 30 mins, ±repeat

·      Maintenance: 4-2-1 rule (plasmalyte? 4% glucose + 0.18% NaCl?)

Goals:

·      Volume: normal weight, UO >0.5mL/kg/h

·      Acid-base: Cl >105, HCO3 <30

Induction

·      Large bore orogastric tube + four quadrant suction

·      Folded towel under the shoulders

·      Pre-oxygenate

·      IV induction ± bag-mask ventilation

·      Atropine + propofol + suxamethonium + sevoflurane

·      MAC 1, size 3.5 coETT

·      Check ETT position and cuff pressure

Post-op care

·      Risk of apnoea: 12 hour line of sight monitoring

·      Analgesia: just local anaesthetic + paracetamol (avoid opioid)

·      Fluid: 100mL/kg/day until feeding normally

 

Neonate:

Airway

Anatomy:

·      Small dimensions

·      Laryngomalacia in 30%

·      High larynx (C3-4)

·      Large occiput

·      Obligate nose breather

Management:

·      BMV: keep mouth open, don’t press on neck

·      LMA: only as a get-out-of-jail card

·      ETT: towel under the shoulders, check cuff pressure (risk of stenosis)

Breathing

·      Rapid desaturation when apnoeic

·      Oxygenation highly PEEP-dependent

·      Risk of oxygen toxicity

·      Risk of post-op apnoea: esp if prem, ↓temp, ↓BSL, ↓Hb

Circulation

·      Hypoxia causes bradycardia

·      Fairly fixed stroke volume

Drugs

·      High risk of drug dose error

·      High risk of significant air embolism

·      Variably slower rate of metabolism

External

·      TNZ 32-34°

·      Get cold very quickly when exposed

·      Hypothermia causes apnoea

Fluids

·      Get dehydrated quickly when exposed

·      Easy to flood (2 x normal saline ampoules = 10mL/kg)

Glucose

·      Hypoglycaemic if not fed frequently

Haemoglobin

·      HbF 170-180 g/L

·      Visually small blood loss may be significant

 

 

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