A 6-week-old child presents with a history of intolerance to feedings. The patient has had nonbilious projectile vomiting for the past 48 hours, vomiting immediately after feedings.
Laboratory: K 5.9; HCO3 30; Cl 96 (after 24 hours of hydration, K 4.7; HCO3 23; Cl 101).
Physical exam: Olive-shaped mass palpated in right upper quadrant.
Pyloric stenosis is a hypertrophy of the pyloric muscles, typically seen between 2 and 12 weeks of age. Patients present with projectile vomiting after feedings, dehydration, and failure to thrive. The diagnosis can be made by history and physical examination alone; barium swallow and ultrasound are confirmatory tests. Ongoing loss of potassium, hydrogen, and chloride ions leads to contraction alkalosis. The loss of potassium through vomiting, the exchange of hydrogen ions for extracellular potassium, and the renal potassium loss all lead to hypokalemia.
The patient should have a plasma chloride >100 and urine chloride >20; serum bicarbonate should be less than 28 mEq/dL prior to the surgery.
Once diagnosed, patients should be given nothing by mouth, a nasogastric tube should be inserted, and intravenous fluids should be administered. Pyloric stenosis is not a surgical, but a medical emergency.
Decompress the stomach prior to initiating induction. Consider using an anticholinergic to blunt the vagal response to suctioning. Consider sitting the patient upright and rolling the patient from side to side to ensure that all gastric content is aspirated.
Consider awake intubation versus rapid-sequence induction.
Be cautious when using muscle relaxant; large doses of rocuronium can last for hours.
Avoid opioids; rectal acetaminophen and infiltration with local anesthetic are sufficient.
Maintain anesthesia with Sevoflurane or desflurane and a remifentanil infusion. You may give a small amount of a muscle relaxant for the incision and then limit the volatile anesthetic.
Most patients can start feeding within hours. No intensive care unit admission is necessary.
DOs and DON’Ts
✓ Do an awake intubation, a rapid-sequence induction, or a modified rapid-sequence induction.
⊗ Do not do a mask induction.
✓ Do empty the stomach with the patient in four different positions prior to airway management.
⊗ Do not give opioids.
Mucosal damage was initially reported more often with the laparoscopic approach. A leak can be detected intraoperatively by inflating the stomach with an orogastric tube; the pylorus is observed for leaking air.
In developing countries, pyloric stenosis is treated mainly with medical management, which includes anticholinergics and fluid management for two weeks. Only patients who medically failed (20%!) are operated on.