Critical pulmonary stenosis: challenges following surgical correction.

A 20-day-old girl was diagnosed with critical pulmonary valvular stenosis with patent ductus arteriosus (PDA). She underwent surgical pulmonary valvotomy and infundibular resection. A trial snaring of the PDA resulted in significant systemic desaturation, and the PDA was left undivided. A continuous infusion of prostaglandin was used to keep the PDA open for the next 8 days. The PDA acted as a "natural systemic-to-pulmonary shunt" to provide pulmonary blood flow until right ventricular compliance and function improved. The various causes of persistent desaturation following pulmonary valvotomy are discussed.