Postoperative fetal circulation: POFC.
Active pulmonary vasoconstriction and subsequent right-to-left atrial and/or ductal shunting of venous blood may influence the course of many neonatal cardiorespiratory disorders. The term "persistent fetal circulation" has been applied to these infants. This report concerns the late occurrence of fetal circulation after major intraabdominal operative procedures in two neonates. The first patient was a full-term, 3.6-kg infant with a covered, large liver-containing omphalocele. Cyanosis, hypoxia, and a right-to-left shunt were present at birth, but were improved by 24 hr of life. Primary repair was delayed for 6 days, in the belief that fetal circulation was unlikely to recur. On day 7, primary fascial closure of the omphalocele was followed by severe hypoxia secondary to right-to-left shunt, documented to be due to postoperative fetal circulation (POFC). The second was a 1600-g premature infant who was well until noted to be lethargic on the fourth day of life. Radiologic findings of pneumoperitoneum led to laparotomy and closure of a spontaneous gastric perforation. Twenty-four hours later the patient developed severe hypoxia and a right-to-left shunt at the atrial level was documented with contrast echocardiogram, again supporting the diagnosis of POFC. Each patient survived and has a normal heart. Both patients responded to hyperventilation and/or tolazoline therapy. Contrast echocardiography was a helpful, noninvasive means of establishing the diagnosis. This diagnosis should be considered in postoperative neonates after more common cardiac and pulmonary causes of hypoxia are excluded.