Deborah A. Davis

Staged repair of pentalogy of Cantrell with tetralogy of Fallot

We report a successful two-stage repair of tetralogy of Fallot associated with pentalogy of Cantrell. The first stage, performed in the neonatal period, consisted of repairing the omphalocele, separating the peritoneal from the pericardial cavities, and covering the heart. The second stage, performed at 6 years of age, consisted of complete intracardiac repair and placing the heart in the chest. The patient is alive and well 18 months after the operation.

Management of Airway Obstruction in Patients with Congenital Heart Defects

Airway obstruction may complicate the course of infants undergoing repair of congenital heart disease. Airway obstruction was encountered in seven patients following surgery for complex congenital heart defects (two with interrupted aortic arch, one with pulmonary atresia and a ventricular septal defect, one with tetralogy of Fallot and an abnormal left anterior descending coronary artery, one with truncus arteriosus, and two with complex univentricular heart). In four patients, a conduit was implanted at the time of surgery. In all cases, bronchoscopy accurately demonstrated the cause of the airway obstruction. Two infants had hypoplasia of the left bronchus, and five had tracheobronchomalacia associated with extrinsic compression of the airway by a great vessel or conduit. All were treated conservatively with therapeutic bronchoscopy, tracheotomy, and/or stenting with prolonged mechanical ventilation. Follow-up ranged from 2 to 40 months. Four infants have been weaned from mechanical ventilation and decannulated; two are awaiting decannulation; and one was decannulated and died awaiting surgical repair. To reduce morbidity in infants undergoing surgery for congenital heart disease, the presence of preoperative airway anomalies should be sought and surgery planned to avoid airway compression. Conservative management using diagnostic and therapeutic bronchoscopy, tracheotomy, and stenting together with prolonged ventilator care is rewarding.

High-frequency jet versus conventional ventilation in infants undergoing Blalock-Taussig shunts☆

Nine infants undergoing modified Blalock-Taussig shunts were randomized to both high-frequency jet ventilation (HFJV) and conventional ventilation (CV). Vital signs, blood gases, mean airway pressure, lung mechanics, functional residual capacity, and lung movement were compared on both modes of ventilation keeping peak inspiratory and expiratory pressures constant. The mean airway pressure was lower on HFJV than on CV (8.5 versus 10.9 cm H2O). Arterial partial pressure of oxygen was greater on HFJV than on CV (55 versus 46 mm Hg), arterial partial pressure of carbon dioxide was lower on HFJV than on CV (28 versus 37 mm Hg), whereas compliance (0.54 versus 0.56 mL.cm H2O-1.kg-1). resistance (110 versus 95 cm H2O/L.s), and functional residual capacity (23 versus 22.5 mL/kg) remained the same. Lung movement and degree of retraction necessary for surgical exposure as evaluated by an independent observer was less with HFJV compared with CV. Compared with CV during the creation of Blalock-Taussig shunts, HFJV provides better gas exchange at lower mean airway pressure with similar lung function, lung volume, and hemodynamics.

Successful treatment of acute postoperative pulmonary hypertension with nifedipine

We report the successful use of nifedipine in the treatment of acute pulmonary hypertension in an infant after a cardiac operation. This patient had undergone total surgical correction of his truncus arteriosus malformation. He had signs of severe pulmonary artery hypertension unresponsive to hyperventilation, oxygenation, sedation, and a myriad of vasodilators. Nifedipine, 0.2 mg/kg every 4 hours, effectively treated his pulmonary artery hypertension and allowed for a smooth postoperative course and positive outcome.

Endothelial Dysfunction in Cerebral Microcirculation During Hypothermic Cardiopulmonary Bypass in Newborn Lambs † 1908

OBJECTIVES Inflammatory stimuli or mechanical stresses associated with hypothermic cardiopulmonary bypass could potentially impair cerebrovascular function, resulting in inadequate cerebral perfusion. We hypothesize that hypothermic cardiopulmonary bypass is associated with endothelial or vascular smooth muscle dysfunction and associated cerebral hypoperfusion. Therefore we studied the cerebrovascular response to endothelium-dependent vasodilator, acetylcholine, endothelium-independent nitric oxide donor, sodium nitroprusside, and vasoactive amine, serotonin, in newborn lambs undergoing hypothermic cardiopulmonary bypass (nasopharygeal temperature = 18 degrees C). METHODS Studies were performed on 13 newborn lambs equipped with a closed cranial window, allowing for direct visualization of surface pial arterioles. Six animals were studied while undergoing hypothermic cardiopulmonary bypass, whereas seven served as nonbypass, warm (37 degrees C) controls. Pial arteriolar caliber (range = 111 to 316 microm diameter) was monitored using video microscopy. RESULTS Topical application of acetylcholine caused a dose-dependent increase in arteriolar diameter in the control group that was absent in animals undergoing hypothermic cardiopulmonary bypass. Hypothermic cardiopulmonary bypass did not alter the vasodilation in response to sodium nitroprusside. Furthermore, the contractile response to serotonin was fully expressed during hypothermic cardiopulmonary bypass. CONCLUSIONS The specific loss of acetylcholine-induced vasodilation suggests endothelial cell dysfunction rather than impaired ability of vascular smooth muscle to respond to nitric oxide. It is speculated that loss of endothelium-dependent regulatory factors in the cerebral microcirculation during hypothermic cardiopulmonary bypass may enhance vasoconstriction, and impaired cerebrovascular function may be a basis for associated neurologic injury during or after hypothermic cardiopulmonary bypass.

Infant thoracic surgery: Procedure-dependent pulmonary response

Respiratory insufficiency is a common complication of thoracic surgery in infants. To better define this dysfunction, pulmonary compliance (CL) and resistance (R) were measured for 17 infants who underwent common thoracic procedures: Blalock-Taussing shunting (n = 7) repair of congenital coarctation of the aorta (n = 10). Measurements were obtained preoperatively and 0, 1, and 3 days postoperatively. Preoperatively, CL was lower and R was similar for the two groups. Both groups had decreased CL and increased R on postoperative day 0; infants with coarctation had recovery to preoperative values by postoperative day 1 for CL, and day 3 for R. CL and R did not return to the preoperative values by postoperative day 3 in infants with a shunt procedure. The changes in R were greater than those in CL for both groups in the postoperative period. These data indicate that such thoracic procedures are associated with pulmonary morbidity that is airway-predominant, and that the degree of compromise and the time until recovery are, in part, procedure-specific.