Donald C. Watson

Plastic bronchitis occurring late after the Fontan procedure : Treatment with aerosolized urokinase

Objective To describe the use of aerosolized urokinase in a patient with plastic bronchitis after a Fontan procedure. Design Case report. Setting Pediatric intensive care unit in a university-affiliated children’s hospital. Patients Report of one patient with acute respiratory failure secondary to plastic bronchitis. Interventions Aerosolized urokinase, multiple bronchoscopies, corticosteroids, mucolytics, bronchodilators, and atrial pacing. Measurements and Main Results Airway obstruction secondary to recurring casts improved with the treatments. Histologic analysis of the casts demonstrated less fibrin after treatments with aerosolized urokinase. No adverse events were noted. Conclusions The addition of aerosolized urokinase to this patient’s treatment regimen helped to resolve life-threatening airway obstruction secondary to fibrin casts.

Pulmonary/systemic flow ratio in children after cavopulmonary anastomosis

OBJECTIVES This study attempted to provide a formula for calculation of the pulmonary/systemic flow ratio in children after bidirectional cavopulmonary anastomosis. BACKGROUND With the bidirectional cavopulmonary anastomosis, only the superior vena cava blood is oxygenated by the lungs. The inferior vena cava flow recirculates into the systemic circulation. The ratio of these flows will determine systemic arterial saturation. METHODS According to the Fick principle, 1) Systemic cardiac output (liters/min) = Pulmonary venous flow + Inferior vena cava flow; 2) Systemic blood oxygen transport (ml/min) = Pulmonary venous blood oxygen transport + Inferior vena cava blood oxygen transport. By substituting the first equation into the second, Pulmonary/systemic flow ratio = (Systemic saturation - Inferior vena cava saturation)/(Pulmonary venous saturation - Inferior vena cava saturation). RESULTS We applied the third formula to data obtained from 34 catheterizations in 29 patients after bidirectional cavopulmonary anastomosis. Mean [+/- SD] age at operation was 1.70 +/- 1.43 years, and mean age at catheterization was 2.95 +/- 1.65 years. The pulmonary/systemic flow ratio calculated for all 29 patients was 0.58 +/- 0.09. Of 17 patients with aortography, 10 had systemic to pulmonary collateral vessels. Patients with collateral vessels had a significantly higher pulmonary/systemic flow ratio (0.61 +/- 0.07 vs. 0.53 +/- 0.07, respectively, p < 0.02) and systemic saturation (88 +/- 4% vs. 82 +/- 4%, respectively, p < 0.002) than those without collateral vessels. The pulmonary/systemic flow ratio in those patients with no collateral vessels was similar to the previously reported echocardiographically derived superior vena cava/systemic flow ratio in normal children. CONCLUSIONS The pulmonary/systemic flow ratio after bidirectional cavopulmonary anastomosis can be calculated. Pulmonary blood flow in these patients determines systemic saturation and accounts for the majority of venous return in young children.

A prospective, randomized, double-blind comparison of calcium chloride and calcium gluconate therapies for hypocalcemia in critically ill children.

Disturbances of ionized calcium levels have been reported in sick neonates, l and we have found a high rate of occurrence of ionized hypocalcemia, 2 which was associated with a significantly increased mortality rate in critically ill nonneonatal pediatric patients. Calcium chloride and calcium gluconate are two of the standard salt preparations that are used to correct hypocalcemia; the former is usually preferred because it is in the ionized form and therefore provides more readily available ionized calcium for use. In this study, critically ill pediatric patients with ionized hypocalcemia received either calcium chloride or calcium gluconate in a randomized manner. The purposes of this study were (1) to determine whether calcium chloride and calcium gluconate provide equal bioavailability of ionized calcium and (2) to assess whether there were any differences in physiologic effects after administration of the two salts. METHODS Patient selection. All patients admitted to the Le Bonheur Childrens Medical Center intensive care unit were eligible for participation in this study if they were found to have hypocalcemia. Patients were enrolled in the study after informed consent was obtained in compliance with the investigational review boards of the University of Tennessee and LBCMC. Exclusion criteria were (1) calcium administration before arrival in the ICU and (2) no documentation of

The fate of homograft conduits in children with congenital heart disease: an angiographic study

The use of homograft conduits in the repair of congenital heart disease is widely accepted. We reviewed the catheterization and angiographic data from 20 patients with homograft conduits. All conduits were to the pulmonary arteries. The age at operation was 4.7 +/- 5.6 years (mean +/- standard deviation) and at follow-up catheterization, 7.8 +/- 6.7 years. At implantation, conduit cross-sectional area and Z value were 219 +/- 96 mm2 and 3.5 +/- 1.8, respectively. At subsequent catheterization, the conduit diameters were measured in two projections at the shaft, annulus, valve opening, and insertion into the pulmonary artery. The transconduit gradient was 47 +/- 26 mm Hg. The cross-sectional areas were 149 +/- 56 mm2 at the shaft, 151 +/- 92 mm2 at the annulus, 108 +/- 116 mm2 at the valve opening, and 127 +/- 84 mm2 at the pulmonary artery insertion. The Z values were -0.9 +/- 2.5, -0.9 +/- 2.8, -3.8 +/- 4.0, and -2.0 +/- 3.4, respectively. The cross-sectional areas and the Z values at the levels of measurement were significantly smaller than the corresponding values at implantation. The change in cross-sectional areas and Z values exceeded what would be expected from growth alone. These data indicate that there is a decrease, with time, in the functional lumen of homograft conduits, and this may have implications for follow-up strategy after implantation.

Double patch closure of ventricular septal defect with increased pulmonary vascular resistance

BACKGROUND Closure of a large ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance is associated with significant morbidity and mortality. Pulmonary hypertensive episodes continue to be a major cause of postoperative morbidity and mortality. We designed a fenestrated flap valve double VSD patch in an effort to decrease the morbidity and mortality associated with the closure of a large VSD with elevated pulmonary vascular resistance. METHODS Eighteen children (mean age, 5.7 years) with a large VSD and elevated pulmonary vascular resistance (mean, 11.4 Wood units) underwent double patch VSD closure using moderately hypothermic cardiopulmonary bypass and cardioplegic arrest. The routine VSD patch was fenestrated (4 to 6 mm) and on the left ventricular side of the patch, a second, smaller patch was attached to the fenestration along its superior margin before closure of the VSD. RESULTS All children survived operation and were weaned from inotropic and ventilator support within 48 hours postoperatively. Postoperative pulmonary artery pressures were significantly lower than preoperative values. One child died 9 months postoperatively. CONCLUSIONS Closure of a large VSD in children with elevated pulmonary vascular resistance can be performed with low morbidity and mortality when a flap valve double VSD patch is used.

Balloon valvuloplasty in children with dysplastic pulmonary valves

Abstract Percutaneous balloon valvuloplasty for congenital pulmonary valvar stenosis (PS) is a safe and effective method for relief of obstruction. 1–3 Previous reports deal primarily with the classic form of PS. The characteristics of classic PS at surgery or necropsy include thickening of the cusps combined with commissural fusion. 4 The dysplastic valve, in contrast, is characterized by stenosis without fusion of its cusps. Obstruction is a result of immobile cusps that consist of fibrous tissue. 5 We report use of balloon valvuloplasty in 3 children with a dysplastic pulmonary valve.

Impact of Ultrafiltration on Blood Use for Atrial Septal Defect Closure in Infants and Children

BACKGROUND Infants and children undergoing open cardiac operations have a high incidence of blood product transfusion. Ultrafiltration has been shown to reverse hemodilution and improve myocardial function and hemodynamics after cardiopulmonary bypass (CPB). METHODS The effect of ultrafiltration on the amount of blood transfusion and hospital charge in 39 consecutive patients who underwent elective atrial septal defect repair was examined. Patients in group I (n=26) had a conventional cardiopulmonary circuit prime with blood, whereas 13 patients had bloodless prime (group II). Ultrafiltration was used immediately after weaning from CPB in group II. The patients in group I received blood products after discontinuation of CPB to achieve a hematocrit of 30%. The amount of blood product used, hematocrit immediately after CPB and on arrival in intensive care unit, postoperative hemodynamics and saturations, total operating room charge, blood charge, hospital stay, and hospital charge were compared. RESULTS Mean body weight (15.8 kg in group I versus 17.5 kg in group II) and preoperative hematocrit values (35.6% in group I versus 34.2% in group II) were similar. Mean hematocrit immediately after CPB was 22% and 14% in group I and II, respectively (p < 0.0001). The mean hematocrit upon arrival to the intensive care unit was 34% in group I and 22% in group II (p < 0.0001). The amount of blood product transfusion was 32 mL/kg in group I and 3 mL/kg in group II patients (p < 0.0001). The patients in group II had significantly less blood bank charges; however, operating room charges and total hospital charges were similar between the two groups. CONCLUSIONS Elective atrial septal defect repair was performed with no blood product transfusion without increased morbidity or hospital stay. Ultrafiltration can be used to reverse hemodilution resulting from a bloodless CPB prime without an increase in hospital charge.

Atrioventricular septal defect repair in infants

From September 1984 through August 1989, 33 consecutive infants (mean age, 9 months; 13 male) received a single-stage intracardiac repair of complete atrioventricular septal defect. Preoperative evaluation of valvar morphology and function involved echocardiograms in 21% (7/33) and echocardiograms with cineangiograms in 79% (26/33). All infants operated on were included in the analysis. Patients with other complicating abnormalities were not excluded. All operations used a two-patch technique for closure of the atrioventricular septal defect in association with mitral valve repair. The newly formed septal leaflet of the mitral valve was repaired using unpledgeted interrupted sutures. Preoperative and postoperative echocardiograms were used to evaluate mitral valve regurgitation and left ventricular dysfunction as mild, moderate, or severe. The 30-day mortality was 6% (2/33). Follow-up ranged from 1 month to 60 months. Postoperative mitral valve insufficiency was mild in 84% versus 6% preoperatively, moderate in 3% versus 52% preoperatively, and severe in 13% versus 42% preoperatively. Mitral valve dysfunction necessitating reoperation occurred in 6% (2/31). Mitral valve function postoperatively was improved compared with preoperatively (p less than 0.001). The low 30-day operative mortality and the excellent late postoperative valvar function demonstrate the value of single-stage two-patch repair of atrioventricular septal defect early in life.

The Wandering Pacemaker: Intraperitoneal Migration of an Epicardially Placed Pacemaker and Femoral Nerve Stimulation

A premature child with congenital complete heart block had an epicardial single-chamber pacemaker implanted at 2 days of age. At 21 months of age, while sitting or standing, the patients right anterior thigh muscles contracted at her pulse rate. Surgical exploration revealed a free-floating pacemaker in her peritoneum. A new dual-chamber pacemaker was implanted into the abdominal wall with resolution of the childs symptoms.

Construction of an aortic homograft conduit for right ventricle to pulmonary artery continuity

Over the past decade the aortic homograft has become the extracardiac conduit of choice for repair of many congenital cardiac defects. Anastomosis of the homograft annulus to the right ventricle may distort the valve and render it incompetent. Prosthetic tube grafts have been used to bridge the right ventricle and distal homograft. We propose and have use successfully a method for establishing right ventricle to pulmonary artery continuity that is free of prosthetic materials, is technically simple, and places the homograft valve in the hilum, away from the distorting right ventricle free wall.