Noninvasive cerebral oximeter as a surrogate for mixed venous saturation in children.

We evaluated the relationship between regional cerebral oxygen saturation (rSO(2)) measured by near-infrared spectroscopy (NIRS) cerebral oximeter with superior vena cava (SVC), inferior vena cava (IVC), right atrium (RA), and pulmonary artery (PA) saturation measured on room air and 100% inspired oxygen administered via a non-rebreather mask (NRB) in children. Twenty nine pediatric post-orthotopic heart transplant patients undergoing an annual myocardial biopsy were studied. We found a statistically significant correlation between rSO(2) and SVC saturations at room air and 100% inspired oxygen concentration via NRB (r = 0.67, p = 0.0002 on room air; r = 0.44, p = 0.02 on NRB), RA saturation (r = 0.56, p = 0.002; r = 0.56, p = 0.002), and PA saturation (r = 0.67, p < 0.001; r = 0.4, p = 0.03). A significant correlation also existed between rSO(2) and measured cardiac index (r = 0.45, p = 0.01) and hemoglobin levels (r = 0.41, p = 0.02). The concordance correlations were fair to moderate. Bias and precision of rSO(2) compared to PA saturations on room air were -0.8 and 13.9%, and they were 2.1 and 15.6% on NRB. A stepwise linear regression analysis showed that rSO(2) saturations were the best predictor of PA saturations on both room air (p = 0.0001) and NRB (p = 0.012). In children with biventricular anatomy, rSO(2) readings do correlate with mixed venous saturation.

Ductus arteriosus aneurysm with community-acquired methicillin-resistant Staphylococcus aureus infection and spontaneous rupture: a potentially fatal quandary.

We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.

Cardiopulmonary bypass for adults with congenital heart disease: pitfalls for perfusionists.

The fixed incidence of congenital heart defects and improved survival have resulted in increasing numbers of adults with congenital heart disease (CHD) who have undergone complex repairs and/or palliations. Eventually, there will be more adults with CHD than children. They will require cardiac surgical interventions associated with progression of their CHD or for age-related disease, such as coronary revascularization. During bypass, anatomical shunts may exist within or without the heart. Left-to-right shunts can result in dramatically lower systemic blood flow than pump flow due to 'steal', while pulmonary edema ensues due to excessive pulmonary flow. Right-to-left shunts carry risks of massive air embolism and double or triple venous cannulation may be necessary. Cannulation of composite reconstructed aortas may be difficult, risking dissection or aortic obstruction, and double arterial cannulation may be indicated. Aberrant coronary arterial and venous anatomy may .preclude adequate myocardial preservation with common techniques and can be complicated by aortic insufficiency. Valves and conduits may exhibit failure. Conventional monitoring, such as central venous oximetry, may be misleading. Monitoring, such as serial lactate measurement, near-infrared spectroscopy and transcranial Doppler blood velocity, offer advantages for such patients. The perfusionist needs to be aware of such conditions as much congenital aberrancy may present unexpectedly during cardiac surgery.

The first successful DeBakey VAD child implantation as a bridge to transplant.

A 14-year-old boy with repaired transposition of the great arteries and ventricular septal defect presented with atrial flutter and severe congestive heart failure. Despite successful cardioversion and optimal medical therapy, the patient deteriorated and was supported with extracorporeal membrane oxygenation (ECMO). Two days after initiating ECMO support, we implanted the DeBakey VAD Child ventricular assist device (MicroMed Technology, Inc., Houston, TX) under the Humanitarian Device Exemption program. Later, he was able to pursue normal daily activities including physical rehabilitation and ambulation in the hospital. After 56 days, he underwent a successful cardiac transplantation. After 3 months, he had good cardiac function and no evidence of rejection. The DeBakey VAD Child device is a valuable option for cardiac support as a bridge to transplantation.

Adequacy of peritoneal dialysis in children following cardiopulmonary bypass surgery.

Acute renal failure requiring renal replacement therapy can complicate cardiopulmonary bypass in children. Peritoneal dialysis has been shown to stabilize electrolytes and improve fluid status in these patients. To assess dialysis adequacy in this setting, we prospectively measured Kt/V and creatinine clearance in five patients (6-839 days of age) requiring renal replacement therapy at our institution. Median dialysis creatinine clearance was 74.25 L/week/1.73m(2) (range 28.28-96.63 L/week/1.73m(2)). Residual renal function provided additional solute clearance as total creatinine clearance was 215.97 L/week/1.73m(2) (range 108.04-323.25 L/week/1.73m(2)). Dialysis Kt/V of >2.1 (median 4.84 [range 2.12-5.59]) was achieved in all patients. No dialysis-associated complications were observed. We conclude that peritoneal dialysis is a safe, simple method of providing adequate clearance in children who develop acute renal failure following exposure to cardiopulmonary bypass.

Gadolinium-enhanced magnetic resonance angiography of right ventricle to pulmonary artery shunts following Norwood 1 palliation in infants.

The classic Norwood I palliation for the treatment of hypoplastic left-heart disease includes an atrial septectomy, neoaorta creation, and a systemic-to-pulmonary artery shunt. The Norwood I palliation has been modified by the use of a right ventricle-to-pulmonary artery shunt instead of a traditional systemic-to-pulmonary artery shunt. Right ventricle-to-pulmonary artery shunts were non-invasively imaged in four infants using gadolinium-enhanced magnetic resonance angiography. Diagnostic MR angiograms were performed in all infants throughout the length of the shunt and were useful in the detection of shunt patency, stenosis, and aneurysm. Associated surgical conduits and shunts were also evaluated. All findings were verified by subsequent conventional angiography or surgery.

Management of continuous venous gas emboli during extracorporeal life support utilizing the Kolobow gas trap.

Extracorporeal life support (ECLS) with a roller pump system uses a closed cardiopulmonary bypass (CPB) circuit not equipped with a venous reservoir. Hence, gas emboli cannot escape the ECLS circuit, predisposing to clot formation, membrane failure and potential gas embolism. Rarely, some patients may develop a continuous release of gas into the venous circulation from multiple sources. Two pediatric ECLS cases are presented with continuous venous gas embolism. A 'gas trap' was devised by creating a column of fluid erected vertically on the venous line. This allowed gas to rise within the column, separating it from the ECLS circuit, thus, preventing gas from lodging in the membrane.

Venovenous extracorporeal membrane oxygenation for cyanotic congenital heart disease.

BACKGROUND: Severe, refractory hypoxemia complicating uncorrected cyanotic congenital heart disease is a potentially lethal condition, even when urgent surgical intervention is undertaken. When a viral pneumonia initiates hypoxemia, the likelihood of a satisfactory outcome is further reduced. We examined our policy of venovenous extracorporeal membrane oxygenation support through the hypoxic event and performing delayed surgery, if required, to separate from extracorporeal membrane oxygenation. METHODS: A single institution, retrospective review of an Institutional Review Board approved database was undertaken. Over a 6-year period, 18 instances were identified for 17 patients who became acutely hypoxemic from either inadequate pulmonary blood flow (8 instances) or a viral pneumonia (10 instances) complicating their cyanotic heart disease. Demographics, duration of venovenous extracorporeal membrane oxygenation and outcomes are reported. RESULTS: The length of venovenous extracorporeal membrane oxygenation ranged from 13.5 to 362.5 hours (mean 130 +/- 121 hours). During 10 supports, operations were performed to facilitate weaning from support. In 7 patients, extracorporeal support was weaned during this surgery. Follow-up was obtained in all patients over a period ranging from 4 months to 7 years (mean 39.0 +/- 23.0 months). There were two late deaths due to sepsis 1.4 and 2.5 months after extracorporeal support. CONCLUSIONS: Venovenous extracorporeal membrane oxygenation allows time for the recovery of acute hypoxic insult and resolution of some viral pneumonia processes. Palliative surgical procedures may be safely undertaken during extracorporeal support. Viral pneumonia is a risk for prolonged support. Venovenous extracorporeal membrane oxygenation is useful in these high-risk patients.

Successful surgical management of a neonate with a saddle pulmonary embolus.

A female neonate presented with evidence of a massive ventilation-perfusion mismatch. She was subsequently found to have a saddle pulmonary embolus. The infant successfully underwent surgical pulmonary embolectomy.

Expanding the donor pool: use of a donor heart having undergone recent cardiac surgery.

The current shortage of donor organs is a well-recognized global phenomenon. The goal of contemporary transplant practice is to optimize and expand the organ donor pool. Despite biologic and technologic advancements, the single most important limitation remains underutilization and non-recovery of potential organs. We report the use of a donor cardiac organ from a 5-year-old child who had undergone recent (<72 hours) closure of an atrial septal defect. The heart was harvested successfully and implanted with no apparent hemodynamic compromise.

Optimizing cardioplegia strategy for donor hearts.

Variability in organ preservation strategy has thus far prevented meaningful analysis of clinical donor heart cardioplegia strategies. This paper describes our donor heart procurement protocol, techniques, and recovery team responsibilities. We present 21 patients receiving cardiac transplantation at our institution with an adopted cardioplegia protocol. The procurement team perfusionist ensures consistent attention to myocardial protection with standards that are similar to those applied to native hearts for all congenital heart surgeries.

Cardiac transplantation in twins with autosomal dominant Emery-Dreifuss muscular dystrophy.

Emery-Dreifuss muscular dystrophy (EDMD) is a neuromuscular disorder resulting in progressive muscle weakness, contractures, and cardiomyopathy. We report successful cardiac transplantation in identical twin brothers with autosomal dominant EDMD, complicated by ventricular arrhythmias and end-stage cardiomyopathy. Early recognition of progressive cardiac disease and subsequent cardiac transplantation are lifesaving in children with EDMD.

Selective timing for the arterial switch operation.

BACKGROUND: To determine outcomes for the arterial switch operation individualized according to the underlying anatomy and clinical status. METHODS: A retrospective review of a consecutive series of infants less than 90 days of age who underwent the arterial switch operation at a single institution. RESULTS: From July 1993-April 2001, 117 infants underwent an arterial switch operation before 90 days of age. Seventy-five patients (64%) had transposition of the great arteries with intact ventricular septum with the aim of operation before 14 days of age; however, 8 of these patients had delayed presentation (range 15-46 days). Thirty-five patients (30%) had transposition with a ventricular septal defect (30 patients) or double outlet right ventricle (5 patients) and normal arch anatomy and were repaired within the first 90 days of life depending on the severity of heart failure at a median of 12 days of age (range 3-83 days). Seven patients (6%) had associated aortic coarctation (5 patients) or interrupted aortic arch (2 patients). One patient died during hospitalization (0.85% hospital mortality) and one patient died from noncardiac causes during a median follow-up of 35 months (1.7% total mortality). Four patients required intervention during follow-up (3.4%) for new aortic coarctation (2 patients), supravalvar pulmonic stenosis (1 patient), or right hemi-diaphragm paralysis (1 patient). CONCLUSIONS: Individualized timing for the arterial switch operation within the first ninety days of life produces excellent survival rates for all types of transposition physiology with the expectation of a satisfactory course during follow-up.

Magnetic resonance flow analysis of classic and extracardiac Fontan procedures: the seesaw sign.

BACKGROUND: Energy inefficiencies lead to Fontan procedure failures. Our purpose was to quantify energy inefficiencies of various Fontan procedures using flow analysis. MATERIALS AND METHODS: The study included 12 patients with Fontan operations; 7 with classic trans-atrial flow and five extra-cardiac Fontans. Flow analysis was used to determine the systolic and diastolic flow in the superior vena cava and inferior venous circulations (IVC, right atrium or conduit). Retrograde flow fractions were calculated. Inferior venous flow analysis was obtained in 12 patients and superior vena cava in 9 patients. RESULTS: A seesaw pattern (augmented inferior venous flow during diastole and augmented superior vena cava flow in systole) was present in five of seven patients with trans-atrial Fontan procedures, but no patient with an extra-cardiac Fontan procedure. Significant retrograde flow occurred in the superior vena cava in three children with trans-atrial Fontan procedures (retrograde flow fractions of 15-22%). Inferior venous flow occurred predominantly during diastole in five of seven children with trans-atrial Fontan procedures. Retrograde flow occurred in all seven children with the retrograde flow fractions ranging from 9 to 37% (mean 25%). Extracardiac Fontan flow was characterized by continuous balanced flow during systole and diastole. The association of the seesaw pattern with trans-atrial Fontan procedures was statistically significant (p = 0.028). CONCLUSIONS: Classic trans-atrial Fontan procedures are characterized by energy inefficiency creating a seesaw flow pattern of forward and reverse flow. Extra-cardiac Fontan procedures are more energy efficient. Magnetic resonance imaging is useful in detecting flow inefficiencies in patients palliated by the Fontan procedure.

Hemodynamic troubleshooting for mechanical malfunction of the extracorporeal membrane oxygenation systems using the PPP triad of variables.

Prolonged usage of disposable extracorporeal membrane oxygenation (ECMO) circuitry increases the risk of mechanical complications due to breakdown or malposition of the circuit elements. Often, such complications are life threatening for the critically ill patient. Such problems need to be rapidly identified and corrected. Algorithms can be especially helpful in such acute, life-threatening situations. We have outlined an algorithm that uses the relationship between three hemodynamic variables that can be used to rapidly identify mechanical dysfunctions associated with use of the ECMO circuit. These hemodynamic variables are premembrane pressure, pump flow, and patient mean systemic arterial pressure (the PPP triad). These variables are interrelated as a change in one variable results in a change in another. Mechanical malfunction can eliminate this relationship. Changes in one variable only suggest mechanical impairment or failure of the ECMO system. When such a change is detected, a checklist can be rapidly reviewed that directs an immediate logical assessment of potential mechanical causes of hemodynamic compromise.

Mitral valve replacement in children: predictors of long-term outcome.

BACKGROUND: Mitral valve replacement (MVR) in children has been associated with a high complication rate. We sought to assess predictors of outcomes in children undergoing MVR. METHODS: A retrospective review of clinical, surgical, and echocardiographic records of patients undergoing MVR was performed. Between 1982 and 2000, 53 children underwent 76 MVR procedures at a median age of 5 years (range, 1 day to 18 years) and weight of 17 kg (range, 3 to 121 kg). Eighteen patients (34%) had more than one MVR. Previous cardiac surgery had been performed in 39 (74%), with 27 (51%) undergoing previous mitral repair. Patients were followed for 9.2 +/- 4.8 (range, 2 to 20) years. RESULTS: There were 14 patient deaths, with 6 patients dying within 30 days, and five transplants (36%). Ten-year freedom from reoperation was 66%. Long-term survivors were older at initial repair (7.0 vs 2.5 years, p = 0.02), with a lower incidence of residual cardiac lesions (3% vs 37%, p < 0.001) and a lower incidence of surgical procedures at the time of MVR (31% vs 63%, p = 0.04). Survivors had better left ventricular function preoperatively (ejection fraction, 68% vs 54%; p = 0.001) and placement of a prosthetic valve within 1 z-score of the echocardiographically measured mitral valve annulus (p = 0.02). CONCLUSIONS: Adverse outcome after MVR is common, particularly in the young child undergoing palliative surgery or requiring additional surgical procedures. Preoperative assessment of mitral valve size and ventricular function is essential for risk stratification of these patients.