Total body water in children with congenital heart disease, before and after cardiac surgery.

The aim of this study was to measure total body water in children with congenital heart disease before and after cardiac surgery and to compare the results of deuterium and 18oxygen dilution methods. Seventeen children (aged 4 to 33 months) were given aliquots of isotopically labeled water 1 week before and 6 hours after cardiac surgery. Isotope equilibration and analysis of the declining enrichment of daily urine samples allowed calculation of the total body water content. Before operation, total body water was significantly elevated (p < 0.001, Wilcoxon test); after operation it fell to approximately normal values. This finding is in contrast to those of previous reports, but may be explained in that the method used for calculation depended on measurements taken over a 7-day period rather than on a single measurement of isotope dilution as used elsewhere. Nevertheless, these results do suggest that surgery can correct the preoperative fluid overload. Comparison of deuterium and 18oxygen dilution methods showed a 2% to 2.5% overestimation of the total body water content with deuterium sampling.

Energy expenditure in children with congenital heart disease, before and after cardiac surgery.

Failure to thrive is a common feature of children with congenital heart disease. Whether this is the result of poor nutrition or an abnormally high basal metabolic rate is unknown, yet the state of nutrition has a profound effect on the metabolic response to injury and strongly influences the outcome of surgical treatment. The aim of this study was therefore to measure the preoperative and postoperative energy requirements of children with congenital heart disease. Eighteen children (aged 4 to 33 months) were given two oral doses of doubly labeled water (H2(18)O and 2H2O), the first 1 week before operation and the second 6 hours after the end of cardiac surgery. By measuring the relative loss of each isotope from the body water pool, we were able to calculate the rate of carbon dioxide production and therefore total energy expenditure. In five patients, energy expenditure was clearly elevated, suggesting that a raised basal metabolic rate is an important factor in the observed failure to thrive in at least a proportion of such children. Postoperatively, energy expenditure fell to values below normal for healthy children (not having an operation), which suggests that the stress of surgery leads to smaller energy requirements than have previously been thought.

Experience with aortic and mitral valve replacement in children.

Ninety-two children underwent aortic (AVR) or mitral valve replacement (MVR), or both, at the Hospital for Sick Children in Toronto from 1963 to February, 1980. No early or late deaths occurred in 39 children having AVR. However, in 50 children having MVR, the operative mortality was 32% and the actuarial survival rate 5 years after operation was only 50%. Major complications occurred with almost equal frequency in the two groups; 50% of children surviving AVR or MVR experienced major complications within 6 years of operation. Retrospective comparison of results with tissue and mechanical valves showed no clear advantage with either type of prosthesis. Outgrowth of a prosthetic valve was satisfactorily managed in children with AVR but presented a difficult problem in those with MVR, who required frequent reoperation to increase the prosthetic valve to adult size. Prosthetic valve replacement in children is a palliative procedure at best, and every effort should be made to preserve the natural valve by a more conservative repair technique.

The effects of cardiopulmonary bypass on thyroid function in infants weighing less than five kilograms.

Triiodothyronine is an important regulator of cellular metabolism and may have potential use as an inotropic agent. The aim of this study was to determine the effects of cardiopulmonary bypass on thyroid function in infants weighing less than 5 kg. Serial measurements of triiodothyronine, thyroxine, and thyroid-stimulating hormone were made in 10 infants and corrected for the effects of hemodilution. We demonstrated a fall in triiodothyronine and thyroxine levels, with some recovery after 3 to 6 hours. An additional decrease then occurred, reaching a trough at 48 hours (representing a fall of 78% for triiodothyronine and 57% for thyroxine) before hormone levels returned to normal at 5 to 7 days. Thyroid-stimulating hormone concentrations increased and decreased, predating and complementing exactly the changes in triiodothyronine and thyroxine. These results are quantitatively and, for thyroid-stimulating hormone, qualitatively different from those previously reported in adults. In two patients who died, however, and in one who had a particularly difficult postoperative course, no increase in triiodothyronine, thyroxine, or thyroid-stimulating hormone concentrations was found after a trough had been reached at 48 to 72 hours, which suggests abnormal function at the hypothalamopituitary level.

Concomitant cor triatriatum and coronary sinus total anomalous pulmonary venous connection.

Successful repair of the rare anomaly of concomitant cor triatriatum and coronary sinus total anomalous pulmonary venous connection in a neonate is described. The presence of pulmonary venous obstruction or cardiomegaly, or both, in a child with total anomalous pulmonary venous connection should alert to the possibility of a coexistent cor triatriatum.

False aneurysm formation: a complication following the modified Blalock-Taussig shunt.

False aneurysm formation is a rare complication of the modified Blalock-Taussig shunt. A patient is described in whom this complication arose 11 months after operation. Death resulted from rupture of the aneurysm into the right lung with associated massive hemoptysis. The onset of hemoptysis in patients with a functioning modified Blalock-Taussig shunt may be the first evidence of a developing false aneurysm.

Somatosensory evoked potentials in the detection of spinal cord ischemia in aortic coarctation repair.

Cortical somatosensory evoked potential (SEP) monitoring was used in 15 patients 2 to 50 years old undergoing repair of aortic coarctation to detect the onset of spinal cord ischemia during the cross-clamp period. Three different response patterns were observed. In 8 patients (53%), the SEP remained unchanged throughout the cross-clamping. This was designated a type 1 response. Six patients (40%) showed a gradual deterioration in the SEP after 15 minutes of cross-clamping (type 2 response). All SEPs returned to normal levels within 5 minutes of release of the clamp. One patient (7%) demonstrated a decline in SEP commencing prior to the application of the cross-clamp when an intercostal vessel was controlled with slings. The SEP completely disappeared within 5 minutes of cross-clamping, but after 19 minutes the repair was completed and the SEP returned within 3 minutes of reperfusion (type 3 response). No patient sustained neurological sequelae of repair. We believe that SEP monitoring offers the potential to identify the patient at risk of developing spinal cord ischemia intraoperatively before irreversible damage occurs. However, it is susceptible to deep halothane anesthesia, which abolishes all cortical responses and requires expert monitoring.

Left atrial myxoma in a preschool child.

A case of left atrial myxoma successfully removed using cardiopulmonary bypass in a 5-year-old child is presented. Review of the literature emphasizes the rarity and clinically aggressive behavior of this tumor in this age group.

Effects of dopamine on liver blood flow in children with congenital heart disease.

BACKGROUND: A reduction in liver function is common after cardiac operations, particularly in children with preexisting cardiac failure. The etiology is multifactorial, but the redistribution of organ blood flow that occurs during cardiopulmonary bypass implicates ischemia as one of the principal causes of injury. Dopamine hydrochloride is known to have specific effects on the renal circulation, and the aim of this study was to investigate its effects on hepatic perfusion. METHODS: Eight children with congenital heart disease were studied 6 hours after the end of cardiopulmonary bypass when they were fully rewarmed and hemodynamically stable. Using noninvasive auricular densitometry, we determined the percent disappearance rate of indocyanine green as an index of liver blood flow both before and 1 hour after commencing an infusion of dopamine at 4 micrograms.kg-1.min-1. RESULTS: Results showed an increase of approximately 31% in the percent disappearance rate of indocyanine green with the addition of low-dose dopamine (4 micrograms.kg-1.min-1) (p < 0.01). CONCLUSIONS: Dopamine may have a therapeutic role in increasing hepatic perfusion and minimizing any loss in liver function.

Coronary ostial patch angioplasty in children.

Patch angioplasty for coronary artery ostial stenosis was first reported in adults in 1952 and only sparsely used until 1983 when Hitchcock reviewed the technique in adults. We present two cases that highlight our use of this technique in inflammatory diseases of the aorta in children. Patch angioplasty restores physiologic perfusion of the coronary artery tree, preserves conduit material for further procedures later in life, and allows subsequent percutaneous transluminal coronary angioplasty of stenosis. For these reasons we believe that patch angioplasty holds undoubted advantage over the available alternatives.

Aortic origin of right pulmonary artery: successful surgical correction in three consecutive patients.

Over a period of four years (1981 through 1984), 3 infants with aortic origin of the right pulmonary artery were seen in our surgical unit. Two infants had a persistent ductus arteriosus, which arose from the left subclavian artery in 1 of them who also had a right-sided aortic arch. There were no other associated abnormalities. Preoperative diagnosis was established by echocardiography in 2 infants. Anatomical surgical correction was undertaken in all 3 infants under cardiopulmonary bypass. There were no operative deaths. One child required reoperation at 15 months for anastomotic stenosis. All 3 children were well two to five years postoperatively with scintillographic evidence of normal ventilation and perfusion. Our experience indicates that this rare but severe congenital cardiac anomaly is easily diagnosed by echocardiography, and confirms that it is eminently amenable to surgical correction.

Transcutaneous iodine absorption in infants undergoing cardiac operation.

Povidone-iodine is an effective antiseptic, but its topical use has been associated with a number of adverse reactions in burn patients and in neonates as a result of transcutaneous absorption. In particular, high plasma iodine concentrations are known to cause renal failure, metabolic acidosis, and thyroid suppression. Because of the permeable nature of the skin in small infants and the large areas cleaned before cardiac operations, it is possible that significant transcutaneous iodine absorption might occur in this situation. We have studied 17 infants, less than 3 months of age, who were undergoing closed cardiac or thoracic procedures. After povidone-iodine skin preparation in 15 (covering 20% to 30% of body surface area), plasma total iodine concentrations rose fourfold (range, 160% to 1,440%). This increase was significantly different from the preoperative level at 6, 12, 18, and 24 hours. There was no increase in plasma iodine concentration in 2 patients who were not exposed to povidone-iodine or any other iodine-containing compound. We discuss the implications for a topical antisepsis policy in infants.

Sinus venosus defect: single-patch repair with caval enlargement.

We present a single pericardial patch repair of the sinus venosus defect with anomalously connected pulmonary veins, incorporating enlargement of the superior vena cava. In our small series to date this procedure has been carried out without morbidity or mortality. Noninvasive follow-up by echocardiography and electrocardiography, over the short term, has not detected any stenosis of the venous pathways or sinus node dysfunction.

Intraaortic balloon pumping in children.

From June, 1977, to December, 1978, 14 children had intraaortic balloon support after open-heart operation. There were 6 long-term survivors. Four of 5 children more than 10 years old and 2 of 5 children between 5 and 10 years old survived. All 4 children less than 5 years old died. In the youngest group, it was difficult to use the balloon successfully because of their very low cardiac output coming off bypass and their greater aortic elasticity. The smallest sizes of balloon available were found to be too long, extending well below the diaphragm in younger patients. In 7 out of 10 patients 5 years old or more, augmentation was obtained.

Assessment of mortality rates for congenital heart defects and surgeons' performance.

BACKGROUND: In the absence of reliable national data, we have collected results of all operations for congenital heart defects from five departments to assess mortality rates and compare them among surgeons and departments. METHODS: Data relating to all operations (2,718) carried out at the five centers during a period from April 1, 1997 through March 31, 1999. Clearly defined criteria were agreed for the classification of patients into various subgroups. RESULTS: The overall hospital mortality was 4.4% (95% confidence intervals 3.7%-5.3%). Mortality for open-operations was 12.6% in neonates, 5.1% in infants, and 3.5% in children. Mortality rates were 1.1% for coarctation, 0.4% ventricular septal defect, 4.1% atrioventricular septal defect, 2.9% Fallot, 0.9% switch, and 15.6% truncus arteriosus. Although individual surgeons' mortality rates ranged from 1.8% to 7.5%, none of the 12 surgeons' data were above 95% confidence intervals. For individual surgeons, the change in mortality rates between the 2 years ranged between -3.3% and +3.8%. CONCLUSIONS: With 2 years' data available, estimates of mortality rates are more precise as reflected by tighter confidence intervals. There were relatively small data sets for individual hospitals and surgeons, which made statistical evaluation difficult. For setting standards, data from more departments for a longer period will be required. Statistical methods alone cannot be used as a sole arbiter of what is considered acceptable performance.

Acute-phase responses to cardiopulmonary bypass in children weighing less than 10 kilograms.

BACKGROUND: Cardiopulmonary bypass induces a systemic inflammatory response. This study investigated, in a pediatric population, cytokine-induced responses and their potential modification by intraoperative steroid administration. METHODS: Markers of the acute-phase response were measured perioperatively in 24 children weighing less than 10 kg undergoing cardiac operations. Those having operations with cardiopulmonary bypass were randomized to receive either no steroid (group I, n = 8) or 10 mg/kg methylprednisolone in the pump prime (group II, n = 10); patients undergoing nonbypass procedures were controls (group III, n = 6). RESULTS: In all groups, plasma interleukin-6 level was elevated (p < 0.01) above baseline throughout the post-operative period, peaking earlier in group I. Levels of C-reactive protein peaked at 48 hours, and postoperative core temperature was raised in all groups. Levels of interleukin-6 from 2 to 6 hours and C-reactive protein at 24 hours postoperatively were greater (p < 0.05) in group I than in group II. Maximum interleukin-6 level, C-reactive protein level, and temperature were all significantly greater in group I than in group III. Maximum interleukin-6 level correlated with maximum C-reactive protein level in group I only (rs = 0.76; p < 0.05) and showed no association with temperature. Duration of bypass did not correlate with levels of interleukin-6. CONCLUSIONS: This study demonstrated a marked acute-phase response to operation; the greater response to procedures with cardiopulmonary bypass was abrogated by intraoperative steroid administration. The importance of interleukin-6 as an inducer of acute phase proteins after bypass is supported by its association with C-reactive protein levels, but other factors must be important in the induction of pyrexia.

Transoesophageal echocardiographic assessment of primum, secundum and sinus venosus atrial septal defects.

We compared the ability of transthoracic and transoesophageal echocardiography to determine the presence and site of an atrial septal defect and associated anomalous pulmonary venous connexions in 13 school age children (aged 5 to 15 years) and 12 adults (aged 25 to 68 years). Transthoracic echocardiography detected atrial septal defects in 12 children and 6 adults. Transoesophageal echocardiography confirmed the position of 16 (13 secundum, 3 primum) of these 18 defects but altered the diagnosis from a secundum defect to a sinus venosus defect in one and from a sinus venosus defect to a high secundum defect in another. In addition to these 18, transoesophageal echocardiography diagnosed a defect in 5 adults (3 secundum and 2 sinus venosus defects) and 1 child (secundum defect). In an adult with inconclusive transthoracic findings, transoesophageal echocardiography enabled clear visualisation of the atrial septum and excluded an atrial septal defect. Transoesophageal echocardiography showed anomalous attachment of a pulmonary vein into the region of a sinus venosus defect (n = 3) but did not show anomalous connexions to the superior caval vein (n = 3) or the inferior caval vein (n = 1). Transoesophageal echocardiography provides a reliable method of diagnosing or excluding an atrial septal defect in patients with inconclusive transthoracic findings and is of particular diagnostic value in sinus venosus defects.

Role of ECMO in neonatal myocardial infarction.

A neonate with myocardial infarction who failed to respond to conventional treatment was supported by extracorporeal membrane oxygenation (ECMO). Severe mitral valve regurgitation necessitated mitral valve replacement while receiving ECMO following which the infant was successfully weaned. ECMO should be considered for potentially treatable causes of catastrophic heart failure.

Management of an infected pseudoaneurysm following an aortoventriculoplasty.

An 11-year-old child developed prosthetic valve endocarditis with associated infection of the prosthetic and pericardial patches 6 months following an aortoventriculoplasty. Angiography revealed an associated false aneurysm which communicated with both the ascending aorta and the right ventricular outflow tract. This report discusses the surgical management of this patient.