Mauri Leijala

Delayed impairment of cerebral oxygenation after deep hypothermic circulatory arrest in children

BACKGROUND Clinical studies of deep hypothermic circulatory arrest (DHCA) have focused only on the immediate postoperative period. However, experimental findings suggest impairment of cerebral oxygenation at 2 to 8 hours after reperfusion. METHODS In 10 children who had DHCA for heart operations, transcerebral differences of hemoglobin oxygen saturation and plasma hypoxanthine, xanthine, and lactoferrin concentrations were measured in concurrently obtained cerebral venous, arterial, and mixed venous samples up to 10 hours postoperatively. RESULTS Compared with preoperative levels (57% +/- 7%), cerebral venous oxygen saturation was not significantly reduced until 2 hours (44% +/- 6%) and 6 hours (42% +/- 5%) after DHCA (p < 0.05). A statistically significant transcerebral (ie, cerebral vein versus artery) concentration difference of hypoxanthine was observed at 30 minutes (3.6 +/- 0.9 micromol/L), 1 hour (3.4 +/- 1.1 micromol/L), and 2 hours (3.1 +/- 0.8 micromol/L) after DHCA but not preoperatively (0.4 +/- 0.2 micromol/L). A transcerebral concentration difference of lactoferrin occurred 30 minutes after DHCA (196 +/- 70 microg/mL) but not preoperatively (16 +/- 20 microg/mL). CONCLUSIONS Cerebral venous oxygen saturation of hemoglobin decreased as late as 2 to 6 hours after DHCA, in association with impaired cerebral energy status. Neutrophil activation in the cerebral circulation occurred 30 minutes after reperfusion.

Amrinone Versus Dopamine-Nitroglycerin After Reconstructive Surgery for Complete Atrioventricular Septal Defect

OBJECTIVES To compare the effectiveness and safety of amrinone and a combination of dopamine and nitroglycerin in infants after reconstructive surgery for congenital heart disease. DESIGN A prospective, randomized, double-blind study. SETTING Pediatric intensive care unit in a university hospital. PARTICIPANTS Thirty-two infants with complete atrioventricular septal defect. INTERVENTIONS Amrinone loading dose, 2 mg/kg, followed by a maintenance infusion, 7.5 micrograms/kg/min, was given to 17 infants before separation from cardiopulmonary bypass. The remaining 15 patients received a combination of dopamine, 5 micrograms/kg/min, and nitroglycerin, 1 microgram/kg/min. MEASUREMENTS AND MAIN RESULTS The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (2.5 +/- 0.7 L/min/m2) compared with the dopamine-nitroglycerin group (2.0 +/- 0.6 L/min/m2, mean +/- SD). The pulmonary blood flow index in the amrinone group was higher (2.9 +/- 0.6 L/min/m2) than in the dopamine-nitroglycerin group (2.2 +/- 0.6 L/min/m2); no significant difference was noted in the mean pulmonary artery pressure. The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.41 +/- 0.07) compared with the amrinone group (0.34 +/- 0.08). Despite lower platelet counts in the amrinone group, no hemorrhagic complications were seen in any patient. CONCLUSIONS With this dosage regimen, amrinone provides a higher cardiac output, more favorable oxygen dynamics, and lower pulmonary vascular resistance than dopamine and nitroglycerin.

Prolonged granulocyte activation, as well as hypoxanthine and free radical production after open heart surgery in children

ObjectiveTo investigate granulocyte activation, as well as hypoxanthine and free radical production in children during the first day after cardiopulmonary bypass.Design: A prospective study of pediatric patients undergoing either cardiac surgery with a cardiopulmonary bypass or thoracotomy and extracardiac vascular surgery not requiring a cardiopulmonary bypass.SettingOperative and intensive care units, Childrens Hospital, University of Helsinki, Finland.PatientsSeven consecutive patients undergoing elective correaction of a ventricular septal defect and six patients undergoing extracardiac surgery for ligation of a patent ductus arteriousus or repair a coarctation of the aorta.Measurements and main resultsPlasma concentrations of myeloperoxidase (140–334 μg/l preoperatively, 460–1692 μg/l at 0.2 h after declamping, 471–1386 μg/l at 0.5 h after declamping) and lactoferrin (77–258 μg/l preoperatively, 533–1783 at 0.2 h 404–1482 μg/l at 0.5 h) as markers of granulocyte activation, and hypoxanthine (0–5.7 μmol/l preoperatively, 4.3–17.0 μmol/l at 0.2 h, 6.5–17.9 μmol/l at 0.5 h) increased in a biphasic manner at 0.2–0.5 h and 6–10 h postoperatively (allp<0.05). Expired ethane, as an index of free radical activity, increased at 10 h postoperatively (36–119 pmol/kg per min preoperatively, 72–152 pmol/kg per min,p<0.05).ConclusionGranulocyte activation, and hypoxanthine and free radical production occur at least 10 h after cardiopulmonary bypass. In children undergoing open heart surgery, attempts to reduce free radical activity should be extended to the postoperative period.

Pancreatitis after open heart surgery in children

Between January 1981 and March 1986, we found 54 children with abnormal serum amylase values or clinical pancreatitis after open heart surgery. Of these 33, had increased serum amylase values only, and 19 had increased serum amylase values in conjunction with clinical pancreatitis. Two patients had haemorrhagic pancreatitis identified at autopsy. The mortality was 42.9% (9/21) in patients with pancreatitis compared to 9.1% (3/33) with amylasaemia only. Pancreatitis is a serious complication after complex open heart surgery in children. The aetiology is probably of vascular origin, and routine serum amylase screening is recommended.

PRIMARY MEDIASTINAL TUMORS IN CHILDREN

From 1950-1986, a total of 159 children (age 1 day-16 years) were treated for primary mediastinal tumors at our hospital. There were 77 malignant and 82 benign tumors. Tracheal compression causing respiratory distress was a significant symptom in 45.3% (24/53) of the children under 2 years of age. The diagnosis was based on the chest X-ray and the findings at surgery. Malignant lymphoma was usually diagnosed by cervical lymph node biopsy (23/39) but the treatment protocol was non-surgical. Non-lymphatic malignant tumors were completely or partially excised in 59.0% (23/39) of the cases. There was no early or late mortality in patients with benign tumors. At follow-up (0.5-24 years; mean 6.0 years), 62.3% (48/77) of the patients with malignant tumors were alive and symptom free. About half of the mediastinal tumors in children are malignant. Mediastinal tumors in small children can cause severe respiratory symptoms demanding urgent treatment. The treatment of choice is surgery (except in lymphomas) and the results are good even in malignant tumors.

Iatrogenic, unexpected and other vascular rings in children.

Between May 1955 and July 1987, 33 children with a vascular ring compression syndrome were treated at this institution. There were 4 iatrogenic, 2 unexpectedly found and 27 symptomatic congenital vascular rings. Accurate diagnosis is based on a water soluble iodine contrast dye oesophagogram, bronchoscopy and angiography which are complementary examinations. All symptomatic congenital vascular rings were treated successfully without mortality, but the mortality was 50% if the lesion was iatrogenic in origin or unexpectedly found during palliative or corrective cardiac surgery.

Cardiac rhabdomyomas in a newborn baby. Early diagnosis and treatment.

ABSTRACT. Cardiac tumours are rarities in newborn infants. The majority of them are rhabdomyomas as a manifestation of the basic disease‐tuberous sclerosis. The clinical picture may vary from serious arrhythmias to A‐V valve obstruction and gross myocardial dysfunction. Therefore these patients are extremely poor candidates for invasive diagnostic procedures and surgical treatment. Our patient had intrauterine cardiac arrhythmias, and a prenatal echocardiogram showed features of A‐V septal defect malformation. Therefore the echocardiogram was repeated soon after birth and it revealed intracardiac tumours. The patient was operated on the first day of life and four intracavitary tumours were successfully removed.

SURGERY FOR VENTRICULAR SEPTAL DEFECT

Of 255 patients undergoing closure of ventricular septal defect (VSD), 48% were younger than 2 years, 59% had associated cardiac and 26% non-cardiac abnormality, 13% had multiple, and only 29% isolated VSD. VSD was closed via the left ventricular apex in seven cases, without increased morbidity or mortality. The three early and six late deaths occurred in patients with complicated defects. Pulmonary vascular occlusive disease caused four deaths (1 early, 3 late). At follow-up (mean c. 3, range 1-11 years), 79% of the patients were well, 10% had cardiac symptoms and 7.5% had symptoms from associated noncardiac anomalies. Reoperation for significant residual VSD was required in 12 cases (4 single and 8 multiple VSD). Complete, pacemaker-requiring A-V block was found in four patients (none with simple VSD closure). It is concluded that 1) concomitant cardiac and non-cardiac lesions are common in VSD, 2) mortality is closely related to such lesions and to pulmonary vascular occlusive disease, 3) the latter is a rare, but real cause of death, 4) left ventricular approach need not increase mortality or morbidity, 5) significant residual VSD is rare after single, but common in multiple VSD, and 6) risk of complete A-V block after simple VSD closure is very low.

Comparison of hollow fibre membrane oxygenators during cardiopulmonary bypass in children: Dideco Masterflo versus Terumo Capiox II.

This prospective study was planned to compare two different (reversed blood and gaseous compartments) hollow fibre membrane oxygenators, Dideco Masterflo and Terumo Capiox II, in order to find out which of these oxygenators was less injurious during cardiopulmonary bypass (CPB) surgery in small children. Twenty children underwent CPB surgery for complex congenital cardiac malformations. Ten patients were selected for each study group by matching age and weight. Oxygenators were the only variables in the CPB circuit, and special attention was focused on the kinetics of white blood cell count (WBC), complement C3, anaphylatoxin C3a, total haemolytic complement (CH100), C-reactive protein (CRP) and haptoglobin. There were no significant differences between the parameters studied at any sample time. However, there was less intense C3a (peak C3a levels 2506 ± 1187 SD versus 4302 ± 3958 SD; p = 0.19) generation, and also less intense CH100 consumption (percentual drop of initial CH100 values was 30% versus 55.2%) in the Dideco Masterflo group of patients. Moreover, postoperative respiratory treatment was somewhat shorter when using Masterflo oxygenators (2.4 ± 2.41 SD versus 4.0 ± 2.49 SD days; p = 0.16), although statistical significance was not obtained. These findings may be important in high-risk paediatric patients undergoing open-heart surgery.

Lung mechanics and airway pressure transmission in infants after open heart surgery

To evaluate the effects of positive airway pressure on lung mechanics and airway pressure transmission into the intrathoracic space, airway and intrathoracic pressure were recorded during stepwise lung inflation in 17 infants undergoing open heart surgery during the first year of life. Eleven of the 17 patients had cuffed tracheal tubes allowing calculation of lung and chest wall compliance. In 7 of these 11 patients, lung inflation to 2.5 ml/kg above functional residual capacity produced an improvement in initially low lung compliance. This volume increment required elevation of airway pressure by 4-11 cm H2O above ambient. Further lung inflation to 10 ml/kg did not effect an improvement in lung mechanics. In the remaining patients, initial lung compliance was high and remained unchanged throughout the range of lung inflation. Transmission of pressure into the intrathoracic space averaged 47 +/- 9% (mean +/- SD) and ranged from 33% to 61% when airway pressure was 10-15 cm H2O. The results indicate that the use of moderately elevated airway pressure is required to optimize lung distensibility in most infants immediately after open heart surgery. When evaluating circulatory effects of elevated airway pressure, assumption of a 50% pressure transmission is appropriate for clinical purposes. However, the observed wide range of pressure transmission warrants careful hemodynamic monitoring during continuous positive pressure breathing.