Bo Lundell

OXYGEN CONSUMPTION IN INFANTS AND CHILDREN DURING HEART CATHETERIZATION

Oxygen consumption was measured in infants, children, and adolescents during diagnostic heart catheterizations. A total of 825 measurements of oxygen consumption (VO2) was performed in 504 subjects using a semiopen hood system and a paramagnetic oxygen analyzer. In 256 subjects under 3 years of age, body dimensions and heart rate were found to be significant factors for oxygen consumption. The regression equation for both sexes was: VO2/BSA (ml/min·m2)=3.42·height (cm)−7.83·weight (kg) +0.38·HR −54.1 (r2=0.39, SD=38.7), where BSA is body surface area and HR is heart rate. VO2/BSA was significantly lower in infants less than 3 months of age (133±33 ml/min·m2 compared with infants of 3–12 months (171±37 ml/min·m2;p<0.01). In 272 children aged 3 years and older and adolescents, gender was a significant factor in oxygen consumption together with BSA and HR. The regression line equation for males was VO2/BSA (ml/min·m2)=0.79·HR−7.4·BSA(m2+108.1 (r2=0.45, SD=34.2). The regression line equation for females is VO2/BSA (ml/min·m2)=0.77·HR−5.2·BSA(m2)+106.8 (r2=0.43, SD=34.4). Hematocrit, systemic oxygen saturation, and blood pressure were not significant factors. The predictive value of nomograms for oxygen consumption is limited because of the large interindividual variations not explained by differences in gender, body size, or simple hemodynamic variables. Preferably, oxygen consumption is measured; but if nomograms for oxygen consumption are used for hemodynamic assessment, the wide confidence intervals should be considered.

Inhaled nitric oxide in neonates and children with pulmonary hypertension

Fourteen critically ill neonatal and paediatric intensive care patients with various primary diagnoses and signs of associated pulmonary hypertension received inhaled nitric oxide (NO), 20–80 ppm, after failure of conventional therapy to improve oxygenation. NO administration was found to be associated with a significant improvement in postductal arterial oxygen tension (pre‐NO: 3.75 (SD 1.39) kPa; post‐NO: 6.05 (SD 1.70) kPa; p = 0.004). In 10 patients, NO was found to increase arterial oxygen tension with more than 1 kPa. In 2 of these patients, ECMO treatment could be avoided due to the pronounced improvement in gas exchange seen after the initiation of NO administration. The remaining 4 patients failed to respond to NO administration. One patient developed methaemoglobinaemia (13.9%) which required treatment with methylthionine. Since we were unable to produce any beneficial effect of NO in the late phase of the pulmonary disease process, we believe that, in order to be successful, inhaled NO should be instituted when conventional treatment has failed and the administration of an iv vasodilator is usually considered.

Long-term survival in children with atrioventricular septal defect and common atrioventricular valvar orifice in Sweden

BACKGROUND The survival for patients with atrioventricular septal defect has improved markedly over the last decades and, during the same period, the survival of children with Downs syndrome has also increased. The aim of our study was to investigate long-term survival in patients having atrioventricular septal defect with common valvar orifice, but without associated significant congenital heart defects, in the setting of Downs syndrome, comparing the findings to those in chromosomally normal children with the same malformation. METHODS AND RESULTS In a population-based retrospective study, we scrutinised the medical records from 801 liveborn children with atrioventricular septal defect born in Sweden during the period 1973 through 1997. Data on gender, presence or absence of Downs syndrome, associated congenital heart defects, date of birth, operation and death were recorded and followed up until 2001. An isolated atrioventricular septal defect with common atrioventricular valvar orifice was present in 502 children, of whom 86% had Downs syndrome. We found a significant reduc tion over time in age at operation, and in postoperative mortality at 30 days, from 28 to 1%. Using a multiple logistic regression model, we found no significant differences in mortality between genders, nor between those with or without Downs syndrome. Early corrective surgery could not be identified as a significant independent factor for survival. The 5-year postoperative survival in patients with Downs syndrome increased from 65% over the period from 1973 through 1977, to about 90% in the period 1993 through 1997, and the same trend was observed in chromosomally normal patients. CONCLUSIONS Survival in uncomplicated atrioventricular septal defect with common atrioventricular valvar orifice has greatly increased, and surgical correction is now equally successful in patients with Downs syndrome and chromosomally normal patients, and for both genders. Death in connection with surgery is no longer the major threat, and focus must now be on long-term follow-up.

Changes in Intracranial Arterial Blood Flow Velocities during Surgical Ligation of the Patent Ductus Arteriosus

ABSTRACT. A combined continuous and range‐gated Doppler instrument was used to assess intracranial arterial blood flow velocity changes in infants and neonates undergoing surgical ligation of the Ductus Arteriosus (DA). Continuous recordings during DA closure in six infants (3.5‐10 months old), showed an abrupt increase in diastolic blood flow velocity simultaneous with an increase in systolic and diastolic arterial blood pressure. In five infants, these changes were followed by a rapid fall in systolic and diastolic blood pressure without a concomitant change in blood flow velocity, which may be secondary to a rapid fall in intracranial vascular resistance. The mean blood flow velocity increase following DA closure was 27 % (8‐43 %) and the changes in diastolic and mean blood flow velocity were significant (p<0.01). In seven preterm neonates (24‐28 weeks) studied before and after surgery, a mean blood flow velocity increase of 50 % (14‐115 %) (p<0.01), mainly due to an increase in diastolic blood flow velocity (p<0.01), was recorded. These rapid intracranial hemodynamic changes during surgical DA closure should be taken into consideration when selecting techniques for DA closure.

POSTNATAL CHANGES IN INTRACRANIAL BLOOD FLOW VELOCITY IN PRETERM INFANTS

ABSTRACT. Postnatal changes in intracranial arterial blood flow velocity, were studied in preterm infants of less than 34 weeks of gestation. The blood flow velocity was measured in an artery on the base of the skull, using a range‐gated Doppler ultrasound velocimeter. Ten healthy infants (mean gestational age 32.5 weeks), and ten infants with transitional respiratory disease (mean gestational age 31.3 weeks) were studied at 1, 2, 5, 24 h, and 2, 3, 5 and 10 days after birth. The healthy infants showed a consistent pattern of changes on the first day, with an average reduction in mean flow velocity of 29% between 1 and 5 h. At 24 h after birth, mean flow velocity had almost returned to the level of the 1 h recording. After 24 h there was a gradual increase in systolic and mean flow velocity until 10 days, while diastolic flow velocity remained unchanged. In the infants with respiratory disease there were no systematic changes in mean flow velocity on the first day, although large individual changes were seen. After 24 h no differences were seen between the healthy infants and the infants with respiratory disease. These findings indicate a transient decrease in cerebral perfusion during early circulatory transition in healthy preterm infants, and that mild to moderate respiratory disease causes larger individual variations in intracranial blood flow velocity.

Evaluating national guidelines for the prophylactic treatment of respiratory syncytial virus in children with congenital heart disease

This is the first study to evaluate compliance with the 2003 Swedish national guidelines for prophylactic treatment of respiratory syncytial virus (RSV) in children with congenital heart disease (CHD). We estimated the relative risk (RR) of children with CHD being hospitalised with a RSV infection, studied the extent to which RSV prophylactic treatment with palivizumab corresponded to the guidelines and determined the morbidity of children with CHD who developed RSV infection despite prophylaxis.

Respiratory Tract Infection and Risk of Hospitalization in Children with Congenital Heart Defects During Season and Off-Season: A Swedish National Study

Respiratory tract infections (RTI) are common among young children, and congenital heart defect (CHD) is a risk factor for severe illness and hospitalization. This study aims to assess the relative risk of hospitalization due to RTI in winter and summer seasons for different types of CHD. All children born in Sweden and under the age of two, in 2006–2011, were included. Heart defects were grouped according to type. Hospitalization rates for respiratory syncytial virus (RSV) infection and RTI in general were retrieved from the national inpatient registry. The relative risk of hospitalization was calculated by comparing each subgroup to other types of CHD and otherwise healthy children. The relative risk of hospitalization was increased for all CHD subgroups, and there was a greater increase in risk in summer for the most severe CHD. This included RSV infection, as well as RTI in general. The risk of hospitalization due to RTI is greater for CHD children. Prophylactic treatment with palivizumab, given to prevent severe RSV illness, is only recommended during winter. We argue that information to healthcare staff and parents should include how the risk of severe infectious respiratory tract illnesses, RSV and others, is present all year round for children with CHD.

A Case of Neonatal Endocarditis

Bacterial endocarditis is extremely rare in neonates. Neonatal intensive care, however, with its different invasive procedures may increase the risk of bacteremia, septicemia and probably also endocarditis in newborns. We report on a case of documented Staphylococcus aureus endocarditis in a 6week-old girl. She had signs of septicemia and was investigated with echocardiography because of a heart murmur. A large vegetation on the septal mitral valve leaflet was discovered and successfully removed surgically.