Christian Balmer

Cardiac output measurement in children: comparison of Aesculon® cardiac output monitor and thermodilution

BACKGROUND We compared cardiac output (CO) measurements by the non-invasive electrical velocimetry (Aesculon) monitor with the pulmonary artery catheter (PAC) thermodilution method in children. METHODS CO values using the Aesculon monitor and PAC thermodilution were simultaneously recorded during cardiac catheterization in children. Measurements were performed under general anaesthesia. To compare, three consecutive measurements for each patient within 3 min were obtained. The means of the three values were compared using simple regression and Bland-Altman analysis. Data were presented as mean (sd). A mean percentage of <30% was defined to indicate clinical useful reliability of the Aesculon monitor. RESULTS A total of 50 patients with a median (range) age of 7.5 (0.5-16.5) yr were enrolled in the study. Mean CO values were 3.7 (1.5) litre min(-1) (PAC thermodilution) and 3.1 (1.7) litre min(-1) (Aesculon) monitor). Analysis for CO measurement showed a good correlation between the two methods (r=0.894; P<0.0001). The bias between the two methods was 0.66 litre min(-1) with a precision of 1.49 litre min(-1). The mean percentage error for CO measurements was 48.9% for the Aesculon monitor when compared with PAC thermodilution. CONCLUSIONS Electrical velocimetry using the Aesculon monitor did not provide reliable CO values when compared with PAC thermodilution. Whether the Aesculon monitor can be used as a CO trend monitor has to be assessed by further investigations in patients with changing haemodynamics.

Familial X-linked cardiomyopathy (Danon disease): diagnostic confirmation by mutation analysis of the LAMP2gene.

A boy presented at age 2.5 years with mild left ventricular hypertrophy and mild myopathy. Hypertrophic cardiomyopathy progressed relentlessly, leading to death at age 16 years shortly before planned heart transplantation. During the course of the disease, his mother developed severe dilated cardiomyopathy and died of its complications at 46 years of age. The combination of myopathy and cardiomyopathy, the biochemical and electron microscopy findings in a muscle biopsy, and the pedigree suggested Danon disease (MIM 300257), an X-linked lysosomal storage disorder caused by deficiency of lysosome-associated membrane protein-2 (LAMP2). The diagnosis was confirmed by the identification of a novel mutation, G138A, in the LAMP2gene, leading to the premature stop codon W46X. Conclusion:Early diagnosis of Danon disease is important for genetic counselling and timely cardiac transplantation, the only effective therapeutic option.

Feasibility of perfusion cardiovascular magnetic resonance in paediatric patients

AimsAs coronary artery disease may also occur during childhood in some specific conditions, we sought to assess the feasibility and accuracy of perfusion cardiovascular magnetic resonance (CMR) in paediatric patients.Methods and resultsFirst-pass perfusion CMR studies were performed under pharmacological stress with adenosine and by using a hybrid echo-planar pulse sequence with slice-selective saturation recovery preparation. Fifty-six perfusion CMR examinations were performed in 47 patients. The median age was 12 years (1 month-18 years), and weight 42.8 kg (2.6-82 kg). General anaesthesia was required in 18 patients. Mean examination time was 67 ± 19 min. Diagnostic image quality was obtained in 54/56 examinations. In 23 cases the acquisition parameters were adapted to patients size. Perfusion CMR was abnormal in 16 examinations. The perfusion defects affected the territory of the left anterior descending coronary artery in 11, of the right coronary artery in 3, and of the circumflex coronary artery in 2 cases. Compared to coronary angiography, perfusion CMR showed a sensitivity of 87% (CI 52-97%) and a specificity of 95% (CI 79-99%).ConclusionIn children, perfusion CMR is feasible and accurate. In very young children (less than 1 year old), diagnostic image quality may be limited.

Successful cardiac resynchronization with single-site left ventricular pacing in children

BACKGROUND Dyssynchronous left ventricular (LV) contraction due to permanent right ventricular apex (RVA) pacing or delayed electrical activation as typically observed in left bundle brunch block (LBBB) has a negative impact on LV function. Objective was to evaluate the impact of epicardial single-site LV pacing in children on LV function and resynchronization. PATIENTS Single-site epicardial LV free wall pacing was established in 6 children with congenital heart disease and echocardiographic signs of LV dyssynchrony. Reasons for dyssynchrony were either long-term RVA pacing (n=5; pacing duration: 7.7+/-2.4 years) or LBBB with drug-resistant congestive heart failure (n=1). RESULTS After 1 month of single-site LV pacing, LV ejection fraction increased (41+/-6 versus 53+/-8%) and LV enddiastolic volume decreased (70+/-22 versus 63+/-18 ml/m(2)) as compared to pre-implant measurements. Interventricular mechanical delay decreased (67+/-15 versus 16+/-15 ms) and intraventricular synchrony was restored (septal-to-posterior wall motion delay: 312+/-24 versus 95+/-57 ms). Accordingly, circumferential 2D strain demonstrated a decrease of LV mechanical delay (201+/-35 versus 99+/-23 ms). CONCLUSION After 1 month of single-site LV pacing, conventional and 2D strain derived echocardiographic measurements indicated improved ventricular function and synchronization in children with previous RVA pacing or LBBB. Further studies are needed to evaluate whether single-site LV pacing may be sufficient for resynchronization therapy.

Intubation depth markings allow an improved positioning of endotracheal tubes in children

ObjectivesTo evaluate the position of the new Microcuff® pediatric tracheal tube, based upon intubation depth markings.MethodsWith Institutional Ethics Committee approval and informed parental consent, we included patients from birth (≥ 3 kg) to 16 yr undergoing interventional cardiac catheterization requiring general anesthesia with oro-tracheal intubation. The intubation depth mark of the tracheal tube was placed between the vocal cords by direct laryngoscopy. The distance between tube tip and tracheal carina was measured from routinely taken cardiac catheterization posterior-anteriorx-ray computer images with the patient supine and the head in a neutral position. Evaluation was performed for 20 tubes size 3.0 mm internal diameter (ID) and for ten tubes of each size from 3.5 to 7.0 mm ID.Results100 patients were studied (47 girls; 53 boys). Tracheal tube tip advancement into the trachea ranged from 40.6% to 68.6% (median 51.4%). The shortest distance from tube tip to the tracheal carina was 15.7 mm using a 3.0 mm ID tube. Using a standard formula for tube insertion in children aged ≥ two years [12 cm + (age/2)], in one patient the tube tip would have been below the carina and in seven patients the tube cuffs would have been placed within the larynx.ConclusionThe intubation depth markings of the new Microcuff® pediatric tracheal tube allow safe placement of the tracheal tube with a cuff-free laryngeal zone without the risk for endobronchial intubation. Placement using the intubation depth markings was superior to predicted insertion using a standard formula.RésuméObjectifÉvaluer la position du nouveau tube endotrachéal pédiatrique Microcuff® ďaprès le marquage de la profondeur du tube.MéthodeAvec ľaccord du Comité ďéthique et des parents, nous avons étudié des patients, de bébé naissant (≥3 kg) à 16 ans, devant subir une exploration cardiaque par cathétérisme nécessitant une anesthésie générale avec intubation orotrachéale. La marque de la profondeur ďinsertion du tube a été placée entre les cordes vocales par laryngoscopie directe. Le patient étant couché et sa tête en position neutre, la distance entre la pointe du tube et la carène de la trachée a été mesurée à partir ďimages radiographiques informatisées postéro-antérieures, couramment prises, du cathétérisme cardiaque. L’évaluation a été réalisée pour 20 tubes de diamètre interne (DI) de 3,0 mm et pour 10 tubes de chaque taille entre 3,5 et 7,0 mm de DI.RésultatsNous avons étudié 100 patients (47 filles et 53 garçons). Le pourcentage ďoccupation de la trachée par le tube endotrachéal variait de 40,6 % à 68,6 % (médiane de 51,4 %). La plus courte distance entre la pointe du tube et la carène a été de 15,7 mm avec un tube de DI de 3,0 mm. Selon la formule standard ďinsertion ďun tube chez les enfants de ≥deux ans [12 cm + (âge/2)], la pointe du tube aurait été en un point distal de la carène chez un patient et le ballonnet au niveau du larynx chez sept patients.ConclusionLe marquage de la profondeur ďinsertion du nouveau tube endotrachéal pédiatrique Microcuff® permet une mise en place sûre du tube et assure une zone laryngée libre de ballonnet sans le risque ďintubation endobronchique. Le placement guidé par des marques de profondeur du tube a été supérieur à ľinsertion prédite selon la formule standard.

Congenital Prothrombotic Disorders in Children with Peripheral Venous and Arterial Thromboses

Aims: To evaluate the prevalence of congenital prothrombotic disorders in children with peripheral venous and arterial thromboses. Methods: Deficiencies in antithrombin (AT), proteins C (PC) and S (PS), and increased lipoprotein (a), and the presence of factor V (FV) G1691A, prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) mutations were investigated. Results: Forty-eight patients (mean age, 3.4 years) were investigated. Of these patients, 23 had venous thrombosis, 22 had arterial thrombosis, and 3 had both. No patients had AT, PC or PS deficiency. FV G1691A mutation was present in 2 (7.6%) and 3 (12%) patients with venous and arterial thromboses, respectively. The prothrombin G20210A mutation was present in 1 (4%) patient with arterial thrombosis. Homozygous MTHFR C677T mutation was detected in 4 (18%) and 2 (9%) patients with venous and arterial thromboses, respectively. Increased lipoprotein (a) was present in 2 (10%) and 1 (4.5%) patients with venous and arterial thromboses, respectively. Regarding acquired risk factors, 79% of all thrombotic events were related to catheter usage. An underlying disease was present in 96% of the patients. Conclusions: Compared to acquired risk factors, congenital prothrombotic disorders are rarely present in children with peripheral venous and arterial thromboses. These results do not support general screening of children with venous and arterial thromboses for congenital prothrombotic disorders.

Children with genetic disorders undergoing open-heart surgery: are they at increased risk for postoperative complications?

Objectives: Children with congenital heart disease and genetic disorders may be at increased risk for postoperative mortality and morbidity compared with children with congenital heart disease alone. The aim of the present study was to determine differences in postcardiopulmonary bypass outcome between these two groups. Design: Prospective cohort study. Setting: Tertiary university childrens hospital. Patients: We enrolled 211 infants (<1 yr) who underwent bypass surgery for congenital heart disease. Data on perioperative course were compared between infants with and without genetic disorders. Univariate analysis was followed by regression analysis to control for confounders. Interventions: None. Measurements and Main Results: We enrolled 148 infants without and 63 infants with a genetic disorder. The majority of infants with genetic disorders had trisomy 21 (n = 32), six had microdeletion 22q11, and 25 had other genetic disorders. There was no significant difference in mortality between infants with and without genetic disorders. An underlying genetic disorder was an independent risk factor for renal insufficiency (p = .003) and reintubation (p = .02). Trisomy 21 was an independent risk factor for chylothorax (p = .01) and sepsis (p = .05). The length of hospital stay was longer in infants with genetic disorders other than trisomy 21 compared with infants with trisomy 21 (p = .009). Conclusions: Infants with congenital heart disease and genetic disorders are not at increased risk for postoperative mortality. However, a genetic disorder is a risk factor for reintubation and renal insufficiency, whereas infants with trisomy 21 have a higher risk of chylothorax and sepsis. Intensive care providers need to be aware of these differences in morbidity to improve management decisions and parental counseling.

Cardiomyopathy in newborns and infants: a broad spectrum of aetiologies and poor prognosis

Aim: This study set out to describe the initial clinical findings, morbidity, mortality and aetiology of infant cardiomyopathy focusing on potential risk factors for an adverse outcome.

Interventions using foreign material to treat congenital heart disease in children increase the risk for infective endocarditis.

Background: Congenital heart disease (CHD) is a risk factor for infective endocarditis (IE). We aimed to assess the impact of cardiac interventions on the frequency and microbial profile of IE in children with CHD. Methods: Episodes of IE were analyzed in children aged ≤18 years with CHD between 1995 and 2005 with respect to cardiac surgery or catheter interventions with or without implantation of foreign material. Results: Diagnosis of IE was made in 14 (0.36%) of 3826 children with CHD including native IE in 6 and postinterventional IE in 8 patients. During the period 3029 cardiac interventions (1944 surgeries; 1085 catheters) were performed; foreign material was implanted in 1360 interventions (1139 surgeries; 221 catheters) including all 8 patients with postinterventional IE. Cardiac intervention by itself did not change the risk for IE compared with no intervention. The risk of IE after implantation of foreign material was higher than following intervention without implantation (odds ratio, 21.0; 95% confidence interval, 1.2–365; P < 0.05). Pacemaker implantation was associated with the highest risk for IE (odds ratio, 11.0; 95% confidence interval, 2.6–46.5; P < 0.001). Staphylococci were the most frequently isolated organisms in foreign material-associated IE. Conclusions: Cardiac intervention in children with CHD does not increase the risk for IE. Postinterventional IE in children with CHD is strongly linked to implantation of foreign material, especially of pacemaker.

Prevalence and predictors of later feeding disorders in children who underwent neonatal cardiac surgery for congenital heart disease

AIM We thought of assessing the prevalence and predictors of feeding disorders in patients with congenital heart defects after neonatal cardiac surgery. METHODS Retrospective study of 82 consecutive neonates (48 males, 34 females) who underwent surgery for congenital heart defects from 1999 to 2002. Information was taken from patient charts and nursing notes. The presence of a feeding disorder was assessed by a questionnaire sent to the paediatricians when the child was 2 years of age. A feeding disorder was defined as a need for tube feeding, inadequate food intake for age, or failure to thrive. Data were analysed with descriptive statistics and logistic regression. RESULTS Feeding disorders occurred in 22% of the study population. Reoperation and early feeding disorders were identified as independent risk factors for later feeding disorders (odds ratio 5.8, p 0.01; odds ratio 20.7, p 0.02). There was a trend towards more feeding disorders in patients with neurological abnormalities during the first hospital stay. CONCLUSION Feeding disorder is a frequent, long-term sequela after neonatal cardiac surgery. Patients with congenital heart defects who undergo multiple cardiac surgeries and those with early feeding disorders are at risk of developing later feeding disorders. Patients with these risk factors need to be selected for preventive strategies.