Legislation and refusal of blood transfusion by a minor Jehovah-Witness in Belgium.

The refusal of blood transfusion by Jehovah's Witnesses in critical situations constitutes an ethical and juridical dilemma. The refusal to receive blood products by Jehovah's Witnesses is based on biblical verses. Recurring arguments to sustain this refusal regard the right to self-determination and the right to freedom of faith. If minors are involved, the problem is rendered even more difficult as the parental authority over young children needs to be taken into account. When adolescents are concerned, the situation if even more ambiguous since adolescents might be considered as mature enough to provide autonomous consent. On the basis of three cases, the most frequent bottlenecks that can come up in paediatric emergency services are highlighted: (1) the refusal of a blood transfusion by the parents of a young child; (2) the refusal by an adolescent and (3) prior refusal based on a "No Blood"-document. Regarding minors, the law on patients' rights in Belgium contains safety mechanisms concerning the preservation of physical integrity. Therefore, a key responsibility has been assigned to the physician. A step-by-step plan and a synoptic diagram are presented.

Child's and parents' catastrophizing about pain is associated with procedural fear in children: a study in children with diabetes and their mothers.

The contribution of the child's and parents' catastrophizing about pain was explored in explaining procedural pain and fear in children. Procedural fear and pain were investigated in 44 children with Type I diabetes undergoing a finger prick. The relationships between parents' catastrophizing and parents' own fear and estimates of their child's pain were also investigated. The children and their mothers completed questionnaires prior to a routine consultation with the diabetes physician. Children completed a situation-specific measure of the Pain Catastrophizing Scale for Children (PCS-C) and provided ratings of their experienced pain and fear on a 0-10 numerical rating scale (NRS). Parents completed a situation-specific measure of the Pain Catastrophizing Scale For Parents (PCS-P) d provided estimates of their child's pain and their own experienced fear on a 0-10 NRS. Analyses indicated that higher catastrophizing by children was associated with more fear and pain during the finger prick. Scores for parents' catastrophzing about their children's pain were positively related to parents' scores for their own fear, estimates of their children's pain, and child-reported fear, but not the amount of pain reported by the child. The findings attest to the importance of assessing for and targeting child and parents' catastrophizing about pain. Addressing catastrophizing and related fears and concerns of both parents and children may be necessary to assure appropriate self-management. Further investigation of the mechanisms relating catastrophizing to deleterious outcomes is warranted.

The role of acceptance in psychological functioning in adolescents with cystic fibrosis: a preliminary study.

This study explored the role of acceptance in accounting for the heterogeneity in psychological functioning in adolescents suffering from cystic fibrosis. Thirty-four adolescents completed a battery of questionnaires assessing acceptance, anxiety, depression, and disability. Regression analyses revealed that acceptance had a significant and unique contribution in explaining adolescents' anxiety, depression, and disability beyond the effects of demographic variables and parameters of disease severity. Forced expiratory volume, a parameter of disease severity, had a unique contribution in explaining disability, but not in explaining anxiety and depression. Our results support the idea that accepting the limitations imposed by a chronic disease and readjusting life goals has a positive effect upon psychological functioning in adolescents with cystic fibrosis. Acceptance-based therapies might prove useful in promoting well-being in adolescents with cystic fibrosis.

Expressive dimensions of pain catastrophizing: a comparative analysis of school children and children with clinical pain.

We investigated the role of the child's pain catastrophizing in explaining (1) children's self-reported tendency to verbally share their pain experience with others and (2) different dimensions of pain expression, as described by the mother and the father, including non-verbal and verbal communicative pain behaviour and protective pain behaviour. Participants were school children, children with chronic or recurrent pain, and their parents. The results showed that: (1) Pain catastrophizing was associated with children's greater self-acknowledged tendency to verbally share their pain experience with others. (2) Mothers and fathers perceived highly catastrophizing children to be more communicative about their pain. (3) The role of pain catastrophizing in the child's verbal sharing of pain experiences and in explaining expressive behaviour as rated by parents did not differ between the school children and children with recurrent and chronic pain. (4) Nevertheless, findings indicated marked differences between school children and the clinical sample. Children of the clinical sample experienced more severe pain, more pain catastrophizing, more protective pain behaviour, but less verbal communications about their pain. These results further corroborate the position that catastrophic thoughts about pain have interpersonal consequences. Findings are discussed in terms of the possible functions and effects upon others of pain catastrophizing and associated categories of pain behaviour.

Renal functional changes in relation to hemodynamic parameters during exercise test in normoalbuminuric insulin-dependent children.

AIM: To examine the relationship between filtration fraction and systemic vasculopathy, in normoalbuminuric insulin-dependent diabetic adolescents. METHODS: We calculated filtration fraction from measured glomerular filtration rate and renal plasma flow during a hypotonic saline perfusion test in 30 normotensive adolescent diabetic patients (9-19 years), with a mean duration of diabetes of 7.4 years. Blood pressure and heart rate were measured in basal conditions, during a 24-h ambulatory monitoring and during a dynamic exercise test on a cycle ergometer and peripheral vascular resistance was calculated. RESULTS: Filtration fraction was increased in the diabetic children compared with controls (30+/-6% vs. 22+/-4%, p<0.001), while renal plasma flow was significantly lower (453+/-133 mL/min/1.73 m2 vs. 593+/-155 mL/min/1.73 m2, p<0.001). Peripheral vascular resistance was significantly higher at peak exercise in diabetic children compared to controls (16.3+/-1.3 mmHg/L min m2 vs. 11.4+/-0.5 mmHg/L min m2, p<0.01). CONCLUSION: These results indicate that in young patients with IDDM, without apparent nephropathy or apparent systemic vasculopathy, filtration fraction is increased, suggesting an increased intraglomerular pressure. The associated reduced decrease of peripheral vascular resistance (increased diastolic blood pressure during exercise) suggests that renal functional abnormalities may be partly explained by a systemic vasculopathy, also present in the kidney.

Is morbidity influenced by staging in the fontan palliation? A single center review.

In a retrospective study of 32 consecutive patients undergoing a total cavopulmonary connection (TCPC), we tried to determine if the trend for decreasing age at Fontan completion and reducing the intervals between the staged procedures during the past decade was associated with a change in morbidity and outcome. In 8 patients the Fontan circulation was completed in one stage and in 24 patients an intermediate step by hemi-Fontan or bidirectional cavopulmonary anastomosis was performed before Fontan completion. Mean age at TCPC and mean interval since the previous palliation have decreased significantly during the past decade. Although major complications were significantly reduced over time the occurrence and duration of postoperative pleural effusions were not. Decreasing age as well as intervals in staged Fontan palliation have beneficial influence on major complications and outcome, without significantly affecting the duration of pleural effusions at Fontan completion.

The use of Tissue Doppler Imaging for the assessment of changes in myocardial structure and function in inherited cardiomyopathies.

Although there is still a long way to go, our understanding of the genetic basis of cardiomyopathies--dilated or hypertrophic--has significantly improved over the past decade. This new and intriguing era of cardiogenetics has already answered some important questions concerning the pathophysiology of these disorders, but it has also raised some new questions: how do we define "presymptomatic" mutation carriers? Should we treat them? Do we have any diagnostic tools to identify the presymptomatic subjects in those families where the underlying mutation has not been identified yet? To address at least part of these questions, there is a clear need for screening techniques in the early stage of the disease which have to be sensitive and non-invasive. In recent years Tissue Doppler Imaging (TDI) has emerged as a well suited technique for these purposes and several interesting papers on this issue have been published. This paper reviews the findings from TDI in several forms of inherited cardiomyopathy. Although the implementation of this technique in everyday clinical practice still requires some refinement, the results from these studies are encouraging and TDI is likely to be complementary to other established screening tools such as ECG and conventional echocardiography.

Genetic fibrillinopathies: new insights in molecular diagnosis and clinical management.

The Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with a prevalence of 2-3 per 10,000 individuals and symptoms ranging from skeletal overgrowth, cutaneous striae to ectopia lentis and aortic dilatation leading to dissection. Mutation in the gene for fibrillin-1 (FBN1) cause MFS and other related disorders of connective tissue, grouped as fibrillinopathies. Fibrillin-1 is the main constituent of extracellular microfibrils. Microfibrils can exist as individual structures or associate with elastin to form elastic fibers. This article provides an overview of the current diagnostic criteria and medical management, estimates the role of fibrillin-1 mutation analysis, sheds new light on genotype-phenotype correlations and summarizes new insights on the pathogenesis of this disorder based on mouse models.

The midwall stress-velocity relationship during manipulation of afterload.

Despite providing a physiological correction, measurements of contractility using the midwall stress-velocity relationship still show evidence of an unexplained hypercontractile state in some children. We investigated if by using midwall shortening indexes, the known overestimation of contractility at low afterload could be prevented. In 12 piglets (5 or 6 weeks old), afterload was manipulated by balloon occlusion of the descending aorta and infusion of sodium nitroprusside up to 5 mg/kg/min, and left ventricular function was measured using multiple variables. The regression line between the echocardiographically derived midwall velocity of circumferential fiber shortening and end systolic wall stress differed from the regression line of the endocardial stress-velocity relationship. Although the midwall regression line was almost horizontal (or afterload independent) for end systolic wall stress values of more than 30 g/cm2, the slope was still steeper below a certain point of afterload. The increased midwall velocity of fiber shortening at low afterload is comparable to the endocardial stress-velocity relationship and could account for the pseudo-hypercontractile state found in some children.

Fixed region of nondistensibility after coarctation repair: in vitro validation of its influence on Doppler peak velocities.

After coarctectomy, local loss of distensibility is noted in addition to mild anatomic narrowing. We hypothesize that the increased Doppler peak velocities measured at the aortic isthmus in these patients partly reflect obstruction secondary to the stiff surgical scar. The hypothesis was studied in a pulsatile hydraulic model. Thirty-one patients (13.0 +/- 4.0 years of age), 10.5 +/- 4.7 years after coarctectomy by end-to-end anastomosis, were studied clinically and echocardiographically. Indexes of distensibility were calculated. The effect of isolated increased stiffness was studied in vitro with a stiff and a compliant 1:1 scale latex model of the aorta mounted in a pulsatile full-scale circulation loop. Local stiffening was obtained by a rigid ring mounted around the aorta, fitted to the dimension of the unloaded aorta. For different pressure and flow regimens, pressures and Doppler velocities were measured across the ring. Mean peak velocities at the surgical scar were 2.2 +/- 0.4 m/s. Mild anatomic stenosis was present. All distensibility indexes indicated locally increased stiffness (P <.001). In the stiff latex model, Doppler peak velocities increased from 1.89 +/- 0.04 m/s to 2.32 +/- 0.06 m/s (P <.03); in the compliant model, from 1.15 +/- 0.03 m/s to 1.79 +/- 0.05 m/s (P <.001). The increase of Doppler peak velocities depends on model compliance only and is independent of flow rate, length of the noncompliant segment, and viscosity of the perfusion fluid. Velocities do not change when semicircular stiffening is applied. We have demonstrated in vitro that isolated local nondistensibility leads to vessel narrowing during vascular distension. The relative contribution of local scar stiffness in the increase of Doppler peak velocities after coarctectomy was hereby assessed.

Carbohydrate availability affects ammonemia during exercise after beta 2-adrenergic blockade.

PURPOSE: Beta-adrenergic blockade increases blood ammonia concentration during exercise. The purpose of this study was to assess the role of decreased carbohydrate availability in this process. METHODS: Wistar rats (N = 47) were injected intravenously with a selective beta 2-adrenoceptor blocker (ICI 118,551), placebo, or beta 2-blocker + glucose 1 h before a treadmill exercise test. Blood samples were taken to measure the concentration of ammonia, glucose, lactic acid, free fatty acids (FFA), glycerol, branched-chain amino acids (BCAA), and muscle samples for determination of glycogen content. RESULTS: Beta 2-adrenergic blockade shortened running time to exhaustion (23 +/- 4.3 min compared to 44 +/- 5.2 min with placebo), increased blood ammonia levels (146.7 +/- 16.21 micromol x L(-1) compared to 47.5 +/- 0.92 micromol x L(-1) with placebo) and prevented exercise-induced glycogen breakdown in soleus and gastrocnemius muscles. Pre-exercise supplementation of glucose during beta 2-blockade restored exercise-induced glycogen breakdown and reduced blood ammonia concentration during exercise (66.5 +/- 5.65 mmol x L(-1)) but did not improve exercise capacity (26 +/- 3.2 min) when compared with beta2-blockade alone. CONCLUSION: The results suggest that the enhanced rise in blood ammonia concentration during exercise after beta-blockade is caused by impaired carbohydrate availability.

Development of a phase-displacement equation for panoramic interferometry.

We developed the parametric equations that are needed to quantify the modulations in the sensitivity vector that occur when the phase-displacement equation is applied to make panoramic interferometric measurements. The measurement system relies on two collinear panoramic annular lenses, one to illuminate and the other to image their surroundings. When a coherent light source is used and a reference beam is added, interference occurs over the region of interest defined by the illuminating and viewing lenses. A holographic system is used to demonstrate the approach and quantify the analysis. We obtained interference fringes in real time by comparing holograms recorded before and after a section of cylindrical pipe is displaced relative to the measurement system. The annular images and the holographic fringes are acquired and stored digitally in a computer system, and image transformation algorithms are applied to remove optical distortions in the holographic patterns. Excellent agreement is obtained when the fringe loci are compared with those predicted on the basis of theory.

The influence of low afterload on the nature of the stress-velocity relationship.

OBJECTIVES: Correct assessment of contractility by conventional methods during manipulation of afterload is often disappointing. To this purpose, the stress-velocity relationship offers assessment of contractility at different levels of afterload. We decided to study the influence of afterload on the nature of the stress-velocity relation. BACKGROUND: Although linear at baseline conditions in a population older than two years, data in newborns or after administration of low-dose dobutamine suggest a different nature of this relationship at low afterload. METHODS: Ten healthy piglets (five to six weeks; 11 to 13 kg) were studied. End-systolic meridional wall stress (ESWS) and rate-corrected velocity of circumferential fiber shortening (VcFc) were measured in these piglets at baseline, after balloon occlusion of the descending aorta, and at nitroprusside infusion rates of 1, 2 and 5 microg/kg/min. To eliminate inotropic influences mediated by reflex tachycardia, we subsequently studied five piglets and six adult pigs after bilateral cervical vagotomy. RESULTS: The ESWS changed from a baseline mean of 50 g/cm2 to 137 g/cm2 after balloon occlusion and to 19 g/cm2 at 5 microg/kg/min of nitroprusside. The VcFc changed from 1.19 c/s (circumference/second) to values of 0.9 c/s and 1.73 c/s, respectively. The ensuing stress-velocity regression line proved to be curvilinear instead of linear. The steeper slope at low afterload could suggest enhanced contractility compared to expected values had the relationship been linear. CONCLUSIONS: Data from young piglets and adult pigs suggest a curvilinear relationship of the stress-velocity relationship. This could probably explain some of the "hypercontractile states" encountered in conditions with low afterload.

Effect of branched-chain amino acids (BCAA), glucose, and glucose plus BCAA on endurance performance in rats.

PURPOSE: The purpose of this study was to assess the effects of pre-exercise administration of branched-chain amino acids (BCAA), glucose, and glucose plus BCAA on time to exhaustion during treadmill exercise in rats. METHODS: Wistar rats were injected intraperitoneally with 1 mL of saline (0.9% NaCl), BCAA (30 mg), glucose (100 mg), or glucose plus BCAA 5 min before either 45 min of submaximal exercise (N = 32) or running to exhaustion (N = 24). After the submaximal exercise test, blood was collected for the measurement of ammonia, BCAA, free tryptophan (free TRP), glucose, free fatty acid, and lactic acid, and muscle samples were taken from the m. soleus for determination of glycogen content. RESULTS: Mean run time to exhaustion was significantly longer after BCAA administration (158+/-26 min) compared with that after saline (118+/-35 min)(P<0.05) but not compared with that after glucose administration (179+/-21 min). When glucose is administered before exercise, the supplementary administration of BCAA had no additional effect on performance (171+/-12 min). The data on blood ammonia, ratio of free TRP/BCAA, and muscle glycogen did not provide a clue for explaining the higher endurance performance after BCAA supplementation. CONCLUSION: The results support the hypothesis that the effect of BCAA administration on performance could be related to carbohydrate availability during exercise.

Influence of age and low afterload on the stress-velocity relation of the left ventricle.

The relation between systolic meridional wall stress (WS) and velocity of circumferential fiber shortening (VcFc) is widely accepted as a preload-independent index of contractility, with a linear relation in most subjects older than 2 y. However, this relation seems to become different in infants and after administration of inotropic agents. We decided to study the nature of the stress-velocity relation by a cross-sectional assessment of the influence of age, low afterload, and increased contractility. Study subjects were 30 healthy infants, 32 healthy older children, and 35 asymptomatic older children after completion of anthracycline chemotherapy. WS and VcFc at rest were studied in these infants and children. WS and VcFc were also studied after dobutamine infusion in both groups of older children. Linear regression analysis of the stress-velocity relation showed parallel slopes between the older children at rest and the post anthracycline children after dobutamine. The regression lines between the infants at rest and the healthy older children after dobutamine were also parallel, but with a different and steeper slope compared with the former groups. When comparing the stress-velocity relation of the overall population at rest with the overall population after dobutamine, the resulting regression lines are curvilinear and parallel, with a steeper slope at low afterload. The stress-velocity relation in infants and after dobutamine, resulting in low afterload is different compared with the stress- velocity relation in older children at rest and at higher afterload. Data of the overall population at rest and after dobutamine suggest a curvilinear relation.

Low-dose dobutamine stress echocardiography in children and young adults.

Dobutamine stress echocardiography has become widely accepted in the evaluation of adult patients with coronary heart disease. We wanted to assess the feasibility and the physiologic responses of stress echocardiography at low doses of dobutamine in a population of normal children and adults. Once achieved, we submitted a group of post-anthracycline patients to the test to assess the sensitivity of low-dose dobutamine stress echocardiography in the detection of cardiac dysfunction. Thirty-two healthy children and young adults (19 male and 13 female subjects, median age 15 years [range 6 to 26]) were studied. After the initial study of normal subjects, we submitted a cohort of 39 patients (18 female and 21 male, aged 6 to 25 years), who completed anthracycline chemotherapy, to the same protocol. Dobutamine was infused at rates of 0.5 to 2.5 and 5 microg/kg/min and echocardiographic measurements were obtained at rest and at the end of each stage. The test could be completed in 100% of the subjects without major complications. Statistically significant differences between resting echocardiographic values of systolic and diastolic function and values at 2.5 and 5 microg/kg/min of dobutamine were found. Moreover, dobutamine revealed or enhanced differences between normal subjects and the post-anthracycline patients. Thus, low-dose dobutamine stress echocardiography is feasible and safe in older children. The test is very sensitive for the detection of subclinical cardiac dysfunction in post-anthracycline patients and could possibly assess functional myocardial reserve.

Entrapment of a guide wire during percutaneous occlusion of a coronary artery fistula.

Coronary artery fistulas are extremely rare and coil occlusion by intervention techniques seems to be the therapy of choice. We describe the case of a 3-month-old infant with a coronary artery fistula. During occlusion of the fistula a coronary guide wire got entrapped in a small coronary branch, but could be successfully retrieved with a microsnare without damage to the heart. The microsnare technique prevented rupture of the guide wire.

Inhaled salbutamol decreases blood ammonia levels during exercise in normal subjects.

The present study examines the effect of salbutamol, a beta2-adrenoreceptor agonist, on blood ammonia levels during an incremental cycle exercise test in healthy non-asthmatic subjects. Blood ammonia levels were lower after inhalation of 400 mcg of salbutamol than after placebo during submaximal exercise: 33+/-2 micromol x l(-1) v.s. 48+/-9 micromol x l(-1) at 220 W and 39+/-2 micromol x l(-1) v.s. 50+/-4 micromol x l(-1) at 260 W. At peak exercise there were no significant differences. The results suggest that beta2-adrenoreceptors are involved in the regulation of blood ammonia during exercise.