Blood pressure in the first year of life in healthy infants born at term

Postnatal renal tubule development: roles of tubular flow and flux

PURPOSE OF REVIEW

Postnatal renal tubule development is critical to adult kidney function. Several postnatal changes regulate the differentiation and proliferation of renal tubular cells. Here, we review the literature and our efforts on thick ascending limb (TAL) development in Bartter syndrome (BS).

RECENT FINDINGS

Glomerular filtrate quickly increases after birth, imposing fluid shear stress and circumferential stretch on immature renal tubules. Recent studies showed that kidney organoids under flow (superfusion) have better development of tubular structures and the expression of cilia and solute transporters. These effects are likely mediated by mechanosensors, such as cilia and the piezo1 channel. Improved renal oxygenation and sodium pump-dependent active transport can stimulate mitochondrial respiration and biogenesis. The functional coupling between transport and mitochondria ensures ATP supply for energy-demanding reactions in tubular cells, including cell cycle progression and proliferation. We recently discovered that postnatal renal medulla maturation and TAL elongation are impaired in Clc-k2-deficient BS mice. Primary cultured Clc-k2-deficient TAL cells have G1-S transition and proliferation delay. These developmental defects could be part of the early pathogenesis of BS and worsen the phenotype.

SUMMARY

Understanding how tubular flow and transepithelial ion fluxes regulate renal tubule development may improve the treatment of congenital renal tubulopathies.

Common Clinical Scenarios of Systemic Hypertension in the NICU

Hypertension affects ∼1% to 3% of newborns in the NICU. However, the identification and management of hypertension can be challenging because of the lack of data-driven diagnostic criteria and management guidelines. In this review, we summarize the most recent approaches to diagnosis, evaluation, and treatment of hypertension in neonates and infants. We also identify common clinical conditions in neonates in whom hypertension occurs, such as renal vascular and parenchymal disease, bronchopulmonary dysplasia, and cardiac conditions, and address specific considerations for the evaluation and treatment of hypertension in those conditions. Finally, we discuss the importance of ongoing monitoring and long-term follow-up of infants diagnosed with hypertension.

A Computational Model of Ventricular Dimensions and Hemodynamics in Growing Infants

Previous computer models have successfully predicted cardiac growth and remodeling in adults with pathologies. However, applying these models to infants is complicated by the fact that they also undergo normal, somatic cardiac growth and remodeling. Therefore, we designed a computational model to predict ventricular dimensions and hemodynamics in healthy, growing infants by modifying an adult canine left ventricular growth model. The heart chambers were modeled as time-varying elastances coupled to a circuit model of the circulation. Circulation parameters were allometrically scaled and adjusted for maturation to simulate birth through 3 yrs of age. Ventricular growth was driven by perturbations in myocyte strain. The model successfully matched clinical measurements of pressures, ventricular and atrial volumes, and ventricular thicknesses within two standard deviations of multiple infant studies. To test the model, we input 10th and 90th percentile infant weights. Predicted volumes and thicknesses decreased and increased within normal ranges and pressures were unchanged. When we simulated coarctation of the aorta, systemic blood pressure, left ventricular thickness, and left ventricular volume all increased, following trends in clinical data. Our model enables a greater understanding of somatic and pathological growth in infants with congenital heart defects. Its flexibility and computational efficiency when compared to models employing more complex geometries allow for rapid analysis of pathological mechanisms affecting cardiac growth and hemodynamics.

Comparison of cerebral oxygen desaturation events between children under general anesthesia and chloral hydrate sedation - a randomized controlled trial

BACKGROUND

During pediatric general anesthesia (GA) and sedation, clinicians aim to maintain physiological parameters within normal ranges. Accordingly, regional cerebral oxygen saturation (rScO2) should not drop below preintervention baselines. Our study compared rScO2 desaturation events in children undergoing GA or chloral hydrate sedation (CHS).

METHODS

Ninety-two children undergoing long auditory assessments were randomly assigned to two study arms: CHS (n = 40) and GA (n = 52). Data of 81 children (mean age 13.8 months, range 1-36 months) were analyzed. In the GA group, we followed a predefined 10 N concept (no fear, no pain, normovolemia, normotension, normocardia, normoxemia, normocapnia, normonatremia, normoglycemia, and normothermia). In this group, ENT surgeons performed minor interventions in 29 patients based on intraprocedural microscopic ear examinations. In the CHS group, recommendations for monitoring and treatment of children undergoing moderate sedation were met. Furthermore, children received a double-barreled nasal oxygen cannula to measure end-tidal carbon dioxide (etCO2) and allow oxygen administration. Chloral hydrate was administered in the parent's presence. Children had no intravenous access which is an advantage of sedation techniques. In both groups, recommendations for fasting were followed and an experienced anesthesiologist was present during the entire procedure. Adverse event (AE) was a decline in cerebral oxygenation to below 50% or below 20% from the baseline for ≥1 min. The primary endpoint was the number of children with AE across the study arms. Secondary variables were: fraction of inspired oxygen (FIO2), oxygen saturation (SpO2), etCO2, systolic and mean blood pressure (BP), and heart rate (HR); these variables were analyzed for their association with drop in rScO2 to below baseline (%drop_rScO2).

RESULTS

The incidence of AE across groups was not different. The analysis of secondary endpoints showed evidence that %drop_rScO2 is more dependent on HR and FIO2 than on BP and etCO2.

CONCLUSIONS

This study highlights the strong association between HR and rScO2 in children aged < 3 years, whereas previous studies had primarily discussed the role of BP and etCO2. Prompt HR correction may result in shorter periods of cerebral desaturation.

TRIAL REGISTRATION

The study was retrospectively registered with the German Clinical Trials Registry (DRKS00024362, 04/02/2021).

Neonatal hypertension: concerns within and beyond the neonatal intensive care unit

Neonatal hypertension occurs in 1%-2% of neonates in the neonatal intensive care unit (NICU) although may be underdiagnosed. Blood pressure values in premature neonates change rapidly in the first days and weeks of life which may make it more difficult to recognize abnormal blood pressure values. In addition, the proper blood pressure measurement technique must be used to ensure the accuracy of the measured values as most blood pressure devices are not manufactured specifically for this population. In premature neonates, the cause of the hypertension is most commonly related to prematurity-associated complications or management while in term neonates is more likely to be due to an underlying condition. Both oral and intravenous antihypertensive medications can be used in neonates to treat high blood pressure although none are approved for use in this population by regulatory agencies. The natural history of most neonatal hypertension is that it resolves over the first year or two of life. Of concern are the various neonatal risk factors for later cardiovascular and kidney disease that are present in most NICU graduates. Prematurity increases the risk of adulthood hypertension while intrauterine growth restriction may even lead to hypertension during childhood. From neonates through to adulthood NICU graduates, this review will cover each of these topics in more detail and highlight the aspects of blood pressure management that are established while also highlighting where knowledge gaps exist.

The Effects of Acidosis on eNOS in the Systemic Vasculature: A Focus on Early Postnatal Ontogenesis

The activity of many vasomotor signaling pathways strongly depends on extracellular/intracellular pH. Nitric oxide (NO) is one of the most important vasodilators produced by the endothelium. In this review, we present evidence that in most vascular beds of mature mammalian organisms metabolic or respiratory acidosis increases functional endothelial NO-synthase (eNOS) activity, despite the observation that direct effects of low pH on eNOS enzymatic activity are inhibitory. This can be explained by the fact that acidosis increases the activity of signaling pathways that positively regulate eNOS activity. The role of NO in the regulation of vascular tone is greater in early postnatal ontogenesis compared to adulthood. Importantly, in early postnatal ontogenesis acidosis also augments functional eNOS activity and its contribution to the regulation of arterial contractility. Therefore, the effect of acidosis on total peripheral resistance in neonates may be stronger than in adults and can be one of the reasons for an undesirable decrease in blood pressure during neonatal asphyxia. The latter, however, should be proven in future studies.

Blood Pressure Profile and Trends in the Neonatal Transitioning Period: A Comparative Study of Term Asphyxiated and Healthy Newborns

Background. Extra-uterine transition difficulties including BP abnormalities have been documented following perinatal asphyxia. Aim. The study aimed to determine the BP changes in the early neonatal transitioning period. Method. This comparative, cross-sectional study was conducted at the Ekiti State University Teaching Hospital, Ado-Ekiti, Nigeria. Result. A total of 246 term babies were analyzed. Their mean (standard deviation) systolic, diastolic and mean arterial blood pressures (SBP, DBP, and MBP) at birth were 68.2 (9.0), 39.9 (7.0), and 49.4 (6.9) mmHg and 67.4 (7.9), 37.1 (6.1), and 47.2 (5.8) mmHg, respectively. Asphyxiated neonates had significantly higher initial DBP (P < .001) and MAP (P = .008), lower SBP (P < .001) and MAP (P = .024) at 6 hours and lower SBP at 12 hours after birth, statistically. Conclusion. This study showed that while the BP of healthy neonates steadily increases in the first 48 hours after birth, it fluctuated markedly within the first 12 hours of birth among asphyxiated babies.

Systemic Hypertension in Infants with Bronchopulmonary Dysplasia

PURPOSE OF REVIEW

Neonatal hypertension is increasingly recognized as improvements in neonatal intensive care have led to increased survival of premature infants. Among infants with bronchopulmonary dysplasia (BPD), the rates of hypertension are much higher than the general neonatal population. However, the etiology and pathophysiology of this increased risk of hypertension in neonates with lung disease remain unclear.

RECENT FINDINGS

Among infants with bronchopulmonary dysplasia, the rates of hypertension are much higher than the general neonatal population. New studies suggest outcomes in neonates with BPD with hypertension are usually good, with resolution of hypertension in most infants with lung disease. Several potential mechanisms of hypertension in this patient population have been recently proposed. This review focuses on the recent epidemiologic data on prevalence of hypertension in neonates with bronchopulmonary dysplasia, reviews the typical clinical course, and discusses available strategies for management of infants with bronchopulmonary dysplasia that develop hypertension.

Baroreflex sensitivity and blood pressure in premature infants - dependence on gestational age, postnatal age and sex

To characterize the differences in baroreflex sensitivity (BRS), blood pressure (BP), heart rate (HR) and respiration rate (RR) in preterm infants with a similar postconceptional age reached by various combinations of gestational and postnatal ages. To detect potential sex differences in assessed cardiovascular parameters. The study included 49 children (24 boys and 25 girls), postconceptional age 34.6+/-1.9 weeks. Two subgroups of infants were selected with the similar postconceptional age (PcA) and current weight, but differing in gestational (GA) and postnatal (PnA) ages, as well as two matched subgroups of boys and girls. Blood pressure (BP) was recorded continuously using Portapres device (FMS). A stationary segment of 250 beat-to-beat BP values was analyzed for each child. Baroreflex sensitivity (BRS) was calculated by cross-correlation sequence method. Despite the same PcA age and current weight, children with longer GA had higher BRS, diastolic and mean BP than children with shorter GA and longer PnA age. Postconceptional age in preterm infants is a parameter of maturation better predicting baroreflex sensitivity and blood pressure values compared to postnatal age. Sex related differences in BRS, BP, HR and RR were not found in our group of preterm infants.

Intrauterine L-NAME Exposure Weakens the Development of Sympathetic Innervation and Induces the Remodeling of Arterial Vessels in Two-Week-Old Rats

Nitric oxide (NO) has been shown to stimulate differentiation and increase the survival of ganglionic sympathetic neurons. The proportion of neuronal NOS-immunoreactive sympathetic preganglionic neurons is particularly high in newborn rats and decreases with maturation. However, the role of NO in the development of vascular sympathetic innervation has never been studied before. We tested the hypothesis that intrauterine NO deficiency weakened the development of vascular sympathetic innervation and thereby changed the contractility of peripheral arteries and blood pressure level in two-week-old offspring. Pregnant rats consumed NOS inhibitor L-NAME (250 mg/L in drinking water) from gestational day 10 until delivery. Pups in the L-NAME group had a reduced body weight and blood level of NO metabolites at 1–2 postnatal days. Saphenous arteries from two-week-old L-NAME offspring demonstrated a lower density of sympathetic innervation, a smaller inner diameter, reduced maximal active force and decreased α-actin/β-actin mRNA expression ratio compared to the controls. Importantly, pups in the L-NAME group exhibited decreased blood pressure levels before, but not after, ganglionic blockade with chlorisondamine. In conclusion, intrauterine L-NAME exposure is followed by the impaired development of the sympathetic nervous system in early postnatal life, which is accompanied by the structural and functional remodeling of arterial blood vessels.

Intrauterine Nitric Oxide Deficiency Weakens Differentiation of Vascular Smooth Muscle in Newborn Rats

Nitric oxide (NO) deficiency during pregnancy is a key reason for preeclampsia development. Besides its important vasomotor role, NO is shown to regulate the cell transcriptome. However, the role of NO in transcriptional regulation of developing smooth muscle has never been studied before. We hypothesized that in early ontogeny, NO is important for the regulation of arterial smooth muscle-specific genes expression. Pregnant rats consumed NO-synthase inhibitor L-NAME (500 mg/L in drinking water) from gestational day 10 till delivery, which led to an increase in blood pressure, a key manifestation of preeclampsia. L-NAME reduced blood concentrations of NO metabolites in dams and their newborn pups, as well as relaxations of pup aortic rings to acetylcholine. Using qPCR, we demonstrated reduced abundances of the smooth muscle-specific myosin heavy chain isoform, α-actin, SM22α, and L-type Ca²⁺-channel mRNAs in the aorta of newborn pups from the L-NAME group compared to control pups. To conclude, the intrauterine NO deficiency weakens gene expression specific for a contractile phenotype of arterial smooth muscle in newborn offspring.

Determinants of Blood Pressure in Neonates and Infants: Predictable Variability

The blood pressure (BP) of neonates, especially those born premature, changes rapidly over the first days and weeks of life. Neonatal BPs may be affected by maternal factors, perinatal factors or events, and intrinsic or extrinsic infant factors. Unfortunately, the effect of many maternal health and disease states has only been studied in small numbers or has shown conflicting results. Many events around the time of delivery have the potential to influence the neonatal BP, and while definitive studies are often lacking, some observational data support physiological expectations. The strongest determinants of neonatal BP are the infant factors of gestational age at birth, birth weight, and postmenstrual age. Understanding the expected pattern of BP changes, identifying the potential influencing factors, and accurately measuring the BP are all essential to determine whether there is a BP abnormality present but are also more complex in the neonatal population. This review describes the evidence for maternal conditions, perinatal events, and infant factors to affect neonatal BP. It also explains what is currently known about the changing BP patterns in neonates including those born preterm. In addition, by examining the physiological process of hemodynamic adaptation to the extrauterine environment and compensatory cardiovascular responses, we can gain insight into the expected and unexpected vascular responses, making the variability of neonatal BP seem a little more predictable.

[Infantile arterial hypertension: A diagnostic challenge in paediatrics]

Arterial Hypertension prevalence (HTN) has significantly increased in paediatric patients, mainly in older children and teenagers. In these subjects the most common type is essential or primary HTN. However, in infants HTN prevalence is significantly lower and is almost always due to secondary causes, which can be potentially severe. Hence the importance of its detection, in order to establish an etiological diagnosis and provide an appropriate treatment, which usually requires a specialist physician. In addition to the technical difficulties of blood pressure measurement in infants, the lack of recommendations to perform a systematic screening in this age range and the absence of well-established normal values turns infancy-onset HTN into a diagnostic and therapeutic challenge for the physician. By means of the exposition of three infancy-onset HTN cases, the aim is to increase the paediatrician's awareness of this pathology and also to provide information about its diagnostic and therapeutic approach, dealing also with pharmacological measures of treatment.

The hypertensive neonate

Hypertension in neonates is increasingly recognized because of improvements in neonatal intensive care that have led to improved survival of premature infants. Although normative data on neonatal blood pressure remain limited, several factors appear to be important in determining blood pressure levels in neonates, especially gestational age, birth weight and maternal factors. Incidence is around 1% in most studies and identification depends on careful blood pressure measurement. Common causes of neonatal hypertension include umbilical catheter associated thrombosis, renal parenchymal disease, and chronic lung disease, and can usually be identified with careful diagnostic evaluation. Given limited data on long-term outcomes and use of antihypertensive medications in these infants, clinical expertise may need to be relied upon to decide the best approach to treatment. This review will discuss these concepts and identify evidence gaps that should be addressed.

Neonatal Blood Pressure Standards: What Is "Normal"?

Blood pressure (BP) is routinely measured in newborn infants. Published BP nomograms demonstrate a rise in BP following delivery in healthy infants at all gestational ages (GA) and evidence that BP values are higher with increasing birth weight and GA. However, the complex physiology that occurs in newborn infants and range of BP values observed at all GA make it difficult to identify "normal" BP for a specific infant at a specific time under specific conditions. As such, complete hemodynamic assessment should include the physical examination, perinatal history, other vital signs, and laboratory values in addition to BP values.

Single blood pressure chart for children up to 13 years to improve the recognition of hypertension based on existing normative data

OBJECTIVE

To produce a single 'growth-chart-style' blood pressure (BP) chart with clear diagnostic thresholds to assist paediatricians to make prompt and accurate diagnoses of hypertension.

DESIGN

The well-established but complex published data on normal BP ranges in prepubertal children were identified and analysed to determine if it was possible to produce a single, user-friendly, colour-coded chart, showing diagnostic hypertension thresholds for systolic and diastolic BP without losing clinically important information.

RESULTS

There were sufficient published normative childhood BP data available to define systolic and diastolic BP centiles from term onwards but only sufficient to determine systolic BP centiles from 28 weeks of gestation to term. Up to 13 years of age, it was possible to combine boys' and girls' data without loss of precision and to define the threshold between stage 1 and stage 2 (severe) hypertension as the 95th centile +12 mm Hg. This allowed the production of single colour-coded charts for systolic and diastolic BP and to advise on making simple adjustments for the impact of stature on individual children's results.

CONCLUSIONS

A simplified, integrated BP chart with colour-coded diagnostic thresholds was produced to assist the prompt diagnosis of hypertension in prepubertal children. This information could be included into a Paediatric Early Warning System score.

Results of a phase 1 multicentre investigation of dexmedetomidine bolus and infusion in corrective infant cardiac surgery

BACKGROUND

Dexmedetomidine (DEX) is increasingly used intraoperatively in infants undergoing cardiac surgery. This phase 1 multicentre study sought to: (i) determine the safety of DEX for cardiac surgery with cardiopulmonary bypass; (ii) determine the pharmacokinetics (PK) of DEX; (iii) create a PK model and dosing for steady-state DEX plasma levels; and (iv) validate the PK model and dosing.

METHODS

We included 122 neonates and infants (0-180 days) with D-transposition of the great arteries, ventricular septal defect, or tetralogy of Fallot. Dose escalation was used to generate NONMEM® PK modelling, and then validation was performed to achieve low (200-300 pg ml-1), medium (400-500 pg ml-1), and high (600-700 pg ml-1) DEX plasma concentrations.

RESULTS

Five of 122 subjects had adverse safety outcomes (4.1%; 95% confidence interval [CI], 1.8-9.2%). Two had junctional rhythm, two had second-/third-degree atrioventricular block, and one had hypotension. Clearance (CL) immediately postoperative and CL on CPB were reduced by approximately 50% and 95%, respectively, compared with pre-CPB CL. DEX clearance after CPB was 1240 ml min-1 70 kg-1. Age at 50% maximum clearance was approximately 2 days, and that at 90% maximum clearance was 18 days. Overall, 96.1% of measured DEX concentrations fell within the 5th-95th percentile prediction intervals in the PK model validation. Dosing strategies are recommended for steady-state DEX plasma levels ranging from 200 to 1000 pg ml-1.

CONCLUSIONS

When used with a careful dosing strategy, DEX results in low incidence and severity of adverse safety events in infants undergoing cardiac surgery with cardiopulmonary bypass. This validated PK model should assist clinicians in selecting appropriate dosing. The results of this phase 1 trial provide preliminary data for a phase 3 trial of DEX neuroprotection.

CLINICAL TRIALS REGISTRATION

NCT01915277.

A comparison of clinical paediatric guidelines for hypotension with population-based lower centiles: a systematic review

Background

Different definitions exist for hypotension in children. In this study, we aim to identify evidence-based reference values for low blood pressure and to compare these with existing definitions for systolic hypotension.

Methods

We searched online databases until February 2019 (including MEDLINE, EMBASE, Web of Science) using a comprehensive search strategy to identify studies that defined age-related centiles (first to fifth centile) for non-invasive systolic blood pressure in healthy children < 18 years. Existing cut-offs for hypotension were identified in international guidelines and textbooks. The age-related centiles and clinical cut-offs were compared and visualized using step charts.

Results

Fourteen studies with population-based centiles were selected, of which 2 addressed children < 1 year. Values for the fifth centile differed 8 to 17 mmHg for age. We identified 13 clinical cut-offs of which only 5 reported accurate references. Age-related cut-offs for hypotension showed large variability (ranging from 15 to 30 mmHg). The clinical cut-offs varied in agreement with the low centiles. The definition from Paediatric Advanced Life Support agreed well for children < 12 years but was below the fifth centiles for children > 12 years. For children > 12 years, the definition of Parshuram’s early warning score agreed well, but the Advanced Paediatric Life Support definition was above the fifth centiles.

Conclusions

The different clinical guidelines for low blood pressure show large variability and low to moderate agreement with population-based lower centiles. For children < 12 years, the Paediatric Advanced Life Support definition fits best but it underestimates hypotension in older children. For children > 12 years, the Advanced Paediatric Life Support overestimates hypotension but Parshuram’s cut-off for hypotension in the early warning score agrees well. Future studies should focus on developing reference values for hypotension for acutely ill children.

Neonatal adrenal insufficiency: Turkish Neonatal and Pediatric Endocrinology and Diabetes Societies consensus report

It is difficult to make a diagnosis of adrenal insufficiency in the newborn, because the clinical findings are not specific and the normal serum cortisol level is far lower compared to children and adults. However, dehydratation, hyperpigmentation, hypoglycemia, hyponatremia, hyperkalemia and metabolic acidosis should suggest the diagnosis of adrenal insufficiency. Hypotension which does not respond to vasopressors should especially be considered a warning. If the adrenocorticotropin hormone level measured simultaneously with a low serum cortisol level is 2-fold higher than the upper normal limit of the reference range, a diagnosis of primary adrenal insufficiency is definite. Even if the serum cortisol level is normal, a diagnosis of relative adrenal insufficiency can be made with clinical findings, if the patient is under heavy stress. The serum cortisol level should be measured using the method of ‘high pressure liquid chromatography’ or ‘LC mass spectrometry’. Adrenal steroid biosynthesis can be evaluated more specifically and sensitively with ‘steroid profiling’. Rennin and aldosterone levels may be measured in addition to serum electrolytes for the diagnosis of mineralocorticoid insufficiency. Adrenocorticotropic hormone stimulation test may be used to confirm the diagnosis and elucidate the etiology. In suspicious cases, treatment can be initiated without waiting for the adrenocorticotropic hormone stimulation test. In schock which does not respond to vasopressors, intravenous hydrocortisone at a dose of 50-100 mg/m² or a glucocorticoid drug at an equivalent dose should be initiated. In maintanence treatment, the physiological secretion rate of hydrocortisone is 6 mg/m²/day (15 mg/m²/day in the newborn). The replacement dose should be adjusted with clinical follow-up and by monitoring growth rate, weight gain and blood pressure. Fludrocortisone (0,1 mg tablet) is given for mineralocorticoid treatment (2x0,5-1 tablets). A higher dose may be needed in the neonatal period and in patients with aldosterone resistance. If hyponatremia persists, oral NACl may be added to treatment. In the long-term follow-up, patients should carry an identification card and the glucocorticoid dose should be increased 3-10-fold in cases of stress.

The relative incidence of cardiogenic and septic shock in neonates

Objective

To evaluate the relative incidence of cardiogenic and septic shock in term neonates and identify findings that help differentiate the two entities.

Study Design

We conducted a retrospective chart review of term neonates presenting to British Columbia Children's Hospital (BCCH) with decompensated shock of an undiagnosed etiology between January 1, 2008 and January 1, 2013. Charts were reviewed to determine the underlying diagnoses of all neonates meeting our inclusion criteria. Patients were categorized as having septic, cardiogenic, or other etiologies of shock. We then evaluated potential demographic, clinical, and biochemical parameters that could help differentiate between septic and cardiogenic shock.

Results

Cardiogenic shock was more common than septic shock (relative risk=1.53). A history of cyanosis was suggestive of cardiogenic shock (positive likelihood ratio, LR+=3.2 and negative likelihood ratio, LR-=0.4). Presence of a murmur or gallop (LR+=5.4, LR-=0.3), or decreased femoral pulses (LR+=5.1, LR-=0.5) on physical exam were also suggestive of cardiogenic shock as was cardiomegaly on chest x-ray (LR+=4.9, LR-=0.5). Notably, temperature instability (LR+=0.7, LR-=1.8) and white blood cell count elevation or depression (LR+=0.8, LR-=1.1) were all poor predictors of septic shock.

Conclusion

Cardiogenic shock is a more common cause of decompensated shock than septic shock. A history of cyanosis, murmur or gallop, or decreased femoral pulses on exam and cardiomegaly on chest x-ray are useful indicators of cardiogenic shock. In evaluating the neonate with decompensated shock, early consideration for Cardiology consultation and interventions to treat the underlying condition is warranted.

Neonatal hypertension: an educational review

Hypertension is encountered in up to 3% of neonates and occurs more frequently in neonates requiring hospitalization in the neonatal intensive care unit (NICU) than in neonates in newborn nurseries or outpatient clinics. Former NICU neonates are at higher risk of hypertension secondary to invasive procedures and disease-related comorbidities. Accurate measurement of blood pressure (BP) remains challenging, but new standardized methods result in less measurement error. Multiple factors contribute to the rapidly changing BP of a neonate: gestational age, postmenstrual age (PMA), birth weight, and maternal factors are the most significant contributors. Given the natural evolution of BP as neonates mature, a percentile cutoff of 95% for PMA has been the most common definition used; however, this is not based on outcome data. Common causes of neonatal hypertension are congenital and acquired renal disease, history of umbilical arterial catheter placement, and bronchopulmonary dysplasia. The treatment of neonatal hypertension has mostly been off-label, but as evidence accumulates, the safety of medical management has increased. The prognosis of neonatal hypertension remains largely unknown and thankfully most often resolves unless secondary to renovascular disease, but further research is needed. This review discusses important factors related to neonatal hypertension including BP measurement, determinants of BP, and management of neonatal hypertension.

Neonatal hypertension: cases, causes, and clinical approach

Neonatal hypertension is increasingly recognized as dramatic improvements in neonatal intensive care, advancements in our understanding of neonatal physiology, and implementation of new therapies have led to improved survival of premature infants. A variety of factors appear to be important in determining blood pressure in neonates, including gestational age, birth weight, and postmenstrual age. Normative data on neonatal blood pressure values remain limited. The cause of hypertension in an affected neonate is often identified with careful diagnostic evaluation, with the most common causes being umbilical catheter-associated thrombosis, renal parenchymal disease, and chronic lung disease. Clinical expertise may need to be relied upon to decide the best approach to treatment in such patients, as data on the use of antihypertensive medications in this age group are extremely limited. Available data suggest that long-term outcomes are usually good, with resolution of hypertension in most infants. In this review, we will take a case-based approach to illustrate these concepts and to point out important evidence gaps that need to be addressed so that management of neonatal hypertension may be improved.

Research Gaps in Primary Pediatric Hypertension

Hypertension affects >40% of the US population and is a major contributor to cardiovascular-related morbidity and mortality. Although less common among children and adolescents, hypertension affects 1% to 5% of all youth. The 2017 Clinical Practice Guideline for the Diagnosis and Management of High Blood Pressure in Children and Adolescents provided updates and strategies regarding the diagnosis and management of hypertension in youth. Despite this important information, many gaps in knowledge remain, such as the etiology, prevalence, and trends of hypertension; the utility and practicality of ambulatory blood pressure monitoring; practical goals for lifestyle modification that are generalizable; the long-term end-organ impacts of hypertension in youth; and the long-term safety and efficacy of antihypertensive therapy in youth. The Eunice Kennedy Shriver National Institute of Child Health and Human Development, in collaboration with the National Heart, Lung, and Blood Institute and the US Food and Drug Administration, sponsored a workshop of experts to discuss the current state of childhood primary hypertension. We highlight the results of that workshop and aim to (1) provide an overview of current practices related to the diagnosis, management, and treatment of primary pediatric hypertension; (2) identify related research gaps; and (3) propose ways to address existing research gaps.

High blood pressure, a red flag for the neonatal manifestation of urea cycle disorders

BACKGROUND

Neonatal manifestation of life-threatening hyperammonemic encephalopathy in urea cycle disorders (UCD) is often misdiagnosed as neonatal sepsis, resulting in significantly delayed start of specific treatment and poor outcome. The major aim of this study was to identify specific initial symptoms or signs to clinically distinguish hyperammonemic encephalopathy in neonates from neonatal sepsis in order to identify affected individuals with UCD and to start metabolic therapy without delay. Furthermore, we evaluated the impact of diagnostic delay, peak plasma ammonium (NH₄⁺) concentration, mode of emergency treatment and transfer to a tertiary referral center on the outcome.

METHODS

Detailed information of 17 patients (born between 1994 and 2012) with confirmed diagnosis of UCD and neonatal hyperammonemic encephalopathy were collected from the original medical records.

RESULTS

The initially suspected diagnosis was neonatal sepsis in all patients, but was not confirmed in any of them. Unlike neonatal sepsis and not previously reported blood pressure increased above the 95th percentile in 13 (81%) of UCD patients before emergency treatment was started. Respiratory alkalosis was found in 11 (65%) of UCD patients, and in 14 (81%) plasma NH₄⁺concentrations further increased despite initiation of metabolic therapy.

CONCLUSION

Detection of high blood pressure could be a valuable parameter for distinguishing neonatal sepsis from neonatal manifestation of UCD. Since high blood pressure is not typical for neonatal sepsis, other reasons such as encephalopathy and especially hyperammonemic encephalopathy (caused by e.g. UCD) should be searched for immediately. However, our result that the majority of newborns with UCD initially present with high blood pressure has to be evaluated in larger patient cohorts.

Changes in Endothelial Nitric Oxide Production in Systemic Vessels during Early Ontogenesis-A Key Mechanism for the Perinatal Adaptation of the Circulatory System

Nitric oxide (NO) produced in the wall of blood vessels is necessary for the regulation of vascular tone to ensure an adequate blood supply of organs and tissues. In this review, we present evidence that the functioning of endothelial NO-synthase (eNOS) changes considerably during postnatal maturation. Alterations in NO-ergic vasoregulation in early ontogeny vary between vascular beds and correlate with the functional reorganization of a particular organ. Importantly, the anticontractile effect of NO can be an important mechanism responsible for the protectively low blood pressure in the immature circulatory system. The activity of eNOS is regulated by a number of hormones, including thyroid hormones which are key regulators of the perinatal developmental processes. Maternal thyroid hormone deficiency suppresses the anticontractile effect of NO at perinatal age. Such alterations disturb perinatal cardiovascular homeostasis and lead to delayed occurring cardiovascular pathologies in adulthood. The newly discovered role of thyroid hormones may have broad implications in cardiovascular medicine, considering the extremely high prevalence of maternal hypothyroidism in human society.

Survey of 23 Nordic university hospitals showed that 77% lacked written procedures for measuring and interpreting blood pressure in infants

AIM

This study determined the use of standardised procedures for infant noninvasive blood pressure (NIBP) measurements in the Nordic countries and aimed to identify factors included in the standardisation and interpretation of NIBP measurements in infants.

METHODS

A cross-sectional electronic questionnaire survey was sent to 84 physicians in all 23 university hospitals in Sweden, Norway, Denmark, Finland and Iceland and was completed from February to March 2017. The survey contained respondent characteristics, the presence and description of standardised procedures for NIBP measurements, daily practice of NIBP measurements and methodological considerations and interpretation of NIBP measurements in a healthy six-month-old child.

RESULTS

We received responses from 55 of 84 physicians working in all 23 Nordic university hospitals, in paediatric cardiology (n = 22), general paediatrics (n = 16), paediatric nephrology (n = 14) and other fields (n = 3). Less than a quarter (23%) said their hospital issued specific NIBP procedures relating to infants and they referred to 19 different sources of information. The factors that were most commonly assessed for interpretation were age (100%), arousal state (78%) and cuff size (76%).

CONCLUSION

Most of the university hospital units treating children lacked age-specific written procedures for measuring and interpreting infant NIBP, and there is a strong need for common Nordic guidelines.

Incidence of neonatal hypertension from a large multicenter study [Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates-AWAKEN]

BACKGROUND

Hypertension occurs in up to 3% of neonates admitted to the Neonatal Intensive Care Unit (NICU), and is a potentially under-recognized condition. The aim of this study was to examine the incidence of documented and undiagnosed hypertension from the 24-center Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) database, and to assess risk factors for hypertension according to gestational age.

METHODS

Diagnosed hypertension was documented if an infant had a discharge diagnosis of hypertension and/or discharged on antihypertensive medications. Undiagnosed hypertension was defined when infants did not have a diagnosis of hypertension, but >50% of the lowest mean, diastolic and systolic blood pressure recordings were >95^th percentile for gestational age.

RESULTS

Of the 2162 neonates enrolled in the study, hypertension was documented in 1.8%. An additional 3.7% were defined as having undiagnosed hypertension. There was a significant correlation with neonatal hypertension and acute kidney injury (AKI). Additional risk factors for neonatal hypertension were hyperbilirubinaemia, Caucasian race, outborn, vaginal delivery, and congenital heart disease. Protective factors were small for gestational age, multiple gestations, and steroids for fetal maturation.

CONCLUSIONS

Neonatal hypertension may be an under-recognized condition. AKI and other risk factors predispose infants to hypertension.

Characteristics of hypertension in premature infants with and without chronic lung disease: a long-term multi-center study

BACKGROUND

Many causes for neonatal hypertension in premature infants have been described; however in some cases no etiology can be attributed. Our objectives are to describe such cases of unexplained hypertension and to compare hypertensive infants with and without chronic lung disease (CLD).

METHODS

We reviewed all cases of hypertension in premature infants referred from 18 hospitals over 16 years. Inclusion criteria were hypertension occurring at <6 months of age and birth at <37 weeks gestation; the main exclusion criterion was known secondary hypertension. Continuous variables were compared using analysis of variance. Nominal variables were compared using chi-square tests.

RESULTS

A total of 97 infants met the inclusion criteria, of whom 37 had CLD. Among these infants, hypertension presented at a mean of 11.3 ± 3.2 chronological weeks of age and a postmenstrual age of 39.6 ± 3.6 weeks. Diagnostic testing was notable for plasma renin activity (PRA) being <11 ng/mL/h in 98% of hypertensive infants. Spironolactone was effective monotherapy in 51 of 56 cases of hypertension. Hypertension resolved in all infants, with an average treatment duration of 25 weeks. Significant differences between the two groups of infants were a 0.4 kg lower birthweight and a 2.5 weeks younger gestational age at birth in those with CLD (p < 0.01, p < 0.01, respectively). Hypertension presented in those with CLD 1.8 weeks later, but at the same postmenstrual age as those without CLD (p < 0.01, p = 0.45, respectively).

CONCLUSION

Premature infants with unexplained hypertension, with and without CLD, presented at a postmenstrual age of 40 weeks with low PRA, transient time course, and a favorable response to spironolactone treatment.

Asynchronous Pumping of a Pulsatile Ventricular Assist Device in a Pediatric Anastomosis Model

BACKGROUND

Both pulsatile and continuous flow ventricular assist devices are being developed for pediatric congenital heart defect patients. Pulsatile devices are often operated asynchronously with the heart in either an "automatic" or a fixed beat rate mode. However, most studies have only investigated synchronized ejection.

METHODS

A previously validated viscoelastic blood solver is used to investigate the parameters of pulsatility, power loss, and graft failure in a pediatric aortic anastomosis model.

RESULTS

Pulsatility was highest with synchronized flow and lowest at a 90° phase shift. Power loss decreased at 90° and 180° phase shifts but increased at a 270° phase shift. Similar regions of potential intimal hyperplasia and graft failure were seen in all cases but with phase-shifted ejection leading to higher wall shear stress on the anastomotic floor and oscillatory shear index on the anastomotic toe.

CONCLUSION

The ranges of pulsatility and hemodynamics that can result clinically using asynchronous pulsatile devices were investigated in a pediatric anastomosis model. These results, along with the different postoperative benefits of pump modulation, can be used to design an optimal weaning protocol.

Identifying Children at Risk of Malignant Bordetella pertussis Infection

OBJECTIVE

To identify factors associated with malignant pertussis.

DESIGN

A retrospective case notes review from January 2003 to August 2013. Area under the receiver-operator characteristic curve was used to determine how well vital sign and white cell characteristics within 48 hours of hospital presentation identified children with malignant pertussis.

SETTING

The national children's hospital in Auckland, New Zealand.

PATIENTS

One hundred fifty-two children with pertussis.

MEASUREMENTS AND MAIN RESULTS

There were 152 children with confirmed pertussis identified, including 11 children with malignant pertussis. The area under the receiver-operator characteristic curve was 0.88 (95% CI, 0.78-0.97) for maximum heart rate. The optimal cut-point was 180 beats/min, which predicted malignant pertussis with a sensitivity of 73% and a specificity of 91%. The area under the receiver-operator characteristic curve was 0.92 (95% CI, 0.81-1.0) for absolute neutrophil count, 0.85 (95% CI, 0.71-0.99) for total WBC count, 0.80 (95% CI, 0.63-0.96) for neutrophil-to-lymphocyte ratio, and 0.77 (95% CI, 0.58-0.92) for absolute lymphocyte count. All children with malignant pertussis had one or more of heart rate greater than 180 beats/min, total WBC count greater than 25 × 10/L, and neutrophil-to-lymphocyte ratio greater than 1.0 with an area under the receiver-operator characteristic curve of 0.96 (95% CI, 0.91-1.0) for a multivariate model that included these three variables.

CONCLUSIONS

Clinical predictors of malignant pertussis are identifiable within 48 hours of hospital presentation. Early recognition of children at risk of malignant pertussis may facilitate early referral to a PICU for advanced life support and selection for trials of investigational therapies.

Novelty in hypertension in children and adolescents: focus on hypertension during the first year of life, use and interpretation of ambulatory blood pressure monitoring, role of physical activity in prevention and treatment, simple carbohydrates and uric acid as risk factors

The present article intends to provide an update of the article "Focus on prevention, diagnosis and treatment of hypertension in children and adolescents" published in 2013 (Spagnolo et al., Ital J Pediatr 39:20, 2013) in this journal. This revision is justified by the fact that during the last years there have been several new scientific contributions to the problem of hypertension in pediatric age and during adolescence. Nevertheless, for what regards some aspects of the previous article, the newly acquired information did not require substantial changes to what was already published, both from a cultural and from a clinical point of view. We felt, however, the necessity to rewrite and/or to extend other parts in the light of the most recent scientific publications. More specifically, we updated and extended the chapters on the diagnosis and management of hypertension in newborns and unweaned babies, on the use and interpretation of ambulatory blood pressure monitoring, and on the usefulness of and indications for physical activity. Furthermore, we added an entirely new section on the role that simple carbohydrates (fructose in particular) and uric acid may play in the pathogenesis of hypertension in pediatric age.

Hemodynamics in a Pediatric Ascending Aorta Using a Viscoelastic Pediatric Blood Model

Congenital heart disease is the leading cause of infant death in the United States with over 36,000 newborns affected each year. Despite this growing problem there are few mechanical circulatory support devices designed specifically for pediatric and neonate patients. Previous research has been done investigating pediatric ventricular assist devices (PVADs) assuming blood to be a Newtonian fluid in computational fluid dynamics (CFD) simulations, ignoring its viscoelastic and shear-thinning properties. In contrast to adult VADs, PVADs may be more susceptible to hemolysis and thrombosis due to altered flow into the aorta, and therefore, a more accurate blood model should be used. A CFD solver that incorporates a modified Oldroyd-B model designed specifically for pediatric blood is used to investigate important hemodynamic parameters in a pediatric aortic model under pulsatile flow conditions. These results are compared to Newtonian blood simulations at three physiological pediatric hematocrits. Minor differences are seen in both velocity and wall shear stress (WSS) during early stages of the cardiac cycle between the Newtonian and viscoelastic models. During diastole, significant differences are seen in the velocities in the descending aorta (up to 12%) and in the aortic branches (up to 30%) between the two models. Additionally, peak WSS differences are seen between the models throughout the cardiac cycle. At the onset of diastole, peak WSS differences of 43% are seen between the Newtonian and viscoelastic model and between the 20 and 60% hematocrit viscoelastic models at peak systole of 41%.

Continuous and Pulsatile Pediatric Ventricular Assist Device Hemodynamics with a Viscoelastic Blood Model

To investigate the effects of pulsatile and continuous pediatric ventricular assist (PVAD) flow and pediatric blood viscoelasticity on hemodynamics in a pediatric aortic graft model. Hemodynamic parameters of pulsatility, along with velocity and wall shear stress (WSS), are analyzed and compared between Newtonian and viscoelastic blood models at a range of physiological pediatric hematocrits using computational fluid dynamics. Both pulsatile and continuous PVAD flow lead to a decrease in pulsatility (surplus hemodynamic energy, ergs/cm(3)) compared to healthy aortic flow but with continuous PVAD pulsatility up to 2.4 times lower than pulsatile PVAD pulsatility at each aortic outlet. Significant differences are also seen between the two flow modes in velocity and WSS. The higher velocity jet during systole with pulsatile flow leads to higher WSSs at the anastomotic toe and at the aortic branch bifurcations. The lower velocity but continuous flow jet leads to a much different flow field and higher WSSs into diastole. Under a range of physiological pediatric hematocrit (20-60%), both velocity and WSS can vary significantly with the higher hematocrit blood model generally leading to higher peak WSSs but also lower WSSs in regions of flow separation. The large decrease in pulsatility seen from continuous PVAD flow could lead to complications in pediatric vascular development while the high WSSs during peak systole from pulsatile PVAD flow could lead to blood damage. Both flow modes lead to similar regions prone to intimal hyperplasia resulting from low time-averaged WSS and high oscillatory shear index.

Clinical overview of hypertensive crisis in children

Hypertensive emergencies and hypertensive urgencies in children are uncommonly encountered in the pediatric emergency department and intensive care units, but the diseases are potentially a life-threatening medical emergency. In comparison with adults, hypertension in children is mostly asymptomatic and most have no history of hypertension. Additionally, measuring accurate blood pressure values in younger children is not easy. This article reviews current concepts in pediatric patients with severe hypertension.

Strengths and limitations of current pediatric blood pressure nomograms: a global overview with a special emphasis on regional differences in neonates and infants

The availability of robust nomograms is essential for the correct evaluation of blood pressure (BP) values in children. A literature search was conducted by accessing the National Library of Medicine by using the keywords BP, pediatric and reference values/nomograms. A total of 43 studies that evaluated pediatric BP nomograms were included in this review. Despite the accuracy of the latest studies, many numerical and methodological limitations still remain. The numerical limitations include the paucity of data for neonates/infants and for some geographic areas (Africa/South America/East Europe/Asia) and ethnicities. Furthermore, the data on ambulatory BP and response to exercise are extremely limited, and the criteria for stress-test interruption are lacking. There was heterogeneity in the methodologies employed to perform the measurements, in the inclusion/exclusion criteria (often not reported), in the data normalization and the data expression (Z-scores/percentiles/mean values). Although most studies adjusted the measurements for age and/or height, the classification by specific age/height subgroups varied. Gender differences were generally considered, whereas other confounders (that is, ethnicity/geographic area/environment) were seldom evaluated. As a result, nomograms were heterogeneous, and when comparable, at times showed widely different confidence intervals. These differences are most likely because of both methodological limitations and differences among the populations studied. Some robust nomograms exist (particularly those from the USA); however, it has been demonstrated that if adopted in other countries/continents, they may generate an unpredictable bias in the evaluation of BP values in children. Actual pediatric BP nomograms present consistent limitations that affect the evaluation of BP in children. Comprehensive nomograms, which are based on a large population of healthy children (including neonates/infants) and use standardized methodology, are warranted for every country/region.

Leigh Syndrome Caused by the MT-ND5 m.13513G>A Mutation: A Case Presenting with WPW-Like Conduction Defect, Cardiomyopathy, Hypertension and Hyponatraemia

Mitochondrial disease can present with a wide range of clinical phenotypes, and knowledge of the clinical spectrum of mitochondrial DNA mutation is constantly expanding. Leigh syndrome (LS) has been reported to be caused by the m.13513G>A mutation in the ND5 subunit of complex I (MT-ND5 m.13513G>A). We present a case of a 12-month-old infant initially diagnosed with tachyarrhythmia requiring defibrillation, subsequent presentation with hypertension and hyponatraemia secondary to renal salt loss and presumed inappropriate ADH secretion. Complex I activity in the muscle tissue was 54%, and mutation load in the muscle and lymphocytes was 50%. This case of Leigh syndrome caused by the m.13513G>A mutation in the ND5 gene illustrates that hyponatraemia due to renal sodium loss and inappropriate ADH secretion and hypertension can be features of this entity in addition to the previously reported cardiomyopathy and WPW-like conduction pattern and that they present additional challenges in diagnosis and management.

Neonatal hypertension

The incidence of neonatal hypertension (HTN) remains low, at less than 2%, and its etiology is varied. Strict definitions of HTN in neonates are unavailable, and the decision to treat is based on opinion rather than evidence. More studies are needed to define normal blood pressure in neonates and to refine current reference values, thus permitting a better definition of HTN. Most causes of neonatal HTN, the most common of which seems to be renovascular disease, are determined by history and basic clinical investigations. Treatment is guided by clinical judgment and expert opinion, given the limited number of clinical trials.

Determinants of neonatal blood pressure

Blood pressure (BP) measurements have been increasingly used across neonatal intensive care units to determine and monitor hemodynamic status in neonates. A number of studies have attempted to derive normative blood pressure data in both preterm and term infants. However, this still remains a complex process, as several maternal and neonatal factors influence neonatal blood pressure. Maternal conditions, including hypertension and preeclampsia, seem to have some impact on neonatal BP, while maternal drugs, in particular antenatal steroids, seem to have a strong influence. Among the neonatal factors, gestational age, post-conceptual age and weight seem to have the strongest influence. The paucity of data on the short and long term effects of maternal conditions and medication on neonatal BP requires further research.

Cardiovascular and blood glucose parameters in infants during propranolol initiation for treatment of symptomatic infantile hemangiomas

OBJECTIVES

We sought to determine the effect of propranolol on cardiovascular and blood glucose parameters in infants with symptomatic infantile hemangiomas who were hospitalized for initiation of treatment, and to analyze adverse effects of propranolol throughout the course of inpatient and outpatient treatment.

METHODS

A retrospective cohort analysis was performed on 50 infants (age less than 12 months) with symptomatic infantile hemangiomas who were hospitalized for propranolol initiation between 2008 and 2012. Demographic data and disease characteristics were recorded. Systolic and diastolic blood pressures, heart rate, blood glucose values, and adverse events recorded during hospitalization were analyzed. An additional cohort of 200 consecutively treated children was also assessed for adverse events associated with outpatient propranolol use.

RESULTS

The median age among the inpatient cohort was 3.4 months (range, 0.8 to 12.0 months). Infants older than 6 months were more likely to exhibit bradycardia than were younger infants (p < 0.001). Hypotensive and/or bradycardic periods were infrequent and were not associated with observable clinical symptoms. The mean systolic and diastolic blood pressures and the mean heart rate decreased significantly from day 1 of hospitalization to day 2 (p = 0.004; p = 0.008; p < 0.001), but not from day 2 to day 3, when the propranolol dose was increased to target. Hypoglycemia was rare (0.3% incidence.) Among the 250 outpatients, 2 infants developed lethargy and hypoglycemia during a viral illness and recovered without sequelae. One infant experienced recurrent bronchospasm with viral illnesses and required concomitant bronchodilator therapy.

CONCLUSIONS

Frequent deviations from normal ranges of blood pressure and heart rate occur upon initiation of propranolol, but are clinically asymptomatic. These findings support that outpatient initiation of propranolol in healthy, normotensive infants appears to be a relatively safe alternative to inpatient initiation. Hypoglycemia is rare, but can occur throughout the treatment period; parent counseling is of paramount importance.

Neonatal blood pressure monitoring: visual assessment is an unreliable method for selecting cuff sizes

AIM

To compare current practice of cuff size selection for noninvasive blood pressure measurement in a single-centre, tertiary-level neonatal intensive care unit (visual assessment of bladder width/limb length closest to 2/3) with common recommendations for appropriate cuff selection.

METHODS

Visual assessment of the appropriate cuff size ('2/3 rule') for upper arm, forearm and calf in 103 neonates (309 cuff selections) was compared with the following recommendations: (i) Method A - guidelines of the cuff manufacturer, (ii) Method B - cuff width/limb circumference ratio 0.44-0.60 and (iii) Method C - cuff width/limb length ratio closest to 0.66.

RESULTS

The upper arm cuff size was correctly chosen in 84% of cases (Method A), 43% (Method B) and 56% (Method C). The forearm cuff size was correctly chosen in 94% of cases (Method A), 68% (Method B) and 54% (Method C). The calf cuff size was correctly chosen in 96% of cases (Method A), 72% (Method B) and 63% (Method C).

CONCLUSION

The accuracy of selecting cuff size by visual assessment is low. Further research on accurate cuff selection for neonates, including at the forearm and calf, is warranted.

Preliminary experience on treatment of infantile hemangioma with low-dose propranolol in China

We aimed to assess the efficacy and safety of low-dose propranolol for treatment of infantile hemangiomas (IHs) in China. Our prospective study included data from 89 patients with IH, aged 1-12 months. Plasma renin activity, angiotensin II, and aldosterone were measured before initiation of propranolol therapy. Patients were administered propranolol (0.75-1 mg/kg/day) under close observation. The volume, texture, and color of lesions were used to evaluate efficacy. Safety endpoints included heart rate, systolic and diastolic blood pressures, alanine transaminase, aspartate transaminase, thyroid function tests, and fasting blood glucose. Adverse effects were recorded. Mean plasma angiotensin II concentration in patients with IH was higher than that in age-matched healthy children, whereas mean plasma renin activity was lower. Mean aldosterone level was higher at 1-3 months but lower at 4-12 months, than values reported previously. After propranolol therapy for 6 months, IH regression was classed as grade IV in 44 patients (49.4 %), grade III in 21 patients (23.6 %), and grade II in 24 patients (27.0 %); none were grade I. Mild adverse effects, including diarrhea, restless sleep, nausea, cold extremities, and hypoglycemia, occurred in 12 patients (13.5 %). Slight decreases in heart rate and blood pressure occurred in all patients (p < 0.05). The IHs of four patients (4.5 %) relapsed after treatment cessation at 4-5 months.

CONCLUSION

Low-dose propranolol is effective and safe for Chinese children with IH, and larger-scale studies are merited. Mechanisms underlying IH pathogenesis, and possible involvement of the renin-angiotensin-aldosterone system, deserve study.

Initiation and use of propranolol for infantile hemangioma: report of a consensus conference

Infantile hemangiomas (IHs) are common neoplasms composed of proliferating endothelial-like cells. Despite the relative frequency of IH and the potential severity of complications, there are currently no uniform guidelines for treatment. Although propranolol has rapidly been adopted, there is significant uncertainty and divergence of opinion regarding safety monitoring, dose escalation, and its use in PHACE syndrome (PHACE = posterior fossa, hemangioma, arterial lesions, cardiac abnormalities, eye abnormalities; a cutaneous neurovascular syndrome characterized by large, segmental hemangiomas of the head and neck along with congenital anomalies of the brain, heart, eyes and/or chest wall). A consensus conference was held on December 9, 2011. The multidisciplinary team reviewed existing data on the pharmacologic properties of propranolol and all published reports pertaining to the use of propranolol in pediatric patients. Workgroups were assigned specific topics to propose protocols on the following subjects: contraindications, special populations, pretreatment evaluation, dose escalation, and monitoring. Consensus protocols were recorded during the meeting and refined after the meeting. When appropriate, protocol clarifications and revision were made and agreed upon by the group via teleconference. Because of the absence of high-quality clinical research data, evidence-based recommendations are not possible at present. However, the team agreed on a number of recommendations that arose from a review of existing evidence, including when to treat complicated IH; contraindications and pretreatment evaluation protocols; propranolol use in PHACE syndrome; formulation, target dose, and frequency of propranolol; initiation of propranolol in infants; cardiovascular monitoring; ongoing monitoring; and prevention of hypoglycemia. Where there was considerable controversy, the more conservative approach was selected. We acknowledge that the recommendations are conservative in nature and anticipate that they will be revised as more data are made available.

First-attack pediatric hypertensive crisis presenting to the pediatric emergency department

BACKGROUND

Hypertensive crisis in children is a relatively rare condition presenting with elevated blood pressure (BP) and related symptoms, and it is potentially life-threatening. The aim of this study was to survey children with first attacks of hypertensive crisis arriving at the emergency department (ED), and to determine the related parameters that predicted the severity of hypertensive crisis in children by age group.

METHODS

This was a retrospective study conducted from 2000 to 2007 in pediatric patients aged 18 years and younger with a diagnosis of hypertensive crisis at the ED. All patients were divided into four age groups (infants, preschool age, elementary school age, and adolescents), and two severity groups (hypertensive urgency and hypertensive emergency). BP levels, etiology, severity, and clinical manifestations were analyzed by age group and compared between the hypertensive emergency and hypertensive urgency groups.

RESULTS

The mean systolic/diastolic BP in the hypertensive crisis patients was 161/102 mmHg. The major causes of hypertensive crisis were essential hypertension, renal disorders and endocrine/metabolic disorders. Half of all patients had a single underlying cause, and 8 had a combination of underlying causes. Headache was the most common symptom (54.5%), followed by dizziness (45.5%), nausea/vomiting (36.4%) and chest pain (29.1%). A family history of hypertension was a significant predictive factor for the older patients with hypertensive crisis. Clinical manifestations and severity showed a positive correlation with age. In contrast to diastolic BP, systolic BP showed a significant trend in the older children.

CONCLUSIONS

Primary clinicians should pay attention to the pediatric patients who present with elevated blood pressure and related clinical hypertensive symptoms, especially headache, nausea/vomiting, and altered consciousness which may indicate that appropriate and immediate antihypertensive medications are necessary to prevent further damage.