Systemic Venous Diameters, Collapsibility Indices, and Right Atrial Measurements in Normal Pediatric Subjects

Echocardiographic estimation of pulmonary arterial and right atrial pressures in children with congenital heart disease: a comprehensive prospective study and introduction of novel equations

BACKGROUND

Pediatric pulmonary hypertension (PH) is characterized by a mean pulmonary arterial pressure exceeding 20 mmHg. There is limited research on the suitability of adult-based methods for estimating PH in pediatric populations. Using established formulas for adults, this study aimed to evaluate the correlation between echocardiographic estimates of systolic, diastolic, and mean pulmonary arterial pressures, and mean right atrial pressures in children with congenital heart disease (CHD).

METHODS

A prospective study was conducted involving children with CHD undergoing cardiac catheterization without prior cardiac surgery. We used echocardiography to estimate pulmonary and right atrial pressures and compared these with invasively measured values. Four reliable regression equations were developed to estimate systolic, diastolic, and mean pulmonary arterial pressures, and mean right atrial pressures. Cutoff values were determined to predict the occurrence of PH. Linear regression, Bland-Altman analysis, and receiver operating characteristic curve analysis were performed to assess the accuracy of echocardiography and establish diagnostic thresholds for PH.

RESULTS

The study involved 55 children (23 with normal pulmonary arterial pressure and 32 with PH) with acyanotic CHD aged 1 to 192 months. Four equations were developed to detect high pulmonary arterial pressures, with cutoff values of 32.9 for systolic pulmonary arterial pressure, 14.95 for diastolic pulmonary arterial pressure, and 20.7 for mean pulmonary arterial pressure. The results showed high sensitivity and moderate specificity but a tendency to underestimate systolic and mean pulmonary arterial pressures at higher pressures.

CONCLUSIONS

The study provides valuable insights into the use of adult-based echocardiographic formulas for estimating PH in pediatric patients with acyanotic CHD.

Transcatheter Covered Stent Exclusion of Superior Sinus Venosus Defects

BACKGROUND

Transcatheter correction of sinus venosus defects (SVDs) using balloon-mounted covered stents provides an attractive surgical alternative. Surgery may be complicated by superior vena caval or right upper pulmonary vein (RUPV) stenosis, sinus nodal dysfunction, and residual additional pulmonary veins.

OBJECTIVES

Being a new intervention, technical modifications would simplify the procedure, improve universal applicability, and reduce or tackle complications.

METHODS

Patients were included if balloon interrogation of cavoatrial junction confirmed closure of SVD and redirected RUPV to the left atrium. A single-center experience was analyzed to summarize the procedural modifications over 8 years. Transesophageal echocardiogram (TEE) on follow-up was done to identify residual shunt, RUPV flows, and stent thrombosis.

RESULTS

A total of 100 patients including 9 children with a median age of 35 years (range, 4-69 years) underwent SVD closure after balloon interrogation. Among 57 patients balloon interrogated in the first 5 years, 70% underwent transcatheter closure, with 2 failures. RUPV occlusion caused the exclusions. Inclusions improved to 94% among the subsequent 65 balloon interrogations when RUPV protection was implemented, with 1 failure. Stent embolization caused the 3 failures warranting surgery. Recent modifications included limited transesophageal echocardiogram without anesthesia, avoiding venovenous circuit, interrogation with semicompliant balloons, trans-septal RUPV protection, overlapping stents to permit additional vein drainage to superior vena cava and tackle embolizations. There were no deaths. Minor complications included stent embolizations stabilized in catheterization laboratory in 2 patients, left innominate vein jailing in 2 patients, insignificant residual flows, and nonocclusive asymptomatic stent thrombosis in 4 patients.

CONCLUSIONS

Procedural success was 97%. Recent modifications increased patient inclusions, decreased complications, and simplified the intervention.

Percutaneous treatment of symptomatic deep vein thrombosis in adolescents using large-bore thrombectomy systems

BACKGROUND

While large-bore mechanical thrombectomy provides effective venous thrombus removal, often with avoidance of thrombolytics, literature surrounding the application of these devices in pediatric patients is sparse.

OBJECTIVE

To report technical success and outcomes following large-bore thrombectomy systems in adolescent patients with deep venous thrombosis.

MATERIALS AND METHODS

A retrospective review identified all patients less than 18 years of age undergoing mechanical venous thrombectomy at a single institution between 2018 and 2022. No patients were excluded. Technical success was defined as extraction of thrombus sufficient to restore unimpeded flow in affected segments. Clinical success was defined as resolution of presenting symptoms.

RESULTS

Nine consecutive patients (6 females, 3 males; age range 15-17 years) underwent 10 thrombectomy procedures using ClotTriever (n=6; 60%), FlowTriever (n=2; 20%), or both (n=2; 20%). Chronicity of thrombus was categorized as acute (<2 weeks) in 6 (60%), subacute (2-6 weeks) in 1 (10%), and chronic (>6 weeks) in 3 (30%). Distribution of thrombus was lower extremity and/or inferior vena cava (IVC) in 9 (90%) and unilateral axillo-subclavian in 1 (10%). Technical success was achieved in 9 interventions (90%). Clinical success was achieved in 8 patients (88.9%). No patients received thrombolytics. There were no intraprocedural adverse events (AE). Minor complications (Society of Interventional Radiology mild adverse events) were observed in a delayed fashion following 2 interventions (20%).

CONCLUSIONS

This preliminary experience demonstrated high rates of technical and clinical success with large-bore deep venous thrombectomy in adolescent patients across a range of thrombus chronicity and locations.

Point-of-Care Ultrasonography for the Assessment of Dehydration in Children: A Systematic Review

OBJECTIVES

Accurate estimation of the degree of dehydration remains a diagnostic challenge. The primary objective was to systematically review the literature on the role of ultrasound in assessment of the degree of dehydration in children.

METHODS

Data sources included Ovid MEDLINE, Web of Science Core Collection, Current Index to Nursing and Allied Health Literature, Cochrane Library, ClinicalTrials.gov , and Trip Pro Database. Two independent reviewers used screening protocol to include articles on assessment of dehydration in children with the use of point-of-care ultrasonography (POCUS). The level of evidence was assessed in accordance with the "The Oxford 2011 Levels of Evidence." The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to evaluate risk of bias.

RESULTS

We identified 108 studies, and 8 studies met our inclusion criteria. All studies were prospective cohort studies (level of evidence, 3-4). The authors of 5 studies used difference between ill weight and weight after rehydration as the reference standard for dehydration, and the authors of 3 studies used clinical dehydration scale. Two studies from the United States showed acceptable areas under the curve for inferior vena cava to aorta (IVC/Ao) diameter ratio at 0.72 and 0.73 for prediction of significant dehydration (>5% weight loss). The IVC/Ao ratio with cut-off at 0.8 had sensitivity of 67% and 86% and specificity of 71% and 56% for prediction of significant dehydration. Studies from the resource-limited settings were more heterogeneous. One study with acceptable risk of biases reported poor sensitivity (67%) and specificity (49%) of Ao/IVC ratio with cut-off of 2.0 for predicting severe dehydration (>9% weight loss) with area under the curve at 0.6. Three studies showed increase in IVC diameter with fluid resuscitation with mean change in IVC diameter by 30% in children with significant dehydration (>5% weight loss) and by 22% without significant dehydration (<5% weight loss). Metaanalysis was not completed due to high heterogeneity.

CONCLUSIONS

This study showed that the quantity and quality of research on the application of POCUS for the assessment of dehydration in children is limited. There is no criterion standard for assessing the degree of dehydration and no universal definition of the degree of dehydration. Thus, more methodologically rigorous studies are required. Current systematic review does not support the routine use of US to determine the severity of dehydration in children. Despite these limitations, the use of POCUS in children with dehydration demonstrates potential. Given the clear increase in IVC size with rehydration, repeated IVC US scans may be helpful in guiding fluid resuscitation in children with dehydration. From different proposed US parameters, IVC/Ao ratio has better diagnostic accuracy in detecting significant dehydration than Ao/IVC ratio and IVC collapsibility index. Despite low to moderate diagnostic performance, US still showed better assessment of dehydration than physician gestalt and World Health Organization score.

Echocardiographic caudal vena cava measurements in healthy cats and in cats with congestive heart failure and non-cardiac causes of cavitary effusions

BACKGROUND

Echocardiographic indices of the inferior vena cava have been associated with elevated right atrial pressures in humans.

HYPOTHESIS/OBJECTIVES

Describe caudal vena caval (CVC) sonographic dimensions in healthy cats compared to cats with cardiogenic cavitary effusion (CCE), cardiogenic pulmonary edema (CPE), or non-cardiac causes of cavitary effusion (NCE).

ANIMALS

30 healthy control cats and 52 client-owned cats with CCE, CPE, or NCE examined at two university hospitals.

METHODS

Sagittal 2-dimensional (2D) and M-mode CVC dimensions were acquired from the subxiphoid view. Caudal vena cava collapsibility index (CVC-CI) was calculated. Variables were compared between study groups using Kruskal-Wallis and Dunn's Bonferroni testing. Receiver operating characteristic curves were used to assess sensitivity and specificity for diagnostic categories.

RESULTS

Healthy cats had sagittal 2D and M-mode (median, interquartile range) CVC maximal dimensions of 2.4 mm (1.3-4.0) and 3.4 mm (1.5-4.9) and CVC-CI of 52% (45.2-61.8) and 55% (47.8-61.3), respectively. The CVC maximal dimensions in healthy controls were smaller than in cats with cavitary effusions or pulmonary edema (all P<0.05). CVC-CI was different between CCE and NCE (P<0.0001) with cutoffs of CVC-CI ≤38% (2D) or ≤29% (M-mode) being 90.5% and 85.7% sensitive, and 94.4% and 100% specific for diagnosis of CCE, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Caudal vena cava measurements are larger in cats with cavitary effusions and cats with CPE than healthy cats. In cats with cavitary effusion, decreased CVC-CI, ≤38% (2D) or ≤29% (M-mode), was helpful in distinguishing between cardiogenic and noncardiogenic etiology.

Contemporary Use of Ultrasonography in Acute Care Pediatrics

Use of ultrasonography by clinicians at the point of care has expanded widely and rapidly. Pediatric acute care providers now leverage this valuable tool to guide procedures, diagnose pathophysiologic processes, and inform time-sensitive decisions in sick and unstable children. However, the deployment of any new technology must be packaged with training, protocols, and safeguards to optimize safety for patients, providers, and institutions. As ultrasonography is increasingly incorporated into residency, fellowship, and even medical student curricula, it is important that educators and trainees are aware of the diversity of its clinical applications. This article aims to review the current state of point-of-care ultrasonography in acute care pediatrics, with an emphasis on the literature supporting the use of this important clinical tool.

Recommendations for Cardiac Point-of-Care Ultrasound in Children: A Report from the American Society of Echocardiography

Cardiac point-of-care ultrasound has the potential to improve patient care, but its application to children requires consideration of anatomic and physiologic differences from adult populations, and corresponding technical aspects of performance. This document is the product of an American Society of Echocardiography task force composed of representatives from pediatric cardiology, pediatric critical care medicine, pediatric emergency medicine, pediatric anesthesiology, and others, assembled to provide expert guidance. This diverse group aimed to identify common considerations across disciplines to guide evolution of indications, and to identify common requirements and infrastructure necessary for optimal performance, training, and quality assurance in the practice of cardiac point-of-care ultrasound in children. The recommendations presented are intended to facilitate collaboration among subspecialties and with pediatric echocardiography laboratories by identifying key considerations regarding (1) indications, (2) imaging recommendations, (3) training and competency assessment, and (4) quality assurance.

Baseline Diameter of the Inferior Vena Cava Measured with Sonography in Euvolemic Children and its Relationship to Somatic Variables

PURPOSE

 To determine normative data for the inferior vena cava (VCI) diameter in euvolemic children and its correlation with different somatic parameters in a pediatric population at one center in Europe.

MATERIALS AND METHODS

 This prospective observational study enrolled healthy children aged 4 weeks to 18y that visited our outpatient clinic. Weight, height, body surface area, and age were recorded. The children were grouped according to weight, as follows (80 children/group): < 10 kg, 10-19.9 kg, 20-29.9 kg, 30-59.9 kg, and 60-90 kg. Children were placed in a supine position and, during quiet respiration, the maximum and minimum VCI diameters were measured with M-mode ultrasonography. The collapsibility index (CI) was also automatically calculated for each subject: CI = [VCI maximum (expiratory) diameter - VCI minimum (inspiratory) diameter]/VCI maximum (expiratory) diameter.

RESULTS

 From May 2016 through November 2018 we retrieved data for 415 children that underwent VCI diameter evaluations. 400 children were included (mean age: 7.8y ± 5.8, mean weight: 32 kg ± 24.4, 46 % girls). The VCI_max and the VCI_min were significantly correlated with age (r = 0.867, p < 0.001, r = 0.797, p < 0.001), height (r = 0.840, p < 0.001, r = 0.772, p < 0.001), weight (r = 0.858, p < 0.001, r = 0.809, p < 0.001), and BSA (r = 0.878, p < 0.001, r = 0.817, p < 0.001). Correlations between the CI and age, weight, height, and BSA were not statistically significant.

CONCLUSION

 This prospective study provided reference values for sonographic measurements of VCI diameters in euvolemic children and might greatly assist in assessing fluid status in sick children.

Predictive Value of the Respiratory Variation in Inferior Vena Cava Diameter for Ventilated Children With Septic Shock

OBJECTIVES

This study aimed to investigate the predictive utility of respiratory variations of inferior vena cava diameters on fluid responsiveness in children with septic shock.

DESIGN

A prospective observational single-center study.

SETTING

A pediatric intensive care unit in a tertiary hospital in China.

PARTICIPANTS

Patients with sepsis shock who require invasive mechanical ventilation were recruited between 1 December 2017 and 1 November 2021.

INTERVENTIONS AND MEASUREMENTS

Volume expansion (VE) was induced by a 30-min infusion of 20 ml/kg of normal saline. Hemodynamics indexes were obtained through bedside transthoracic echocardiography (TTE) measurement and calculation.

RESULTS

A total of 86 patients were enrolled in this study, among them, 45 patients (52.3%) were considered to be non-responders (NR), with an increase in stroke volume variation (SVV) <15% after VE. Multivariate logistic analysis showed that ΔIVC (adjusted OR = 1.615, 95% CI 1.092-2.215, p = 0.012) was the significant predictor associated with the fluid responsiveness. The area under the ROC of ΔIVC was 0.922 (95% CI: 0.829-1.000, p < 0.01), and the cutoff value of ΔIVC used to predict fluid responsiveness was 28.5%, with a sensitivity and specificity of 95.4 and 68.5%, respectively.

CONCLUSIONS

The ΔIVC was found to have a potential value in predicting fluid responsiveness in mechanically ventilated children with septic shock.

Non-invasive assessment of liver abnormalities in pediatric Fontan patients

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Pericardial Constriction and Myocardial Restriction in Pediatric Mulibrey Nanism: A Complex Disease With Diastolic Dysfunction

Background

Mulibrey nanism (MUL) is a rare condition with profound growth delay. Congestive heart failure is a major determinant of prognosis. The aim was to delineate pericardial constriction and myocardial functional abnormalities in a pediatric MUL sample.

Methods

A total of 23 MUL patients and 23 individually sex- and age-matched healthy control subjects were prospectively assessed in a cross-sectional study with echocardiography.

Results

Clinical signs of heart failure were present in 7 MUL patients, with severe congestive heart failure in 2. Significant diastolic dysfunction, mainly related to constriction, was found in MUL patients without pericardiectomy (N = 18)—septal bounce, pronounced hepatic vein atrial reversal and right heart inflow–outflow variations, and decreased inferior vena cava collapse during respiration. The appearance of the pericardium was not different from that of control subjects. Longitudinal diastolic myocardial velocities were similar to those in control subjects, suggesting an absence of significant myocardial restriction. Right ventricular free wall longitudinal systolic strain and bilateral longitudinal myocardial systolic velocities were decreased in MUL patients, indicating mild biventricular systolic dysfunction. Myocardial motion abnormalities and persistent congestive heart failure were common (in 3 of 6) in MUL patients with a history of pericardiectomy. Cardiac dimensions were similar between MUL patients and control subjects when adjusting for body size, except for smaller biventricular volumes.

Conclusions

MUL disease presents with significant constriction-related diastolic dysfunction and mild bilateral systolic dysfunction. Constriction–restriction assessments during follow-up could be of benefit in decision-making regarding pericardiectomy in MUL disease. Myocardial abnormalities were prevalent among MUL patients who had undergone pericardiectomy and are consistent with progression of myocardial disease in a significant proportion of patients.

A guide to echocardiographic assessment in children and adolescents with pulmonary hypertension

While the current definition of pulmonary hypertension (PH) is still based on haemodynamic variables, transthoracic echocardiography is the most important diagnostic clinical tool for the first assessment and evaluation of a patient, in whom PH is suspected. In addition, it is the most important clinical modality in long term follow-up and the utility of echocardiography has widely been demonstrated in patients with PH. Echocardiography not only reveals the underlying cardiac morphology and diagnosis of any associated cardiac defects. In most patients with PH right ventricular (RV) pressure estimation is feasible. In addition, ventricular systolic and diastolic function, as well as ventricular-ventricular interactions of both ventricles can be assessed by using echocardiography. Maximizing the use of echocardiography by reporting several measures to gain information and quantitatively describe the parameters, that are linked to prognosis, seem particularly appealing in these children, in whom other advanced imaging modalities requiring anaesthesia is associated with a considerable risk. Herein we provide a practical approach and a concise and clinically applicable echocardiographic guidance and present basic variables, which should be obtained at any assessment. Moreover, we present additional advanced echocardiographic measures, that can be applied in a research or clinical setting when progressive PH needs a deeper insight to assess heart function, estimation of pulmonary artery pressures among others, by echocardiography. Finally, clinically relevant studies in view of the prognostic properties with a focus on the most important echocardiographic variables in pediatric PH are summarized.

Use of Point-of-Care Ultrasound for Evaluation of Extravascular and Intravascular Fluid Status in Pediatric Patients Maintained on Chronic Hemodialysis

AIMS

Traditional methods that use clinical parameters to determine dry weight in hemodialysis patients are inaccurate. This study aimed to compare clinical assessment of fluid status to sonographic parameters of fluid status in pediatric patients undergoing chronic hemodialysis.

METHODS

In a prospective observational study, pediatric patients maintained on chronic hemodialysis (ages 2.3-20 years) were evaluated clinically and sonographically before and after dialysis at 6 consecutive sessions. Sonographic parameters examined were number of lung B-lines as a measure of extravascular volume and inferior vena cava (IVC)/aorta ratio as a measure of intravascular volume. Clinical assessment of fluid status was compared to sonographic assessment.

RESULTS

Twelve patients were evaluated during 72 dialysis sessions. Sonographic parameters were significantly lower post-dialysis than pre-dialysis (B-lines number 4.5 ± 5 vs. 7.69 ± 7.46, p < 0.0001; IVC/aorta ratio 0.9 ± 0.2 vs. 1.1 ± 0.2, p < 0.0001, respectively). Ultrafiltration volume correlated with change in B-lines number during dialysis (r = 0.39, p < 0.01). Percent of blood volume drop correlated with post-dialysis IVC/aorta ratio (r = 0.48, p < 0.001). A higher percent of symptomatic episodes occurred with post-dialysis IVC/aorta ratio <0.8 versus ≥0.8 (39.1 vs. 15.2%, p = 0.036). Four patients were hypertensive, a clinical parameter implying fluid overload, in only one sonographic evaluation indicated fluid overload. Eight patients were clinically determined to be euvolemic, in three of them sonographic evaluation discovered covert fluids.

CONCLUSION

Bedside ultrasound is a single modality that can be used to assess both extravascular and intravascular fluid status. It may contribute to clinical decisions differentiating fluid-related versus fluid-unrelated hypertension and identifying patients with covert fluids.

Focused ultrasound of the caudal vena cava in dogs with cavitary effusions or congestive heart failure: A prospective, observational study

INTRODUCTION

Ultrasonographic indices of the inferior vena cava are useful for predicting right heart filling pressures in people.

OBJECTIVES

To determine whether ultrasonographic indices of caudal vena cava (CVC) differ between dogs with right-sided CHF (R-CHF), left-sided CHF (L-CHF), and noncardiac causes of cavitary effusion (NC).

MATERIALS AND METHODS

113 dogs diagnosed with R-CHF (n = 51), L-CHF (30), or NC effusion (32) were enrolled. Seventeen of the R-CHF dogs had pericardial effusion and tamponade. Focused ultrasound was performed prospectively to obtain 2-dimensional and M-mode subxiphoid measures of CVC maximal and minimal size (CVCmax and CVCmin), CVCmax indexed to aortic dimension (CVC:Ao), and CVC collapsibility index (CVC-CI). Variables were compared between study groups using Kruskal-Wallis and Dunn's-Bonferroni testing, and receiver operating characteristics curves were used to assess sensitivity and specificity.

RESULTS

All sonographic CVC indices were significantly different between R-CHF and NC dogs (P < 0.001). Variables demonstrating the highest diagnostic accuracy for discriminating R-CHF versus NC were CVC-CI <33% in 2D (91% sensitive and 96% specific) and presence of hepatic venous distension (84% sensitive and 90% specific). L-CHF dogs had higher CVC:Ao and lower CVC-CI compared to NC dogs (P = 0.016 and P = 0.043 in 2D, respectively) but increased CVC-CI compared to the R-CHF group (P < 0.001).

CONCLUSIONS

Ultrasonographic indices of CVC size and collapsibility differed between dogs with R-CHF compared to NC causes of cavitary effusions. Dogs with L-CHF have CVC measurements intermediate between R-CHF and NC dogs.

A trend skill that makes pediatric intensivists stand out: Critical care echocardiography

Recently, the use of point-of-care ultrasonography (POCUS) by pediatricians especially in emergency and intensive care departments has become increasingly popular. Critical care echocardiography (CCE) quickly and accurately identifies cardiac function, allowing intensivists to manage critically ill pediatric patients by manipulating vasoactive-inotrope-fluid treatment based on the echocardiographic results. Training courses for POCUS are increasingly available and more intensivists are learning how to use CCE. In this review, we focus on the importance and utility of CCE in pediatric intensive units and how it assists in the management of hemodynamically unstable pediatric patients. We highlight the common measurements carried out by intensive care specialists and emphasize the role of the CCE methods in PICUs.

Inferior Vena Cava Collapsibility Index to Assess Central Venous Pressure in Perioperative Period Following Cardiac Surgery in Children

The inferior vena cava collapsibility index (IVCCI) is an ultrasound method used to assess central venous pressure (CVP). Our objective was to evaluate the correlation between IVCCI and CVP in children during the early period following surgery for congenital heart disease (CHD). Prospective study performed in a single tertiary care center. Patients  ≤ 18 years old, who underwent cardiopulmonary bypass surgery for CHD, were enrolled. Ultrasound images of the inferior vena cava (IVC) were obtained at two time points; the first was within 2 h of arrival to the CICU and the second was 12-18 h from the first measurement. CVP measured by catheter placed during surgery was recorded within minutes of performing ultrasound. Maximum and minimum IVC diameters were measured by 2D images and M mode method. Seventy patients (47.1% males), with median age 7 months (IQR 4-47 months) and weight 6.9 kg (IQR 4.8-13.5 kg), were evaluated. The 2D IVCCI had inverse correlation with CVP in patients breathing spontaneously; r =  - 0.76 (p < 0.01) and r =  - 0.73 (p < 0.01), during the first and second measurements, respectively. The 2D IVCCI ≤ 0.24 had sensitivity, specificity, and negative predictive value of 94%, 79%, and 88.9% , respectively, to detect CVP ≥ 10 mmHg. No correlation was found between IVCCI and CVP during positive pressure ventilation. There is a significant inverse correlation between 2D IVCCI and CVP in spontaneously breathing children after surgery for CHD. Use of 2D IVCCI for monitoring CVP could reduce the frequency and duration of CVP catheters and their inherent complications.

Central venous pressure, global end-diastolic index, and the inferior vena cava collapsibility/distensibility indices to estimate intravascular volume status in critically ill children: A pilot study

BACKGROUND

The assessment of the volume status in critically ill paediatric patients in intensive care units is vitally important for fluid therapy management. The most commonly used parameter for detecting volume status is still central venous pressure (CVP); however, in recent years, various kinds of methods and devices are being used for volume assessment in intensive care units.

OBJECTIVES

We aimed to evaluate the relationship between CVP, the global end-diastolic index (GEDI), and ultrasound measurements of the collapsibility and distensibility indices of the inferior vena cava (IVC) in paediatric patients undergoing Pulse index Contour Cardiac Output (PiCCO) monitoring.

METHODS

Fifteen patients receiving PiCCO monitoring were prospectively included in the study. Forty-nine PiCCO measurements were evaluated, and simultaneous CVP values were noted. After each measurement, IVC collapsibility (in spontaneously breathing patients) and distensibility (in mechanically ventilated patients) indices were measured with bedside ultrasound.

RESULTS

The mean age was 93.2 ± 61.3 months. Significant and negative correlations of the GEDI were found with the IVC collapsibility index (in spontaneously breathing patients) and the IVC distensibility index (in mechanically ventilated patients) (r = -0.502, p < 0.001; r = -0.522, p = 0.001, respectively). A significant and weakly positive correlation was found between the GEDI and CVP (r = 0.346, p = 0.015), and a significant and negative correlation was found between the IVC collapsibility index and CVP (r = -0.482, p = 0.03). The correlation between the IVC distensibility index and CVP was significant and negative (r = -0.412, p = 0.04).

CONCLUSION

The use of PiCCO as an advanced haemodynamic monitoring method and the use of bedside ultrasound as a noninvasive method are useful to evaluate the volume status in critically ill paediatric patients in intensive care. These methods will gradually come to the fore in paediatric intensive care.

Fontan Hemodynamics Investigation via Modeling and Experimental Characterization of Idealized Pediatric Total Cavopulmonary Connection

Simulation of the human body normal operating conditions is the important issue in the engineering process of designing biomedical devices intended for implantation. As an example of such process the Fontan procedure aims to support the human body function. It is a standard palliative treatment method for patients with a functionally univentricular heart. Nevertheless, this procedure has significant drawbacks. For instance, overload of the only functional ventricle leads to the inevitability of the heart transplantation. Herein, we perform simulation and experimental characteristics of the pediatric total cavopulmonary connection (TCPC) influence on the blood flow. We investigate and design three different types of pediatric TCPC configurations; we detect fluorescent particles via a high-speed camera in order to analyze distribution of the blood flow velocity modulus in different types of TCPCs. Finally, we evaluate hydraulic power losses for various cases. This work is particularly relevant for the improvement of existing TCPCs quality that can extend the life of Fontan patients. Moreover, it also applies to the reduction of morbidity and mortality of the patients waiting for a heart transplantation.

Ultrasonographic inferior vena cava collapsibility and distensibility indices for detecting the volume status of critically ill pediatric patients

Especially in recent years, the use of point-of-care ultrasound by non-radiologist clinicians has become widespread. Point-of-care ultrasound provides rapid responses to the problems of critically ill patients at the bedside. This technique has many important advantages, including being non-invasive, cheap, repeatable, painless, and radiation-free. Numerous studies have revealed the most important clinical benefits of point-of-care ultrasound use by pediatric intensive care providers. The inferior vena cava is a vessel that is highly sensitive to fluid changes. The inferior vena cava diameter can be measured by a point-of-care ultrasound, and represents a critical parameter in assessing the patient’s fluid status. The inferior vena cava collapsibility index (in spontaneously breathing patients) and the inferior vena cava distensibility index (in mechanically ventilated patients) are calculated by determined formulas by using maximum and minimum diameters of the inferior vena cava. The indices are important guides for pediatric intensive care providers for managing their patients’ fluid treatment. Although some authors claim it is not a reliable method, the technique is coming to fore in intensive care units day by day, and has an increasing trend among pediatric intensive care specialists. Here, we aim to give detailed information on the ultrasonographic inferior vena cava diameter measurement methods, and calculations of the inferior vena cava collapsibility index and inferior vena cava distensibility index, and emphasize the importance of a noninvasive, bedside, and objective method of detecting the volume status of critically ill patients for pediatric intensive care specialists according to the published literature.

Caudal vena cava collapsibility index in healthy cats by ultrasonography

ABSTRACT The objective of this study was to calculate the collapsibility index (CI) in a group of 15 healthy adult mixed breed cats via right hepatic intercostal ultrasound view. The minimal and the maximal diameters of the caudal vena cava (CVC) were obtained during inspiration and expiration, respectively, then CI was calculated. The mean diameter of the CVC was 0.5cm. The mean CI was 28±3% and CI was not significantly associated with gender. As in human medicine, there is a growing need for less invasive monitoring in small animal practice. The CI enables the assessment of estimated volemia without the need for a central venous catheter. This is the first reported study investigating CI in cats.

Inferior Vena Cava Diameter Predicts Nephropathy in Patients Late After Fontan Palliation

Single ventricle congenital heart defect patients have improved survival with Fontan palliation. However, they remain at risk for nephropathy, as indicated by pathologic microalbuminuria. We sought to investigate whether echocardiographic measures of the inferior vena cava diameter (a surrogate for elevated CVP) indexed to the body surface area (iIVC) or cardiac index (CI) can predict the presence of nephropathy in Fontan patients. We performed a single-center case-control study, including 39 asymptomatic Fontan (age 14.8 ± 7.9 years) and 29 healthy controls (age 12.7 ± 2.7 years). The primary outcome was abnormal microalbumin-creatinine ratio (MCR) from the first-morning void urine in Fontan patients. Measurements of iIVC and CI were derived using transthoracic echocardiography by two investigators with a high intra-class correlation coefficient (ICC = 0.97). Group comparison between Fontan and controls as well as between Fontan with normal and abnormal MCR was performed using Fisher's exact and t tests. Pearson and Spearman's correlations and multivariate regressions were performed to analyze the relations between the MCR, iIVC, and CI. Abnormal MCR was noted in 13/39(33%) of Fontan patients. The mean iIVC was larger in the Fontan compared to controls (p < 0.0001) and in Fontan with abnormal MCR compared to those with normal MCR (p = 0.0006). A positive correlation (r = 0.62; p < 0.001) was noted between MCR and iIVC. All patients with abnormal MCR had the iIVC > 1 cm/m². There were no significant relations between the CI and MCR. Significant prevalence of nephropathy late after Fontan palliation warrents screening. Echocardiographic measurement of iIVC could serve as one of the screening measures. The finding of the iIVC diameter > 1 cm/m² should prompt further renal evaluation.

Inferior vena cava, abdominal aorta, and IVC-to-aorta ratio in healthy Caucasian children: Ultrasound Z-scores according to BSA and age

The pediatric ultrasound measurement of the inferior vena cava (IVC) and aorta (AO) with the study of the collapsibility index (CI) and of IVC-to-AO ratio (IVC/AO) can provide clinicians in the acute care setting with information on abnormal volume status but one of the major limitations is a lack of reference normal values by body surface area (BSA) and age. The aim of this study was to provide reference ranges for the sonographic measurement of IVC, AO, and IVC/AO ratio in healthy Caucasian Italian children.

METHODS

We enrolled prospectively 516 healthy Caucasian Italian children aged between 1 month and 16 years. Echocardiographic IVC and AO diameters were collected and presented separately for children aged ≤1 year and for children aged over 1 year. For children >1 year we categorized subjects into 3 years classes. CI and IVC/AO for the systolic aortic diameter were then calculated. For children over 1 year, age reference ranges were age-related or BSA-related; for children of ≤1 year, reference ranges were determined with their 90% confidence intervals regardless of age and of BSA.

RESULTS

Tables and charts with reference ranges for all the echocardiographic measurements are presented for children aged >1 year according to age and BSA. The equations to obtain percentile and Z-score for each echocardiographic measurement are provided. The reference ranges for children aged ≤1 year are shown considering the small 90% confidence intervals for upper and lower limits. CI was 30% (SD 17%) in children >1 year and 36% (SD 16%) in children <1 year. IVC/AOs showed age-dependent values from 0.83 (SD 0.20) age <1 year to 1.22 (SD 0.31) in older subjects.

CONCLUSIONS

We report reliable reference ranges for echocardiographic measurement of IVC, AO, CI, and IVC/AO for a Caucasian Italian healthy pediatric population.

Age-Related Changes in Inferior Vena Cava Dimensions among Children and Adolescents with Syncope

OBJECTIVE

To test the hypothesis that increased venous compliance manifested as inferior vena cava (IVC) dilation is an important substrate for syncope in children.

STUDY DESIGN

IVC diameters were measured in 191 children and adolescents with syncope and in 95 controls. Subjects were divided based on age <12 years (younger group) and ≥12 years (older group). IVC measurements at the right atrial junction (IVC-RA), 10 mm below the IVC-RA junction (IVC-RA10), and at the point of maximal diameter (IVCmax) were made. The linear relation to body surface area (BSA) was confirmed, as were dimensions indexed to BSA (iIVC). Relationships between iIVC and the time of day were evaluated.

RESULTS

In the syncope group, the mean age was 12.9 ± 3.6 years, mean weight was 54.7 ± 23 kg, and mean BSA was 1.5 ± 0.4 m². Among controls, all IVC dimensions varied linearly with BSA (P < .001). In the older group (140 patients with syncope and 60 controls), all iIVC dimensions were larger in the syncope cohort: iIVC-RA, 9 vs 7.7 mm/m² (P < .0001); iIVC-RA10, 9.4 vs 8.1 mm/m² (P < .0001); iIVCmax, 11.7 vs 10.6 mm/m² (P = .002). In the younger group (51 patients with syncope and 35 controls), there were no differences in iIVC measurements between the syncope cohort and controls: iIVC-RA, 10.2 vs 11.3 mm/m²; iIVC-RA10, 11.7 vs 12.0 mm/m²; iIVCmax, 14.2 vs 14.7 mm/m² (P > .05 for all).

CONCLUSIONS

The IVC is enlarged in teenagers with syncope compared with controls, suggesting that venous capacitance and resultant pooling play roles in the pathogenesis of syncope. In contrast, younger children with syncope do not demonstrate IVC dilation, suggesting that their syncope arises from a different mechanism.

Dual-Propeller Cavopulmonary Pump for Assisting Patients with Hypoplastic Right Ventricle

Various congenital heart defects (CHDs) are characterized by the existence of a single functional ventricle, which perfuses both the systemic and pulmonary circulation. A three-stage palliation procedure, including the final Fontan completion, is often adopted by surgeons to treat patients with such CHDs. The completion Fontan involves the creation of a total cavopulmonary connection (TCPC), commonly accomplished with an extracardiac conduit. This TCPC results in nonphysiologic flow conditions that can lead to systemic venous hypertension, reduced cardiac output, and ultimately the need for heart transplantation. A modest pressure rise of 5-6 mm Hg could correct the abnormal flow dynamics in these patients. To achieve this, we propose a novel conceptual design of a dual-propeller pump inside a flared TCPC. The TCPC dual-propeller conjunction was examined for hydraulic performance, blood flow pattern, and potential for hemolysis inside the TCPC using computational fluid dynamics (CFD). The effect of axial distance between the two propellers on the blood flow interference and energy loss was studied to determine the optimal separation distance. Both the inferior vena cava (IVC) and superior vena cava (SVC) propellers provided a pressure rise of 1-20 mm Hg at flow rates ranging from 0.4 to 7 lpm while rotating at speeds of 6,000-12,000 rpm. Larger separation distance provided favorable performance in terms of flow interference, energy loss, and blood damage potential. The ability of a dual-propeller micropump to provide the required pressure rise would help to augment the cavopulmonary flow and mimic flows seen in normal biventricular circulation.

Pulmonary thromboembolic events in patients with congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal abnormalities and Klippel-Trénaunay syndrome

OBJECTIVE

Patients with Klippel-Trénaunay syndrome (KTS) and congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and spinal/skeletal abnormalities (CLOVES) syndrome have central phlebectasia and enlarged persistent embryonic veins that are often incompetent and prone to thromboembolism. The purpose of the study was to determine the presence of phlebectasia and the incidence of symptomatic pulmonary embolism (PE).

METHODS

A retrospective review was conducted of patients referred to the Vascular Anomalies Center at our institution during a 21-year period who were diagnosed with KTS and CLOVES syndrome. Of these, the patients who had PE were screened for thromboembolic risk factors in addition to phlebectasia and the presence of persistent embryonic veins. Treatment outcomes following subsequent endovascular and medical therapies were reported.

RESULTS

A total of 12 KTS patients of 96 (12.5%) and 10 CLOVES syndrome patients of 110 (9%) suffered PE. Fourteen patients (64%) developed PE after surgery or sclerotherapy. All of the patients had abnormally dilated central or persistent embryonic veins; 20 patients were treated with anticoagulation (1 died at the time of presentation, and no information was available for 1) after PE, and 14 (66%) patients underwent subsequent endovascular treatment. Five patients developed recurrent PE despite anticoagulation. Two of the patients died of PE. No patients treated with endovascular closure of dilated veins had subsequent evidence of PE.

CONCLUSIONS

Patients with KTS and CLOVES syndrome are at high risk for PE, particularly in the postoperative period.

A Retrospective Evaluation of Echocardiograms to Establish Normative Inferior Vena Cava and Aortic Measurements for Children Younger Than 6 Years

OBJECTIVES

The ability to plot the inferior vena cava (IVC) size on a normal curve for pediatric patients may prove beneficial. First, in patients with normal cardiac anatomy who present in shock, assessing IVC size may be valuable for evaluating the degree of dehydration. Second, in children with heart disease, understanding how a child's IVC size compares to normal could be particularly beneficial for patients with right heart disease. We sought to create normal curves for the IVC and aorta in children younger than 6 years.

METHODS

Data were gathered from 347 echocardiograms of healthy children younger than 6 years in a retrospective study at a quaternary care children's hospital. From the subcostal long- and short-axis images, maximum diameters in the transverse and longitudinal views were obtained for both the IVC and the aorta.

RESULTS

Both IVC and aortic dimensions increased in a linear fashion and had excellent correlations with the body surface area, body mass, and height (IVC, r = 0.78-0.81; P < .0001; aorta, r = 0.82-0.86; P < .0001).

CONCLUSIONS

In children younger than 6 years, the IVC and aorta increase linearly as the children grow. Such normal curves will be beneficial for assessing a pediatric patient's hydration status or right heart function in patients with congenital heart disease.

Establishment of reference values of the caudal vena cava by fast-ultrasonography through different views in healthy dogs

BACKGROUND

Clinical assessment of intravascular volume status is challenging. In humans, ultrasonographic assessment of the inferior vena cava diameter, directly or as a ratio to the aortic diameter is used to estimate intravascular volume status.

OBJECTIVES

To ultrasonographically obtain reference values (RV) for caudal vena cava diameter (CVCD ), area (CVCa ) and aortic ratios using 3 views in awake healthy dogs.

ANIMALS

One hundred and twenty-six healthy adult dogs from clients, students, faculty, or staff.

METHODS

Prospective, multicenter, observational study. Two observer pairs evaluated CVCD by a longitudinal subxiphoid view (SV), a transverse 11th-13th right hepatic intercostal view (HV), and a longitudinal right paralumbar view (PV). Inter-rater agreements were estimated using concordance correlation coefficients (CCC). For body weight (BW)-dependent variables, RVs were calculated using allometric scaling for variables with a CCC ≥ 0.7.

RESULTS

The CCC was ≤0.43 for the CVC/aorta ratio at the PV and ≤0.43 in both inspiration and expiration for CVC at the SV. The RVs using allometric scaling for CVCa at the HV for inspiration, expiration, and for CVCD at the PV were 6.16 × BW0.762 , 7.24 × BW0.787 , 2.79 × BW0.390 , respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

The CVCD , measured at the HV and PV in healthy awake dogs of various breeds has good inter-rater agreement suggesting these sites are reliable in measuring CVCD . Established RVs for CVCD for these sites need further comparison to results obtained in hypovolemic and hypervolemic dogs to determine their usefulness to evaluate volume status in dogs.

Normative Data for IVC Diameter and its Correlation with the Somatic Parameters in Healthy Indian Children

OBJECTIVE

To determine the normative data for inferior vena cava (IVC) diameter in children and its correlation with various somatic parameters like height, weight and body surface area in Indian children. Readily available baseline data of IVC diameter in normal children shall be of great help in rapid assessment of variations in sick children.

METHODS

Total 475 healthy children aged one month to 12 y visiting out patient clinics (OPD's) were enrolled in this study. Weight, height and body surface area were calculated at the time of examination. The maximum and minimum diameters of IVC were measured during the expiratory and inspiratory phase of the respiratory cycle respectively using M mode ultrasonography. Collapsibility Index was also calculated for each subject by measuring difference between the maximum (expiratory) and minimum (inspiratory) IVC diameters divided by the maximum diameter.

RESULTS

The mean age of study subjects was 4.72 ± 3.72 y. Out of 475 subjects, 285 (60%) were boys and 190 (40%) were girls. Mean weight for age (%) of subjects was 89.18 ± 13.26%. Correlation was studied between physical parameters and IVC diameter which revealed a positive correlation of age, height and weight with both maximum and minimum IVC diameter. Regression analysis was also performed to derive the equations for maximum and minimum diameters of children from 1 y to 12 y.

CONCLUSIONS

This study provides reference values of IVC diameters for Indian children of different age groups.

Fluid status evaluation by inferior vena cava diameter and bioimpedance spectroscopy in pediatric chronic hemodialysis

Background

Evaluation of patient’s dry weight remains challenging in chronic hemodialysis (HD) especially in children. Inferior Vena Cava (IVC) measurement was reported useful to assess fluid overload both in adults and children.

Methods

We performed a monocentric prospective study to evaluate the relation between predialytic IVC diameter measurements and hydration status evaluated by physicians and bioimpedance spectroscopy (BIS) and between IVC measurements and persistent hypertension.

Results

Forty-eight HD sessions in 16 patients were analyzed. According to physicians, patients were overhydrated in 84.5% of dialysis sessions, 20.8% according to BIS, and 0%, 4.1% and 20.8% according to IVC inspiratory, expiratory and collapsibility index reference curves respectively. There was no correlation between relative overhydration evaluated by BIS and IVC measurements z-scores (p = 0.20). Patients whose blood pressure normalized after HD had a more dilated maximal IVC diameter before dialysis session than patients with persistent hypertension (median − 0.07SD [−0.8; 0.88] versus −1.61SD [−2.18; −0.74] (p = 0.03)) with an optimal cut-off of −0.5 SD.

Conclusions

In our study, IVC measurement is not reliable to assess fluid overload in children on HD and was not correlated with extracellular fluid volume assessed by BIS measurements. However, IVC measurements might be of interest in differentiating volume-dependant hypertension from volume-independant hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0793-1) contains supplementary material, which is available to authorized users.

Regression equations for calculation of z scores for echocardiographic measurements of right heart structures in healthy Han Chinese children

OBJECTIVE

Clinical decision making in children with congenital and acquired heart disease relies on measurements of cardiac structures using two-dimensional echocardiography. We aimed to establish z-score regression equations for right heart structures in healthy Chinese Han children.

METHODS

Two-dimensional and M-mode echocardiography was performed in 515 patients. We measured the dimensions of the pulmonary valve annulus (PVA), main pulmonary artery (MPA), left pulmonary artery (LPA), right pulmonary artery (RPA), right ventricular outflow tract at end-diastole (RVOTd) and at end-systole (RVOTs), tricuspid valve annulus (TVA), right ventricular inflow tract at end-diastole (RVIDd) and at end-systole (RVIDs), and right atrium (RA). Regression analyses were conducted to relate the measurements of right heart structures to 4body surface area (BSA). Right ventricular outflow-tract fractional shortening (RVOTFS) was also calculated. Several models were used, and the best model was chosen to establish a z-score calculator.

RESULTS

PVA, MPA, LPA, RPA, RVOTd, RVOTs, TVA, RVIDd, RVIDs, and RA (R²  = 0.786, 0.705, 0.728, 0.701, 0.706, 0.824, 0.804, 0.663, 0.626, and 0.793, respectively) had a cubic polynomial relationship with BSA; specifically, measurement (M) = β0 + β1 × BSA + β2 × BSA²  + β3 × BSA.³ RVOTFS (0.28 ± 0.02) fell within a narrow range (0.12-0.51).

CONCLUSIONS

Our results provide reference values for z scores and regression equations for right heart structures in Han Chinese children. These data may help interpreting the routine clinical measurement of right heart structures in children with congenital or acquired heart disease. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:293-303, 2017.

Relation of Right Atrial Volume, Systemic Venous Dimensions, and Flow Patterns to Right Atrial Pressure in Infants and Children

Echocardiographic assessment of right atrial (RA) volume, inferior vena cava (IVC) diameter, and hepatic vein flow velocity independently correlate with the RA pressure by direct catheter measurement in adults. We prospectively collected invasive RA pressure measurements and echocardiographic data in infants and young children with the goal of developing a predictive model to noninvasively determine normal RA pressure. All subjects had a central venous catheter through which RA pressure could be transduced. Specific inclusion criteria consisted of (1) biventricular heart, (2) absence of inotropes, (3) sinus rhythm, and (4) at least 24 hours from surgery. Two-dimensional echocardiography (2DE)-Doppler and 3DE-Doppler were used to measure RA volume, systemic venous diameters, and flow velocity. Regression equations of RA pressure with RA volume, systemic venous size, and flow velocity were explored. Of 46 studies, 43 (93%) had echocardiograms adequate for analysis. RA pressure did not correlate with body surface area or age (p = 0.69, p = 0.87). The mean indexed RA volume by 3DE-Doppler was significantly higher than by 2DE (p <0.005). On multivariable analysis, only IVC systolic flow velocity and systolic 2D Simpson's derived indexed RA volume demonstrated significant independent correlation with RA pressure, resulting in the equation: RA pressure (mm Hg) = 7.35 - 0.0025 × IVC systolic flow velocity (cm/s) + 0.119 × indexed RA volume by systolic 2D Simpson's (ml/m²). RA pressure did not show correlation with systemic venous diameters or systolic and diastolic flow velocities in the SVC and hepatic veins. In conclusion, regression incorporating 2DE-derived RA volume and IVC systolic flow velocity provided the best noninvasive estimate of normal RA pressure in infants and children. The model derived requires validation in an independent sample.

Cardiomyopathy in children: Can we rely on echocardiographic tricuspid regurgitation gradient estimates of right ventricular and pulmonary arterial pressure?

Introduction Agreement between echocardiography and right heart catheterisation-derived right ventricular systolic pressure is modest in the adult heart failure population, but is unknown in the paediatric cardiomyopathy population.

METHODS

All patients at a single centre from 2001 to 2012 with a diagnosis of cardiomyopathy who underwent echocardiography and catheterisation within 30 days were included in this study. The correlation between tricuspid regurgitation gradient and catheterisation-derived right ventricular systolic pressure and mean pulmonary artery pressure was determined. Agreement between echocardiography and catheterisation-derived right ventricular systolic pressure was assessed using Bland-Altman plots. Analysis was repeated for patients who underwent both procedures within 7 days. Haemodynamic data from those with poor agreement and good agreement between echocardiography and catheterisation were compared.

RESULTS

A total of 37 patients who underwent 48 catheterisation procedures were included in our study. The median age was 11.8 (0.1-20.6 years) with 22 males (58% total). There was a modest correlation (r=0.65) between echocardiography and catheterisation-derived right ventricular systolic pressure, but agreement was poor. Agreement between tricuspid regurgitation gradient and right ventricular systolic pressure showed wide 95% limits of agreement. There was a modest correlation between the tricuspid regurgitation gradient and mean pulmonary artery pressure (r=0.6). Shorter time interval between the two studies did not improve agreement. Those with poor agreement between echocardiography and catheterisation had higher right heart pressures, but this difference became insignificant after accounting for right atrial pressure.

CONCLUSION

Transthoracic echocardiography estimation of right ventricular systolic pressure shows modest correlation with right heart pressures, but has limited agreement and may underestimate the degree of pulmonary hypertension in paediatric cardiomyopathy patients.

Noninvasive Assessment of Pulmonary Artery Pressure in Patients with Extracardiac Conduit Total Cavopulmonary Connection

To assess quantitative measurement of mean pulmonary artery pressure (PAP) in extracardiac total cavopulmonary connection (TCPC) patients by noninvasive echocardiographic inferior vena cava collapsibility index (IVC-CI) and also correlation between the peripheral vein pressure and mean PAP. In 19 TCPC patients with at least 1-year follow-up after completion of TCPC, complete echocardiography including IVC-CI was recorded. All patients underwent cardiac catheterization for mean PAP pressure, peripheral vein pressure (PVP) and contrast study. Different cutoff points of mean PAP were analyzed, and based on the highest cutoff point, patients were categorized into two groups: mean PAP < 17 mmHg (acceptable) and > = 17 mmHg (high) for comparison analysis. Between 2006 and 2015, from 43 patients who had undergone TCPC, nineteen patients with a mean age 12.9 ± 6.6 years and mean follow-up time of 3.4 ± 1.9 years were included in this study. Mean PAP was 14.6 ± 3.97 (range 8-22 mmHg). Thirteen (68 %) patients had PAP < 17 mmHg. No significant statistical difference was detected with respect to age, sex, type of congenital heart disease and fenestration between these two groups. But, right ventricular dominancy was more prevalent in the high PAP group (50 % vs. 7.7 % P value 0.03). IVC-CI had a correlation with mean PAP (r 0.67, P < 0.001). IVC-CI < 21.8 % can predict PAP > = 17 mmHg with 83 % sensitivity and 100 % specificity. Regression analysis proposed an equation for PAP measurement: PAP (mmHg) = 20.2097-0.1796 × (IVC-CI), (r2 = 0.56). Peripheral vein pressure measurement also showed a good correlation with mean PAP and may be used to estimate PAP with the following equation: PAP (mmHg) = 0. 8675 × PVP, (r 0.90, P < 0.0001). In conclusion, IVC-CI as noninvasive and peripheral vein pressure measurement as a minimal invasive method may be useful for quantitative estimation of PAP in patients with extracardiac TCPC.

Inferior Vena Cava Aneurysm in Children: A Case Report

The presence of aneurysms in the territory of the inferior vena cava (IVC) is an extremely rare finding in children and few cases have been reported in the literature. Etiology is unknown and some authors have hypothesized that it can be related to a congenital defect. Most cases present as incidental radiologic findings in asymptomatic patients, but can appear as life-threatening massive thrombosis. Clinical presentation is very heterogeneous and it should be included in the differential diagnosis of patients with retroperitoneal masses. Owing to the rarity of this condition, little is known about the natural history; thus, there is no consensus about the treatment and follow-up of inferior vena cava aneurysms.

Effect of Inhalational Anesthetics and Positive-pressure Ventilation on Ultrasound Assessment of the Great Vessels: A Prospective Study at a Children's Hospital

BACKGROUND

Bedside ultrasound has emerged as a rapid, noninvasive tool for assessment and monitoring of fluid status in children. The inferior vena cava (IVC) varies in size with changes in blood volume and intrathoracic pressure, but the magnitude of change to the IVC with inhalational anesthetic and positive-pressure ventilation (PPV) is unknown.

METHODS

Prospective observational study of 24 healthy children aged 1 to 12 yr scheduled for elective surgery. Ultrasound images of the IVC and aorta were recorded at five time points: awake; spontaneous ventilation with sevoflurane by mask; intubated with peak inspiratory pressure/positive end-expiratory pressure of 15/0, 20/5, and 25/10 cm H2O. A blinded investigator measured IVC/aorta ratios (IVC/Ao) and changes in IVC diameter due to respiratory variation (IVC-RV) from the recorded videos.

RESULTS

Inhalational anesthetic decreased IVC/Ao (1.1 ± 0.3 vs. 0.6 ± 0.2; P < 0.001) but did not change IVC-RV (median, 43%; interquartile range [IQR], 36 to 58% vs. 46%; IQR, 36 to 66%; P > 0.99). The initiation of PPV increased IVC/Ao (0.64 ± 0.21 vs. 1.16 ± 0.27; P < 0.001) and decreased IVC-RV (median, 46%; IQR, 36 to 66% vs. 9%; IQR, 4 to 14%; P < 0.001). There was no change in either IVC/Ao or IVC-RV with subsequent incremental increases in peak inspiratory pressure/positive end-expiratory pressure (P > 0.99 for both).

CONCLUSIONS

Addition of inhalational anesthetic affects IVC/Ao but not IVC-RV, and significant changes in IVC/Ao and IVC-RV occur with initiation of PPV in healthy children. Clinicians should be aware of these expected vascular changes when managing patients. Establishing these IVC parameters will enable future studies to better evaluate these measurements as tools for diagnosing hypovolemia or predicting fluid responsiveness.

Serial Measurements of Splanchnic Vein Diameters in Rats Using High-Frequency Ultrasound

The purpose of this study was to investigate serial ultrasound imaging in rats as a fully non-invasive method to (1) quantify the diameters of splanchnic veins in real time as an indirect surrogate for the capacitance function of those veins, and (2) assess the effects of drugs on venous dimensions. A 21 MHz probe was used on anesthetized male Sprague–Dawley rats to collect images containing the portal vein (PV), superior mesenteric vein (SMV), abdominal inferior vena cava (IVC), and splenic vein (SpV; used as a landmark in timed studies) and the abdominal aorta (AA). Stable landmarks were established that allowed reproducible quantification of cross-sectional diameters within an animal. The average diameters of vessels measured every 5 min over 45 min remained within 0.75 ± 0.15% (PV), 0.2 ± 0.09% (SMV), 0.5 ± 0.12% (IVC), and 0.38 ± 0.06% (AA) of baseline (PV: 2.0 ± 0.12 mm; SMV: 1.7 ± 0.04 mm; IVC: 3.2 ± 0.1 mm; AA: 2.3 ± 0.14 mm). The maximal effects of the vasodilator sodium nitroprusside (SNP; 2 mg/kg, i.v. bolus) on venous diameters were determined 5 min post SNP bolus; the diameters of all noted veins were significantly increased by SNP, while mean arterial pressure (MAP) decreased 29 ± 4 mmHg. By contrast, administration of the venoconstrictor sarafotoxin (S6c; 5 ng/kg, i.v. bolus) significantly decreased PV and SpV, but not IVC, SMV, or AA, diameters 5 min post S6c bolus; MAP increased by 6 ± 2 mmHg. In order to determine if resting splanchnic vein diameters were stable over much longer periods of time, vessel diameters were measured every 2 weeks for 8 weeks. Measurements were found to be highly reproducible within animals over this time period. Finally, to evaluate the utility of vein imaging in a chronic condition, images were acquired from 4-week deoxycorticosterone acetate salt (DOCA-salt) hypertensive and normotensive (SHAM) control rats. All vessel diameters increased from baseline while MAP increased (67 ± 4 mmHg) in DOCA-salt rats compared to SHAM at 4 weeks after pellet implantation. Vessel diameters remained unchanged in SHAM animals. Together, these results support serial ultrasound imaging as a non-invasive, reliable technique able to measure acute and chronic changes in the diameter of splanchnic veins in intact rats.

Echocardiographic Reference Values for Right Atrial Size in Children with and without Atrial Septal Defects or Pulmonary Hypertension

Right atrial (RA) size may become a very useful, easily obtainable, echocardiographic variable in patients with congenital heart disease (CHD) with right-heart dysfunction; however, according studies in children are lacking. We investigated growth-related changes of RA dimensions in healthy children. Moreover, we determined the predictive value of RA variables in both children with secundum atrial septal defect (ASD) and children with pulmonary hypertension (PH) secondary to CHD (PH-CHD). This is a prospective study in 516 healthy children, in 80 children with a secundum ASD (>7 mm superior-inferior dimension), and in 42 children with PH-CHD. We determined three RA variables, i.e., end-systolic major-axis length, end-systolic minor-axis length, and end-systolic area, stratified by age, body weight, length, and surface area. RA end-systolic length and area z scores were increased in children with ASD and PH-CHD when compared to those variables in the healthy control population. Using the Youden Index to determine the best cutoff scores in sex- and age-specific RA dimensions, we observed a sensitivity and specificity up to 94 and 91 %, respectively, in ASD children and 98 and 94 %, respectively, in PH-CHD children. We provide normal values (z scores -2 to +2) for RA size and area in a representative, large pediatric cohort. Enlarged RA variables with scores >+2 were predictive of secundum ASD and PH-CHD. Two-dimensional determination of RA size can identify enlarged RAs in the setting of high volume load (ASD) or pressure load (PH-CHD).

Finding covert fluid: methods for detecting volume overload in children on dialysis

BACKGROUND

Lung ultrasound is a novel technique for detecting generalized fluid overload in children and adults with end-stage renal disease (ESRD). Echocardiography and bioimpedance spectroscopy are established methods, albeit variably adopted in clinical practice. We compared the practicality and accuracy of lung ultrasound with current objective techniques for detecting fluid overload in children with ESRD.

METHODS

A prospective observational study was performed to compare lung ultrasound B-lines, echocardiographic measurement of inferior vena cava parameters and bioimpedance spectroscopy in the assessment of fluid overload in children with ESRD on dialysis. The utility of each technique in predicting fluid overload, based on short-term weight gain, was assessed. Multiple linear regression models to predict fluid overload by weight were explored.

RESULTS

A total of 22 fluid assessments were performed in 13 children (8 on peritoneal dialysis, 5 on haemodialysis) with a median age of 4.0 (range 0.8-14.0) years. A significant linear correlation was observed between the number of B-lines detected by lung ultrasound and fluid overload by weight (r = 0.57, p = 0.005). A non-significant positive linear correlation was observed between fluid overload by weight and bioimpedance spectroscopy (r = 0.43, p = 0.2), systolic blood pressure (r = 0.19, p = 0.4) and physical examination measurements (r = 0.19, p = 0.4), while a non-significant negative linear relationship was found between the inferior vena cava collapsibility index and fluid overload by weight (r = -0.24, p = 0.3). In multiple linear regression models, a combination of three fluid parameters, namely lung ultrasound B-lines, clinical examination and systolic blood pressure, best predicted fluid overload (R ²  = 0.46, p = 0.05).

CONCLUSIONS

Lung ultrasound may be superior to echocardiographic methods and bioimpedance spectroscopy in detecting volume overload in children with ESRD. Given the practicality and sensitivity of this new technique, it can be adopted alongside clinical examination and blood pressure in the routine assessment of fluid status in children with ESRD.