Continuous intra-gastral monitoring of intra-abdominal pressure in critically ill children: a validation study.

BACKGROUND: In critically ill children, detection of intra-abdominal hypertension (IAH > 10 mmHg) and abdominal compartment syndrome (ACS = IAH + organ dysfunction) is paramount and usually monitored through intra-vesical pressures (IVP) as current standard. IVP, however, carries important disadvantages, being time-consuming, discontinuous, with infection risk through observer-dependent manipulation, and ill-defined for catheter sizes. Therefore, we sought to validate air-capsule-based measurement of intra-gastric pressure (ACM-IGP). METHODS: We prospectively compared ACM-IGP with IVP both in vivo and in vitro (water column), according to Abdominal-Compartment-Society validation criteria. We controlled for patient age, admission diagnosis, gastric filling/propulsive medication, respiratory status, sedation levels and transurethral catheters, all influencing intra-abdominal pressure (IAP). RESULTS: In tertiary care PICU setting, finally, n = 97 children were enrolled (median age, 1.3 years [range 0 days-17 years], LOS-PICU 8.0 [1-332] days, PRISM-III-Score 13 [0-35]). In n = 2.770 measurements pairs, median IAP was 6.7 [0.9-23.0] mmHg, n = 38 (39%) children suffered from IAH > 10 mmHg, n = 4 from ACS. In vitro against water column, ACM-IGP correlated perfectly (r2 0.99, mean bias - 0.1 ± 0.5 mmHg, limits of agreement (LOA) - 1.1/+ 0.9, percentage error [PE] 12%) as compared with IVP (r2 0.98, bias + 0.7 ± 0.6 mmHg, LOA - 0.5/+ 1.9, PE 15%). With larger IVP catheters at higher pressure levels, IVP underestimated pressures against water column. In vivo, agreement between either technique was strong (r2 0.95, bias 0.3 ± 0.8 mmHg, LOA - 1.3/+ 1.9 mmHg, PE 23%). No impact of predefined control variables on measurement agreement was observed. CONCLUSIONS: In a large PICU population with high IAH prevalence, ACM-IGP agreed favourably with IVP. More widespread usage of ACM-IGP may improve detection rates of ACS in critically ill children. Trial registration WHO-ICTRP-No. DRKS00006556 (German Clinical Trial Register). Registered 12th September 2014, URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00006556.

Differences in right ventricular-pulmonary vascular coupling and clinical indices between repaired standard tetralogy of Fallot and repaired tetralogy of Fallot with pulmonary atresia.

PURPOSE: The purpose of this study was to compare ventricular vascular coupling ratio (VVCR) between patients with repaired standard tetralogy of Fallot (TOF) and those with repaired TOF-pulmonary atresia (TOF-PA) using cardiovascular magnetic resonance (CMR). MATERIALS AND METHODS: Patients with repaired TOF aged>6 years were prospectively enrolled for same day CMR, echocardiography, and exercise stress test following a standardized protocol. Sanz's method was used to calculate VVCR as right ventricle (RV) end-systolic volume/pulmonary artery stroke volume. Regression analysis was used to examine associations with exercise test parameters, New York Heart Association (NYHA) class, RV size and biventricular systolic function. RESULTS: A total of 248 subjects were included; of these 222 had repaired TOF (group I, 129 males; mean age, 15.9±4.7 [SD] years [range: 8-29 years]) and 26 had repaired TOF-PA (group II, 14 males; mean age, 17.0±6.3 [SD] years [range: 8-29 years]). Mean VVCR for all subjects was 1.54±0.64 [SD] (range: 0.43-3.80). Mean VVCR was significantly greater in the TOF-PA group (1.81±0.75 [SD]; range: 0.78-3.20) than in the standard TOF group (1.51±0.72 [SD]; range: 0.43-3.80) (P=0.03). VVCR was greater in the 68 NYHA class II subjects (1.79±0.66 [SD]; range: 0.75-3.26) compared to the 179 NYHA class I subjects (1.46±0.61 [SD]; range: 0.43-3.80) (P<0.001). CONCLUSION: Non-invasive determination of VVCR using CMR is feasible in children and adolescents. VVCR showed association with NYHA class, and was worse in subjects with repaired TOF-PA compared to those with repaired standard TOF. VVCR shows promise as an indicator of pulmonary artery compliance and cardiovascular performance in this cohort.

Multicentre reference values for cardiac magnetic resonance imaging derived ventricular size and function for children aged 0-18 years.

AIMS: Cardiovascular magnetic resonance (CMR) imaging is an important tool in the assessment of paediatric cardiac disease. Reported reference values of ventricular volumes and masses in the paediatric population are based on small cohorts and several methodologic differences between studies exist. We sought to create steady-state free precession (SSFP) CMR reference values for biventricular volumes and mass by combining data of previously published studies and re-analysing these data in a standardized manner. METHODS AND RESULTS: A total of 141 healthy children (68 boys) from three European centres underwent cine-SSFP CMR imaging. Cardiac structures were manually contoured for end-diastolic and end-systolic phases in the short-axis orientation according to current standardized CMR post-processing guidelines. Volumes and masses were derived from these contours. Age-related reference curves were constructed using the lambda mu sigma method. Median age was 12.7 years (range 0.6-18.5). We report biventricular volumes and masses, unindexed and indexed for body surface area, stratified by age groups. In general, boys had approximately 15% higher biventricular volumes and masses compared with girls. Only in children aged <6 years old no gender differences could be observed. Left ventricle ejection fraction was slightly higher in boys in this study population (median 67% vs. 65%, P = 0.016). Age-related reference curves showed non-linear relations between age and cardiac parameters. CONCLUSION: We report volumetric SSFP CMR imaging reference values for children aged 0-18 years old in a relatively large multi-centre cohort. These references can be used in the follow-up of paediatric cardiac disease and for research purposes.

Back to the roots? Dual cannulation strategy for ambulatory ECMO in adolescent lung transplant candidates: An alternative?

Bridging critically ill pediatric patients to lung transplantation still remains a major challenge. Although still controversial, within the last 5 years, ECMO has been increasingly used as a bridge to lung transplantation concept in adult and pediatric patients with acceptable outcomes. The outstanding developments in the field of extracorporeal devices and the introduction of awake ECMO concepts with the avoidance of mechanical ventilation have led to a real paradigm shift in the ICU management of pretransplant candidates with severe respiratory failure. Therefore, ECMO is no longer seen as a contraindication for lung transplantation at least at our center. Nevertheless, how to bridge these patients on ECMO still remains controversial. Thus, we introduced an ambulatory ECMO approach in adolescent lung transplant candidates with acute respiratory failure using a dual cannulation strategy and hereby present first results from this procedure.

Minimal invasive lung support via umbilical vein with a double-lumen cannula in a neonatal lamb model: a proof of principle.

PURPOSE: Acute respiratory distress syndrome, with the need for invasive mechanical ventilation (MV) remains a major cause of neonatal mortality and morbidity. Although venovenous extracorporeal lung support (VV-ECLS) has become a standard of care procedure in neonatal patients with acute pulmonary failure there are no reports regarding the use of a double-lumen cannula for extracorporeal minimal invasive lung support via the umbilical vein. METHODS: A neonatal lamb model was used (n = 3). Umbilical vein was cannulated with a double-lumen catheter allowing venovenous extracorporeal gas exchange. Cannula was positioned with its tip in the right atrium. VV-ECLS was started and ventilation was stopped. Providing oxygenation and CO2 removal solely through VV-ECLS hemodynamics, blood gases were measured. RESULTS: Total VV-ECLS without MV was applied to all three neonatal lambs. Time on venovenous ECLS was 60, 120 and 120 min. Initial pCO2 was 60, 56 and 65 mmHg compared to 31, 32 and 32 mmHg at the end of VV-ECLS. Initial pO2 was 30, 27 and 26 mmHg compared to 22, 19 and 23 mmHg. Initial lactate was 5, 10 and 3.7 mmol/l compared to 13.3, 12.6 and 11.3 mmol/l at the end of VV-ECLS. MAP at baseline was 51, 52 and 65 mmHg compared to 36, 38 and 41 mmHg at the end of VV-ECLS. In all three lambs inotropes were admitted to maintain MAD >35 mmHg. CONCLUSION: Even without mechanical ventilation we were able to sufficiently remove pCO2 with our new minimal invasive VV-ECLS using a double-lumen catheter via the umbilical vein, supporting the idea of a lung protective strategy in neonatal acute respiratory failure. pO2 was measured 22, 19 and 23 mmHg, respectively, at the end of VV-ECLS, at least partially caused by recirculation phenomenon, which could possibly be improved by different cannula design. Inotropic support was necessary during VV-ECLS to achieve targeted MAD > 35 mmHg. While technically feasible, this new approach might allow further research in the field of extracorporeal lung support and therefore will follow the concept of a lung protective strategy in acute neonatal respiratory failure.

Cardiovascular magnetic resonance feature-tracking assessment of myocardial mechanics: Intervendor agreement and considerations regarding reproducibility.

AIM: To assess intervendor agreement of cardiovascular magnetic resonance feature tracking (CMR-FT) and to study the impact of repeated measures on reproducibility. MATERIALS AND METHODS: Ten healthy volunteers underwent cine imaging in short-axis orientation at rest and with dobutamine stimulation (10 and 20 µg/kg/min). All images were analysed three times using two types of software (TomTec, Unterschleissheim, Germany and Circle, cvi(42), Calgary, Canada) to assess global left ventricular circumferential (Ecc) and radial (Err) strains and torsion. Differences in intra- and interobserver variability within and between software types were assessed based on single and averaged measurements (two and three repetitions with subsequent averaging of results, respectively) as determined by Bland-Altman analysis, intraclass correlation coefficients (ICC), and coefficient of variation (CoV). RESULTS: Myocardial strains and torsion significantly increased on dobutamine stimulation with both types of software (p<0.05). Resting Ecc and torsion as well as Ecc values during dobutamine stimulation were lower measured with Circle (p<0.05). Intra- and interobserver variability between software types was lowest for Ecc (ICC 0.81 [0.63-0.91], 0.87 [0.72-0.94] and CoV 12.47% and 14.3%, respectively) irrespective of the number of analysis repetitions. Err and torsion showed higher variability that markedly improved for torsion with repeated analyses and to a lesser extent for Err. On an intravendor level TomTec showed better reproducibility for Ecc and torsion and Circle for Err. CONCLUSIONS: CMR-FT strain and torsion measurements are subject to considerable intervendor variability, which can be reduced using three analysis repetitions. For both vendors, Ecc qualifies as the most robust parameter with the best agreement, albeit lower Ecc values obtained using Circle, and warrants further investigation of incremental clinical merit.

"Awake Veno-arterial Extracorporeal Membrane Oxygenation" in Pediatric Cardiogenic Shock: A Single-Center Experience.

In pediatric patients with acute refractory cardiogenic shock (CS), extracorporeal membrane oxygenation (ECMO) remains an established procedure to maintain adequate organ perfusion. In this context, ECMO can be used as a bridging procedure to recovery, VAD or transplantation. While being supported by ECMO, most centers tend to keep their patients well sedated and supported by invasive ventilation. This may be associated with an increased risk of therapy-related morbidity and mortality. In order to optimize clinical management in pediatric patients with ECMO therapy, we report our strategy of veno-arterial ECMO (VA-ECMO) in extubated awake and conscious patients. We therefore present data of six of our patients with CS, who were treated by ECMO being awake without continuous analgosedation and invasive ventilation. Of these six patients, four were <1 year and two >14 years of age. Median time on ECMO was 17.4 days (range 6.9-94.2 days). Median time extubated, while receiving ECMO support was 9.5 days. Mean time extubated was 78 % of the total time on ECMO. Three patients reached full recovery of cardiac function on "Awake-VA-ECMO," whereas the other three were successfully bridged to destination therapy (VAD, heart transplantation, withdrawal). Four out of our six patients are still alive. Complications related to ECMO therapy (i.e., severe bleeding, site infection or dislocation of cannulas) were not observed. We conclude that "Awake-VA-ECMO" in extubated, spontaneously breathing conscious pediatric patients is feasible and safe for the treatment of acute CS and can be used as a "bridging therapy" to recovery, VAD implantation or transplantation.

Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI.

This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-making.

Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI.

This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-making.

Community and hospital acquired Clostridium difficile in South Australia - ribotyping of isolates and a comparison of laboratory detection methods.

UNLABELLED: A total of 274 samples were screened for toxigenic Clostridium difficile using a combination of several commercially available assays, and positive isolates ribotyped. A two-step algorithm assisted in demonstrating an increased prevalence of C. difficile infection in South Australia of 9·8%, most of which were ribotypes 014 and 052. A glutamate dehydrogenase assay followed by the detection of genes associated with toxin production was the most sensitive and specific algorithm for screening for toxigenic C. difficile. SIGNIFICANCE AND IMPACT OF THE STUDY: Rapid and accurate detection of toxigenic Clostridium difficile is important for the diagnosis of C. difficile colitis and the management of patients in healthcare institutions to minimize the spread of disease. A critical review of currently available commercial methods supports a recommendation for a 2-step algorithm that is relatively inexpensive and amenable to the routine pathology laboratory. It is anticipated that the detection of C. difficile will increase with improved detection methods, and the ribotype prevalence presented in this manuscript will be useful for any current and future source tracking purposes.

A technical assessment of pulse wave velocity algorithms applied to non-invasive arterial waveforms.

Non-invasive assessment of arterial stiffness through pulse wave velocity (PWV) analysis is becoming common clinical practice. However, the effects of measurement noise, temporal resolution and similarity of the two waveforms used for PWV calculation upon accuracy and variability are unknown. We studied these effects upon PWV estimates given by foot-to-foot, least squared difference, and cross-correlation algorithms. We assessed accuracy using numerically generated blood pressure and flow waveforms for which the theoretical PWV was known to compare with the algorithm estimates. We assessed variability using clinical measurements in 28 human subjects. Wave shape similarity was quantified using a cross correlation-coefficient (CCCoefficient), which decreases with increasing distance between waveform measurements sites. Based on our results, we propose the following criteria to identify the most accurate and least variable algorithm given the noise, resolution and CCCoefficient of the measured waveforms. (1) Use foot-to-foot when the noise-to-signal ratio ≤10%, and/or temporal resolution ≥100 Hz. Otherwise (2) use a least squares differencing method applied to the systolic upstroke.

Generating anatomical models of the heart and the aorta from medical images for personalized physiological simulations.

The anatomy and motion of the heart and the aorta are essential for patient-specific simulations of cardiac electrophysiology, wall mechanics and hemodynamics. Within the European integrated project euHeart, algorithms have been developed that allow to efficiently generate patient-specific anatomical models from medical images from multiple imaging modalities. These models, for instance, account for myocardial deformation, cardiac wall motion, and patient-specific tissue information like myocardial scar location. Furthermore, integration of algorithms for anatomy extraction and physiological simulations has been brought forward. Physiological simulations are linked closer to anatomical models by encoding tissue properties, like the muscle fibers, into segmentation meshes. Biophysical constraints are also utilized in combination with image analysis to assess tissue properties. Both examples show directions of how physiological simulations could provide new challenges and stimuli for image analysis research in the future.

[Consensus recommendations of the German Radiology Society (DRG), the German Cardiac Society (DGK) and the German Society for Pediatric Cardiology (DGPK) on the use of cardiac imaging with computed tomography and magnetic resonance imaging]. / Konsensusempfehlungen der DRG/DGK/DGPK zum Einsatz der Herzbildgebung mit Computertomografie und Magnetresonanztomografie.

Cardiac magnetic resonance imaging (MRI) and computed tomography (CT) have been developed rapidly in the last decade. Technical improvements and broad availability of modern CT and MRI scanners have led to an increasing and regular use of both diagnostic methods in clinical routine. Therefore, this German consensus document has been developed in collaboration by the German Cardiac Society, German Radiology Society, and the German Society for Pediatric Cardiology. It is not oriented on modalities and methods, but rather on disease entities. This consensus document deals with coronary artery disease, cardiomyopathies, arrhythmias, valvular diseases, pericardial diseases and structural changes, as well as with congenital heart defects. For different clinical scenarios both imaging modalities CT and MRI are compared and evaluated in the specific context.

[Preoperative and postoperative imaging in patients with transposition of the great arteries]. / Prä- und Postoperative Bildgebung bei Patienten mit Transposition der großen Gefäße.

Transposition of the great arteries (TGA) is a rare disease representing not more than 3-5% of all congenital heart diseases. TGA is a cardiac anomaly in which the aorta arises entirely or largely from the morphological right ventricle and the pulmonary artery from the morphological left ventricle. This is called a ventriculo-arterial discordant connection and when accompanied by an atrio-ventricular concordant connection it is called a complete or D-transposition (D-TGA). The terms congenitally corrected TGA (ccTGA) or L-TGA describe an atrio-ventricular discordant connection. In D-TGA survival can only be achieved if additional shunting is simultaneously present, which possibly has to be created post-natal by the so-called Rashkind maneuver.Nowadays, an early anatomic correction using the arterial switch operation is the treatment of choice. Up to the 1980s, an atrial switch operation according to Senning/Mustard was performed. Apart from echocardiography the imaging modality of choice is usually MRI to assess the complex postoperative anatomy, viability of the myocardium and to perform a volumetric and functional assessment, including MR flow measurements. Multidetector computed tomography (MDCT) is used if there are contraindications to MRI or if an assessment of cardiac and especially coronary anatomy is the main interest.

Value of postmortem magnetic resonance imaging for fatal neonatal congenital heart disease: a case report.

Autopsies after neonatal death due to suspected or insufficient diagnosed cardiac malformations provide important information to parents and the involved obstetric and pediatric physicians. The autopsy rate, however, is declining. Postmortem magnetic resonance imaging may be an alternative option for selected cases, providing detailed morphologic information about the cardiovascular system. This case report demonstrates the beneficial use of postmortem magnetic resonance imaging in a newborn with a suspected complex cardiac malformation. The magnetic resonance imaging was able to complete the diagnosis of situs inversus totalis, with transposition of great arteries, and to provide valuable information about the underlying physiology.

A novel implantation technique for closure of an atypical fenestration connecting the right atrial appendage to an extracardiac conduit by use of a 15 mm Helex device in a patient with total cavopulmonary connection.

We report on a 7-years old patient after total cavopulmonary anastomosis with an extracardiac conduit. An atypical fenestration was created during the operation connecting the right atrial appendage to the extracardiac conduit. Because of arterial desaturation, the fenestration connecting the anterior wall of the extracardiac conduit to the posterior wall of the right atrial appendage was successfully occluded with a 15 mm Helex device by use of a modified implantation technique.

Noninvasive quantification of left-to-right shunt in pediatric patients: phase-contrast cine magnetic resonance imaging compared with invasive oximetry.

BACKGROUND: Blood flow can be quantified noninvasively by phase-contrast cine MRI (PC-MRI) in adults. Little is known about the feasibility of the method in children with congenital heart disease. METHODS AND RESULTS: In 50 children (mean age 6.2 years, range 1.1 to 17.7 years) with an atrial- or ventricular-level shunt, blood flow rate in the great vessels was determined by PC-MRI, and the ratio of pulmonary to aortic flow (Qp/Qs) was compared with Qp/Qs by oximetry. We found a difference of 2% and a range of -20% to +26% (limits of agreement, mean +/-2 SD). In another 7 children with congenital heart disease but no cardiac shunting (mean age 7.9 years, range 1.3 to 13.5 years), Qp/Qs by PC-MRI was 1.02 (SD +/-0.06). No difference between systemic venous and aortic flow volumes was found (range -17% to +20%, n=37). Blood flow through a secundum atrial septal defect as assessed by PC-MRI (n=24) overestimated the shunt compared with the difference between pulmonary and aortic flows. The mean difference between 3 repeated PC-MRI measurements in each location was 5.3% (SD +/-4.0%, n=522), demonstrating good precision. The interobserver variability was low. The accuracy of PC-MRI was confirmed by in vitro experiments. CONCLUSIONS: Determination of Qp/Qs by PC-MRI in children is quick, safe, and reliable compared with oximetry. Systemic venous flow can be quantified by PC-MRI, whereas through-plane shunt measurement within an atrial septal defect is inaccurate.