Understanding the Role of Surface Charge on Nanobubble Capillary Bridging during Particle-Particle Interaction.

The interactions between particles due to long-range hydrophobic forces have been extensively investigated. The hydrophobic force is likely a capillary force that arises from the formation of capillary bridges due to the merging of nanobubbles. In this study, we aim to investigate the impact of the nanobubble surface charge on the capillary bridge and, subsequently, the interaction between particles. The surface charge of the nanobubbles was altered in the presence of various surfactants (cationic, anionic, and nonionic) and salts (mono-, di-, and trivalent). The particle-particle interaction was quantified by measuring the aggregate size of the hydrophobized glass particles. Both experimental and theoretical findings confirm that the interaction between particles was enhanced when the surface potential of the nanobubble was around the neutral regime. This is probably because, when the surface potential was close to neutral, the interaction between two surface-deposited nanobubbles dominated over electrostatic repulsion, which was more conducive to the formation of the nanobubble capillary bridge. The estimation of the constrained Gibbs potential also showed the capillary bridge to be more stable when surface charge density along the bridge gas-liquid interface was minimal.

Public-Private Partnership for Treatment of Congenital Heart Diseases: Experiences From an Indian State.

Background: Treatment of congenital heart disease (CHD), being the most common congenital anomaly, puts immense financial burden in low- and middle-income countries (LMICs) and contributes significantly to infant mortality. We report experiences of treatment of CHD in the Indian state of West Bengal by a public-private partnership (PPP) model. Methods: Under the Rashtriya Bal Swasthya Karyakram, the government of the state of West Bengal in India launched a program called the "Sishu Sathi Scheme" to provide free treatment to children who need heart surgeries, irrespective of economic status. Treatment was provided in selected private hospitals and some public hospitals in a reimbursement model where government compensated the hospitals. Data were collected on such procedures from 2013 to 2022 and analyzed. Results: A total of 27,844 patients with CHD received treatment under the Sishu Sathi Scheme from August 2013 to December 2022. The average number of patients per year was 3,093. Detailed data of procedures from January 2016 to December 2022 showed a total of 22,572 procedures (6,249 device interventions, 4,840 cardiac catheterizations, and 11,483 surgical interventions). The in-hospital mortality of surgical procedures and catheterization lab procedures were 5.2% and 0.9%, respectively. Conclusions: A large number of patients with CHD were successfully treated under a PPP in the state of West Bengal in India. In spite of its inherent challenges, this model is of special relevance in LMICs where access and affordability for treatment of CHD always remain a challenge.

Use of cardiopulmonary bypass machine in intensive care unit as a short term mechanical circulatory support for recovery of cardiac function.

INTRODUCTION: Extracorporeal Membrane Oxygenation (ECMO) is used as a bridge to recovery of cardiac function following completion of congenital cardiac surgeries where there is failure to wean from cardiopulmonary bypass (CPB) or severe low cardiac output states in the post operative periods. Although ECMO is a well-established form of mechanical circulatory support, the associated cost can be a huge financial burden on families. We are an ECMO center and use the same in post operative congenital cardiac surgeries for mechanical cardiovascular support if needed. However, a significant proportion of the children, whom we operate, are funded by government aides. The resources are limited in such circumstances. If needed, we use the same CPB circuit and cannulae used in the Operating Room (OR) and support them at a significantly lower cost compared to ECMO. METHODS: We report our experience of using conventional CPB machine as a short-term bridge to recovery of cardiac function in Intensive Care Unit where there was limitation of funds. Essentially same CPB circuit with roller pump is retained, by omitting cardiotomy suckers. We use D901 Lilliput 1 Oxygenator (Sorin, Italy) for children <5 kg and D902 Lilliput 2 (Sorin, Italy) Oxygenator for children >5 Kg. RESULTS: We supported nine patients on CPB between March 2019 and December 2021. During this time, 1392 congenital cardiac surgeries were performed. We could wean off three patients (33.3%) and discharge two patients (22.2%). Our support time ranged from 21 h to 60 h with a median of 48 h. Beyond 48 h of support, we experienced several CPB induced complications in our cohort. CONCLUSION: In resource-limited settings, conventional CPB machines can be used for short-term cardiac support. Although results may not be comparable to using ECMO, some patients can be definitely salvaged, who would otherwise die in the absence of institution of mechanical circulatory support.

Spectrum and outcome of the use of noninvasive ventilation in a pediatric cardiac intensive care unit: A single-center experience.

Background and Aims: The pediatric cardiac intensive care unit (PCICU) frequently uses noninvasive ventilation (NIV). There are several reasons for its use, including prophylactic use right after the patient has been extubated. It is also used when patients are experiencing acute respiratory failure due to either cardiac or noncardiac reasons but are still able to maintain their airways. The objective of this study was to understand the spectrum of use of NIV following congenital cardiac surgery and analyze the outcome. Methods and Results: A retrospective observational study was conducted in a 14-bed PCICU, reviewing data from August 2019 to August 2022. Among 1750 congenital cardiac surgeries, 523 patients (29.9%) received NIV. The median age of the population was 2.5 months. Factors such as higher Risk-Adjusted Classification for Congenital Heart Surgery-1 category, longer intraoperative cardiopulmonary bypass time, and aortic cross-clamp time were associated with increased NIV use. Preoperative ventilator needs, infections, genetic syndromes, diaphragmatic paralysis, high vasoactive inotrope score (VIS) in the first 24 h, neonatal age, and weight <5 kg were independently associated with increased NIV need. The NIV group had a longer intensive care unit (ICU) stay compared to non-NIV patients. The success rate of NIV was 84%, with 440 successful cases and 83 failures. The mortality rate in the success and failure groups was not significantly different (5.27% vs. 6.0%). Conclusions: NIV is widely used in PCICU, but it is associated with longer ICU stays. It proves beneficial after congenital cardiac surgery, especially for patients with specific risk factors. However, NIV may not directly impact mortality rates, suggesting that other factors contribute to patient survival.

Late presentation of aortopulmonary window: a contemporary series.

Late presentation of aortopulmonary window (APW) beyond infancy is uncommon and many of these cases are inoperable due to development of progressive pulmonary hypertension and Eisenmenger syndrome. Outcome data in this cohort is thus sparse and the aim of this study was to analyze the outcomes in patients with APW operable beyond 1 year of age. Between September 2016 and March 2020, in a single center, 12 consecutive patients older than 1 year, undergoing surgery for APW, were included in the study. The median age and weight at presentation were 7.5 years (interquartile range (IQR) 4-9.5) and 15 kg (IQR 11.7-19.5). Ten (83.3%) patients had type 1 APW (proximal type) and 2 (16.6%) had a type 2 APW (distal type). Eight (66.6%) patients had associated lesions. Transaortic patch closure of APW was done in all cases. Seven (58.3%) patients were extubated within 3.5 h of admission in intensive care. There were no early deaths or during follow-up. The median follow-up duration was 20.5 months (IQR 7.5-24), and all patients were in New York Heart Association (NYHA) class I at last follow-up. Follow-up echocardiography did not reveal any significant residual shunts necessitating any additional procedure and a consistent decrease in pulmonary artery pressures. Surgery in patients with APW beyond 1 year of age is possible in selected patients. The early and intermediate surgical outcomes in patients who remain operable are excellent.

Basics of extra corporeal membrane oxygenation: a pediatric intensivist's perspective.

Extra Corporeal membrane oxygenation (ECMO) is one of the most advanced forms of life support therapy in the Intensive Care Unit. It relies on the principle where an external artificial circuit carries venous blood from the patient to a gas exchange device (oxygenator) within which blood becomes enriched with oxygen and has carbon dioxide removed. The blood is then returned to the patient via a central vein or an artery. The goal of ECMO is to provide a physiologic milieu for recovery in refractory cardiac/respiratory failure. The technology is not a definitive treatment for a disease, but provides valuable time for the body to recover. In that way it can be compared to a bridge, where patients are initiated on ECMO as a bridge to recovery, bridge to decision making, bridge to transplant or bridge to diagnosis. The use of this modality in children is not backed by a lot of randomized controlled trials, but the use has increased dramatically in our country in last 10 years. This article is not intended to provide an in-depth overview of ECMO, but outlines the basic principles that a pediatric intensive care physician should know in order to manage a kid on ECMO support.

Novel strategies to enhance hydrodynamic cavitation in a circular venturi using RANS numerical simulations.

Hydrodynamic cavitation is a popular advanced oxidation technique and it has received wide range of applications from waste water treatment to the nanoparticles synthesis in recent years. The enhancement of the intensity of the hydrodynamic cavitation is always been an emerging field of research. Within this framework, we have proposed and investigated three distinct strategies to enhance the intensity of cavitation in a circular venturi, namely, (1) by introducing the surface roughness on the wall (2) single or multiple circular hurdles in the diverging section (3) By modifying the diverging section from planer to the trumpet shape. RANS (Reynolds Averaged Navier-Stokes) based numerical simulations are carried out the over wide range of conditions: 2≤PR≤6 (pressure ratio), 6.2∘≤ß≤10∘ (half divergent angle), 15∘≤α≤20∘ (half convergent angle), and 1≤l/d≤3 (throat length). An extensive numerical and experimental validation with the literature have been presented to ensure the reliability and accuracy of present work. Detailed results on velocity fields, local and average volume fraction, pressure loss coefficients, cavitation number, discharge coefficient and pressure distribution are reported as function of dimensionless parameters. Five designs of various combinations of surface roughness, circular hurdles, and trumpet diverging section have been compared. The effect of surface roughness on trumpet diverging wall has been observed to be more pronounced than the other designs. Trumpet diverging wall with surface roughness is found to be optimum for the practical applications.

Surgical repair of total anomalous pulmonary venous connection: Lateral approach.

We describe the lateral approach to the surgical repair of a total anomalous pulmonary venous connection in this video tutorial. The goal of the operation is to create an unobstructed anastomosis between the pulmonary confluence and the left atrium, ligate the systemic venous connections, and close the atrial septal defect. After a median sternotomy and initial dissection of the structures surrounding the heart, cardiopulmonary bypass is initiated by aortobicaval cannulation. The patient is then cooled to attain mild hypothermia (30°C). The heart is arrested by a dose of antegrade cold cardioplegia. The right pleural cavity is opened widely. The heart is retracted and pushed into the right pleural cavity. The vertical vein is ligated near its connection with the innominate vein. An incision is made along the length of the confluence, stopping short of the individual pulmonary veins. The left atrial appendage is retracted, and the left atrium is opened in alignment with the opening in the confluence. The left atrium and the pulmonary confluence are anastomosed widely with 7-0 polypropylene suture material. The heart is put back into the mediastinum. Rewarming is started. The atrial septal defect is closed through the right atrium using a large untreated autologous pericardium patch. The patient is then weaned off cardiopulmonary bypass.

A systematic approach to epicardial echocardiography in pediatric cardiac surgery: An important but underutilized intraoperative tool.

Intraoperative echocardiography is an integral component of the peri-operative management of pediatric heart disease. It confirms the adequacy of surgery, identifies residual lesions, and can provide useful hemodynamic data. It, therefore, helps to decide on the need for revision of repair and guides the postoperative management strategy. Intraoperative echocardiography is done with the use of either an epicardial probe or a transesophageal probe. Epicardial echocardiography is a simple, useful modality and has the ability to perform imaging in cases where transesophageal echocardiography cannot be easily performed, for example, in low birth weight babies. We attempt to describe in detail the technique of epicardial echocardiography and the various views that we have found useful for a complete postsurgical evaluation. The limitations of the technique are also discussed in detail.

A case of partial anomalous systemic venous drainage and perioperative detection of cerebral arteriovenous malformations.

We report a case of 8-year-old boy with unexplained desaturation and clubbing. Echocardiography showed anomalous drainage of right superior vena cava into left atrium. He did not have any neurological symptoms preoperatively. Some perioperative observations and subtle postoperative behavioral changes prompted us to investigate him further. He was found to have extensive cerebral arteriovenous malformations and hemiatrophy of brain.

Utility of late pulmonary artery banding in single-ventricle physiology: A mid-term follow-up.

BACKGROUND: The standard first stage palliation for univentricular heart with unrestricted pulmonary blood flow (PBF) is surgical pulmonary artery (PA) banding for which the ideal age is within the first 8 weeks of life. This study aimed to look for the utility of PA band done beyond 3 months of age for patients presenting beyond the stipulated period. MATERIALS AND METHODS: This is a retrospective analysis of the outcome of twenty patients with single ventricle (SV) physiology with unrestricted PBF who presented late and were selected on the basis of clinical, radiological, and echocardiographic parameters for PA banding. RESULTS: The median age of the patients was 5.5 months (3.5-96 months), and the median body weight was 4.7 kg (3.2-22.0 kg). The patients were divided into three groups as follows: ten patients between 3 and 6 months of age (Group A), seven patients between 6 months to 1 year of age (Group B), and three patients > 1 year of age with additional features of pulmonary venous hypertension (Group C). The mean reduction of PA pressures following PA band was 60.9%, 48.8%, and 58.3% and the mean fall in oxygen saturation was 10.4%, 8.0%, and 6.6% in the three groups, respectively. The postoperative mortality rate was 10%. The mean follow up duration was 13.5 months (7-23 months). There was a statistically significant improvement in weight for age Z scores following PA band (P = 0.0001). On follow up cardiac catheterization, the mean PA pressures were 16.6 (±3.6), 22.7 (±5.7), and 33.3 (±12.4) mmHg, respectively, in the three groups, and the mean pulmonary vascular resistance index was 1.86 (±0.5), 2.45 (±0.7), and 3.5 (±1.6) WU.m2, respectively. Subsequently, seven patients in Group A, three patients in Group B, and one patient from Group C underwent successful bidirectional Glenn (BDG) surgery. CONCLUSIONS: Late PA band in selected patients with SV physiology can have definite benefit in terms of correction of heart failure symptoms and subsequent conversion to BDG and can potentially change the natural history of disease both in terms of survival and quality of life.

Total circulatory arrest as a support modality in congenital heart surgery: review and current evidence.

The use of total circulatory arrest (TCA)/deep hypothermic circulatory arrest (DHCA) as a support modality in congenital heart surgery is a time-tested strategy. However, with technological advances, the widespread use of this technique has decreased. Adjunctive cerebral perfusion with continuous cardiopulmonary bypass (CPB) gradually has become more popular with a view to reduce the complications related to DHCA. In addition, better neuromonitoring and neuroprotective strategies have made DHCA much safer. However, the level of evidence to support the best way to protect the brain during congenital heart surgery is insufficient. This review analyzes the history, physiology, techniques of DHCA, as well as other alternative strategies like selective cerebral perfusion and presents the current available evidence.

Congenital right ventricular diverticulum: An atypical presentation.

Congenital ventricular diverticulum is a rare congenital malformation of the heart. It remains mostly asymptomatic unless associated with other congenital cardiac defects. We present a case of a 4-month-old child who had dextrocardia, large inlet ventricular septal defect, amounting to single ventricle, and severe pulmonary artery hypertension. There was a right ventricular diverticulum which passed through the foramina of Morgagni to give rise to a pulsating lump in the epigastrium. Right ventricular diverticulum presenting with a pulsating mass in the abdomen is a rare entity. The confirmation of diverticulum was made with histopathology.

Mid-Term Follow-Up of Neonatal Neochordal Reconstruction of Tricuspid Valve for Perinatal Chordal Rupture Causing Severe Tricuspid Valve Regurgitation.

BACKGROUND: Papillary muscle rupture in the perinatal period is a rare event that leads to severe mitral or tricuspid insufficiency due to a flail leaflet. Neonatal tricuspid chordal reconstruction for this condition is rarely reported. Early recognition and treatment have the potential to be lifesaving. We present our surgical experience with five such patients, along with their midterm follow-up. METHODS: Between August 2010 and November 2012, five neonates (aged 1-30 days) underwent surgery for severe atrioventricular valve regurgitation. All neonates had severe tricuspid regurgitation due to ruptured chordae. In addition, two had moderate mitral regurgitation; one due to ruptured chordae of the posterior mitral leaflet and the other due to prolapse of the anterior mitral leaflet. All underwent emergent surgery where the ruptured chordae to the anterior tricuspid leaflet were replaced with neochordae made with expanded polytetrafluoroethylene (ePTFE) suture. The mitral valve was repaired in two patients. RESULTS: All patients survived surgery without the need for postoperative mechanical circulatory assist. Predischarge echocardiograms showed good coaptation of tricuspid and mitral leaflets with minimal regurgitation in all. At follow-up between 75 months to 102 months, four patients had excellent outcomes with less than mild tricuspid regurgitation. One child with flail tricuspid and mitral leaflets developed progressive tricuspid and mitral regurgitation requiring surgical re-repair at 20 months following the initial surgery. CONCLUSION: Repair of chordal rupture of the tricuspid valve in neonates using ePTFE neo-chordae can provide acute salvage and gratifying midterm results in the management of this potentially fatal condition.

Complete sternal cleft with tetralogy of Fallot.

Complete sternal cleft is a very rare congenital midline defect of the sternum. It is not uncommonly associated with intracardiac defects. We report a case of a 2-year-old child with complete sternal cleft and tetralogy of Fallot who presented with cyanotic spells. The child underwent total correction, followed by chest wall reconstruction on the next day.

Arterial Switch Operation With Neoaortic Valve Replacement in a 13-Year Old Patient With Transposition of Great Arteries With Ventricular Septal Defect and Left Ventricular Outflow Tract Obstruction-A Case Report.

The surgical management of d-transposition of great arteries (d-TGAs) with ventricular septal defect (VSD) and left ventricular outflow tract obstruction (LVOTO) is ever evolving and still remains a challenge because of wide anatomic variability, age of presentation, surgical options available, and their variable long-term results in different series. We describe a patient with d-TGA, VSD, and LVOTO who presented to us at 13 years of age and underwent an arterial switch operation along with neoaortic valve replacement with a mechanical prosthesis. The postoperative course was uneventful, and at hospital discharge, the echocardiogram was satisfactory. We present the pros and cons of this hitherto undescribed treatment option.

Atypical Left Ventricular Myxoma: Unusual Echocardiographic and Histopathological Features.

Cardiac myxomas are the most common primary cardiac tumors and are typically attached to the interatrial septum. Left ventricular myxomas are exceedingly rare and presentation in children is all the more uncommon. We report a case of left ventricular myxoma with very atypical cystic appearance raising an initial suspicion of a hydatid cyst. Subsequently, cardiac magnetic resonance imaging was done, which ruled out the diagnosis of hydatid cyst. Complete surgical excision was done through transaortic and transmitral route. Histopathological examination revealed it to be a cardiac myxoma with vascular proliferation, which on echocardiography had appeared as a polycystic lesion. This is a very unusual histopathological presentation of cardiac myxoma.

Left Superior Vena Cava Draining Into Left Atrium in Tetralogy of Fallot-Four Cases of a Rare Association.

Persistent left superior vena cava is a common congenital anomaly of the thoracic venous system. Left superior vena cava draining into left atrium is a malformation of sinus venosus and caval system. The anomaly may be a cause of unexplained hypoxia even in adults. It may give rise to various diagnostic and technical challenges during cardiac catheterization and open-heart surgery. It is often detected serendipitously during diagnostic workup. Isolated left superior vena cava opening into left atrium is very commonly associated with other congenital heart defects. But tetralogy of Fallot is very rarely associated with persistent left superior vena cava which drains into left atrium. We report four such cases who underwent surgical correction successfully.