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spectrometer output

Understanding low cardiac output after surgery

spectrometer output

Rafael Jaimes, Ph.D., created an algorithm that is being tested in a pre-clinical model to characterize the light absorbance spectrum from different heart regions using a spectrometer.

After intense cardiac surgery, sometimes a patient’s heart is unable to effectively deliver oxygenated blood and nutrients throughout the recovering body. Known as inadequate or low cardiac output, the condition occurs in about a quarter of patients following surgery with cardiopulmonary bypass, including young children who require complex procedures to correct congenital heart defects at Children’s National Health System.

Researchers at the Sheikh Zayed Institute for Pediatric Surgical Innovation are exploring several facets of this challenge, with the goal of better understanding post-operative recovery trajectories in pediatric patients. Rafael Jaimes, Ph.D., a staff scientist at the institute, leads this work to identify when and how low cardiac output occurs, pinpoint the physical hallmarks of this condition and use that information to prevent long term damage and complications after surgery, including cardiac arrest.

“More research needs to be done to understand the cause of this overarching and multi-faceted syndrome,” says Dr. Jaimes. “I’m interested in understanding how metabolic insufficiency contributes to this condition, and also exploring how we can use current imaging and diagnostic tools to measure, track and treat the insufficiencies that contribute to low cardiac output.”

Tracking inadequate oxygen and nutrient delivery to the parts of the heart that have been repaired is one avenue under exploration. Currently, a cardiac-specific real-time device to measure the oxygen state of the heart, while a patient is in post-operative critical care, is under development.

The heart’s complexity has made using current oxygen measurement devices, such as spectrometers, very difficult. To date no tool exists that effectively screens out artifacts and noise to allow clear visualization. However, during his post-doctoral work, Dr. Jaimes has created a new algorithm that may be the first of its kind to accomplish this feat.

This work on low cardiac output recently received a Congenital Heart Defect Research Award, which is a collaborative program of the Children’s Heart Foundation and the American Heart Association that supports innovative research, seeking to understand and treat congenital heart defects.

A new research study will build on his previous studies by using the algorithm to characterize the absorbance spectrum from different heart regions in a pre-clinical model. The data collected will serve as the baseline for development of a prototype spectrometer software, capable of tracking changes in heart oxygenation before, during and after surgery.

The end goal is to more effectively identify when parts of the heart are deprived of oxygen and nutrients and prevent resulting impacts on cardiac metabolism and output. Doing so will decrease short term mortality and morbidity and may also improve circulation systemically, potentially reducing long term health impacts of reduced oxygenation, such as neurodevelopmental disorders.

baby cardioilogy patient

Researchers receive $2.5M grant to optimize brain development in babies with CHD

baby cardioilogy patient

Children’s National Health System researchers Richard Jonas, M.D., Catherine Bollard, M.B.Ch.B., M.D., and Nobuyuki Ishibashi, M.D., have been awarded a $2.5 million, three-year grant from the National Institutes of Health (NIH) to conduct a single-center clinical trial at Children’s National. The study will involve collaboration between the Children’s National Heart Institute, the Center for Cancer and Immunology Research, the Center for Neuroscience Research and the Sheikh Zayed Institute for Pediatric Surgical Innovation.

The goal of the study will be to optimize brain development in babies with congenital heart disease (CHD) who sometimes demonstrate delay in the development of cognitive and motor skills. This can be a result of multiple factors including altered prenatal oxygen delivery, brain blood flow and genetic factors associated with surgery including exposure to the heart lung machine.

The award will be used to complete three specific aims of a Phase 1 safety study as described in the NIH grant:

  • Aim 1: To determine the safety and feasibility of delivering allogeneic bone marrow derived mesenchymal stromal cell (BM-MSC) during heart surgery in young infants less than 3 months of age using the heart lung machine. The optimal safe dose will be determined.
  • Aim 2: To determine the impact of MSC infusion on brain structure using advanced neuroimaging and neurodevelopmental outcomes.
  • Aim 3: To determine differences in postoperative inflammatory and patho-physiological variables after MSC delivery in the infant with CHD.

“NIH supported studies in our laboratory have shown that MSC therapy may be extremely helpful in improving brain development in animal models after cardiac surgery,” says Dr. Ishibashi. “MSC infusion can help reduce inflammation including prolonged microglia activation that can occur during surgery that involves the heart lung machine.”

In addition the researchers’ studies have demonstrated that cell-based intervention can promote white matter regeneration through progenitor cells, restoring the neurogenic potential of the brain’s own stem cells that are highly important in early brain development.

The Phase 1 clinical trial is being implemented in two stages beginning with planning, regulatory documentation, training and product development. During the execution phase, the trial will focus on patient enrollment. Staff from the Cellular Therapy Laboratory, led by director Patrick Hanley, Ph.D., manufactured the BM-MSC at the Center for Cancer and Immunology Research, led by Dr. Bollard. The Advanced Pediatric Brain Imaging Laboratory, led by Catherine Limperopoulos, Ph.D., will perform MR imaging.

The phase 1 safety study will set the stage for a phase 2 effectiveness trial of this highly innovative MSC treatment aimed at reducing brain damage, minimizing neurodevelopmental disabilities and improving the postoperative course in children with CHD. The resulting improvement in developmental outcome and lessened behavioral impairment will be of enormous benefit to individuals with CHD.

Darren Klugman

Children’s National cardiac intensive care experts named to leadership of Pediatric Cardiac Intensive Care Society

Darren Klugman

Darren Klugman, M.D., medical director of the cardiac intensive care unit (ICU) at Children’s National Health System, has been re-elected to the executive board of the Pediatric Cardiac Intensive Care Society (PCICS).

Darren Klugman, M.D., medical director of the cardiac intensive care unit (ICU) at Children’s National Health System, has been re-elected to the executive board of the Pediatric Cardiac Intensive Care Society (PCICS). Klugman will serve a second term as secretary of the organization, which serves to promote excellence in pediatric critical care medicine.

Melissa B. Jones, CPNP-AC, a critical care nurse practitioner at Children’s National, received the honor of being elected Vice President of PCICS. She will take on this leadership role for two years before assuming the presidency of the society in 2020.  Another critical care nurse practitioner at Children’s National, Christine Riley, CPNP-AC, was elected to serve a two-year term on the board of directors.

Congenital heart disease (CHD) is the most common birth defect. There have been many advances in the treatment of children with cardiovascular disorders, leading to a reduction in mortality. However, the extreme complexity of this treatable disease requires specialized care from disciplines beyond cardiology, including critical care, cardiac surgery and anesthesia. PCICS was formed to provide an international professional forum for promoting excellence in pediatric cardiac critical care.

Children’s National has had a large role in PCICS since its inception in 2003. David Wessel, M.D., executive vice president and chief medical officer, Hospital and Specialty Services, was one of the founding members of the international society. Children’s National served as the host of the 13th Annual International Meeting of PCICS in December of 2017 with many experts including Richard Jonas, M.D., division chief of cardiac surgery and co-director of the Children’s National Heart Institute, and Ricardo Muñoz, M.D., division chief of cardiac critical care medicine and executive director of telemedicine, giving talks. Many Children’s National specialists again will lend their expertise to this year’s PCICS annual meeting in Miami, Fla., in December.

As pediatric use of iNO increased, mortality rates dropped

Smiling-baby-boy

iNO, a colorless odorless gas, is used to treat hypoxic respiratory failure in infants born full-term and near term.

Use of inhaled nitric oxide (iNO) among pediatric patients has increased since 2005 and, during a 10-year time period, mortality rates dropped modestly as the therapeutic approach was applied to a broader range of health ailments, according to an observational analysis presented Feb. 26, 2018, during the 47th Critical Care Congress.

iNO, a colorless odorless gas, is used to treat hypoxic respiratory failure in infants born full-term and near term and also has become an important therapy for acute respiratory distress syndrome and pulmonary hypertension in newborns.

Jonathan Chan, M.D., a Children’s National Health System critical care fellow, analyzed de-identified data from patient visits from January 2005 to December 2015 at 47 children’s hospitals around the nation. Dr. Chan included 18,343 patients in the analysis. Among the findings:

  • As a group, the children had an overall mortality rate of 22.7 percent. The mortality rate dropped from 29.1 percent in 2005 to 21.2 percent in 2015.
  • The median adjusted cost per admission was an estimated $158,740 ($5,846 per patient day).

“This large observational study indicates that the use of iNO grew from 2005 to 2015,” Dr. Chan says. “While hospital stays grew longer during the study period, we saw a decrease in mortality of 0.01 percent per year.”

The highest number of admissions with iNO use included:

Dr. Chan notes that because this is a retrospective observational analysis, the study’s findings should be interpreted as exploratory.

“Off-label use of iNO continues to increase among pediatric patients. And an increasing proportion of admissions are for specialty areas other than neonatal care,” he adds. “Increasing off-label use of iNO is associated with decreased mortality. But it also is associated with an increased length of stay, higher hospital costs and more units of iNO administered.”

47th Critical Care Congress presentation

Monday, Feb. 26, 2018

effects of cardiopulmonary bypass surgery on the white matter of piglets.

The effects of cardiopulmonary bypass on white matter development

 cardiopulmonary bypass

Nobuyuki Ishibashi, M.D., and a team of researchers looked the effects of cardiopulmonary bypass surgery on the white matter of an animal model.

Mortality rates for infants born with congenital heart disease (CHD) have dramatically decreased over the past two decades, with more and more children reaching adulthood. However, many survivors are at risk for neurodevelopmental abnormalities  associated with cardiopulmonary bypass surgery (CPB), including long-term injuries to the brain’s white matter and neural connectivity impairments that can lead to neurological dysfunction.

“Clinical studies have found a connection between abnormal neurological outcomes and surgery, but we don’t know what’s happening at the cellular level,” explains Nobuyuki Ishibashi, M.D., Director of the Cardiac Surgery Research Laboratory at Children’s National. To help shed light on this matter, Ishibashi and a team of researchers looked at the effects of CPB on the white matter of an animal model.

The research team randomly assigned models to receive one of three CPB-induced insults: a sham surgery (control group); full-flow bypass for 60 minutes; and 25°C circulatory arrest for 60 minutes. The team then used fractional anisotropy — a technique that measures the directionality of axon mylenation — to determine white matter organization in the models’ brains. They also used immunohistology techniques to assess the integrity of white matter oligodendrocytes, astrocytes and microglia.

The results, published in the Journal of the American Heart Association, show that white matter experiences region-specific vulnerability to insults associated with CPB, with fibers within the frontal cortex appearing the most susceptible. The team also found that fractional anisotropy changes after CPB were insult dependent and that regions most resilient to CPB-induced fractional anisotropy reduction were those that maintained mature oligodendrocytes.

From these findings, Ishibashi and his co-authors conclude that reducing alterations of oligodendrocyte development in the frontal cortex can be both a metric and a goal to improve neurodevelopmental impairment in the congenital heart disease population. “Because we are seeing cellular damage in these regions, we can target them for future therapies,” explains Ishibashi.

The study also demonstrates the dynamic relationship between fractional anisotropy and cellular events after pediatric cardiac surgery, and indicates that the technique is a clinically relevant biomarker in white matter injury after cardiac surgery.

Catherine Limperopoulous

Brain impairment in newborns with CHD prior to surgery

Catherine Limperopoulous

Children’s National researchers led by Catherine Limperopoulos, Ph.D., demonstrate for the first time that the brains of high-risk infants show signs of functional impairment before they undergo corrective cardiac surgery.

Newborns with congenital heart disease (CHD) requiring open-heart surgery face a higher risk for neurodevelopmental disabilities, yet prior studies had not examined whether functional brain connectivity is altered in these infants before surgery.

Findings from a Children’s National Health System study of this question suggest the presence of brain dysfunction early in the lives of infants with CHD that may be associated with neurodevelopmental impairments years later.

Using a novel imaging technique, Children’s National researchers demonstrated for the first time that the brains of these high-risk infants already show signs of functional impairment even before they undergo corrective open heart surgery. Looking at the newborns’ entire brain topography, the team found intact global organization – efficient and effective small world networks – yet reduced functional connectivity between key brain regions.

“A robust neural network is critical for neurons to travel to their intended destinations and for the body to carry out nerve cells’ instructions. In this study, we found the density of connections among rich club nodes was diminished, and there was reduced connectivity between critical brain hubs,” says Catherine Limperopoulos, Ph.D., director of the Developing Brain Research Laboratory at Children’s National and senior author of the study published online Sept. 28, 2017 in NeuroImage: Clinical. “CHD disrupts how oxygenated blood flows throughout the body, including to the brain. Despite disturbed hemodynamics, infants with CHD still are able to efficiently transfer neural information among neighboring areas of the brain and across distant regions.”

The research team led by Josepheen De Asis-Cruz, M.D., Ph.D., compared whole brain functional connectivity in 82 healthy, full-term newborns and 30 newborns with CHD prior to corrective heart surgery. Conventional imaging had detected no brain injuries in either group. The team used resting state functional connectivity magnetic resonance imaging (rs-fcMRI), a imaging technique that characterizes fluctuating blood oxygen level dependent signals from different regions of the brain, to map the effect of CHD on newborns’ developing brains.

The newborns with CHD had lower birth weights and lower APGAR scores (a gauge of how well brand-new babies fare outside the womb) at one and five minutes after birth. Before the scan, the infants were fed, wrapped snugly in warm blankets, securely positioned using vacuum pillows, and their ears were protected with ear plugs and ear muffs.

While the infants with CHD had intact global network topology, a close examination of specific brain regions revealed functional disturbances in a subnetwork of nodes in newborns with cardiac disease. The subcortical regions were involved in most of those affected connections. The team also found weaker functional connectivity between right and left thalamus (the region that processes and transmits sensory information) and between the right thalamus and the left supplementary motor area (the section of the cerebral cortex that helps to control movement). The regions with reduced functional connectivity depicted by rs-fcMRI match up with regional brain anomalies described in imaging studies powered by conventional MRI and diffusion tensor imaging.

“Global network organization is preserved, despite CHD, and small world brain networks in newborns show a remarkable ability to withstand brain injury early in life,” Limperopoulos adds. “These intact, efficient small world networks bode well for targeting early therapy and rehabilitative interventions to lower the newborns’ risk of developing long-term neurological deficits that can contribute to problems with executive function, motor function, learning and social behavior.”