Distributed propulsion enables fast and efficient swimming modes in physonect siphonophores.

Many fishes employ distinct swimming modes for routine swimming and predator escape. These steady and escape swimming modes are characterized by dramatically differing body kinematics that lead to context-adaptive differences in swimming performance. Physonect siphonophores, such as Nanomia bijuga, are colonial cnidarians that produce multiple jets for propulsion using swimming subunits called nectophores. Physonect siphonophores employ distinct routine and steady escape behaviors but-in contrast to fishes-do so using a decentralized propulsion system that allows them to alter the timing of thrust production, producing thrust either synchronously (simultaneously) for escape swimming or asynchronously (in sequence) for routine swimming. The swimming performance of these two swimming modes has not been investigated in siphonophores. In this study, we compare the performances of asynchronous and synchronous swimming in N. bijuga over a range of colony lengths (i.e., numbers of nectophores) by combining experimentally derived swimming parameters with a mechanistic swimming model. We show that synchronous swimming produces higher mean swimming speeds and greater accelerations at the expense of higher costs of transport. High speeds and accelerations during synchronous swimming aid in escaping predators, whereas low energy consumption during asynchronous swimming may benefit N. bijuga during vertical migrations over hundreds of meters depth. Our results also suggest that when designing underwater vehicles with multiple propulsors, varying the timing of thrust production could provide distinct modes directed toward speed, efficiency, or acceleration.

Clinical Outcomes After Tracheostomy in Children With Single Ventricle Physiology: Collaborative Research From the Pediatric Cardiac Intensive Care Society Multicenter Cohort, 2010-2021.

OBJECTIVES: Multicenter studies reporting outcomes following tracheostomy in children with congenital heart disease are limited, particularly in patients with single ventricle physiology. We aimed to describe clinical characteristics and outcomes in a multicenter cohort of patients with single ventricle physiology who underwent tracheostomy before Fontan operation. DESIGN: Multicenter retrospective cohort study. SETTING: Twenty-one tertiary care pediatric institutions participating in the Collaborative Research from the Pediatric Cardiac Intensive Care Society. PATIENTS: We reviewed 99 children with single ventricle physiology who underwent tracheostomy before the Fontan operation at 21 institutions participating in Collaborative Research from the Pediatric Cardiac Intensive Care Society between January 2010 and December 2020, with follow-up through December 31, 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Death occurred in 51 of 99 patients (52%). Cox proportional hazard analysis was performed to determine factors associated with death after tracheostomy. Results are presented as hazard ratio (HR) with 95% CIs. Nonrespiratory indication(s) for tracheostomy (HR, 2.21; 95% CI, 1.14-4.32) and number of weeks receiving mechanical ventilation before tracheostomy (HR, 1.06; 95% CI, 1.02-1.11) were independently associated with greater hazard of death. In contrast, diagnosis of tricuspid atresia or Ebstein's anomaly was associated with less hazard of death (HR, 0.16; 95% CI, 0.04-0.69). Favorable outcome, defined as survival to Fontan operation or decannulation while awaiting Fontan operation with viable cardiopulmonary physiology, occurred in 29 of 99 patients (29%). Median duration of mechanical ventilation before tracheostomy was shorter in patients who survived to favorable outcome (6.1 vs. 12.1 wk; p < 0.001), and only one of 16 patients with neurologic indications for tracheostomy and 0 of ten patients with cardiac indications for tracheostomy survived to favorable outcome. CONCLUSIONS: For children with single ventricle physiology who undergo tracheostomy, mortality risk is high and should be carefully considered when discussing tracheostomy as an option for these children. Favorable outcomes are possible, although thoughtful attention to patient selection and tracheostomy timing are likely necessary to achieve this goal.

Teamwork in the viscous oceanic microscale.

Nutrient acquisition is crucial for oceanic microbes, and competitive solutions to solve this challenge have evolved among a range of unicellular protists. However, solitary solutions are not the only approach found in natural populations. A diverse array of oceanic protists form temporary or even long-lasting attachments to other protists and marine aggregates. Do these planktonic consortia provide benefits to their members? Here, we use empirical and modeling approaches to evaluate whether the relationship between a large centric diatom, Coscinodiscus wailesii, and a ciliate epibiont, Pseudovorticella coscinodisci, provides nutrient flux benefits to the host diatom. We find that fluid flows generated by ciliary beating can increase nutrient flux to a diatom cell surface four to 10 times that of a still cell without ciliate epibionts. This cosmopolitan species of diatom does not form consortia in all environments but frequently joins such consortia in nutrient-depleted waters. Our results demonstrate that symbiotic consortia provide a cooperative alternative of comparable or greater magnitude to sinking for enhancement of nutrient acquisition in challenging environments.

Neuromechanical wave resonance in jellyfish swimming.

For organisms to have robust locomotion, their neuromuscular organization must adapt to constantly changing environments. In jellyfish, swimming robustness emerges when marginal pacemakers fire action potentials throughout the bell's motor nerve net, which signals the musculature to contract. The speed of the muscle activation wave is dictated by the passage times of the action potentials. However, passive elastic material properties also influence the emergent kinematics, with time scales independent of neuromuscular organization. In this multimodal study, we examine the interplay between these two time scales during turning. A three-dimensional computational fluid-structure interaction model of a jellyfish was developed to determine the resulting emergent kinematics, using bidirectional muscular activation waves to actuate the bell rim. Activation wave speeds near the material wave speed yielded successful turns, with a 76-fold difference in turning rate between the best and worst performers. Hyperextension of the margin occurred only at activation wave speeds near the material wave speed, suggesting resonance. This hyperextension resulted in a 34-fold asymmetry in the circulation of the vortex ring between the inside and outside of the turn. Experimental recording of the activation speed confirmed that jellyfish actuate within this range, and flow visualization using particle image velocimetry validated the corresponding fluid dynamics of the numerical model. This suggests that neuromechanical wave resonance plays an important role in the robustness of an organism's locomotory system and presents an undiscovered constraint on the evolution of flexible organisms. Understanding these dynamics is essential for developing actuators in soft body robotics and bioengineered pumps.

Comparison of Ductal Stent Versus Surgical Shunt as Initial Intervention for Neonates with Pulmonary Atresia with Intact Ventricular Septum.

Data comparing surgical systemic-to-pulmonary artery shunt and patent ductus arteriosus (PDA) stent as the initial palliation procedure for patients with pulmonary atresia with intact ventricular septum (PA-IVS) are limited. We sought to compare characteristics and outcomes in a multicenter cohort of patients with PA-IVS undergoing surgical shunts versus PDA stents. We retrospectively reviewed neonates with PA-IVS from 2009 to 2019 in 19 United States centers. Bivariate comparisons and multivariable logistic regression analysis were performed to determine the relationship between initial palliation strategy and outcomes including major adverse cardiovascular events (MACE): stroke, mechanical circulatory support, cardiac arrest, or death. 187 patients were included: 38 PDA stents and 149 surgical shunts. Baseline characteristics did not differ statistically between groups. Post-procedural MACE occurred in 4 patients (11%) with PDA stents versus 38 (26%) with surgical shunts, p = 0.079. Overall, the initial palliation strategy was not significantly associated with MACE (aOR:0.37; 95% CI,0.13-1.02). In patients with moderate-to-severe right ventricle hypoplasia, PDA stents were significantly associated with decreased odds of MACE (aOR:0.36; 95% CI,0.13-0.99). PDA stents were associated with lower vasoactive inotrope scores (median 0 versus 5, p < 0.001), greater likelihood to be extubated at the end of their procedure (37% versus 4%, p < 0.001), and shorter duration of mechanical ventilation (median 24 versus 96 h, p < 0.001). PDA stents were associated with significantly more unplanned reinterventions for hypoxemia compared to surgical shunts (42% vs. 20%, p = 0.009). In this multicenter study, neonates with PA-IVS who underwent PDA stenting received less vasoactive and ventilatory support postoperatively compared to those who had surgical shunts. Furthermore, patients with the most severe morphology had decreased odds of MACE.

A Randomized Trial of an Exclusive Human Milk Diet in Neonates with Single Ventricle Physiology.

OBJECTIVE: To determine whether weight gain velocity (g/kg/day) 30 days after the initiation of feeds after cardiac surgery and other clinical outcomes improve in infants with single ventricle physiology fed an exclusive human milk diet compared with a mixed human and bovine diet. STUDY DESIGN: In this multicenter, randomized, single blinded, controlled trial, term neonates 7 days of age or younger with single ventricle physiology and anticipated cardiac surgical palliation within 30 days of birth were enrolled at 10 US centers. Both groups received human milk if fed preoperatively. During the 30 days after feeds were started postoperatively, infants in the intervention group received human milk fortified once enteral intake reached 60 mL/kg/day with a human milk-based fortifier designed for term neonates. The control group received standard fortification with formula once enteral intake reached 100 mL/kg/day. Perioperative feeding and parenteral nutrition study algorithms were followed. RESULTS: We enrolled 107 neonates (exclusive human milk = 55, control = 52). Baseline demographics and characteristics were similar between the groups. The median weight gain velocity at study completion was higher in exclusive human milk vs control group (12 g/day [IQR, 5-18 g/day] vs 8 g/day [IQR, 0.4-14 g/day], respectively; P = .03). Other growth measures were similar between groups. Necrotizing enterocolitis of all Bell stages was higher in the control group (15.4 % vs 3.6%, respectively; P = .04). The incidence of other major morbidities, surgical complications, length of hospital stay, and hospital mortality were similar between the groups. CONCLUSIONS: Neonates with single ventricle physiology have improved short-term growth and decreased risk of NEC when receiving an exclusive human milk diet after stage 1 surgical palliation. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov (www. CLINICALTRIALS: gov, Trial ID: NCT02860702).

Nectophore coordination and kinematics by physonect siphonophores.

Siphonophores are ubiquitous and often highly abundant members of pelagic ecosystems throughout the open ocean. They are unique among animal taxa in that many species use multiple jets for propulsion. Little is known about the kinematics of the individual jets produced by nectophores (the swimming bells of siphonophores) or whether the jets are coordinated during normal swimming behavior. Using remotely operated vehicles and SCUBA, we video recorded the swimming behavior of several physonect species in their natural environment. The pulsed kinematics of the individual nectophores that comprise the siphonophore nectosome were quantified and, based on these kinematics, we examined the coordination of adjacent nectophores. We found that, for the five species considered, nectophores located along the same side of the nectosomal axis (i.e. axially aligned) were coordinated and their timing was offset such that they pulsed metachronally. However, this level of coordination did not extend across the nectosome and no coordination was evident between nectophores on opposite sides of the nectosomal axis. For most species, the metachronal contraction waves of nectophores were initiated by the apical nectophores and traveled dorsally. However, the metachronal wave of Apolemia rubriversa traveled in the opposite direction. Although nectophore groups on opposite sides of the nectosome were not coordinated, they pulsed with similar frequencies. This enabled siphonophores to maintain relatively linear trajectories during swimming. The timing and characteristics of the metachronal coordination of pulsed jets affects how the jet wakes interact and may provide important insight into how interacting jets may be optimized for efficient propulsion.

A fundamental propulsive mechanism employed by swimmers and flyers throughout the animal kingdom.

Even casual observations of a crow in flight or a shark swimming demonstrate that animal propulsive structures bend in patterned sequences during movement. Detailed engineering studies using controlled models in combination with analysis of flows left in the wakes of moving animals or objects have largely confirmed that flexibility can confer speed and efficiency advantages. These studies have generally focused on the material properties of propulsive structures (propulsors). However, recent developments provide a different perspective on the operation of nature's flexible propulsors, which we consider in this Commentary. First, we discuss how comparative animal mechanics have demonstrated that natural propulsors constructed with very different material properties bend with remarkably similar kinematic patterns. This suggests that ordering principles beyond basic material properties govern natural propulsor bending. Second, we consider advances in hydrodynamic measurements demonstrating suction forces that dramatically enhance overall thrust produced by natural bending patterns. This is a previously unrecognized source of thrust production at bending surfaces that may dominate total thrust production. Together, these advances provide a new mechanistic perspective on bending by animal propulsors operating in fluids - either water or air. This shift in perspective offers new opportunities for understanding animal motion as well as new avenues for investigation into engineered designs of vehicles operating in fluids.

Outcomes of Gastrostomy and Tracheostomy in Infants Undergoing Truncus Arteriosus Repair: Database Study Using the Pediatric Health Information System.

OBJECTIVES: We sought to determine the prevalence of and factors associated with gastrostomy tube placement and tracheostomy in infants undergoing truncus arteriosus repair, and associations between these procedures and outcome. DESIGN: Retrospective cohort study. SETTING: Pediatric Health Information System database. PATIENTS: Infants less than 90 days old who underwent truncus arteriosus repair from 2004 to 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Multivariable logistic regression models were used to identify factors associated with gastrostomy tube and tracheostomy placement and to identify associations between these procedures and hospital mortality and prolonged postoperative length of stay (LOS; > 30 d). Of 1,645 subjects, gastrostomy tube was performed in 196 (11.9%) and tracheostomy in 56 (3.4%). Factors independently associated with gastrostomy tube placement were DiGeorge syndrome, congenital airway anomaly, admission age less than or equal to 2 days, vocal cord paralysis, cardiac catheterization, infection, and failure to thrive. Factors independently associated with tracheostomy congenital airway anomaly, truncal valve surgery, and cardiac catheterization. Gastrostomy tube was independently associated with prolonged postoperative LOS (odds ratio [OR], 12.10; 95% CI, 7.37-19.86). Hospital mortality occurred in 17 of 56 patients (30.4%) who underwent tracheostomy versus 147 of 1,589 patients (9.3%) who did not ( p < 0.001), and median postoperative LOS was 148 days in patients who underwent tracheostomy versus 18 days in those who did not ( p < 0.001). Tracheostomy was independently associated with mortality (OR, 3.11; 95% CI, 1.43-6.77) and prolonged postoperative LOS (OR, 9.85; 95% CI, 2.16-44.80). CONCLUSIONS: In infants undergoing truncus arteriosus repair, tracheostomy is associated with greater odds of mortality; while gastrostomy and tracheostomy are strongly associated with greater odds of prolonged postoperative LOS.

Association Between Birth Weight Z-Scores and Early Outcomes Following Truncus Arteriosus Repair.

In infants undergoing truncus arteriosus (TA) repair, we sought to determine associations between fetal growth restrictions as measured by birth weight Z-score and early outcomes. We utilized the Pediatric Health Information System (PHIS) database to identify infants < 90 days old who underwent TA repair from 2004 to 2019. The primary exposure variable was birth weight Z-score, calculated based on gestational age at birth, gender, and birth weight. The primary outcome was postoperative hospital mortality. Secondary outcomes included major complications, prolonged postoperative length of hospital stay (LOS; > 30 days), and hospital readmission within 1 year. Generalized estimating equation (GEE) models were used to identify adjusted associations between birth weight Z-score, small for gestational age (SGA) status, and mortality and included were 1039 subjects. Median birth weight was 2960 g, gestational age at birth was 38 weeks, and birth weight Z-score was - 0.47. SGA was present in 21% of subjects. Hospital mortality occurred in 104 patients (10%). By multivariable analysis, lower birth weight Z-score was associated with higher hospital mortality [for each unit decrease in birth weight Z-score below - 1.0, adjusted OR 1.71 (95% CI 1.10-4.25)]. SGA status was associated with increased hospital mortality (adjusted OR 2.17; 95% CI 1.39-3.40). Birth weight Z-scores and SGA status were not significantly associated with occurrence of cardiac arrest, ECMO use, gastrostomy tube placement, tracheostomy, seizures, infection, prolonged postoperative LOS, or hospital readmission. In infants undergoing TA repair, lower birth weight Z-scores and SGA status were strongly associated with increased hospital mortality.

Timing of surgical repair and resource utilisation in infants with complete atrioventricular septal defect.

INTRODUCTION: Variation exists in the timing of surgery for balanced complete atrioventricular septal defect repair. We sought to explore associations between timing of repair and resource utilisation and clinical outcomes in the first year of life. METHODS: In this retrospective single-centre cohort study, we included patients who underwent complete atrioventricular septal defect repair between 2005 and 2019. Patients with left or right ventricular outflow tract obstruction and major non-cardiac comorbidities (except trisomy 21) were excluded. The primary outcome was days alive and out of the hospital in the first year of life. RESULTS: Included were 79 infants, divided into tertiles based on age at surgery (1st = 46 to 137 days, 2nd = 140 - 176 days, 3rd = 178 - 316 days). There were no significant differences among age tertiles for days alive and out of the hospital in the first year of life by univariable analysis (tertile 1, median 351 days; tertile 2, 348 days; tertile 3, 354 days; p = 0.22). No patients died. Fewer post-operative ICU days were used in the oldest tertile relative to the youngest, but days of mechanical ventilation and hospitalisation were similar. Clinical outcomes after repair and resource utilisation in the first year of life were similar for unplanned cardiac reinterventions, outpatient cardiology clinic visits, and weight-for-age z-score at 1 year. CONCLUSIONS: Age at complete atrioventricular septal defect repair is not associated with important differences in clinical outcomes or resource utilisation in the first year of life.

Effect of cardiac graft rejection on semilunar valve function: implications for heart valve transplantation.

BACKGROUND: The treatment of neonates with unrepairable heart valve dysfunction remains an unsolved problem because there are no growing heart valve replacements. Heart valve transplantation is a potential approach to deliver growing heart valve replacements. Therefore, we retrospectively analysed the semilunar valve function of orthotopic heart transplants during rejection episodes. METHODS: We included children who underwent orthotopic heart transplantation at our institution and experienced at least one episode of rejection between 1/1/2010 and 1/1/2020. Semilunar valve function was analysed using echocardiography at baseline, during rejection and approximately 3 months after rejection. RESULTS: Included were a total of 31 episodes of rejection. All patients had either no (27) or trivial (4) aortic insufficiency prior to rejection. One patient developed mild aortic insufficiency during a rejection episode (P = 0.73), and all patients had either no (21) or trivial (7) aortic insufficiency at follow-up (P = 0.40). All patients had mild or less pulmonary insufficiency prior to rejection, which did not significantly change during (P = 0.40) or following rejection (P = 0.35). Similarly, compared to maximum pressure gradients across the valves at baseline, which were trivial, there was no appreciable change in the gradient across the aortic valve during (P = 0.50) or following rejection (P = 0.42), nor was there any meaningful change in the gradient across the pulmonary valve during (P = 0.55) or following rejection (P = 0.91). CONCLUSIONS: This study demonstrated that there was no echocardiographic evidence of change in semilunar valve function during episodes of rejection in patient with heart transplants. These findings indicate that heart valve transplants require lower levels of immune suppression than orthotopic heart transplants and provide partial foundational evidence to justify future research that will determine whether heart valve transplantation may deliver growing heart valve replacements for children.

Adverse Maternal Fetal Environment Partially Mediates Disparate Outcomes in Non-White Neonates with Major Congenital Heart Disease.

OBJECTIVE: To determine whether differential exposure to an adverse maternal fetal environment partially explains disparate outcomes in infants with major congenital heart disease (CHD). STUDY DESIGN: Retrospective cohort study utilizing a population-based administrative California database (2011-2017). Primary exposure: Race/ethnicity. Primary mediator: Adverse maternal fetal environment (evidence of maternal metabolic syndrome and/or maternal placental syndrome). OUTCOMES: Composite of 1-year mortality or severe morbidity and days alive out of hospital in the first year of life (DAOOH). Mediation analyses determined the percent contributions of mediators on pathways between race/ethnicity and outcomes after adjusting for CHD severity. RESULTS: Included were 2747 non-Hispanic White infants (reference group), 5244 Hispanic, and 625 non-Hispanic Black infants. Hispanic and non-Hispanic Black infants had a higher risk for composite outcome (crude OR: 1.18; crude OR: 1.25, respectively) and fewer DAOOH (-6 & -12 days, respectively). Compared with the reference group, Hispanic infants had higher maternal metabolic syndrome exposure (43% vs 28%, OR: 1.89), and non-Hispanic Black infants had higher maternal metabolic syndrome (44% vs 28%; OR: 1.97) and maternal placental syndrome exposure (18% vs 12%; OR, 1.66). Both maternal metabolic syndrome exposure (OR: 1.21) and maternal placental syndrome exposure (OR: 1.56) were related to composite outcome and fewer DAOOH (-25 & -16 days, respectively). Adverse maternal fetal environment explained 25% of the disparate relationship between non-Hispanic Black race and composite outcome and 18% of the disparate relationship between Hispanic ethnicity and composite outcome. Adverse maternal fetal environment explained 16% (non-Hispanic Black race) and 21% (Hispanic ethnicity) of the association with DAOOH. CONCLUSIONS: Increased exposure to adverse maternal fetal environment contributes to racial and ethnic disparities in major CHD outcomes.

Cardiovascular health in pediatric heart transplant patients.

BACKGROUND: Ideal "cardiovascular health" (CVH)-optimal diet, exercise, nonsmoking, BMI, BP, lipids, and glucose-is associated with healthy longevity in adults. Pediatric heart transplant (HT) patients may be at risk for suboptimal CVH. METHODS: Single-center retrospective study of HT patients 2003-2014 who survived 1 year post-transplant. Five CVH metrics were collected at listing, 1, 3 and 5 years post-transplant (diet and exercise were unavailable). CVH was scored by summing individual metrics: ideal = 2, intermediate = 1, and poor = 0 points; total scores of 8-10 points were considered high (favorable). CVH was compared between HT patients and the US pediatric population (GP) utilizing NHANES 2007-2016. Logistic regression was performed to examine the association of CVH 1 year post-transplant with a composite adverse outcome (death, re-listing, coronary vasculopathy, or chronic kidney disease) 3 years post-transplant. RESULTS: We included 110 HT patients (median age at HT: 6 years [range 0.1-21]) and 19,081 NHANES participants. CVH scores among HT patients were generally high at listing (75%), 1 (74%), 3 (87%) and 5 (76%) years post-transplant and similar to GP, but some metrics (e.g., glucose) were worse among HT patients. Among HT patients, CVH was poorer with older age and non-Caucasian race/ethnicity. Per 1-point higher CVH score, the demographic-adjusted OR for adverse outcomes was 0.95 (95% CI, 0.7-1.4). CONCLUSIONS: HT patients had generally favorable CVH, but some metrics were unfavorable and CVH varied by age and race/ethnicity. No significant association was detected between CVH and adverse outcomes in this small sample, but study in a larger sample is warranted.

Pulmonary Atresia with Intact Ventricular Septum: Midterm Outcomes from a Multicenter Cohort.

Contemporary multicenter data regarding midterm outcomes for neonates with pulmonary atresia with intact ventricular septum are lacking. We sought to describe outcomes in a contemporary multicenter cohort, determine factors associated with end-states, and evaluate the effect of right ventricular coronary dependency and coronary atresia on transplant-free survival. Neonates treated during 2009-2019 in 19 United States centers were reviewed. Competing risks analysis was performed to determine cumulative risk of each end-state, and multivariable regression analyses were performed to identify factors associated with each end-state and transplant-free survival. We reviewed 295 patients. Median tricuspid valve Z-score was - 3.06 (25%, 75%: - 4.00, - 1.52). Final end-state was biventricular repair for 45 patients (15.2%), one-and-a half ventricle for 16 (5.4%), Fontan for 75 (25.4%), cardiac transplantation for 29 (9.8%), and death for 54 (18.3%). Seventy-six patients (25.7%) remained in mixed circulation. Cumulative risk estimate of death was 10.9%, 16.1%, 16.9%, and 18.8% at 1, 6 months, 1 year, and 5 years, respectively. Tricuspid valve Z-score was inversely, and coronary atresia positively associated with death or transplantation [odds ratio (OR) = 0.46, (95% confidence interval (CI) = 0.29-0.75, p < 0.001) and OR = 3.75 (95% CI 1.46-9.61, p = 0.011), respectively]. Right ventricular coronary dependency and left coronary atresia had a significant effect on transplant-free survival (log-rank p < 0.001). In a contemporary multicenter cohort of patients with PAIVS, consisting predominantly of patients with moderate-to-severe right ventricular hypoplasia, we observed favorable survival outcomes. Right ventricular coronary dependency and left, but not right, coronary atresia significantly worsens transplant-free survival.

A late diagnosis of Pseudohypoaldosteronism type I in an infant with hypoplastic left heart syndrome presenting with failure to thrive.

Pseudohypoaldosteronism type I is caused by a peripheral resistance to aldosterone and can present with electrolyte abnormalities, poor growth, or dehydration. Although a rare disease, several case reports have been published regarding Pseudohypoaldosteronism type I in neonates and infants. We report a case of failure to thrive and hyponatremia in an infant with hypoplastic left heart syndrome who was subsequently found to have Pseudohypoaldosteronism type I.

Paediatric cardiac rapid response systems: a survey of multicentre practices.

INTRODUCTION: While the efficacy and guidelines for implementation of rapid response systems are well established, limited information exists about rapid response paradigms for paediatric cardiac patients despite their unique pathophysiology. METHODS: With endorsement from the Paediatric Cardiac Intensive Care Society, we designed and implemented a web-based survey of paediatric cardiac and multidisciplinary ICU medical directors in the United States of America and Canada to better understand paediatric cardiac rapid response practices. RESULTS: Sixty-five (52%) of 125 centres responded. Seventy-one per cent of centres had ∼300 non-ICU beds and 71% had dedicated cardiac ICUs. To respond to cardiac patients, dedicated cardiac rapid response teams were utilised in 29% of all centres (39% and 5% in centres with and without dedicated cardiac ICUs, respectively) [p = 0.006]. Early warning scores were utilised in 62% of centres. Only 31% reported that rapid response teams received specialised training. Transfers to ICU were higher for cardiac (73%) compared to generalised rapid response events (54%). The monitoring and reassessment of patients not transferred to ICU after the rapid response was variable. Cardiac and respiratory arrests outside the ICU were infrequent. Only 29% of centres formally appraise critical deterioration events (need for ventilation and/or inotropes post-rapid response) and 34% perform post-event debriefs. CONCLUSION: Paediatric cardiac rapid response practices are variable and dedicated paediatric cardiac rapid response systems are infrequent in the United States of America and Canada. Opportunity exists to delineate best practices for paediatric cardiac rapid response and standardise practices for activation, training, patient monitoring post-rapid response events, and outcomes evaluation.

Workforce demographics and unit structure in paediatric cardiac critical care in the United States.

OBJECTIVE: To assess current demographics and duties of physicians as well as the structure of paediatric cardiac critical care in the United States. DESIGN: REDCap surveys were sent by email from May till August 2019 to medical directors ("directors") of critical care units at the 120 United States centres submitting data to the Society of Thoracic Surgeons Congenital Heart Surgery Database and to associated faculty from centres that provided email lists. Faculty and directors were asked about personal attributes and clinical duties. Directors were additionally asked about unit structure. MEASUREMENTS AND MAIN RESULTS: Responses were received from 66% (79/120) of directors and 62% (294/477) of contacted faculty. Seventy-six percent of directors and 54% of faculty were male, however, faculty <40 years old were predominantly women. The majority of both groups were white. Median bed count (n = 20) was similar in ICUs and multi-disciplinary paediatric ICUs. The median service expectation for one clinical full-time equivalent was 14 weeks of clinical service (interquartile range 12, 16), with the majority of programmes (86%) providing in-house attending night coverage. Work hours were high during service and non-service weeks with both directors (37%) and faculty (45%). CONCLUSIONS: Racial and ethnic diversity is markedly deficient in the paediatric cardiac critical care workforce. Although the majority of faculty are male, females make up the majority of the workforce younger than 40 years old. Work hours across all age groups and unit types are high both on- and off-service, with most units providing attending in-house night coverage.

Assessment of physician training and prediction of workforce needs in paediatric cardiac intensive care in the United States.

OBJECTIVE: To assess the training and the future workforce needs of paediatric cardiac critical care faculty. DESIGN: REDCap surveys were sent May-August 2019 to medical directors and faculty at the 120 US centres participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database. Faculty and directors were asked about personal training pathway and planned employment changes. Directors were additionally asked for current faculty numbers, expected job openings, presence of training programmes, and numbers of trainees. Predictive modelling of the workforce was performed using respondents' data. Patient volume was projected from US Census data and compared to projected provider availability. MEASUREMENTS AND MAIN RESULTS: Sixty-six per cent (79/120) of directors and 62% (294/477) of contacted faculty responded. Most respondents had training that incorporated critical care medicine with the majority completing training beyond categorical fellowship. Younger respondents and those in dedicated cardiac ICUs were more significantly likely to have advanced training or dual fellowships in cardiology and critical care medicine. An estimated 49-63 faculty enter the workforce annually from various training pathways. Based on modelling, these faculty will likely fill current and projected open positions over the next 5 years. CONCLUSIONS: Paediatric cardiac critical care training has evolved, such that the majority of faculty now have dual fellowship or advanced training. The projected number of incoming faculty will likely fill open positions within the next 5 years. Institutions with existing or anticipated training programmes should be cognisant of these data and prepare graduates for an increasingly competitive market.

New insights on growth trajectory in infants with complex congenital heart disease.

PURPOSE: We aimed to describe the weight-for-age Z-score growth trajectory (WAZ-GT) of infants with complex congenital heart disease (cCHD) after neonatal cardiac surgery in the first 4 months of life and assess potential risk factors. METHODS: We utilized data from a previously reported trial of the REACH telehealth home monitoring (NCT01941667) program which evaluated 178 infants with cCHD from 2012 to 2017. Over the first 4 months of life, weekly infant weights were converted to WAZ. WAZ-GT classes were identified using latent class growth modeling. Multinomial logistic regression models were used to examine the associations between potential risk factors and WAZ-GT classes. RESULTS: Four distinct classes of WAZ-GT were identified: maintaining WAZ > 0, 14%; stable around WAZ = 0, 35%; partially recovered, 28%; never recovered, 23%. Compared with reference group "stable around WAZ=0," we identified clinical and sociodemographic determinants of class membership for the three remaining groups. "Maintaining WAZ > 0" had greater odds of having biventricular physiology, borderline appetite, and a parent with at least a college education. "Partially recovered" had greater odds of hospital length of stay>14 days and being a single child in the household. "Never recovered" had greater odds hospital length of stay >14 and > 30 days, tube feeding at discharge, and low appetite. CONCLUSIONS: This study described distinct classes of WAZ-GT for infants with cCHD early in infancy and identified associated determinants. PRACTICE IMPLICATIONS: Findings from this study can be used in the identification of infants at risk of poor WAZ-GT and in the design of interventions to target growth in this vulnerable patient population.