CubeSat Active Thermal Management in Support of Cooled Electro-Optical Instrumentation for Advanced Atmospheric Observing Missions

The need for advanced cooled electro-optical instrumentation in remote observations of the atmosphere is well known and demonstrated by SABER on the TIMED mission. The relatively new use of small satellites in remote earth observing missions as, well as the challenges, are epitomized by the upcoming NOAA EON-IR 12U CubeSat missions. These advanced CubeSat missions, which hope to accomplish scientific objectives on the same scale as larger more traditional satellites, require advanced miniaturized cryocoolers and active methods for thermal management and power control. The active CryoCubeSat project (ACCS) is a demonstration of such a technology. Utilizing Ultrasonic Additive Manufacturing (UAM) techniques, a Mechanical Pumped Fluid Loop (MPFL), and miniature pumps and cryocoolers to create a closed loop fluid-based heat interchange system. The ACCS project creates a two-stage thermal control system targeting 6U CubeSat platforms. The first stage is composed of a miniature Ricor K508N cryocooler while the second is formed by a UAM fabricated heat exchanger MPFL system powered by a micro TCS M510 pump. The working fluid is exchanged between a built-in chassis heat exchanger and a deployable tracking radiator. This work details the theory design and testing of a relevant ground-based prototype and the analysis and modeling of the results as well as the development of a design tool to help in customized active thermal control designs for small satellites. Ultimately, the ACCS project hopes to enable a new generation of advanced CubeSat atmospheric observing missions

Multicenter Analysis of Early Childhood Outcomes Following Repair of Truncus Arteriosus

Background Literature describing morbidity and mortality following truncus arteriosus repair is predominated by single-center reports. We created and analyzed a multicenter dataset to identify risk factors for late mortality and right ventricle-to-pulmonary artery (RV-PA) conduit reintervention for this patient population. Methods We retrospectively collected data on children who underwent repair of truncus arteriosus without concomitant arch obstruction at 15 centers between 2009 and 2016. Cox regression survival analysis was conducted to determine risk factors for late mortality, defined as death occurring after hospital discharge and greater than 30 days after surgery. Probability of any RV-PA conduit reintervention was analyzed over time using Fine-Gray modelling. Results We reviewed 216 patients, with median follow-up of 2.9 years (range:0.1-8.8). Operative mortaility occurred in 15 patients (7%). Of the 201 survivors, there were 14 (7%) late deaths. DiGeorge syndrome (HR:5.4; 95%CI:1.6-17.8) and need for postoperative tracheostomy (HR:5.9; 95%CI:1.8-19.4) were identified as independent risk factors for late mortality. At least one RV-PA conduit catheterization or surgical reintervention was performed in 109 patients (median time to reintervention:23 months, range:0.3-93). Risk factors for reintervention included use of pulmonary or aortic homografts versus Contegra® bovine jugular vein conduits (HR:1.9; 95%CI:1.2,3.1) and smaller conduit size (HR per mm/m2:1.05; 95%CI:1.03,1.08). Conclusions In a multicenter dataset, DiGeorge syndrome and need for tracheostomy postoperatively were found to be independent risk factors for late mortality after repair of truncus arteriosus, while risk of conduit reintervention was independently influenced by both initial conduit type and size

Utilization of inhaled nitric oxide after surgical repair of truncus arteriosus: A multicenter analysis

BackgroundElevated pulmonary vascular resistance (PVR) is common following repair of truncus arteriosus. Inhaled nitric oxide (iNO) is an effective yet costly therapy that is frequently implemented postoperatively to manage elevated PVR.ObjectivesWe aimed to describe practice patterns of iNO use in a multicenter cohort of patients who underwent repair of truncus arteriosus, a lesion in which recovery is often complicated by elevated PVR. We also sought to identify patient and center factors that were more commonly associated with the use of iNO in the postoperative period.DesignRetrospective cohort study.Setting15 tertiary care pediatric referral centers.PatientsAll infants who underwent definitive repair of truncus arteriosus without aortic arch obstruction between 2009 and 2016.InterventionsDescriptive statistics were used to demonstrate practice patterns of iNO use. Bivariate comparisons of characteristics of patients who did and did not receive iNO were performed, followed by multivariable mixed logistic regression analysis using backward elimination to identify independent predictors of iNO use.Main ResultsWe reviewed 216 patients who met inclusion criteria, of which 102 (46%) received iNO in the postoperative period: 69 (68%) had iNO started in the operating room and 33 (32%) had iNO initiated in the ICU. Median duration of iNO use was 4 days (range: 1‐21 days). In multivariable mixed logistic regression analysis, use of deep hypothermic circulatory arrest (odds ratio: 3.2; 95% confidence interval: 1.2, 8.4) and center (analyzed as a random effect, p = .02) were independently associated with iNO use.ConclusionsIn this contemporary multicenter study, nearly half of patients who underwent repair of truncus arteriosus received iNO postoperatively. Use of iNO was more dependent on individual center practice rather than patient characteristics. The study suggests a need for collaborative quality initiatives to determine optimal criteria for utilization of this important but expensive therapy.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152533/1/chd12849_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152533/2/chd12849.pd

Characteristics and Operative Outcomes for Children Undergoing Repair of Truncus Arteriosus: A Contemporary Multicenter Analysis

Objective We sought to describe characteristics and operative outcomes of children who underwent repair of truncus arteriosus and identify risk factors for the occurrence of major adverse cardiac events (MACE) in the immediate postoperative period in a contemporary multicenter cohort. Methods We conducted a retrospective review of children who underwent repair of truncus arteriosus between 2009 and 2016 at 15 centers within the United States. Patients with associated interrupted or obstructed aortic arch were excluded. MACE was defined as the need for postoperative extracorporeal membrane oxygenation (ECMO), cardiopulmonary resuscitation (CPR), or operative mortality. Risk factors for MACE were identified using multivariable logistic regression analysis and reported as odds ratios (OR) with 95% confidence intervals (CI). Results We reviewed 216 patients. MACE occurred in 44 patients (20%) and did not vary significantly over time. Twenty-two patients (10%) received postoperative ECMO, 26 (12%) received CPR, and 15 (7%) suffered operative mortality. With multivariable logistic regression analysis (which included adjustment for center effect), factors independently associated with MACE were failure to diagnose truncus arteriosus prior to discharge from the nursery (OR:3.1; 95%CI:1.3,7.4), cardiopulmonary bypass duration greater than 150 minutes (OR:3.5; 95%CI:1.5,8.5), and right ventricle-to-pulmonary artery conduit diameter greater than 50mm/m2 (OR:4.7; 95%CI:2.0,11.1). Conclusions In a contemporary multicenter analysis, 20% of children undergoing repair of truncus arteriosus experienced MACE. Early diagnosis, shorter duration of cardiopulmonary bypass, and use of smaller diameter right ventricle-to-pulmonary artery conduits represent potentially modifiable factors that could decrease morbidity and mortality in this fragile patient population