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Purpose Most post-LVAD Adverse Events (AEs) studies have focused on individual AEs in isolation, neglecting the possible interrelation, or causality between AEs. This study for the first time conducted a novel exploratory analysis to discover sequential chains of AEs following LVAD implantation. Methods This analysis was derived from 58,575 recorded AEs for 13,192 patients in INTERMACS who received a continuous-flow LVAD between 2006 and 2015. The data mining procedure involved three main steps: (1) create a bank of AE sequences, (2) group patients with similar AE sequences using hierarchical clustering, and (3) extract temporal chains of AEs for each group of patients using Markov modeling. Results The mined results indicate the existence of seven groups of sequential chains of AEs, characterized by common types of AEs that occurred in a unique order. A portion of the pattern analysis in this study is shown in Fig.1. The groups were identified as: GRP1(Recurrent bleeding) 862 patients with a minimum of 2 bleeding AEs, GRP2(Trajectory of device malfunction & explant) 1,591 patients who had device malfunction preceded by infection and bleeding, and then commonly had their LVADs removed, GRP3(Infection) 3,438 patients who suffered from recurrent infection or infection accompanied with bleeding , GRP4(Trajectories to transplant) 3,302 patients who received a heart transplant and commonly experienced bleeding, infection, and cardiac arrhythmia , GRP5(Cardiac arrhythmia) 1,275 patients who experienced one or recurrent cardiac arrhythmia commonly accompanied with infection and bleeding, GRP6(Trajectory of neurological dysfunction & death) 1,616 patients, and GRP7(Trajectory of respiratory failure, renal dysfunction & death) 1,108 patients who died with an average of 3 and 5 AEs, respectively, and median time to death of 6 and 3 post-LVAD months, respectively. Conclusion These chains of AEs disclose potential interdependence between post-LVAD AEs and may aid prediction, and prevention, of subsequent AEs - which is the topic of ongoing work.

The authors report the successful operation of an antipodal finline quasi-particle SIS mixer at 230 GHz. The mixer is fed by a waveguide diagonal horn and uses planar circuit technology and integrated tuning. The mixer is tested over the frequency range 213–265 GHz and a receiver noise temperature of ~60 K DSB over the whole of this range is obtained. This work has shown that superconducting finline mixers have low noise and are easy to manufacture, and are therefore suitable for large-format imaging arrays.

Background: To determine the extent and effects of increased metabolic demand represented by Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis (CF). Methods: The study comprised 18 stable children with CF, of whom 10 (6 male/4 female) were colonized with Pseudomonas species and 8 (4 male/4 female) were not. The groups were of similar age range and genotype. Measured resting energy expenditure (REE) was performed by open circuit indirect calorimetry and compared with predicted REE calculated from standard equations. Body composition was determined by dual-energy x-ray absorptiometry, including lean body mass (LBM), fat mass (FM), bone mineral density (BMD), and anterior-posterior spine density (APS); these were compared using z-scores. Routine pulmonary function testing assessed forced vital capacity, forced expiratory volume in 1 second (FEV 1 ), and forced expiratory flow over middle half of vital capacity (FEF 25% to 75% ); these were compared as percent predicted. Results: As expected, results of pulmonary function testing showed significant deterioration among the children colonized with Pseudomonas species when compared with the children who were not, while standard anthropometry showed no differences in weight, height, or weight-for-height percentile and respective z-scores. Although a trend of lower LBM was noted among the children colonized with Pseudomonas species, no significant differences were found between these children and children who were not colonized with Pseudomonas species when z-scores for LBM, FM, BMD, or APS were compared during body composition analysis. In addition, neither REE as kilocalories per day (kcal/d) nor REE expressed as a percent predicted by standard equations discriminated between subgroups of children colonized with Pseudomonas species and children who were not. However, metabolic demand, expressed as resting energy expenditure in kilocalories per kilogram (kcal/kg) of LBM (REE/LBM), revealed significant differences between children colonized with Pseudomonas species and children who were not (75.4 ± 4.4 vs 58.6 ± 2.9 kcal/kg, p

Order sets as part of the Computerized Provider Order Entry (CPOE) system can improve care delivery through allowing faster and easier physician order entry guided by known best practices. This study examines current utilization patterns of order sets and “a la carte” orders in a pediatric environment with a preliminary investigation of methods to automate the creation and modification of order sets using historical ordering data. We examine the current usage of order sets associated with Asthma Minor and Appendectomy Minor patients to understand how physicians are utilizing order sets, and how order set usage is associated with the time of ordering and characteristics of order sets. K-means clustering was applied to orders to generate evidence-based order sets that are learned from historical hospital data. We demonstrate that coverage rate of order sets and ordering efficiency can be increased through modifications of existing sets and creation of new sets.

A device for nasally applied bilevel positive airway pressure, BiPAP (Respironics Inc., Murrysville, PA), is currently being evaluated for the treatment of respiratory failure in pediatric and adult patients. This retrospective case review examines our experience with using BiPAP in the treatment of acute ventilatory deterioration in pediatric patients with chronic respiratory insufficiency. All patients who presented to the intensive care unit with chronic respiratory insufficiency and ventilatory failure but without hypoxia were given a trial on BiPAP. Fifteen patients, ages 4-21 years, received such ventilatory support. Four of them had cystic fibrosis (CF) and 11 had neuromuscular disease (2, spinal muscular atrophy; 7, Duchenne muscular dystrophy; 1, spinal cord injury; and 1, myopathy of undetermined origin). Hospital days, respiratory rates, resting heart rates, arterial blood gases, serum bicarbonates, and subjective assessment by parents and or patients of dyspnea, sleep pattern, and activity tolerance were compared prior to and after initiation of BiPAP. Patients were followed from 1 day to 21 months. In 14 of 15 patients placement of an artificial airway could be avoided. Significant decreases in hospital days, respiratory rate, heart rate, serum bicarbonate, and arterial PCO2 were observed after initiation of BiPAP. Decline in dyspnea (87% with severe distress at rest prior vs. 80% comfortable at rest after BiPAP), increased activity tolerance (57% attending school after BiPAP vs. none prior to BiPAP), and improved quality of sleep (93% with comfortable sleep, no daytime somnolence vs. none with comfortable sleep and 36% with daytime somnolence prior to BiPAP).(ABSTRACT TRUNCATED AT 250 WORDS)

Prior studies have noted that donor retention may be negatively impacted by the total time it takes to complete the blood donation process.To gain a comprehensive understanding of the blood donation process and examine opportunities for operational improvements, an educational partnership established between a blood bank and a university designed and implemented a donor-driven data collection strategy.A large amount of real-time, comprehensive, donor-reported data was collected as donors navigated the process, which has enabled a thorough analysis of the process and its potential improvements.In this paper, we describe the design and implementation efforts, examine the challenges in operationalizing a donor-driven data collection approach, and present insights and recommendations for its application in similar settings.

Pleural space disease, pleural effusions, and parapneumonic empyema present a therapeutic dilemma regarding the most appropriate medical and surgical management (i.e., performing a thoracentesis on admission versus delayed, placing a pigtail catheter versus a regular chest tube, and performing early versus late thoracoscopy). Other questions remain about early surgical intervention to decrease morbidity, shorten hospital stay, and produce cost-effective results. To define a clinical approach for a prospective study, the charts of all patients who were discharged with ICD-9 codes 511.8, 511.9, and 510.9, between June 5, 1991, and May 7, 1995, were reviewed. Thirty-one patients were identified. A database was developed and the results were analyzed. This paper presents a clinical pathway suggested by this retrospective study with cost analysis.

We analyze the determinants of HMO information technology outsourcing using two studies. Study 1 examines the effect of asset specificity on outsourcing for development and operation activities, using HMO specific fixed effects to control for differences between HMOs. Study 2 regresses the HMO specific fixed effects from Study 1, which measure an HMO's propensity to outsource, on HMO characteristics. The data comes from a 1995 InterStudy survey about information technology organization of HMOs. While HMOs split roughly equally in outsourcing information technology development activities, they are extremely unlikely to outsource the day-to-day operation of information systems. The greater an HMO's information technology capability and the complexity of information systems supported, the less likely is an HMO to outsource. While HMOs less than two years old, for-profit HMOs, local or Blue Cross-affiliated HMOs, and mixed HMOs are more likely to outsource, federally qualified HMOs are less likely to outsource. Policy and managerial implications for the adoption and diffusion of new ways of organizing information technology, such as application service providers (ASPs), are discussed.

Coughing is a healthy reflex. Causes of a cough can vary from minor upper respiratory illnesses to malignancy. When a child's cough continues for weeks, parents worry. Primary care providers must decide when reassessment is needed and if a vigorous workup and referral to a pulmonologist are required. The above discussion should assist these physicians.

Over the last several decades, a significant body of knowledge has been developed to assist in planning, organizing, monitoring and controlling project activities. The best documented uses of these techniques are in the construction industry; it can even be argued that modern methods of project management developed on the basis of experiences with these techniques in the construction industry (Proceedings of the Annual Seminar/Symposium of the Project Management Institute (PMI) 1984–1994, Hendrickson and Au 1989, Clough and Sears 1991). While construction is a stereotypical application of project management techniques, there is growing evidence of fruitful application in other functional areas and across industries, such as telecommunications and software development (Whang 1992, PMI Proceedings 1984–1994). Market and organizational pressures to control costs and improve productivity have led corporate managers in many organizations to turn software development into a more controlled production process by the use of project management theory and supporting software tools (Shattow 1990, Chuman 1988).

Tracheostomy is indicated for many patients who are in a prolonged comatose state. The procedure in children is believed to be associated with a higher morbidity and mortality; however, most studies have focused on adult patients. Thus, to better define the incidence, a retrospective study was done on 30 head injured pediatric patients who had tracheostomies at our rehabilitation institution. In 26 patients tracheostomy was indicated for prolonged hyperventilation. The average duration of tracheostomy was 49 days. Twenty-six total complications (86.6%) were reported within seven days of tracheostomy; pneumonia was the most common. Twenty-seven late complications (90%) were reported, with tracheal granuloma being the most common. Ten patients (58%) were successfully decannulated during rehabilitation; seven tracheostomies remained patent when patients were discharged. Results of this study confirm the high rate of airway complications in traumatic brain injury pediatric patients and suggest that most occur within 50 days of intubation. Limiting artificial airway management to less than approximately 50 days may markedly reduce airway complications in the pediatric TBI patient.

In this study, 25 patients between the ages of 12 and 24 years who had neuromuscular diseases, a vital capacity less than 50 percent of predicted, and a history suggestive of nocturnal hypoventilation were observed with overnight monitoring of end-tidal CO2 (EtCO2) and O2 saturation (SaO2). Those patients with a strong clinical history and evidence of nocturnal hypoventilation (increased EtCO2 of 50 to 70 torr and decreased SaO2 [less than 90 percent]) (10 patients) were placed on nocturnal negative pressure ventilation (NNPV). Admission, treatment, and posttreatment arterial blood gases were analyzed by paired statistical "t" tests. Comparison of mean PaO2 values obtained on admission with those obtained during treatment revealed a greater than 97.5 percent confidence (p = 0.025; n = 7). Mean PaO2 values obtained after treatment (off negative pressure ventilation [NPV], awake during daytime) were 65.9 +/- 18.2 mmHg and 79.0 + 14.5 mmHg, respectively (p = 0.005; n = 6). Comparison of post-treatment PaO2 values as a percentage of admission (pretest) values showed a significant change at the 0.5 percent level with an applied Wilcoxan Signed-ranks Matched-pairs Test. The mean PaCO2 values obtained upon admission and those obtained during treatment were 53.7 +/- 15.1 mmHg and 48.1 +/- 14.2 mmHg, respectively (p = 0.05; n = 7), and comparison mean PaCO2 values obtained upon admission and after treatment were 57.9 +/- 16.0 mmHg and 51.2 +/- 7.0 mmHg, respectively (p = 0.1; n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)

Children with neuromuscular scoliosis may develop restrictive pulmonary disease, with substantially lower than normal predicted lung function. Posterior spinal fusion (PSF) is often used to slow down this rapid deterioration of pulmonary function. Postoperatively, these patients frequently develop pulmonary complications. In this retrospective study of 38 patients with neuromuscular scoliosis who underwent PSF, the preoperative vital capacity was related to postoperative pulmonary complications and need for postoperative ventilatory assistance. In two patients who developed postoperative atelectasis and pulmonary edema, the preoperative vital capacity was 44% of that predicted. In six patients who developed atelectasis only, it was 49.2%. In the remaining 30 patients who developed no postoperative pulmonary complications, the average was 64.6%. Low preoperative vital capacity was also shown to correlate with the need for longer postoperative ventilatory assistance. The preoperative vital capacity is an important prognostic parameter in evaluating postoperative pulmonary recovery.

A complete sample of dark clouds is being observed in order to study the processes of star formation. Bipolar outflows have been found in 7 out of the 14 clouds studied to date while 2 further clouds show high-velocity features. It is concluded that a period of mass-loss is a widespread feature of star formation in dark clouds and could have a significant role in cloud evolution.

The power of Gaussian beam mode analysis to accurately describe the propagation of electromagnetic beams and the location of a horn antenna phase-center is illustrated. By way of example, the case of a compensated pyramidal horn fitted with fins to produce a less abruptly tapered E-plane field distribution is discussed, and the results obtained are compared with those from an alternative method published in the literature. Excellent agreement is found. >

21 cm VLA line observations are presented of DR21. These reveal a massive (24Mo) HI jet which is red-shifted by up to 90 km/s. These data are compared with HCO+ J=3-2 data taken at UKIRT. The momentum flux of the HI is sufficient to drive the molecular outflow in a momentum conserving interaction.

Far-infrared and submillimeter photometry of 10 low-mass star formation regions containing embedded IRAS sources is presented. These new observations define the peak of the spectral energy distributions of these objects and provide more precise estimates of their bolometric luminosities. Two new sources, L1527 and L483, are among the reddest known low-mass objects, with spectral energy distribution peaks at 100-200 microns and extremely steep IRAS slopes. These cold sources have spectra which are similar to blackbodies of 30-40 K but have significant excess emission on the Wien side. Models of the spectral energy distributions using a spherically symmetric core structure indicate that these sources have visual extinctions greater than 1000 mag. However, models with these large extinctions predict too little near-infrared emission. A nonspherically symmetric distribution of circumstellar material may play a role in the generation of the extra near-infrared emission.

Resultats d'observation des transitions J=5-4 et 2-1 de 12 C 32 S et 12 C 34 S dans la direction de OMC-1

This paper reports the development of a new algorithmic implementation of the dual algorithm for the capacitated minimum cost network flow problem. Furthermore, it introduces dual reoptimization procedures and compares primal and dual algorithms for the optimization and reoptimization of network problems. The implementation makes use of cut-sets for the efficient execution of the entering variable selection and the selection of the leaving variable is tied to the basis structure at an iteration. Empirical testing of the dual algorithm for optimization shows that it dominates the primal procedure for assignment problems with 400 nodes, transportation problems with more than 600 nodes, and transshipment problems with more than 1500 nodes. Computational testing with typical changes found in decomposition and relaxation procedures indicates the superiority of dual reoptimization over primal reoptimization. For a sequence of parametric changes, as would be typical in large-scale programming techniques, on the average, dual reoptimization is found to require between 75 and 93% fewer pivots and between 20 and 50% less time than primal reoptimization depending on the type of change.

One of the factors determining system sensitivity in radio astronomy measurements of microwave emission and absorption spectra is the flatness of the spectrometer response in the absence of any spectral features. Ripple appears as a quasi-sinusoidal variation of this baseline and occurs whenever two or more components of the same signal reach the receiver by different paths and interfere.

The cross-polarization and reflection properties of grooved dielectric windows are calculated. Measurements on two windows in the range 8-12 GHz are found to be in good agreement with the theory. It is shown that cross-polarization is substantially reduced if the grooves on the front and back faces of the window are orthogonal to each other.

It is now widely recognized that gastroesophageal reflux (GER) causes many symptoms in infants and children; however, the implication of a causal relationship between GER and pulmonary disease still raises skepticism in many clinicians. Recurrent or chronic pulmonary disease (CPD) is a significant cause for morbidity and mortality in infants and children. There is no single, reliable, diagnostic test that consistently demonstrates that pulmonary symptoms are caused directly by GER. This contributes to lack of firm association between GER and CPD. Is GER a contributory factor to the severity of the pulmonary disease, as in chronic asthma? Is it the primary cause of all the respiratory pathophysiology? Or, is GER the result of altered pulmonary mechanics? These are questions that remain unanswered. The purpose of this article is to review the literature raising skepticism among clinicians, paving the way for future directions of research.

Two receiver systems are described. The first is a 220-280 GHz dual-polarization system using cryogenically cooled Schottky-diode mixers pumped with a frequency-multiplied IMPATT local oscillator. The second is a 350 GHz indium antimonide array receiver which uses a novel quasi-optical LO injection scheme.

High-resolution CO J → 1 → 2 observations of the Orion B molecular outflow show that the outflow is unipolar, and that there is evidence of acceleration of molecular gas at up to 0.5pc from the driving star. The highest-velocity material, as well as being furthest from the source, seems to lie close to the central axis of the flow, and is presumably being accelerated by entrainment in the flow or jet emanating from the star. We have also mapped the HCO+J = 3 → 2 emission at 19-arcsec resolution. We derive an excitation temperature of around 25 K in the cloud core, and a core mass of about 75 M⊙, this estimate is in accord with a model in which the core has a kinetic temperature of 30-50 K, with no molecular depletion on to grains. This is in contrast to the recent suggestion that the core contains cold isothermal protostars.

The molecular discs around Young Stellar Objects can be detected through high spatial and spectral resolution observations of their position-velocity diagrams. By mapping a high lying transition of a density-tracing molecule (e.g. HON, HCO+, NH3), the lines should be optically thin and we can expect to see the signature of rotation of the protostellar accretion disc. We present single-dish observations of the S106 system which show evidence for the presence of such a rotating disc. We also discuss a simple disc model which predicts the form of the resulting 1-v diagram. With high quality data, we should be able to do the inverse problem that of recovering the disc properties from the 1-v diagram. We discuss approaches to this inverse problem both by a Singular Value Decomposition (least-squares) method, and by a Maximum Entropy Method.

A dielectric lens, designed to be fed by a wide-angle corrugated conical horn, is described. The radiation pattern of the horn-lens combination is similar to that of a much longer conical horn while retaining wideband characteristics.

There are continued isolated reports of hypertension in patients with orthopaedic problems. We believe this to be a common occurrence. This study was undertaken to determine the incidence and possible etiologies of this blood pressure elevation. We evaluated twenty patients between the ages of ten and eighteen years who were referred for elevated blood pressure (BP) post-operatively and 200 consecutive patients in the same age group undergoing various orthopaedic surgical procedures whose BPs were closely monitored. Patients who had elevation of BP post-operatively were studied regarding their primary problem, family history of hypertension, adequate pain control and metabolic studies to define the etiology. Post-operative elevation of BP occurred most often in patients undergoing procedures involving the extremities. BP elevation was most common in patients with underlying central nervous system problems, labile pre-operative BP and patients with a strong family history of hypertension. None of our patients appeared to have underlying renal disease. The most marked elevation of BP occurred early in the post-operative period. Careful management of post-operative pain appeared to be a major factor in the management of these patients.