ECMO Biocompatibility: Surface Coatings, Anticoagulation, and Coagulation Monitoring

The interaction between the patient and the ECMO (extracorporeal membrane oxygenation) circuit initiates a significant coagulation and inflammatory response due to the large surface area of foreign material contained within the circuit. This response can be blunted with the appropriate mix of biocompatible materials and anticoagulation therapy. The use of anticoagulants, in turn, requires appropriate laboratory testing to determine whether the patient is appropriately anticoagulated. Physicians must balance the risks of bleeding with the risks of thrombosis; the proper interpretation of these tests is often shrouded in mystery. It is the purpose of this chapter to help demystify the coagulation system, anticoagulants, biocompatible surfaces, and coagulation testing so that ECMO practitioners can make informed decisions about their patients and to spur coordinated efforts for future research to improve our understanding of these complex processes

Paracorporeal Lung Devices: Thinking Outside the Box

Extracorporeal Membrane Oxygenation (ECMO) is a resource intensive, life-preserving support system that has seen ever-expanding clinical indications as technology and collective experience has matured. Clinicians caring for patients who develop pulmonary failure secondary to cardiac failure can find themselves in unique situations where traditional ECMO may not be the ideal clinical solution. Existing paracorporeal ventricular assist device (VAD) technology or unique patient physiologies offer the opportunity for thinking “outside the box.” Hybrid ECMO approaches include splicing oxygenators into paracorporeal VAD systems and alternative cannulation strategies to provide a staged approach to transition a patient from ECMO to a VAD. Alternative technologies include the adaptation of ECMO and extracorporeal CO2 removal systems for specific physiologies and pediatric aged patients. This chapter will focus on: (1) hybrid and alternative approaches to extracorporeal support for pulmonary failure, (2) patient selection and, (3) technical considerations of these therapies. By examining the successes and challenges of the relatively select patients treated with these approaches, we hope to spur appropriate research and development to expand the clinical armamentarium of extracorporeal technology

Short- and intermediate-term survival after extracorporeal membrane oxygenation in children with cardiac disease

ObjectivesIn children with cardiac disease, common indications for extracorporeal membrane oxygenation (ECMO) include refractory cardiopulmonary resuscitation (E-CPR), failure to separate from cardiopulmonary bypass (OR-ECMO), and low cardiac output syndrome (LCOS-ECMO). Despite established acceptance, ECMO outcomes are suboptimal with a survival between 38% and 55%. We evaluated factors associated with significantly increased survival in cardiac patients requiring ECMO.MethodsWe conducted a retrospective investigation of consecutive patients undergoing ECMO between 2006 and 2010. Demographic, pre-ECMO, ECMO, and post-ECMO parameters were analyzed. Neurologic outcomes were assessed with the pediatric overall performance category scale at the latest follow-up.ResultsThere were 3524 admissions, 95 (3%) of which necessitated ECMO; 40 (42%) E-CPR, 31 (33%) OR-ECMO, and 24 (25%) LCOS-ECMO. The overall hospital survival was 73%. The within-groups hospital survival was 75% in E-CPR, 77% OR-ECMO and 62% LCOS-ECMO. In the multivariable logistic regression analysis, chromosomal anomalies (odds ratio [OR], 8; 95% confidence interval [CI], 2-35), single ventricle (OR ,6; 95% CI, 3-33), multiple ECMO runs (OR, 15; 95% CI, 4-42), higher 24-hour ECMO flows (OR, 8; 95% CI, 4-22), decreased lung compliance (OR, 5; 95% CI, 2-16), and need for plasma exchange (OR, 5; 95% CI, 3-18) were all significant factors associated with mortality. From the univariate analysis, a common parameter associated with mortality within all groups was intracranial hemorrhage. At 1.9 years (0.9, 2.9) of follow-up, 66% were still alive, and 89% of survivors had normal function or only mild neurodevelopmental disability.ConclusionsECMO was successfully used in children with cardiac disease with 73% and 66% short- and intermediate-term survival, respectively. The majority of the survivors had normal function or only a minimal neurodevelopmental deficit

Protocol for the PACE trial: A randomised controlled trial of adaptive pacing, cognitive behaviour therapy, and graded exercise as supplements to standardised specialist medical care versus standardised specialist medical care alone for patients with the chronic fatigue syndrome/myalgic encephalomyelitis or encephalopathy

<p>Abstract</p> <p>Background</p> <p>Chronic fatigue syndrome (CFS, also called myalgic encephalomyelitis/encephalopathy or ME) is a debilitating condition with no known cause or cure. Improvement may occur with medical care and additional therapies of pacing, cognitive behavioural therapy and graded exercise therapy. The latter two therapies have been found to be efficacious in small trials, but patient organisations' surveys have reported adverse effects. Although pacing has been advocated by patient organisations, it lacks empirical support. Specialist medical care is commonly provided but its efficacy when given alone is not established. This trial compares the efficacy of the additional therapies when added to specialist medical care against specialist medical care alone.</p> <p>Methods/Design</p> <p>600 patients, who meet operationalised diagnostic criteria for CFS, will be recruited from secondary care into a randomised trial of four treatments, stratified by current comorbid depressive episode and different CFS/ME criteria. The four treatments are standardised specialist medical care either given alone, or with adaptive pacing therapy or cognitive behaviour therapy or graded exercise therapy. Supplementary therapies will involve fourteen sessions over 23 weeks and a 'booster session' at 36 weeks. Outcome will be assessed at 12, 24, and 52 weeks after randomisation. Two primary outcomes of self-rated fatigue and physical function will assess differential effects of each treatment on these measures. Secondary outcomes include adverse events and reactions, subjective measures of symptoms, mood, sleep and function and objective measures of physical activity, fitness, cost-effectiveness and cost-utility. The primary analysis will be based on intention to treat and will use logistic regression models to compare treatments. Secondary outcomes will be analysed by repeated measures analysis of variance with a linear mixed model. All analyses will allow for stratification factors. Mediators and moderators will be explored using multiple linear and logistic regression techniques with interactive terms, with the sample split into two to allow validation of the initial models. Economic analyses will incorporate sensitivity measures.</p> <p>Discussion</p> <p>The results of the trial will provide information about the benefits and adverse effects of these treatments, their cost-effectiveness and cost-utility, the process of clinical improvement and the predictors of efficacy.</p

Right ventricular outflow tract reconstruction with bicuspid valved polytetrafluoroethylene conduit.

BACKGROUND: In general, all conduits available for right ventricular outflow tract (RVOT) reconstruction eventually become stenotic or insufficient. Owing to the lack of an ideal conduit and with the hope of reducing the incidence of reoperations, we have developed and utilized a bicuspid valved polytetrafluoroethylene (PTFE) conduit for the reconstruction of the RVOT. The purpose of this study was to review our early experience with this conduit. METHODS: From October 2008 to September 2009, we have implanted bicuspid valved PTFE conduits in 18 patients with a median age of 1.7 years (range 6 days to 16 years). Their diagnoses include tetralogy of Fallot with pulmonary atresia in 8, truncus arteriosus in 6, congenital aortic stenosis in 2, transposition of great arteries in 1, and interrupted aortic arch with a ventricular septal defect in 1. In 16 patients, a complete biventricular repair was performed. In another 2 cases, the conduit was used for palliative RVOT reconstruction. The conduit sizes varied from 10 mm to 24 mm in diameter. Three-dimensional flow fields obtained from computational fluid dynamics studies were utilized in the conduit design process. RESULTS: There was no surgical mortality or reinterventions associated with the PTFE conduit placement in our series. At the time of discharge, none of the patients had any echocardiographic findings consistent with significant conduit stenosis or insufficiency. During the follow-up period of 6.2 ± 3.9 months, all patients were alive and only 3 had more than mild pulmonary insufficiency. CONCLUSIONS: Our bicuspid valved PTFE conduit has an acceptable early performance, with a low incidence of valve insufficiency and no conduit stenosis. Certainly, longer follow-up is necessary to fully assess its long-term benefits.</p

Challenges of nurse delivery of psychological interventions for long-term conditions in primary care: a qualitative exploration of the case of chronic fatigue syndrome/myalgic encephalitis

Background The evidence-base for a range of psychosocial and behavioural interventions in managing patients with long term conditions (LTCs) is now well-established. With increasing numbers of such patients with such conditions being managed in primary care, and a shortage of specialists in psychology and behavioural management to deliver interventions, such therapeutic interventions are increasingly being delivered by general nurses with limited training in psychological interventions. It is unknown what issues this raises for the nurses or their patients. The purpose of the study was to examine the challenges faced by non-specialist nurses when delivering psychological interventions for a long term condition (Chronic Fatigue Syndrome /Myalgic Encephalomyelitis; CFS/ME) within a primary care setting. Methods A qualitative study nested within a randomised controlled trial [ISRCTN 74156610] explored the experiences and acceptability of two different psychological interventions (pragmatic rehabilitation and supportive listening) from the perspectives of nurses, their supervisors and patients. Exploring data from each perspective provides triangulation, and therefore increased trustworthiness, of the analysis. Semi-structured in-depth interviews were conducted with 46 patients, three nurse therapists and three supervisors and an iterative approach was used to develop conceptual categories from the dataset. Results Analyses reveal four sets of challenges that were common to both interventions: i) Being a novice therapist; ii) engaging patients in the therapeutic model; iii) dealing with emotions and iv) complexity of primary care. Each challenge had the potential to cause tension between therapist and patient. A number of strategies were developed by participants to manage the tensions. Conclusion Tensions exist for nurses when attempting to deliver psychological therapy for patients with CFS/ME in a primary care trial which would need to be addressed before implementing within routine clinical practice. Similar tensions may be found for other long term conditions. These have implications for developing therapeutic alliance and highlight the need for regular supervision

Total cavopulmonary connection in patients with apicocaval juxtaposition: optimal conduit route using preoperative angiogram and flow simulation.

OBJECTIVES: Single ventricle with apicocaval juxtaposition (ACJ) is a rare, complex anomaly, in which the optimal position of the conduit for completion of total cavopulmonary connection (TCPC) is still controversial. The purpose of this study was to identify a preoperative method for optimal conduit position using the IVC anatomy and computational fluid dynamics (CFD). METHODS: Twenty-four patients with ACJ (5.3 ± 5.7 years) who underwent TCPC were enrolled. A conduit was placed ipsilateral to the cardiac apex in each of 11 patients, of which 9 were intra-atrial and 2 extracardiac (group A) and, in a further 13 patients, extracardiac on the contralateral side (group B). As control, 10 patients with tricuspid atresia were also enrolled (group C). The location of the IVC in relation to the spine was evaluated from the frontal view of preoperative angiogram, using the following index: IVC-index = IVC width overlapping the vertebra/width of the vertebra × 100%. Energy loss was calculated by CFD simulation. RESULTS: IVC-index of group B was larger than groups A and C (45 ± 26 vs. 20 ± 21 and 28 ± 19%, P = 0.03). Postoperative catheterizations showed that, due to its curvature, conduit length in group B was significantly longer than the others (65 ± 12 vs. 36 ± 14 and 44 ± 10 mm, P CONCLUSIONS: In patients with ACJ, placement of a straighter and shorter conduit on the ventricular apical side provides better laminar blood flow with less energy loss. However, conduit compression and kinking are far more detrimental to the Fontan circulation. A preoperative IVC-index is pivotal for avoiding these factors and deciding the optimal conduit route.</p