Biocompatibility Assessment of the CentriMag-Novalung Adult ECMO Circuit in a Model of Acute Pulmonary Hypertension.

Extracorporeal membrane oxygenation (ECMO) is rarely used in patients with severe pulmonary hypertension (PH) as a bridge to lung transplantation. In this study, we assess the blood biocompatibility of the integrated CentriMag-Novalung ECMO system (venoarterial) in an acute model of PH. Severe PH (≥2/3 systemic) was induced in eight sheep through progressive ligation of the main pulmonary artery. System performance, platelet activation, thromboelastography (TEG) parameters, fibrinogen, plasma-free hemoglobin, and total plasma protein were measured at initiation, 3, and 6 hr of support in the ECMO (N = 4) and sham (N = 4) groups. A stable ECMO flow (2.2 ± 0.1 L/min), low transmembrane pressure gradient, and steady blood O2 and CO2 levels were maintained. Platelet activation was low (<4%) in both the groups, whereas platelet responsiveness to agonist (platelet activating factor) was reduced in the sham group when compared with the ECMO group. There were no differences in the TEG parameters, fibrinogen concentration, plasma-free hemoglobin (<10 mg/dl), and plasma total protein between the two groups. The findings of low levels of platelet activation and plfHb suggest adequate blood biocompatibility of the integrated CentriMag-Novalung circuit use for short-term support in a model of PH.

On the use of computational models for the quantitative assessment of surgery in congenital heart disease.

The surgical repair of congenital heart disease often involves significant modifications to the circulatory tree. Resections, reconstructions, graft insertions and the deployment of implants and biomedical devices have an impact on local and systemic haemodynamics, which may be difficult to foresee or to assess quantitatively by clinical investigation alone. Mathematical models can be employed to visualise, estimate or predict events and physical quantities that are difficult to observe or measure, and can be successfully applied to the study of the pre- and post-operative physiology of cardiovascular malformations. This paper analyses the potentialities of computation fluid dynamics in this respect, outlining the method, its requirements and its limitations. Examples are given of lumped parameter models, axi-symmetric models, three-dimensional models, fluid-structure interaction simulations and multiscale computing applied to total cavo-pulmonary connection, aortic coarctation and aortic arch reconstruction.

Long-segment tracheal stenosis: slide tracheoplasty and a multidisciplinary approach improve outcomes and reduce costs.

OBJECTIVE: Long-segment tracheal stenosis is rare, life-threatening, difficult, and expensive to treat. Management remains controversial. A multidisciplinary tracheal team was formed in 2000 to deal with a large number of children with airway problems referred for management. We review the effect of that service, comparing the era before and after the establishment of the multidisciplinary tracheal team. METHODS: From January 1998 through January 2004, 34 patients with long-segment tracheal stenosis (21 patients with cardiovascular anomalies) underwent surgical intervention. Cardiopulmonary bypass was used in all operations. Before the multidisciplinary tracheal team, pericardial patch tracheoplasty with or without an autograft technique was the preferred method of repair. After the multidisciplinary tracheal team, an integrated care plan preferring slide tracheoplasty was initiated, correcting cardiac lesions simultaneously. RESULTS: Before the establishment of the multidisciplinary tracheal team, pericardial patch tracheoplasty was performed in 15 of 19 patients. Twelve patients had a suspended pericardial patch tracheoplasty, 2 (17%) of whom died late after the operation. Of 3 patients who had had a simple unsuspended patch, 2 (67%) died early after the operation. Four patients were operated on with the tracheal autograft technique, 2 (50%) dying early in the postoperative period. After multidisciplinary tracheal team formation, in the era between 2001 and 2004, 15 patients were operated on with slide tracheoplasty, and there were 2 (13%) early postoperative deaths. A significant reduction in cost and duration of stay has been shown both in the intensive care unit and the hospital. CONCLUSION: Our data suggest that a formalized multidisciplinary team approach and a policy of primary slide tracheoplasty are beneficial in the management of children with long-segment tracheal stenosis.