ABSTRACT
Objective To investigate the effects of banding width on hemodynamic characteristics of pulmonary artery (PA) by constructing pulmonary artery banding (PAB) models with different widths. Methods Based on clinical practice, with the same banding position and degree, computer-aided design (CAD) was utilized to reconstruct three-dimensional PAB models with different banding widths (2, 3, 4, 5 mm). Hemodynamic characteristics of the models with different banding widths, including pressure, streamlines, energy loss, energy efficiency and blood flow distribution ratio, were compared and analyzed through computational fluid dynamics (CFD). Results The pressure of PA decreased significantly, while the change of banding width had no significant effects on the pressure drop level at banding position. With the increase of banding width, the energy loss decreased, and the energy efficiency showed an upward trend. The blood flow of the left PA raised, and the ratio of blood flow distribution between the left PA and right PA increased, with the maximum reaching up to 2.28 : 1. Conclusions The increase of banding width can reduce the energy loss of PA and improve the energy efficiency of blood flow, but it will lead to the imbalance of blood flow distributions between the left and right lungs. Both the balance of blood flow distribution and the energy loss should be considered in choice for banding width of PAB. The virtual design of PAB surgery based on CAD and CFD will assist individualized banding width selection in future.
ABSTRACT
Objective:To investigate hemodynamic characteristics of the modified Blalock-Taussig shunt (MBTS) with the preservation or ligation of ductus arteriosus (DA) based on computational fluid dynamics (CFD), thus to help preoperative surgery design and postoperative prediction.Methods:A patient with pulmonary atresia and patent ductus arteriosus was included. Patient-specific three-dimensional model was reconstructed and virtual surgeries of shunt insertion and ductus ligation or preservation were performed via computer-aided design (CAD). CFD was utilized to analyze hemodynamic parameters preoperatively and postoperatively based on patient-specific anatomy and physiologic data.Results:The preservation of DA competitively reduced the shunt flow but increased total pulmonary perfusion. The shunt flow and ductal flow collided with each other, causing large and complicated turbulence in pulmonary artery where lower wall shear stress and higher oscillatory shear index were distributed, as well as higher energy loss.Conclusion:The preservation of DA is riskier in hemodynamics which may lead to pulmonary over-perfusion, inadequate systemic perfusion and heavier cardiac burden, thus increasing the risk of heart failure and it seems to bring no benefit in terms of reducing risks of thrombosis.
ABSTRACT
According to the actual requirements of pediatric intensive care, a suction detection system of pediatric oral secretions integrated with monitoring function is designed. The system has the function of adjustable intermittent attraction. The duration and proportion of intermittent attraction can be adjusted according to the individualized needs of pediatric intensive care. The suction head of pacifier can reduce the mechanical damage to pediatric oral mucosa as much as possible. Meanwhile, the system can detect and monitor the real-time biochemical indexes of the collected oral secretions, which can be used to help the judgement of aspiration and quantitatively evaluate the microcirculation dysfunction.