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In this work we investigate the removal of emboli from cardiopulmonary bypass circuits via acoustic radiation force. Unless removed, emboli can be a significant source of cognitive deficit after cardiac surgery. We have implemented both inviscid linear and viscous non-linear models for radiation force on a sphere immersed in a fluid. The importance of viscosity is a lingering question in the literature. These models allow for prediction of radiation force as a function of embolus size and can identify the optimal frequency for clinical use. [ABSTRACT FROM AUTHOR]

Background: Heart valve operations during pregnancy still have some significant risks for mother and child. Cardiac operations during the third trimester of pregnancy more confident than the first and second trimesters. If a valve treatment needed during the first and second trimesters trans-catheter valve interventions can be preferred. Valve operations can be performed with the use of cardiopulmonary bypass which has a foreign surface that contacts with blood and causes a systemic inflammation. On the other hand patients had a linear flow which provides an arterial tension between 50 to 80 mm Hg during the cardiopulmonary bypass. Methods: Between 2000 and 2012 6 patients who had mitral valve operation during their pregnancy were evaluated. Out of 2 cases had a mitral valve replacement with a mechanical valve before the pregnancy. They had severe pulmonary edema and stuck valve needing urgent delivery of the child and on-pump cardiac operation. Remaining 4 patients had severe pulmonary edema because of mitral stenosis (3 cases) or mitral regurgitation (1 case). Out of 1 patient had successful transcatheter mitral balloon valvuloplasty, while an other patient had unsuccessful balloon valvuloplasty and needed urgent closed commissurotomy with left thoracotomy. Results: There were no deaths among the patients. Out of 2 cases had sectio and healthy childs after interventions. Among these cases one of them had a mitral balloon valvuloplasty. The other patient had a 24 week pregnancy, severely calcified mitral stenosis and pulmonary edema needing urgent mitral valve replacement with a mecahnical valve. The operation was performed by using the cardioplumonary bypass with a pulsatile pump flow and continous intrauterin monitoring of the child during and after the operation. The patient and child did well after the operation, 12 weeks later she had a successful sectio and a healthy girl. Out of 4 patients had urgent heart valve operations which can not protected the life of child, even one patient had a closed mitral commissurotomy without using the cardiopulmonary bypass. Conclusion: The timing of open heart surgery is very significant in pregnancy. Open heart surgery after the delivery of the baby with sectio is the most advised method, if possible. However, urgent surgery may be needed before maturation of fetus, in this situation cardiopulmonary bypass may be used with pulsatile flow in order to protect the life of child during and after the early term of open heart surgery. [ABSTRACT FROM AUTHOR]

Pulmonary injury is a common complication after cardiopulmonary bypass (CPB) in patients undergoing cardiac surgery. The major causes of tissue damage arise from systemic inflammatory responses, and/or factors released by the ischaemic collapsed lungs. To date, there is no evidence to demonstrate whether this CPB-related pulmonary injury can influence both the permeability and function of the pulmonary arterioles. We developed a method to isolate, cannulate and pressurize porcine pulmonary arterioles to study their vasomotor function, the leak of fluorescent dyes through the arterial wall, and the expression of key proteins. All arterioles were imaged using linescan confocal microscopy. The fluorescent indicators carboxyfluorescein (CF, 0.1 µM, mw 376.3) or FITC-dextran (1 µM, mw 59,000 - 77,000) were perfused into the lumen of arterioles, and increases in fluorescence immediately outside the arteriolar wall (permeability) measured. Tight junction (Zo-1) and caspase 3 staining was performed on the same arterioles, and imaged while still cannulated, to assess the continuity of cell-cell connections and the onset of apoptosis. Arterioles were studied from pigs which had undergone CPB or sham surgery under anaesthesia and categorized into 4 groups: control (lungs collapsed to air with no ventilation during CPB, equivalent to the current method in patients); IPP-ILFV (intermittent pulmonary perfusion with intermittent low frequency ventilation during CPB); IPP-CLFV (intermittent pulmonary perfusion with continuous low frequency ventilation during CPB); and sham (chest opened only). From each group two samples were obtained, one soon after median sternotomy (baseline) and one at 1 hour of recovery after surgery (reperfusion). All baseline and sham pulmonary arterioles had low permeability to CF and FITC-dextran. When studying reperfused arterioles, the arterioles studied following IPP-ILFV and IPP-CLFV were less permeable to CF when compared to control arterioles. The permeability to FITC-dextran was not increased in any group studied, although a TRPV4 agonist did increase permeability to dextran. Furthermore, tight junction staining showed continuous, uniform cell-cell connections in the endothelium of all baseline arterioles. Interestingly, and consistent with the CF leak data, reperfused lung arterioles from the control group did appear to have gaps in tight junction staining and some caspase 3 staining was evident. These data suggest that cardiopulmonary bypass and concomitant lung collapse leads to increased permeability of pulmonary arterioles due to damaged cell-cell adhesions, which can be prevented by intermittent pulmonary perfusion with low frequency ventilation of the lungs during CPB. [ABSTRACT FROM AUTHOR]