Andersons pediatric cardiology 1847

requires placement of an additional arterial cannula to supply flow to the descending thoracic and abdominal aorta during arch reconstruction The site of distal cannulation can include cannulation of the arterial duct, descending thoracic aorta at the level of the diaphragm, or femoral artery During a period of aortic cross-clamping and altered perfusion, arch reconstruction including amalgamation of the aortic and pulmonary roots is accomplished (Fig 71.7).99 A nonrestrictive atrial septal defect is created The cross clamp is released and rewarming completed Finally a source of pulmonary blood flow is established—either a systemic-to-pulmonary artery shunt or a right ventricle-to-pulmonary artery conduit Once rewarming has been completed and cardiac function has returned, vasoactive support is initiated Commonly milrinone and catecholamines are used Prior to weaning from bypass, the patient should be in an AV sequential rhythm, hematocrit should be at least 35%, ionized calcium should be within the normal range, and the systemic vascular resistance should be about 12 Woods units The SVR can be estimated by dividing the mean arterial pressure by the cardiac index Further adjustments of vasoactive agents are made to achieve the target SVR For the patient with a systemic-to-pulmonary artery shunt, the shunt is opened as the cardiopulmonary bypass flow is reduced After successful weaning from bypass, modified ultrafiltration can be performed Evaluation of the procedure is then undertaken This can include echocardiography, either epicardial or transesophageal, to evaluate function, the adequacy of the atrial septal defect, and the degree of tricuspid valve regurgitation Regional perfusion as assessed by NIRS should be used to assess DO2.100 Residual systemic outflow obstruction can be ruled out by comparing the systemic ventricular systolic pressure with a pressure measured from the femoral or umbilical artery catheter Once the clinician is satisfied with the repair, the venous cannula is removed and protamine is administered to reverse anticoagulation The arterial cannula can be left in place until after protamine has been administered It is essential to achieve complete hemostasis Transfusion of platelets and fibrinogen—either fresh frozen plasma or cryoprecipitate—is common Careful inspection of the surgical sites should be undertaken and additional sutures placed as necessary For continued bleeding that does not seem to be surgical and has not responded to component transfusion, additional agents such recombinant factor VIIa or prothrombin complex concentrates can be considered FIG 71.7 Technique of Norwood arch reconstruction (A) After cooling on cardiopulmonary bypass to 18°C, cardioplegic arrest is achieved and antegrade cerebral perfusion established The aortic isthmus is divided, and all the ductal tissue is resected (inset) The extent of resection of ductal tissue is determined by identifying the change in thickness of the vessel, as the ductus is slightly thicker-walled than the aorta In addition, the intercostal vessels arise from the aorta and the ductal tissue ends a few millimeters away from the first set of intercostal vessels (B) After mobilizing the descending thoracic aorta, which requires division of the first two or three sets of intercostal vessels, an incision is made in the aorta from the open end of the aortic isthmus to the level of the pulmonary root A cutback is made in the posterior aspect of the descending thoracic aorta The cutback incision is directed toward the origin of the intercostal vessels (C) An interdigitating arch reconstruction is created The descending thoracic aorta is advanced as far as the distal ascending aorta A large suture line from native tissue to native tissue is created A patch of porcine small intestinal submucosa is fashioned as a quarter circle with a radius of 3.5 cm (inset) The patch is used to augment the arch and ascending aorta and complete the connection of the aorta and pulmonary root The patch is aligned beginning at the white arrow The straight edge, indicated by the black arrow, is sutured to the inner curvature, and the curved edge, indicated by the gray arrow, is sutured to the outer curvature The aortic root is joined to the pulmonary root in an incision in the pulmonary root just leftward of the commissure adjacent to the ascending aorta (D) The patch is being sewn into place (E) Excess patch is trimmed (not shown) and the proximal suture line completed (From Jacobsen RM, Mitchell ME, Woods RK, et al Porcine small intestinal submucosa may be a suitable material for Norwood Arch reconstruction Ann Thorac Surg 2018;106[6]:1847– 1852.) Once hemostasis has been achieved, the decision to close versus leaving the sternum open is made For those patients who have had a long bypass run and are on more than the usual inotropic support, delayed sternal closure may be necessary Although some programs routinely leave the sternum open, there is little question that this prolongs the length of time to extubation and, as a consequence, also CICU length of stay and hospitalization Therefore it seems reasonable to determine whether the sternum can be closed primarily Sternal closure sutures are placed and the sternum reapproximated The hemodynamics are evaluated and if there is no perturbation, sternal closure can be completed and the remainder of the incision closed in the usual manner If sternal approximation results in important hypotension and/or desaturation or if there is evidence of decreased systemic DO2 as assessed by NIRS or venous saturation, the sternum should be left open Once the patient begins to diurese and vasoactive support can be weaned, chest closure can be performed If the patient fails to progress, residual lesions should be ruled out The hybrid approach is defined by placement of individual branch pulmonary artery bands.45 Ductal patency is maintained with either a stent or prostaglandin In addition, catheter-based creation of a nonrestrictive atrial septal defect is necessary if this is not already present Typically the procedure is performed in a hybrid catheterization laboratory A median sternotomy is performed Branch pulmonary artery banding is performed first Rings 2 to 3 mm in diameter are cut from an ePTFE tube graft that is 3.0 or 3.5 mm in diameter With the typical hypoplastic left heart syndrome anatomy, the left pulmonary artery is banded first, as it is the most difficult to access.45,101 The right pulmonary artery is banded next The adequacy of the banding can be directly measured by catheter and additional fine adjustments can be made If a stent is to be placed to maintain duct patency, this is performed last The atrial septal defect can then be enlarged using catheter-based techniques Neonate With Unobstructed Systemic Blood Flow and Pulmonary Stenosis: Balanced Circulation Finally, some neonates with a fUVH are born with without the need for neonatal ... Porcine small intestinal submucosa may be a suitable material for Norwood Arch reconstruction Ann Thorac Surg 2018;106[6] :1847? ?? 1852.) Once hemostasis has been achieved, the decision to close versus leaving the sternum open is made