In Vitro Evaluation of Flow Distribution in All-Region Perfusion during the Norwood Operation.

Continuous all-region perfusion has the potential to reduce total body ischemia during the Norwood procedure. This technique involves placing cannulas in the innominate artery, descending aorta, and native aortic root, thus providing continuous flow to the whole body at mild hypothermia (32-34°C) during the entire operation. However, the cannulation strategy in this approach must be optimized to achieve adequate flow rates to all vascular beds. To ensure appropriate blood flow rates to three cannulas of different caliber supplied by two inflow pumps, a benchtop evaluation of comparative flow rates through branched cannulas with variable independent perfusion pressures was conducted. Two isolated vertical columns with outlets at 10 mmHg intervals to allow for adjustable perfusion pressures were filled with expired banked packed red blood cells and fresh frozen plasma. The main arterial line was bifurcated with an 8-Fr arterial cannula inserted at the base of one column and a 4-mm (outside diameter [OD]) olive tip cannula inserted at the base of the other column. Flow rates were measured on each branch of the »â€³ arterial lines. Under experimental cardiopulmonary bypass (CPB) perfusion pressures of 30-50 mmHg on the 8-Fr arterial cannula column, the branched olive tip cannula accommodated less than 25% of total flow at total flow rates of 50-700 mL/min. This fraction is insufficient to sustain adequate lower body perfusion. However, the olive tip flow fraction was found to be sufficient for coronary blood flow (5-20 mL/kg/min) when olive tip perfusion pressures close to average neonatal diastolic blood pressures (20-60 mmHg) were tested. For all-region perfusion during the Norwood operation, primary CPB arterial flow should be divided to the head and coronary circulation with an independent pump delivering flow to the descending aorta. This should avoid cerebral over-circulation and insufficient flow to the lower body.

Sustained Total All-Region (STAR) Perfusion: An Optimized Perfusion Strategy for Norwood Reconstruction.

Early iterations of the Norwood procedure used aortic cross-clamping, myocardial arrest, and, sometimes, deep hypothermic circulatory arrest. The resulting hypothermia and prolonged ischemia caused frequent cardiac, neurologic, renal, and other end-organ dysfunctions. Our group describes a novel technique, sustained total all-region (STAR) perfusion, which circumvents these issues by providing continuous perfusion to the head, heart, and coronaries at temperatures of 32-34°C. A single DLP® straight venous cannula (Medtronic, Minneapolis, MN) is placed in the right atrium, and a DLP® pediatric arterial cannula, with a high-flow stopcock attached, is placed in the ascending aorta or innominate artery to provide flow to the head. A cardioplegia needle with walrus tubing is connected to the stopcock to provide flow to the coronary arteries. For lower body perfusion, an olive tip cannula is placed into the descending aorta lumen and attached to the 1/8″ line from the cardioplegia system which provides warm arterial blood flow. STAR perfusion allows the Norwood procedure to be completed with mild hypothermia and continuous perfusion to all vascular beds with reduced cardiopulmonary bypass as well as total operative times. This technique is successfully achieved with minimal changes to circuitry, minor modifications to heart-lung machine servoregulation and few additional cannulation disposables.

Prophylactic Subclavian Artery Intraaortic Balloon Counter-Pulsation is Safe in High-Risk Cardiac Surgery Patients.

The objective of this study was to determine the safety of prophylactic subclavian artery intraaortic balloon pumps (SCA-IABP) in high-risk cardiac surgery patients as a bridge to recovery (BTR). From November 2011 to January 2013, 11 consecutive patients at three institutions underwent prophylactic insertion of a SCA-IABP as a BTR. All patients (n = 11) had preoperative ejection fractions of 30% or less. Patients concurrently underwent one or a combination of the following procedures: coronary artery bypass grafting, mitral valve surgery, aortic valve replacement, left ventricular aneurysm resection, and ventricular/atrial septal defect closure. The primary outcome measure was a composite endpoint of device-related complications (including limb ischemia, stroke, device failure, bleeding requiring reoperation, brachial plexus injury, device-related infection, and vascular complications) and in-hospital mortality. Secondary outcome measures included interval to patient ambulation and postoperative length of stay. There were no device-related complications or in-hospital mortalities in this cohort of 11 consecutive patients. Mean time to ambulation, balloon pump support, and postoperative length of stay were 3.70 ± 2.50 days, 8.50 ± 7.00 days, and 15.9 ± 8.25 days, respectively. Prophylactic SCA-IABPs appear to be safe in high-risk cardiac surgery patients as a BTR.