Central Partial Bypass Management Technique for Distal Arch Surgery.

Circulatory arrest and left heart bypass are the most common approaches to manage perfusion during distal arch surgery. We report a novel perfusion technique utilized in the treatment of aneurysmal Komerrell's diverticulum (KD) and aberrant subclavian artery (ASA) that allows for a reliable conduct of perfusion. From 2016 to 2020, 12 adult patients with aneurysmal KD and ASA underwent repair of distal arch through lateral thoracotomy ipsilateral to the arch side using central partial bypass. Once the patients were fully heparinized the lower thoracic aorta and the right atrium were cannulated. The cannulas were connected to the cardiopulmonary bypass (CPB) circuit with an oxygenator. Partial bypass was initiated. Ventilation via anesthesia was continued as the mode of gas exchange to the upper body while the CPB circuit provided gas exchange to the lower body. In all patients, CPB was initiated allowing the patient to maintain a mean arterial pressure >60 mmHg in the femoral artery and a mean arterial pressure (MAP) >80 mmHg in the radial artery to allow adequate native ejection into the proximal circulation. The venous line was partially occluded to control the radial pressure. The aorta was cross clamped proximal and distal to the KD to isolate the aorta to be replaced. KD was excised in all patients having performed contralateral subclavian to carotid transposition previously. Once the aorta was reconstructed, clamps were released and the patients were weaned off CPB. All were extubated on the same day and there was no early mortality.

Novel Applications of Modified Ultrafiltration and Autologous Priming Techniques to Reduce Blood Product Exposure on ECMO.

Patients needing the assistance of extracorporeal membrane oxygenation (ECMO) are at risk of hemodilution and, in some instances, may require exposure to large amounts of allogeneic blood products. Patient outcomes can be improved by taking steps to reduce transfusions and hemodilution. Currently, modified ultrafiltration (MUF) is used across the world to reduce hemodilution after cardiopulmonary bypass (CPB). Another common technique during bypass initiation is autologous priming. By applying modified versions of these techniques, ECMO patients may potentially benefit. Usually, patients requiring immediate transition from CPB to ECMO are not stable enough to tolerate MUF. Through alterations of the CPB and ECMO circuit tubing, MUF can be performed once on ECMO. Another technique to potentially lower the transfusion requirements for ECMO patients is a complete circuit blood transfer during an ECMO circuit exchange. While selective component changes are preferred if possible, occasionally a complete circuit change must be done. To minimize hemodilution or prevent priming with blood products, the original ECMO circuit's blood can be transferred to the new ECMO circuit before connecting to the patient. Both of these techniques, in our opinion, helped to reduce the number of transfusions that our ECMO patients have seen during these critical time periods.

Plasma-free hemoglobin levels in advanced vs. conventional infant and pediatric extracorporeal life support circuits.

Extracorporeal life support (ECLS) is a reliable method to support pediatric patients with reversible cardiorespiratory failure associated with congenital heart disease, respiratory insufficiency, or after cardiac surgery. In 2010, our institution adopted an infant/pediatric extracorporeal membrane oxygenation (ECMO) circuit that contains a magnetically levitated centrifugal pump, polymethylpentene oxygenator, and shorter tubing length (ECMO II circuit). Our prior circuit contained a nonocclusive roller pump, polypropylene oxygenator, venous compliance chamber, and hemoconcentrator (ECMO I circuit). A retrospective chart review comparing ECMO I and ECMO II daily plasma-free hemoglobin (PFH) values was conducted. We hypothesized that the PFH is similar between the two ECMO circuit groups. We reviewed medical records of children 3 years of age or younger weighing less than 13 kg who required ECLS between January 2008 and February 2012. PFH levels from 18 ECMO II patients were compared with levels in a retrospective group of an equal number of well-matched ECMO I circuit patients. There was no significant difference between ECMO I and ECMO II circuit groups regarding mean time on ECMO, age in days, and weight. There was also no significant difference in the group mean levels of PFH between ECMO I and ECMO II circuits. There was a significant increase in PFH with hours on ECMO (p < .01) within and between both circuit groups (p < .01) and a significantly greater increase in PFH with ECMO hours (p = .0091) in the ECMO I circuit group. Although there was no significant difference in average PFH with the change in ECMO II circuit technology, advancements such as the magnetically levitated blood pump and polymethylpentene gas exchange device has been associated with significantly fewer mechanical component change-outs (p = .0156) and less clots and fibrin build-up in the circuits (p = .0548).