Fig. 35.1
Pump output of Berlin Heart EXCOR pediatric at common clinical use. Depending on body size and patient’s needs, pump chambers of different sizes can be chosen
Table 35.1
Ventricular assist devices for long-term support in children and adolescents
Device | Manufacturer | Principle | Patient size |
---|---|---|---|
EXCOR pediatric | Berlin Heart | Paracorporeal pulsatile | >2.5 kg – adult |
HeartMate II | Thoratec | CF, axial | >1.2 m2 BSA |
HeartMate IIIa | Thoratec | CF, centrifugal | >1.2 m2 BSA |
HVADa | HeartWare | CF, centrifugal | >1 m2 BSA |
MVADb | HeartWare | CF | Under investigation |
35.3 Postoperative Management
Postoperative management starts in the operating room. To support the right ventricle during weaning from cardiopulmonary bypass, inhaled nitric oxide, milrinone, and epinephrine are recommended. Mechanical ventilation with normoventilation (pCO2 35–40 mmHg) and long expiratory times are helpful to lower right ventricular afterload. Transesophageal echocardiography is used to rule out inflow obstruction of the cannula, to confirm adequate unloading of the left ventricle without septal shift, and to analyze right ventricular geometry and function. If right ventricular function is severely impaired despite maximal medical therapy and optimal left ventricular pump settings, the implantation of an RVAD is mandatory. Directly after bypass the heparin effect should be completely antagonized. Initial accurate hemostasis is necessary to minimize the need for blood products and avoid volume overload of the right ventricle. Closure of the chest allows for early extubation, and medical support of right ventricular function in the intensive care unit is crucial to avoid secondary heart failure.
A standard protocol for antithrombotic therapy has been proposed [10]. Anticoagulation is withheld during the first 24 h until bleeding has completely stopped. Antithrombotic therapy is initiated with unfractionated heparin and switched to low molecular heparin in infants or warfarin in children older than 1 year of age. Dual antiplatelet therapy is introduced during the first or second week of VAD support. Due to the substantial rate of early thromboembolic events, modifications of this protocol are used in many centers. Examples of strategies to lower the adverse event rate include earlier initiation of unfractionated heparin, higher target ranges for low molecular heparin and warfarin, higher dosages of antiplatelet drugs, and introduction of a third agent. Additionally, various efforts such as timely extubation, early removal of the central lines, early enteral feeding, and early mobilization should be made to reduce the risk for adverse events such as infections or thromboembolic events.