A 55-year-old man supported by a VentrAssist LVAD (Ventracor Limited, Chatswood, Australia) presented for debridement and myocutaneous flap closure of a stage IV sacral decubitus ulcer in the prone position. The device had been implanted as a bridge to transplantation approximately 2 months previously, and the patient was hemodynamically stable. Additional procedures at the time of VAD implantation had included mitral valve replacement, aortic valve replacement, and coronary artery bypass graft surgery to the right coronary distribution. The postoperative course had been complicated by renal failure, anemia, and prolonged respiratory failure for which he had previously undergone tracheostomy, and he was chronically in atrial fibrillation. Medications included heparin infusion, hydromorphone, levetiracetam, cefazolin, levocarnine, quetiapine, darbopoeitin, and insulin. Physical examination revealed a cachectic male weighing 55 kg and measuring 165 cm tall. The driveline of the LVAD exited the abdomen at the left upper quadrant. There was an indwelling right femoral arterial pressure cannula and a 7.5F triple-lumen catheter in the right internal jugular vein. An 8.0 cuffed Shiley tracheostomy tube was present. The patient was transported to the operating room by the anesthesia team and a dedicated VAD nurse. Hemodynamic monitoring was used in transport, and the device was powered by battery packs. Upon arrival to the operating room, the VAD was returned to main AC power. Intraoperative monitoring included an electrocardiogram, pulse oximetry (SpO2), invasive arterial pressure, central venous pressure, transesophageal echocardiography (TEE), and cerebral oximetry (SctO2). In addition to the anesthesia team assigned to the case, a cardiac anesthesiologist and the VAD nurse were present intraoperatively. In addition to infusions of epinephrine and vasopressin, nitric oxide was available in the room, although the tank was not opened as a cost-containment effort. Vital signs on operating room arrival were heart rate of 70 beats/min, mean arterial pressure of 60 to 70 mmHg, central venous pressure of 14 mmHg, SpO2 of 100%, and left SctO2 of 70% and right of 60%. A thorough denitrogenation was accomplished through the tracheostomy, and induction of general anesthesia proceeded smoothly with midazolam (2 mg), fentanyl (250 g), etomidate (8 mg), and vecuronium (10 mg). Anesthesia was maintained with isoflurane in oxygen and additional boluses of vecuronium. After anesthetic induction in the supine position, TEE examination by a cardiac anesthesiologist revealed a dilated and severely hypokinetic left ventricle (LV), a well-functioning right ventricle (RV), absence of tricuspid regurgitation, a well-functioning mitral bioprosthesis, and an intact bioprosthetic aortic valve that was not opening. The inflow cannula to the LVAD could not be visualized in the left ventricular apex (likely because it is quite short with this particular device), but color-flow mapping revealed no apparent turbulence suggesting obstruction to inflow. Outflow from the device in the ascending aorta was visualized, but the outflow cannula itself could not be. Once the baseline TEE examination was completed, the patient was then turned from the supine to the prone position, with careful placement of abdominal and chest bolsters. The patient initially tolerated this position without significant change in arterial or airway pressures. By comparison to the baseline examination in the supine position, the TEE examination in the prone position revealed relatively decreased right ventricular function (Videos 1 and 2 [supplementary videos are available online]). Unfortunately, within just a few minutes (and before skin incision), the airway pressures suddenly increased, SctO2 decreased bilaterally, there was an abrupt loss of the capnogram tracing, and LVAD output rapidly decreased from 6.1 L/min to 3.8 L/min. The patient was immediately returned to the supine position. Attempted manual ventilation revealed significantly decreased lung compliance. Suctioning of the tracheostomy evacuated bloody secretions along with a large clot. Once the bloody plug had been removed, ventilatory parameters, LVAD flows, and SctO2 returned to their previously stable baseline values. Discussion with the surgeons resulted in the procedure being performed in the right lateral decubitus position to allow for better access to the airway during the surgery. The TEE examination revealed that the right-ventricular function had returned to baseline. The airway required suctioning multiple times throughout the procedure for bloody airway secretions, but LVAD flow rates remained steady at approximately 5.7 LPM throughout the remainder of the surgery. The SpO2 monitoring did function intermittently and indicated no oxygen desaturations during those periods. The SctO2 was reliable throughout the case and was stable. At the conclusion of the operation, the patient was transported back to the cardiothoracic ICU by the anesthesiologists, surgeons, and the LVAD nurse with the device running on battery power. DISCUSSION
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Mar 28, 2012
J.D Schmitto + 7
Open Access