The anesthetic experience of implantable left ventricular assist device insertion: a case report
A 75-year-old man (height, 165 cm; weight, 49.5 kg) was admitted for the medically-untreatable congestive heart failure. At 63 years of age, he underwent the aortic valve replacement with Medtronic Hall valve (Medtronic, Inc, Minneapolis, MN, USA) due to severe aortic regurgitation of rheumatic origin. A year after the operation, congestive heart failure was induced by tachycardia. Acute renal failure was wax and wane, according to his condition. He was taking warfarin and platelet aggregation inhibitor. His prothrombin time was 1.52 INR and platelet count was 7,5000/µl. Implantable LVAD insertion was decided as a better therapeutic option than cardiac transplantation because of his old age.\nDobutamine (3 µg/kg/min) had been continuously administered to stabilize vital sign from the ward. On arrival at the operating room, his blood pressure (BP) was 87/55 mmHg and the heart rate was 55 beats/min with atrial fibrillation. An invasive arterial catheter was placed in a radial artery with local anesthetic infiltration. Anesthesia was induced with 20 mg of etomidate, 50 mg of rocuronium, 50 µg of sufentanil and maintained with 1-2% isoflurane-medical air-O2 (fraction of inspired oxygen, 50%). BP immediate after the tracheal intubation () was 70/40 mmHg, but overcame within 3 min after using 20 mg of ephedrine, 20 µg of epinephrine and increasing in dose of continuous dobutamine infusion up to 10 µg/kg/min. Tidal volume was set at 8-10 ml/kg of ideal body weight and respiratory rate was adjusted 6-14/min to maintain arterial carbon dioxide tension at 35-45 mmHg. Mechanical ventilation was continued at 5 cycles/min with tidal volume of 5ml/kg of ideal body weight during cardiopulmonary bypass (CPB) for preventing atelectasis and ischemia reperfusion injury to the lung []. A pulmonary arterial catheter was inserted through the right internal jugular vein to monitor pulmonary artery pressure and obtain hemodynamic profiles, such as cardiac output and mixed venous O2 saturation, and placement of a TEE probe was performed.\nHis left ventricular (LV) ejection fraction was 20% by Simpson's method and the prosthetic valve was well-functioning on TEE. Severely dilated LV internal diameter was 69 mm at the end of contraction and mitral valve tethering with mitral regurgitation was observed. Before initiating CPB, atrial septal defect or patent foramen ovale was evaluated by TEE using agitated saline injection. Agitated saline test was done with pulmonary artery squeezing and confirmed absence of the right to the left shunt.\nRedosternotomy was extended into the upper abdomen. Blood pump pocket was secured below the diaphragm within the abdominal muscles. Outflow graft was anastomosed to the side of the proximal ascending aorta with partial clamping. Activated clotting time (ACT) was 688 sec after 150 mg of heparin administration and CPB flow rate was maintained with 4.2 L/min. Maze operation for atrial fibrillation was also implemented and the mechanical aortic valve was closed by over-sewing both sides of the valve with dacron patches. Using circular blade, LV apex was perforated parallel to the septum, and apical ring was completely inserted into the LV apex after apical muscle resection. Inflow conduit was put into the apical ring and prepared purse string suture enabled the ring tightened.\nAfter implantation, TEE showed the correct placement of inflow cannula near the LV apex () and no evidence of mitral regurgitation or right ventricular (RV) dysfunction. Twenty parts per million (PPM) of inhaled nitric oxide, 0.38 µg/kg/min of milrinone, and 2 µg/kg/min of isoproterenol were started to use before CPB weaning for preventing RV dysfunction after LVAD placement. In addition, 5 µg/kg/min of dobutamine, 0.2 mcg/kg/min of norepinephrine and 6 IU/h of vasopressin were used to manage hypotension and to prevent vasoplegia. After weaning from CPB, protamine 120 mg was slowly injected and ACT was checked 117 sec. Surgeons, anesthesiologists and perfusionists closely communicated volume status to maintain sufficient LVAD flow because of massive bleeding. Volume status was evaluated overall by a visual inspection of the heart, TEE and mixed venous O2 saturation. Estimated bleeding was 5000 ml and 7 units (U) of red blood cell (RBC), 5 U of fresh frozen plasma, 23 U of cryoprecipitate, and 2 U of plateletpheresis concentrate were transfused. A total of 4 gm of tranxaminic acid was injected.\nAfter surgery, he was transferred to the intensive care unit, and ongoing bleeding from the chest tube was 2 L during the first 3hours of admission. Coagulation studies identified no severe coagulopathy showing INR 1.42, ACT 135 sec, fibrinogen 236 mg/dl and platelet count 74,000/µl. Reoperation was immediately performed and LV apical site bleeding was successfully controlled. Extubation was done at 15 hours after the reoperation and he was moved to the general ward on postoperative day 10, without significant complications.