Managing patients with end-stage heart failure with a HeartMate II left ventricular assist device (LVAD) can be challenging for many reasons. The most prevalent perioperative anesthetic concerns are the patients’ dependence on preload especially in the setting of compromised right heart function and their anticoagulation status, which both discourage the use of neuraxial anesthesia. In 2014, Trunfio et al1 successfully managed an anticoagulated LVAD patient with an upper extremity septic joint using an ultrasound-guided axillary block. Similarly, we used a regional technique by blocking the femoral, sciatic, lateral femoral cutaneous, and obturator nerves that allowed us to achieve a surgical block while avoiding the use of general or neuraxial anesthesia. The patient provided written permission for publication of this report.
The patient was a 68-year-old man, weighing 101 kg, with a medical history of paroxysmal atrial fibrillation, paradoxical ventricular tachycardia, and nonischemic cardiomyopathy with end-stage heart failure status after a bridge-to-transplant LVAD and automated implantable cardioverter-defibrillator placement, requiring maintenance of therapeutic anticoagulation with apixaban, which the patient had last taken the day before surgery.
On arrival, he was bridged with intravenous (IV) heparin, which continued until 4 hours before performing the nerve blocks. Because of multiple infections within the pump pocket with Propionibacterium acnes, the patient underwent 3 LVAD pump exchanges within the past year, having the last one replaced 2 months ago. The patient had been on a 6-week course of IV vancomycin and penicillin. His transthoracic echocardiogram from 6 days before surgery showed an ejection fraction of <0.15 and a moderately reduced right ventricular ejection fraction. The patient showed no signs of current LVAD pump infection. His laboratory values were as follows: hemoglobin 13.0 g/dL, hematocrit 39.1%, platelets 207,000/μL, prothrombin time 12.2 seconds, partial thromboplastin time 35.7 seconds, and international normalized ratio 1.1.
The patient had undergone a left total knee arthroplasty in 2006 with no complications until a few days before his current admission, when he experienced increased edema, erythema, and pain in his left knee. The synovial fluid culture never grew a specific organism, but the aspirate revealed a white blood cell count of >6000 × 109/L with a high neutrophil count, which was concerning for septic joint in the setting of his clinical presentation and history of previous LVAD pump infections.
The patient was transferred from a local hospital that day and brought to the operating room for an urgent tibial insert exchange and IV antibiotic administration. We planned on providing surgical anesthesia via a regional technique by blocking the 4 nerves innervating the knee: the femoral, sciatic, lateral femoral cutaneous, and obturator nerves.
The patient received midazolam 2 mg IV in the preoperative area for sedation before performance of the nerve blocks. We first blocked the subgluteal sciatic nerve with 20 mL of 1.5% mepivacaine using both nerve stimulation and ultrasound guidance. We then blocked the femoral nerve with 20 mL of 0.5% ropivacaine using ultrasound guidance. The lateral femoral cutaneous nerve was blocked with 10 mL of 1.5% mepivacaine using ultrasound guidance. Last, the anterior and posterior branches of the obturator nerve were each blocked with 5 mL of 1.5% mepivacaine using both ultrasound guidance and nerve stimulation.
Nerve block assessment in the operating room showed sensory blocks in the distribution of all 4 nerves blocked reflected by respective insensitivities to pinprick with a 21-gauge blunt needle, complete motor block of knee and foot, and motor block of the adductor muscles of the hip. Next, a right radial arterial line was placed using ultrasound guidance, his automated implantable cardioverter-defibrillator was reprogrammed to asynchronous mode, and external defibrillator pads were placed. Although the LVAD suppressed the pulses, we were able to successfully secure an arterial line using ultrasound guidance. Because the patient requested mild sedation, we administered a propofol bolus of 30 mg followed by a propofol infusion of 30 μg/kg/min. The patient became sedated but continued to respond to verbal stimulation throughout the procedure. If the propofol sedation would have had adverse hemodynamic effects, we were prepared to discontinue it. The total time between the last nerve block in the preoperative area and skin incision in the operating room was 37 minutes. We decided on a target thigh tourniquet pressure of 250 mm Hg based on his baseline mean arterial pressures ranging from 70 to 75 mm Hg. The tourniquet was inflated for a total of 78 minutes, and the entire procedure took 97 minutes. Estimated blood loss was 300 mL, and transfusion of blood products was not required.
The patient neither required vasopressor or inotropic medications during the procedure nor analgesics in the postanesthesia care unit. Approximately 6 hours after the blocks were placed, the patient had sensory return to pinprick on the medial, posterior, and lateral surfaces of the thigh, while his anterior thigh surface remained insensate for an additional 4 hours. The patient complained of mild posterior knee pain, for which oxycodone 5 mg was given. Postoperatively, he was given acetaminophen 650 mg every 6 hours and gabapentin 100 mg every 8 hours. He required oxycodone 5 mg every 4 hours during postoperative day (POD) 1, and then every 6–8 hours during the remainder of his hospitalization.
The cardiology service, who managed the anticoagulation during the perioperative period, restarted IV heparin in the postanesthesia care unit and bridged him back to his home dose of apixaban on POD 2. The patient was discharged on POD 4.
Total knee arthroplasties and revisions are commonly performed safely and effectively using neuraxial techniques. However, given our patient’s significant cardiovascular history, we decided against using neuraxial techniques for 2 reasons: a sympathectomy could be detrimental to this patient in the setting of his LVAD and suboptimal right ventricular function. Furthermore, the patient had taken apixaban the day before surgery, which precludes neuraxial anesthesia according to the American Society of Regional Anesthesia guidelines.2
Perioperative management of LVAD patients undergoing noncardiac surgery can pose many challenges. A retrospective review of 31 patients with LVADs showed that 81% of noncardiac procedures were performed under monitored anesthesia care.3 This review showed 1 patient who underwent neuraxial anesthesia for a cystoscopy, but anticoagulation was discontinued for 48 hours because of excessive hematuria, and his prothrombin time, partial thromboplastin time, and international normalized ratio were all within normal limits before receiving spinal anesthesia.3 Because they are anticoagulated, most LVAD patients are not candidates for neuraxial anesthesia.4
The patient requested regional anesthesia after we explained that either general or regional techniques could be administered safely. If one of the blocks failed or wore off, we were prepared to convert to general anesthesia using etomidate and fentanyl for induction, securing an airway, maintaining anesthesia with sevoflurane, and using vasoactive drugs as needed. There was no change in the mean arterial pressure after the tourniquet was deflated, but had there been a sudden decrease from peripheral vascular dilation, we were prepared to treat with vasopressors. Although it would have been ideal to place the arterial line before the nerve blocks to measure beat-to-beat blood pressures in the setting of possible local anesthetic systemic toxicity with the large doses of local anesthetic given, our objective was to safely place the blocks as soon as possible to achieve surgical anesthesia. If there were any evidence of vascular puncture, hematoma, or lack of local anesthetic spread under ultrasound guidance, our plan was to transition to general anesthesia.
By performing selective peripheral nerve blocks, we avoided the risk of hemodynamic changes associated with general anesthesia, the risks of epidural hematoma, and preload reduction associated with neuraxial anesthesia. It is unclear who managed the anticoagulation at the other hospital. Had apixaban been held for at least 3 days and bridged earlier with IV heparin, a lumbar plexus block or even spinal anesthesia via an intrathecal catheter would have been a viable option.
Although Casati et al5 showed that block onset was slowest with 0.5% ropivacaine compared to 0.75% and 1% and Fanelli et al6 showed that 0.75% ropivacaine has a similar onset than 2% mepivacaine when used for sciatic–femoral nerve blocks, we used 0.5% ropivacaine for the femoral nerve block for 2 reasons: higher concentrations were unavailable, and we have anecdotally observed faster onset of action of local anesthetic on the femoral nerve compared to the other 3. The orthopedic team estimated that this procedure would take <2 hours, and given their expressed urgency, we decided to use mepivacaine for the other 3 nerve blocks. Had we known that we had 37 minutes between the last block and incision, which is longer than we expected, we would have used 0.5% ropivacaine for all nerve blocks to achieve the same intensity with a longer duration of action.
Perioperative management of LVAD patients undergoing orthopedic procedures can be challenging because of many factors, including their hemodynamic dependence on preload and anticoagulation status. We present this case to show that a total knee arthroplasty revision can be safely and effectively done with mild to no sedation by achieving a surgical block with femoral, proximal sciatic, lateral femoral cutaneous, and obturator peripheral nerve blocks.
Name: James K. Kim, MD.
Contribution: This author helped conceive the case report, care for the patient, and write the manuscript.
Name: Van Nguyen, MD.
Contribution: This author helped conceive the case report, care for the patient, and revise the manuscript.
This manuscript was handled by: Hans-Joachim Priebe, MD, FRCA, FCAI.
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