Remifentanil for Awake Thoracoscopic Bullectomy

Abstract

We report a case of video-assisted thoracoscopic surgery (VATS) performed under epidural anesthesia in a patient with acute respiratory failure. In this patient, remifentanil was infused alone not to sedate the patient but to slow his respiratory rate while keeping him awake. A 61-year-old man was brought to the emergency room complaining of left-sided chest pain. This patient had been on home oxygenation and steroid therapy for cystic fibrosis since he was 60 years old and was diagnosed as having left-sided lung cancer. After chemotherapy was initiated, he suffered from lung infection with the subsequent development of acute respiratory failure. When an increased dose of steroid was initiated, he suddenly had left-sided chest pain and dyspnea. A computed tomography scan showed multiple bilateral bullae. Although 2 chest tubes were inserted for 3 days, there was massive persistent air leakage, and his arterial oxygen tension was 86.2 mmHg under 70% of oxygen inspiration. Because the left lung did not completely expand, video-assisted thoracoscopic bullectomy was scheduled. Because the patient had multiple bilateral bullae, we planned video-assisted thoracoscopic bullectomy under epidural anesthesia. An epidural catheter was placed at the Th 4/5 level and 30 mL of 0.5% ropivacaine were injected into the epidural space to achieve somatosensory and motor block at the T1 to T8 level while preserving diaphragmatic respiration. The surgical procedure was performed with the patient in the supine position. Because the patient had tachypnea (respiratory rate 32/min) caused by respiratory failure, the surgeon requested to decrease the respiratory rate for safety during the surgical procedure. Confirming that the patient did not have hypercapnea (PaCO2: 42 mmHg), a continuous infusion of remifentanil was initiated to slow the respiratory rate while keeping the patient awake. The patient's respiratory rate gradually decreased from 30/min to 15/min by increasing the dose of remifentanil from 0.005 μg/kg/min up to 0.06 μg/kg/min. A continuous infusion of phenylephrine was initiated as blood pressure gradually decreased by increasing the dose of remifentanil. Even at 0.06 μg/kg/min of remifentanil infusion, the patient was still awake and able to take deep breaths or speak loudly, whereas the respiratory rate decreased to 15/min and PaCO2 reached 52.8 mmHg (pH = 7.382, PaO2 = 106.7 mmHg). At the time of bulla resection, the surgeon requested apnea for a moment. After 100% oxygen inhalation, a bolus dose of 10 μg of remifentanil was injected and the respiratory rate decreased to 6/min, whereas PaCO2 reached 70.6 mmHg (pH = 7.309, PaO2 = 185.5 mmHg). The bulla was safely resected, and the respiratory rate returned to 15/min within 1 minute after the remifentanil bolus. Traditionally, VATS is performed under general anesthesia, with the use of double-lumen endobronchial intubation and single-lung ventilation. To avoid the risks of general anesthesia with one-lung ventilation, VATS under local or epidural anesthesia has been performed in high-risk patients1Mineo T.C. Epidural anesthesia in awake thoracic surgery.Eur J Cardiothorac Surg. 2007; 32: 13-19Crossref PubMed Scopus (80) Google Scholar, 2Mukaida T. Andou A. Date H. et al.Thoracoscopic operation for secondary pneumothorax under local and epidural anesthesia in high-risk patients.Ann Thorac Surg. 1998; 65: 924-926Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar, 3Nezu K. Kushibe K. Tojo T. et al.Thoracoscopic wedge resection of blebs under local anesthesia with sedation for treatment of a spontaneous pneumothorax.Chest. 1997; 111: 230-235Crossref PubMed Scopus (84) Google Scholar and has been shown to provide faster postoperative recovery for minimally invasive thoracoscopic surgery. Pompeo and Mineo4Pompeo E. Mineo T.C. Awake pulmonary metastasectomy.J Thorac Cardiovasc Surg. 2007; 133: 960-966Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar combined thoracic epidural anesthesia with a continuous propofol infusion for awake pulmonary metastasectomy. In addition to sedative drugs, opioids have been successfully added for analgesia and sedation. Gravino et al5Gravino E. Griffo S. Gentile M. et al.Comparison of two protocols of conscious analgosedation in video-assisted talc pleurodesis.Minerva Anestesiol. 2005; 71: 157-165PubMed Google Scholar reported that monitored anesthesia care using midazolam and a continuous infusion of both sufentanil and remifentanil gave satisfactory analgesia and sedation for video-assisted talc pleurodesis.5Gravino E. Griffo S. Gentile M. et al.Comparison of two protocols of conscious analgosedation in video-assisted talc pleurodesis.Minerva Anestesiol. 2005; 71: 157-165PubMed Google Scholar In this case, in addition to thoracic epidural anesthesia, we used remifentanil, a titratable opioid with quick onset and washout, in order to slow the respiratory rate during bulla resection. The patient was kept awake during the procedure. As expected, the continuous infusion of remifentanil gradually slowed the respiratory rate in a dose-dependent manner. In addition, a bolus dose of 10 μg of remifentanil safely decreased the respiratory rate to 6/min, with quick recovery to 15/min within 1 minute. The decreased respiratory rate was accompanied by the development of hypercapnia, which was of little physiologic consequence in the presence of generous supplemental oxygen.