Letters to the Editor: Letters & Announcements
To the Editor:
Total IV anesthesia (TIVA) may preclude the need for muscle relaxants in patients with myasthenia gravis. With IRB approval and written informed consent we anesthetized five myasthenic patients with concurrent remifentanil and propofol infusions for elective, right, video-assisted thoracoscopic (VAT) thymectomy, including placement of the double-lumen endotracheal tube without the use of muscle relaxants.
Patients continued their dose of pyridostigmine up to and including the morning of surgery. We administered IV glycopyrrolate 0.4 mg before anesthesia induction. Anesthesia was induced with propofol 2 mg/kg and remifentanil 2 μg/kg, immediately followed by infusions of propofol, 10 mg · kg−1 · h−1, and remifentanil, 0.5 μg · kg−1 · min−1. We ventilated the patient’s lungs by mask, and approximately 1 min later intubated the patient’s trachea with an appropriately sized left-sided double-lumen endotracheal tube. The anesthesiologist assessed the ease of mask ventilation, jaw relaxation, laryngoscopy, vocal cord position, and patient response to intubation (coughing, limb movement). Table 1 compares patients, disease status, and intubating conditions. The procedure was then performed using one-lung ventilation. The lung was ventilated without difficulty or excessive pressure. We infused propofol at 10 mg · kg−1 · h−1 for the first 10 min, 8 mg · kg−1 · h−1 for the next 10 min, and then at 5–6 mg · kg−1 · h−1 for the duration of the procedure. Remifentanil was maintained at 0.5 μg · kg−1 · min−1 throughout the procedure. At chest closure, the propofol rate was decreased to 4 mg · kg−1 · h−1 and the remifentanil rate was decreased to 0.25 μg · kg−1 · min−1, which were further reduced to 2 mg · kg−1 · h−1 and 0.15 μg · kg−1 · min−1, respectively, at skin closure. We also administered IV morphine 0.12–0.15 mg/kg and infiltrated the incisions with 0.5% bupivacaine.
Both infusions were stopped at the end of surgery. Within 10 min of ending the infusions every patient was awake and generating adequate tidal volumes. Patients were tracheally extubated in the operating room and monitored overnight in the intensive care unit. None of the patients were excessively sedated or had evidence of respiratory compromise.
A recent report described delayed awakening after administration of sevoflurane and remifentanil anesthesia in a myasthenic patient undergoing transsternal thymectomy (1). Our report does not confirm these findings. Rather, our findings are similar to those of other reports (2–6). Our modest series demonstrates that TIVA with propofol and remifentanil can be successfully used for VAT thymectomy in myasthenic patients at doses that provide good conditions for tracheal intubation (with a double-lumen endotracheal tube) and surgery and preclude the need for muscle relaxants.
Ju-Mei Ng, FANZCA
Department of Anaesthesia & Surgical Intensive Care
Singapore General Hospital, Outram Road
1. Baraka AS, Haroun-Bizri ST, Gerges FJ. Delayed postoperative arousal following remifentanil-based anesthesia in a myasthenic patient undergoing thymectomy. Anesthesiology 2004;100:460–1.
2. Lorimer M, Hall R. Remifentanil and propofol total intravenous anaesthesia for thymectomy in myasthenia gravis. Anaesth Intensive Care 1998;26:210–2.
3. Mekis D, Kamenik M. Remifentanil and high thoracic epidural anaesthesia: a successful combination for patients with myasthenia gravis undergoing transsternal thymectomy. Eur J Anaesthesiol 2005; 22:397–8.
4. Lam S, Slater RM. Total intravenous anaesthesia for oculoplastic surgery in a patient with myasthenia gravis without high-dependency care. Anaesthesia 2003; 58:720–1.
5. Fodale V, Pratico C, Piana F, et al. Propofol and remifentanil without muscle relaxants in a patient with myasthenia gravis for emergency surgery. Can J Anaesth 2003;50:1083–4.
6. Mostafa SM, Murthy BVS, Hughes EO. Remifentanil in myasthenia gravis. Anaesthesia 1998;53:721–2.