先天性QT延長症候群患者の顎変形症手術の周術期管理

抄録

  Congenital long QT syndrome (c-LQTS) is a rare malfunction of cardiac ion channels resulting in impaired ventricular repolarization that can lead to torsades de pointes and sudden death. The management approach depends on the genotype of c-LQTS. Here, we present the safe perioperative management of a patient who underwent two orthognathic surgeries. A 19-year-old woman (144 cm, 47.3 kg) was scheduled to undergo a Le Fort I procedure and a sagittal splitting ramus osteotomy. She had been diagnosed as having c-LQTS genotype 1 (LQTS1) at the age of 6 years based on an observed ECG abnormality and was treated with oral propranolol (60 mg per day). She had no history of syncope or palpitation, but her grandmother had died suddenly and had been diagnosed as having a hereditary factor. The patient’s preoperative ECG showed a sinus rhythm and a long QT (QTc : 461 ms). Propranolol (20 mg) was administered orally at 90 min before the induction of anesthesia. Upon the patient’s arrival in the operating room, standard monitoring devices and direct arterial blood pressure monitoring were applied and defibrillation pads were attached. Her QT interval and serum electrolyte levels were monitored throughout the procedure. Since all halogenated volatile anesthetics are known to prolong the QTc, we selected total intravenous anesthesia (TIVA). General anesthesia was induced and maintained with air oxygen, propofol, remifentanil and rocuronium using a target control infusion pump under BIS monitoring. Her QTc times were within the range of 435-463 ms, and propranolol (2.0 mg) was administrated intraoperatively ; torsades de pointes did not occur during the surgery. After monitoring the patient in the ICU, the tracheal tube was removed the following morning and medication with oral propranolol was started. The efficacy of pharmacological treatment for c-LQTS is known to be genotype specific. Patients with LQTS1 have an increased sensitivity to events provoked by catecholamine ; consequently, they respond well to anti-adrenergic therapy. Although no definitive guidelines outlining the anesthetic management of patients with c-LQTS are available, anesthesiologists should keep in mind that certain anesthetic drugs prolong the QTc, and they should consult with cardiologists regarding the treatment of arrythmias according to the genetic type of LQTS.