The patient was a 15-year-old girl (123.5 cm, 20.5 kg). She was born after a normal delivery. At the age of 1 year and 3 months, after it was noted that she was unable to walk, the patient was determined as having mental retardation. She was diagnosed with Rett syndrome at the age of 2 years and 9 months and developed epilepsy. At the age of 7, she underwent gastrostomy for gastroesophageal reflux under general anesthesia in another hospital. We planned laryngotracheal isolation under general anesthesia due to recurring aspiration pneumonia.
In our preoperative examination, trismus due to hypertonia was detected. It was difficult to force her mouth open manually, but it seemed to open upon intraoral cleaning and yawning, indicating that muscular hypertonia rather than contracture of the temporomandibular joints was the likely cause of trismus. Her respiratory rate at rest was 16 cycles per min. SpO2 in room air was 97%. Since her apneic attacks appeared 2–3 times a night and lasted around 20 s, non-invasive positive pressure ventilation (NPPV) was used at night alone. She had no heart disease, and electrocardiogram abnormalities such as prolonged QT or abnormal T waves were absent. Her epilepsy was well controlled with carbamazepine, zonisamide, and levetiracetam. Mutual communication was difficult due to the patients’ mental retardation, and she showed involuntary movement of her arms, joint rigidity, and scoliosis. Since her preoperative blood test showed that the levels of serum total protein and albumin were 6.1 and 3.6 g/dL, respectively, we judged that her nutritional status was relatively good considering her past course.
On the day of surgery, no premedication was administered. In addition to non-invasive sphygmomanometry, an electrocardiogram, and a SpO2 monitor, we used a bispectral index (BIS) monitor. The BIS level before the induction of anesthesia was 98. Fentanyl was administered intravenously in small increments of 10 μg because these patients may be sensitive to narcotics. Spontaneous ventilation was maintained after the first 10 μg; sursumvergence and weakened spontaneous ventilation were observed after 40 μg was administered. Thereafter, anesthesia was induced with 20 mg of propofol intravenously. After confirming the loss of the eyelash reflex, we initiated 1% sevoflurane administration and ensured that ventilation with a mask was possible. Then, 15 mg of rocuronium was administered intravenously. We initiated the intubation maneuver after confirming that the train-of-four (TOF) level was 0 (from 4). The degree of mouth opening observed was 2 breadths of a finger. Her larynx was visualized using a video laryngoscope (McGRATH™, Covidien, Dublin, Ireland) with BURP (Cormack grade II). The trachea was intubated with a spiral tube (6.0 mm inside diameter) without resistance.
Anesthesia was maintained with air, oxygen, sevoflurane, remifentanil, and fentanyl. Sevoflurane and remifentanil were administered at 1.5% of end-tidal concentration and at 0.15–0.2 μg/kg/min during the operation, respectively. The BIS level was approximately 40. In addition to the adjustment of remifentanil, fentanyl was administered several times (at a dose of 10 μg each time) to prevent the excessive rise in blood pressure. Rocuronium was added with reference to TOF, till the operation was completed. A total of 100 μg fentanyl was administered intravenously. For postoperative analgesia, 20 mg of flurbiprofen and 300 mg of acetaminophen were administered intravenously. The surgical wound was infiltrated with 9 mL of 0.25% ropivacaine. Since the TOF level at the end of surgery was 85%, we administered 40 mg of sugammadex intravenously to reverse the neuromuscular relaxant. After discontinuing remifentanil, spontaneous ventilation resumed immediately. Once we confirmed that there were no abnormal findings in the chest X-ray, administration of sevoflurane was stopped. When the BIS recovered to 60, body movement appeared and the cough reflex at the endotracheal suctioning was confirmed. Hypertonia was occasionally detected by stimulation, but disappeared spontaneously. Clear apneic attacks and systemic convulsions were absent. Since the tidal volume was 200–250 mL and respiratory rate was 15–20 times per min stably, we considered her respiratory status stable and mechanical ventilation was weaned. A heat-moisture exchanger (HME) was attached for the tracheotomy while 1 L of oxygen was administered per min.
Since her SpO2 was constantly 99–100%, she was transferred to the ICU under spontaneous ventilation. She followed a good postoperative course without any complications (such as exacerbated apneic attacks or systemic convulsions) and was discharged 4 weeks later.