We obtained written informed consent from the patient and one of her parents for publication of this case report. The manuscript adheres to the CAse REport (CARE) guidelines.
The patient was a 30-year-old woman, with a height of 140 cm and weight of 40 kg. She was born with a low birth weight. A chromosomal test was performed after birth, and she was diagnosed with 21 monosomy, although the details of chromosomal defect are unclear. She had a history of hospitalization for pneumonia as an infant but had not had any illness requiring hospitalization since then, and there was no family history. Her intellectual level was equivalent to a 5-year-old child due to mental retardation. She was scheduled for total laparoscopic hysterectomy and bilateral salpingo-oophorectomy for a uterine cervical tumor. Preoperative airway assessment revealed that cervical retroflection was normal, but the interincisal distance was 3 cm, the mandible was retracted and difficult to protrude, and the Mallampati score was class IV, and airway assessment using the modified Arné score showed a simplified score of 21, indicating that tracheal intubation would be difficult . Mallampati score class IV and mandibular advancement difficulties were risks of mask ventilation difficult. Preoperative examinations including blood test, electrocardiogram, chest X-ray, and transthoracic echocardiography showed no significant findings. The patient had exercise tolerance of more than 4 metabolic equivalents.
General anesthesia with epidural anesthesia was planned. We considered that general anesthesia with total intravenous anesthesia using propofol should be performed because of the possibility of skeletal muscle disease since abnormal muscle tone has been reported as one of the symptoms of monosomy 21 . In addition, tracheal intubation with McGRATH™ MAC (Covidien, Dublin, Ireland) after general anesthesia induction was planned for airway management.
The patient entered the operating room calmly without any problems. After entering the room, standard American Society of Anesthesiologists monitors including a percutaneous oxygen saturation monitor, electrocardiogram, and noninvasive blood pressure monitor were attached, and a venous catheter was inserted. Administration of oxygen at 6 L/min was then started, and a bispectral index monitor was placed on the patient’s forehead. Muscle relaxation monitoring was performed using TOF watch® (Organon Ireland Limited, Organon, Ireland). An electrode was attached to the ulnar side of the patient’s left forearm to monitor the ulnar nerve-maternal adductor muscle. We started target-controlled infusion of propofol at an effect site concentration of 5.0 μg/ml in addition to remifentanil 0.15 μg/kg/min. Train-of-four (TOF) monitoring was performed when the bispectral index fell below 60 and a TOF count of 4/4 was confirmed. Mandibular elevation was difficult, and the interincisal distance was about one fingerbreadth. Moreover, her oral cavity was almost completely occupied by the tongue. Since mask ventilation was difficult, 30 mg (0.75 mg/kg) of rocuronium was immediately administered. Mask ventilation became easier with a tidal volume of approximately 200 ml after administration of rocuronium. Since insertion of a McGRATH™ MAC blade size 3 was impossible because of the restriction of mouth opening, tracheal intubation using a bronchial fiber was performed with caregiver elevation of the mandible. Oxygenation was maintained during the intubation procedure. An epidural catheter was inserted at the Th12/L1 level. We decreased the target concentration of propofol to 2.7 μg/ml, while infusion rate of remifentanil was unchanged during surgery for maintaining BIS between 40 and 60. A TOF count of 4/4 was confirmed about 50 min after the first dose of muscle relaxant, and muscle relaxation was maintained with 10 mg rocuronium administered every 30 mins.
No major problems occurred in anesthesia management during the surgery. The anesthesia time was 4 h and 5 min, and the operation time was 2 h and 5 min. After completion of the operation, remifentanil infusion was discontinued, and 80 mg of sugammadex was intravenously administered. Propofol infusion was discontinued after confirming adequate tidal volume (more than 300 ml) under 5 cmH2O of pressure support and 4 cmH2O of positive end expiratory pressure. The patient was then extubated when body movements were observed. After extubation, no abnormalities were observed in respiratory and circulatory states. The patient was transferred to the hospital ward. Postoperatively, no anesthesia-related complications were observed, and the patient was discharged 7 days after surgery.