Klippel-Feil syndrome (KFS) is a rare disease characterized by a classic triad comprising a short neck, a low posterior hairline, and restricted motion of the neck due to fused cervical vertebrae. We report repeated anesthetic management for orthognathic surgeries for a KFS patient with micrognathia. Because KFS can be associated with a number of other anomalies, we therefore performed a careful preoperative evaluation to exclude them. The patient had an extremely small mandible, significant retrognathia, and severe limitation of cervical mobility due to cervical vertebral fusion. As difficult intubation was predicted, awake nasal endotracheal intubation with a fiberoptic bronchoscope was our first choice for gaining control of the patient's airway. Moreover, the possibility of respiratory distress due to postoperative laryngeal edema was considered because of the surgeries on the mandible. In the operating room, tracheotomy equipment was always kept ready if a perioperative surgical airway control was required. Three orthognathic surgeries and their associated anesthetics were completed without a fatal outcome, although once the patient was transferred to the intensive care unit for precautionary postoperative airway management and observation. Careful preoperative examination and preparation for difficult airway management are important for KFS patients with micrognathia.

Methemoglobinemia is a blood disorder in which an abnormal amount of methemoglobin is produced, and prilocaine is one of the drugs that can cause this disorder. The maximum recommended dose of prilocaine is 8 mg/kg. We report a case of methemoglobinemia caused by the administration of 4.2 mg/kg of prilocaine without other methemoglobinemia-inducing drugs during general anesthesia. A 17-year-old girl with hyperthyroidism and anemia was scheduled to undergo maxillary sinus floor elevation and tooth extraction. The patient's peripheral oxygen saturation (SpO 2 ) decreased from 100% at arrival to 95% after receiving prilocaine with felypressin following induction of general anesthesia. However, the fraction of inspired oxygen was 0.6. Blood gas analysis showed that the methemoglobin level was 3.8% (normal level, 1%–2%), fractional oxygen saturation was 93.9%, partial pressure of oxygen was 327 mmHg, and arterial oxygen saturation was 97.6%. After administration of 1 mg/kg of methylene blue, her SpO 2 improved gradually to 99%, and the methemoglobin value decreased to 1.2%. When using prilocaine as a local anesthetic, it is important to be aware that methemoglobinemia may occur even at doses much lower than the maximum recommended dose.

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Oral surgery can be difficult in patients with chorea-like dyskinesia, which is common in those on long-term levodopa medication for Parkinson's disease, and we know of no conclusive evidence to indicate whether conscious sedation with midazolam is effective in such cases. We report a patient in whom levodopa-induced chorea-like dyskinesia disappeared when midazolam was given intravenously for conscious sedation.

Introduction: Dravet syndrome (DS) is a rare and severe myoclonic epilepsy, with onset commonly occurring in infancy. Seizures are triggered by various causes, including fever, bathing, and light stimulus. DS is refractory to drug treatment. Moreover, status epilepticus (SE) can cause serious encephalopathy and epilepsy-related deaths. There are very few reports of general anesthesia in DS patients. Herein, we report our experience with the anesthetic management of a pediatric patient with DS. Patient concerns and diagnoses: A 5-year-old boy (height, 112 cm; weight, 19 kg) was diagnosed with DS through SCN1A genetic testing, which revealed a de novo novel missense mutation. His medical history included drug-resistant epilepsy, developmental delay, and hypotonia. His seizures tended to be triggered daily by a rise in body temperature (BT), bathing, and light stimulus. He could not receive adequate dental treatment due to DS, although he had previously undergone dental treatment under restraint at the pediatric dentistry department of our hospital. Interventions and outcomes: The patient was scheduled for intensive dental treatment under general anesthesia due to noncooperation, and DS-related limitations. By considering the risk posed by elevated BT, seizure-inducing drugs were avoided, and general anesthesia was completed as planned, uneventfully. Although fluctuation of BT occurred during the procedure, it was finally controlled at the end of anesthesia at about the same level as at anesthesia induction. However, small seizures and a single generalized convulsion were observed accompanied by fever on postoperative day 1. The patient was discharged from the hospital without major problems on postoperative day 3, because of detailed planning and close preoperative cooperation with the attending pediatrician. Conclusion: It is essential to pay attention to managing BT and to avoid drugs that induce seizures during anesthesia for patients with DS. Cautious preoperative planning for anesthesia based on evaluation of the patient and rapid postoperative response in collaboration with the attending pediatrician is necessary in case an epileptic seizure occurs.