An online survey was conducted among dental societies and rural and urban dental clinics in Japan to clarify the status and actual conditions of the in-hospital emergency response system for medical emergencies in dental offices in Japan. The numbers of dental societies and dental offices that responded to the survey were 392 (51.2% response rate) and 392 (25.5% response rate), respectively. Overall, 48.5% of the dental societies had distributed emergency drugs to their members, and 74.5% of the dental offices had emergency medical drugs available. Adrenaline, atropine, and nitroglycerin were the most common drugs distributed by the dental societies and available in dental offices. Among the dental offices surveyed, 5.6% had experience in administering emergency medical drugs. The deployment rates of medical oxygen, biometric monitoring, and AEDs were 82.7%, 66.3%, and 71.5%, respectively. The percentages of dental societies that held training workshops on emergency drug administration and emergency response/resuscitation was 75.8% and 68.9%, respectively. From a medical and ethical standpoint, it is important to have medical emergency drugs and equipment in dental offices and to maintain training to prevent serious life-threatening medical complications and enable an appropriate response when they do occur. Future issues include the selection of emergency medical drugs that can be practically used by dentists and the enhancement of pre- and post-graduate education regarding their use during medical emergencies.

  Arytenoid cartilage dislocation can occur as a complication of tracheal intubation and laryngeal trauma, but there are no reports of the development of this condition as a result of indirect video laryngoscopy. The frequency of arytenoid cartilage dislocation in oral tracheal intubation using a laryngoscope is reported to be about 0.023%-0.11%. In the presently reported case, an anterior dislocation of the left arytenoid occurred after nasal tracheal intubation during the use of an indirect McGRATH^TM MAC video laryngoscope ; the dislocation healed spontaneously with conservative treatment.

  The patient was a 43-year-old female (height, 155 cm ; weight, 40 kg). Bilateral mandibular angulation and implant placement were scheduled under general anesthesia for a diagnosis of mandibular hyperplasia and a mandibular left first molar defect. The tracheal tube was smoothly inserted. Anterior arytenoid cartilage dislocation during tracheal intubation was thought to have occurred due to the tip of the blade of the McGRATH^TM MAC touching the posterior surface of the cricoid cartilage.

  Anterior arytenoid cartilage dislocation was treated conservatively using voice training by breath-holding, vocalization and swallowing, which promotes the movement of the thyroarytenoid muscle, and spontaneously healing occurred. In cases treated using older methods, irreversible changes, such as scar formation, may occur around the joints ; thus, early consultation with an otolaryngologist is recommended.

  Left ventricular non-compaction cardiomyopathy (LVNC) is a disease in which the compaction leading to the formation of the normal myocardial structure during the embryonic period is impaired. LVNC is characterized by a left ventricle with marked trabecular meshwork. The disease can cause heart failure similar to dilated cardiomyopathy, embolism as a result of mural thrombosis, or electrocardiographic abnormalities including a fatal arrhythmia. We report a child with LVNC who exhibited a pronounced QTc prolongation during general anesthesia.

  An eight-year-old boy who was found to have an abnormal electrocardiogram two years earlier and had been diagnosed as having LVNC was scheduled to undergo general anesthesia for the extraction of a mesiodens. His preoperative electrocardiogram showed QTc prolongation (529 ms) with flat or inverted T waves at all leads.

  On the day of surgery, monitoring including electrocardiography, non-invasive blood pressure (NIBP) monitoring, pulse oximetry, and muscle relaxant monitoring were performed. During anesthesia, the QTc and estimated continuous cardiac output (esCCO ; Nihon Kohden, Tokyo, Japan) were also measured. The patient was anesthetized using remifentanil, thiamylal and rocuronium and anesthesia was maintained using with air, O₂, sevoflurane and remifentanil. QTc prolongation (600-650 ms) was observed after the administration of thiamylal and also during awakening. No arrhythmia, such as premature ventricular contraction, and no fluctuations in NIBP, heart rate, or esCCO were observed. His postoperative course was uneventful.

  During anesthesia for children with LVNC and QT prolongation, intraoperative circulatory fluctuations must be monitored, and careful attention must be given to the possible occurrence of arrhythmias. The continuous monitoring of intraoperative QTc and esCCO might be useful.

  Idiopathic hypersomnia (IH) is a chronic neurological disorder affecting sleep regulation and characterized by uncontrollable daytime sleep episodes. We report the anesthetic management of an 18-year-old woman with idiopathic hypersomnia using remimazolam. She had felt excessive daytime sleepiness since the age of 15 years. The patient was diagnosed as having a right mandible ameloblastoma caused by swelling and pain in the right lower gingiva at the age of 16 years. A tumorectomy was scheduled, but it was postponed after she was also diagnosed as having IH. She decided to prioritize her IH treatment and preparing for her university entrance examination. She began started taking modafinil, and she underwent a tumorectomy after university admission. The patient did not take modafinil on the morning of the operation. Anesthesia was induced with remimazolam, remifentanil, and rocuronium, and nasal intubation was performed. The anesthesia was maintained with a continuous infusion of remimazolam and remifentanil. The anesthetic depth was evaluated by electroencephalogram monitoring, including SEF and the bispectral index (BIS). After the completion of the operation, the patient emerged from anesthesia promptly after the administration of flumazenil and was extubated. The patient’s recovery was uneventful, and no excessive sleepiness was observed. IH is a chronic sleep disorder, and the possibilities of a prolonged recovery from general anesthesia, postoperative hypersomnia, and apneic episodes from anesthetic drug sensitivity require attention. Therefore, careful observation is important to avoid intraoperative awareness and/or oversedation after surgery. Although the BIS values were maintained at more than 60 during the surgery, the patient’s vital signs were stable and a spectral edge frequency of 95% was maintained at almost within 14-16 Hz. In conclusion, we report the anesthetic management of a patient with IH who received general anesthesia with remimazolam and remifentanil. Careful monitoring of the anesthetic depth is needed in patients with IH, since the BIS values during remimazolam anesthesia might be higher than those for other anesthetics.

  General anesthesia in patients with Parkinson disease should be performed with caution. Caution is particularly needed when patients with Parkinson disease have been prescribed opioids, since the combination of opioids and MAO inhibitors can cause serotonin syndrome and the use of fentanyl can increase muscle stiffness. The withdrawal of anti-Parkinsonian agents can cause the worsening of symptoms and the development of neuroleptic malignant syndrome, while their continued use may cause intraoperative circulatory changes.

  Here, the case of a 70-year-old male patient with previously diagnosed Parkinson disease who underwent surgical fixation of a left zygomatic and maxillary fracture is reported. The severity of the Parkinson disease was Ⅲ-Ⅳ on the Yahr Scale, and the patient was taking multiple anti-Parkinsonian drugs including dopamine/carbidopa, pramipexole hydrochloride, selegiline hydrochloride, entacapone, and droxidopa. A neurologist instructed the surgical team to limit the use of opioids and to administer levodopa intraoperatively. The patient’s routine medications were continued until the morning of surgery. General anesthesia was induced with intravenous thiamylal sodium, rocuronium bromide, and remifentanil, and the patient was orally intubated. Remifentanil was stopped immediately after intubation. The patient’s blood pressure was controlled with phenylephrine and ephedrine, as appropriate. General anesthesia was maintained with air, oxygen, and sevoflurane ; levodopa was administered intraoperatively. After an uneventful surgery, sugammadex sodium was administered, and the patient was extubated after awakening. Intravenous acetaminophen and flurbiprofen axetil were administered for postoperative analgesia. No worsening of the Parkinson disease symptoms was observed after the operation.

  In this case, we report a good surgical outcome with minimal opioid use and the continued perioperative administration of antiparkinsonian agents.

  Immunoglobulin A (IgA) deficiency is an immunodeficiency disease with an approximate prevalence of 0.007% in Japan. Although most IgA-deficient individuals are asymptomatic, some develop recurrent infections, allergy, and autoimmune disease. IgA, which plays an important role in mucosal immunity, protects against infections of the mucous-secreting membrane lining the mouth, nasal sinus, respiratory tract, and digestive tract. Since dental procedures can cause bleeding and create openings where bacteria can enter the systemic circulation, perioperative infections are a key consideration in managing patients with IgA deficiency.

  We report the case of a 5-year-old girl with IgA deficiency who underwent dental treatment including the extraction of 18 primary teeth under general anesthesia. She had undergone a detailed examination at the age of 4 years because of recurrent episodes of cellulitis, and she was diagnosed as having an IgA deficiency. During the currently reported dental treatment, anesthesia was induced with nitrous oxide, oxygen, and sevoflurane, then maintained with propofol and remifentanil. After 2 minutes of nasal packing with 0.5% povidone iodine along with 0.01% adrenaline solution, nasotracheal intubation was performed using a video laryngoscope. Prior to extubation, the oral cavity was washed with chlorhexidine. The following perioperative antibiotics were administered : 900 mg of amoxicillin (p.o.) 2 hours before surgery, 700 mg of ampicillin (i.v.) immediately before surgery, and 200 mg of amoxicillin (p.o.) three times a day for 4 days following surgery. The perioperative course was uneventful, and the patient was discharged one day after treatment. No symptoms of infection occurred during hospitalization or the post-discharge follow-up period.

  Dental treatment and systemic perioperative management should be cautiously performed in IgA-deficient patients.

  In 2019, total temporomandibular joint replacement (TJR) for severe TMJ disease received medical approval in Japan. We report two cases in which TJR was performed under general anesthesia. Case 1 was a 74-year-old woman with a maximum mouth opening of 20 mm. General anesthesia was induced with remifentanil, sevoflurane, propofol, and rocuronium, and fiberoptic intubation was performed. Case 2 was a 43-year-old woman with a maximum mouth opening of 7 mm. Fiberoptic intubation was performed under sedation with fentanyl and propofol. Both operations were completed uneventfully. The patients’ postoperative mouth opening ranges were 35 mm and 15 mm, respectively.

  TJR consists of joint reconstruction involving the replacement of the condyle of the mandible and part of the temporal bone with artificial materials. Hemorrhage is a complication of TJR that can cause trismus and airway problems. Not using drain tubes for infection prevention increases the risk of hematoma. The necessary incision is larger than that required for TMJ mobilization, increasing the risk of bleeding and the operative time. The inferior border of the mandible contains the mandibular branch of the facial nerve and the facial artery, which can be damaged by the operation. Even after TJR, trismus can persist, especially in cases with severe TMJ ankyloses, and re-intubation after the operation is not always easy. The perioperative management of TJR has these specific risks that differ from those of open surgery for TMJ mobilization, and adequate preparation is necessary.

  Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant disorder that is clinically characterized by progressive ataxia, dysarthria, and the eventual deterioration of bulbar functions. A 43-year-old man (height, 171 cm ; weight, 54 kg) with SCA1 was scheduled to undergo an open reduction and internal fixation of a mandibular fracture under general anesthesia. The clinical manifestations of this patient included gait disturbance, dysarthria, dysphagia, oculomotor deficits and anxiety disorder. A preoperative fiberoptic laryngeal examination revealed that his vocal cord was not paralyzed. A video laryngoscope and bronchial fiberscope were prepared before the induction of anesthesia in case of a difficult tracheal intubation and to evaluate the vocal cord movements after emergence from anesthesia. After the placement of a radial arterial line and electrodes for neuromuscular monitoring, general anesthesia was induced with propofol and remifentanil. The initial dose of rocuronium was titrated using neuromuscular monitoring, and nasotracheal intubation was performed with a McGRATH^TM MAC video laryngoscope. General anesthesia was maintained with desflurane and remifentanil. Etilefrine and phenylephrine were continuously administered to avoid hypotension, which could have been induced by autonomic neuropathy. The surgery was completed uneventfully. Acetaminophen was used for postoperative pain relief instead of opioids. After extubation, the patient had no symptoms of vocal cord paralysis and was transferred to the ICU. When anesthetizing patients with SCA1, perioperative evaluation of the airway and preparation for anticipated difficult airway management are crucial.

  Myhre syndrome (MS) is a rare genetic connective tissue disorder first reported in 1981 ; its clinical characteristics include intellectual disability, growth deficiency, muscular pseudohypertrophy, hearing loss, restricted joint mobility, laryngotracheal stenosis, choanal stenosis, and facial deformities such as short palpebral fissures, mid-face hypoplasia, prognathism, and a narrow mouth. Here, we report a difficult tracheal intubation during the induction of general anesthesia in a patient with MS.

  The patient was a 17-year-old female with MS (height, 132 cm ; weight, 38 kg) who was scheduled to undergo dental treatment under general anesthesia. No cardiopulmonary complications had been diagnosed. Midazolam was administered orally as a pre-anesthetic medication because of the patient’s intellectual disability. After the rapid induction of the general anesthesia, mask ventilation was easily performed. A tracheal tube was inserted via the right nostril with no resistance, allowing nasotracheal intubation. We then attempted to perform endotracheal intubation using video laryngoscopes (GLIDESCOPE^®, McGRATH^TM) but failed because of trismus, macroglossia, and difficulty with neck flexion. We finally succeeded in intubating the patient using a bronchial fiberscope. General anesthesia was maintained uneventfully, and no complications were observed during the postoperative period.

  The clinical manifestations mentioned above should be considered when airway management during general anesthesia is required in patients with MS. Additionally, intubation trauma can reportedly cause or exacerbate airway stenosis due to progressive fibrosis. Elective surgeries should be avoided in patients with MS whenever possible ; if unavoidable, endotracheal intubation should be approached with great caution to avoid this situation.

  Depth-of-anesthesia monitors are very useful for evaluating the degree of sedation during intravenous sedation. The Bispectral Index (BIS) and Patient State Index (PSI), which are indices of anesthesia depth, can be measured using a BIS monitor and SedLine^®, respectively. However, appropriate PSI values for intravenous sedation during dental procedures have not been determined. In this study, we evaluated PSI values during intravenous sedation.

  Patients aged >20 years and with an American Society of Anesthesiologists physical status of 1-2 who were scheduled to undergo dental treatment involving intravenous sedation were assessed for eligibility, and a case-series study was conducted. During the dental treatment, a dental anesthesiologist maintained the Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) score at 3-4 by adjusting the administration of sedatives ; however, the dental anesthesiologists were blinded to the patients’ PSI values. The MOAA/S score and PSI during dental treatment and the patients’ satisfaction with sedation were investigated.

  Twenty-six patients were enrolled in this study. The mean (SD) and median (25th percentile, 75th percentile) PSI during dental treatment were 72.7 (13.6) and 75 (65, 85), respectively. Twenty-four patients (92%) stated that the sedation provided was satisfactory.