Seong In Chi

Spatio-temporal dynamics of multimodal EEG-fNIRS signals in the loss and recovery of consciousness under sedation using midazolam and propofol

On sedation motivated by the clinical needs for safety and reliability, recent studies have attempted to identify brain-specific signatures for tracking patient transition into and out of consciousness, but the differences in neurophysiological effects between 1) the sedative types and 2) the presence/absence of surgical stimulations still remain unclear. Here we used multimodal electroencephalography–functional near-infrared spectroscopy (EEG–fNIRS) measurements to observe electrical and hemodynamic responses during sedation simultaneously. Forty healthy volunteers were instructed to push the button to administer sedatives in response to auditory stimuli every 9–11 s. To generally illustrate brain activity at repetitive transition points at the loss of consciousness (LOC) and the recovery of consciousness (ROC), patient-controlled sedation was performed using two different sedatives (midazolam (MDZ) and propofol (PPF)) under two surgical conditions. Once consciousness was lost via sedatives, we observed gradually increasing EEG power at lower frequencies (<15 Hz) and decreasing power at higher frequencies (>15 Hz), as well as spatially increased EEG powers in the delta and lower alpha bands, and particularly also in the upper alpha rhythm, at the frontal and parieto-occipital areas over time. During ROC from unconsciousness, these spatio-temporal changes were reversed. Interestingly, the level of consciousness was switched on/off at significantly higher effect-site concentrations of sedatives in the brain according to the use of surgical stimuli, but the spatio-temporal EEG patterns were similar, regardless of the sedative used. We also observed sudden phase shifts in fronto-parietal connectivity at the LOC and the ROC as critical points. fNIRS measurement also revealed mild hemodynamic fluctuations. Compared with general anesthesia, our results provide insights into critical hallmarks of sedative-induced (un)consciousness, which have similar spatio-temporal EEG-fNIRS patterns regardless of the stage and the sedative used.

Dexmedetomidine intravenous sedation using a patient-controlled sedation infusion pump: a case report

Dental treatment under sedation requires various sedation depths depending on the invasiveness of the procedure and patient drug sensitivity. Inappropriate sedation depth may cause patient discomfort or endangerment. For these reasons, patient-controlled sedation (PCS) pumps are commonly used. Patients are able to control the sedation depths themselves by pushing the demand button after the practitioner sets up the bolus dose and lock-out time. Dexmedetomidine is an α-2 adrenoreceptor agonist with sedative, analgesic, and anxiolytic properties. It has been widely used for sedation for its minimal respiratory depression; however, there are few studies on PCS using dexmedetomidine. This study assessed the applicability of dexmedetomidine to PCS.

Effects of airway evaluation parameters on the laryngeal view grade in mandibular prognathism and retrognathism patients

Background Failure to maintain a patent airway can result in brain damage or death. In patients with mandibular prognathism or retrognathism, intubation is generally thought to be difficult. We determined the degree of difficulty of airway management in patients with mandibular deformity using anatomic criteria to define and grade difficulty of endotracheal intubation with direct laryngoscopy. Methods Measurements were performed on 133 patients with prognathism and 33 with retrognathism scheduled for corrective esthetic surgery. A case study was performed on 89 patients with a normal mandible as the control group. In all patients, mouth opening distance (MOD), mandibular depth (MD), mandibular length (ML), mouth opening angle (MOA), neck extension angle (EXT), neck flexion angle (FLX), thyromental distance (TMD), inter-notch distance (IND), thyromental area (TMA), Mallampati grade, and Cormack and Lehane grade were measured. Results Cormack and Lehane grade I was observed in 84.2%, grade II in 15.0%, and grade III in 0.8% of mandibular prognathism cases; among retrognathism cases, 45.4% were grade I, 27.3% grade II, and 27.3% grade III; among controls, 65.2% were grade I, 26.9% were grade II, and 7.9% were grade III. MOD, MOA, ML, TMD, and TMA were greater in the prognathism group than in the control and retrognathism groups (P < 0.05). The measurements of ML were shorter in retrognathism than in the control and prognathism groups (P < 0.05). Conclusions Laryngoscopic intubation was easier in patients with prognathism than in those with normal mandibles. However, in retrognathism, the laryngeal view grade was poor and the ML was an important factor.

Local anesthesia of the temporomandibular joint to reduce pain during mouth opening for dental treatment in a patient with spinal muscular atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive, severe neuromuscular disorder in which degeneration of alpha motor neurons in the spine progressively weakens and ultimately paralyzes the proximal muscles. It occurs in one per 6,000–10,000 infants, and is a genetic disorder with the second-highest mortality rate worldwide. An 18-year-old male patient with SMA was referred for general anesthesia for difficulty in performing dental treatment due to limited mouth opening caused by temporomandibular joint (TMJ) pain. However, the patient had a high risk of general anesthesia complications, so TMJ pain during mouth opening was reduced through local anesthesia of the TMJ. Fortunately, the anesthesia was successful in reducing pain during mouth opening, enabling the patient to receive dental treatment with an adequate mouth opening.

Immediate implant placement for schizophrenic patient with outpatient general anesthesia

The difficult oral healthcare in intellectually disabled patients with poor behavioral control has led to debate over the cost-effectiveness and validity of implant treatment in these patients. The patient in the present report had schizophrenia that had led to poor oral care and severe dental caries in the full mouth. Tooth extraction and a removable prosthesis were planned, but the guardian wanted an implant procedure. Since the guardian showed strong will and cooperation with regard to the patients oral healthcare, extraction followed by immediate implant placement was performed across two rounds of general anesthesia. Since the outcome appears successful, we present this case report. Immediate implant placement after tooth extraction requires fewer surgeries and rounds of general anesthesia, reduces horizontal bone resorption, and can achieve better esthetic results. Therefore, as long as a certain degree of oral care is possible, this can be a positive option for restoration of a partially edentulous mouth, even in intellectually disabled patients.

Anesthetic management for simultaneous drug-induced sleep endoscopy and maxillomandibular advancement in a patient with obstructive sleep apnea

Drug-induced sleep endoscopy (DISE) is used to identify areas of upper airway obstruction, which occurs when patients with obstructive sleep apnea (OSA) snore. DISE enables effective diagnosis and appropriate treatment of the obstruction site. Among surgical treatment methods for OSA, maxillomandibular advancement surgery (MMA) is performed to move a jaw forward; the surgery has a high success rate for OSA treatment. In DISE, anesthetics such as propofol and midazolam must be administered to induce snoring while the patient is deeply sedated for an accurate diagnosis to be made. When inducing deep sedation in a patient with OSA, airway obstruction may increase, causing oxygen saturation to drop; airway interventions are necessary in such cases. Effective DISE and MMA surgery can be performed by administering propofol through target-controlled infusion while monitoring the bispectral index (BIS).

Deep sedation for dental treatment in a Down syndrome patient with Eisenmenger syndrome: A case report

Eisenmenger syndrome (ES) is characterized by pulmonary arterial hypertension and right-to-left shunting. The signs and symptoms of ES include cyanosis, shortness of breath, fatigue, hemoptysis, and sudden death. In patients with ES, it is important that the systemic and pulmonary circulations be properly distributed and maintained. General dental treatment is not known to be particularly dangerous. To control pain and anxiety, local anesthetics without epinephrine are usually recommended. However, in cases of difficulty of cooperation, general anesthesia for dental treatment makes the condition worse. In the present case, intravenous deep sedation with propofol and remifentanil was administered for behavioral management during dental treatment successfully.

Use of ADMS™ during sedation for dental treatment of an intellectually disabled patient: a case report

Dental treatment is often performed under general anesthesia or sedation when an intellectually disabled patient has a heightened fear of treatment or has difficulty cooperating. When it is impossible to control the patient due to the severity of intellectual disability, conscious sedation is not a viable option, and only deep sedation should be performed. Deep sedation is usually achieved by propofol infusion using the target controlled infusion (TCI) system, with deep sedation being achieved at a slightly lower concentration of propofol in disabled patients. In such cases, anesthesia depth monitoring using EEG, as with a Bispectral Index (BIS) monitor, can enable dental treatment under appropriate sedation depth. In the present case, we performed deep sedation for dental treatment on a 27-year-old female patient with mental retardation and severe dental phobia. During sedation, we used BIS and a newly developed Anesthetic Depth Monitor for Sedation (ADMS™), in addition to electrocardiography, pulse oximetry, blood pressure monitoring, and capnometry for patient safety. Oxygen was administered via nasal prong to prevent hypoxemia during sedation. The BIS and ADMS™ values were maintained at approximately 70, and dental treatment was successfully performed in approximately 30 min..

Identifying the more suitable nostril for nasotracheal intubation using radiographs

Background One nostril must be selected for nasotracheal intubation. In some cases, structural anomalies within the nasal cavity hinder the insertion of the tube or complications, such as epistaxis, develop. This study examined the possibility of using radiography to select the nostril that would induce fewer complications. Methods Four hundred and five patients who underwent nasotracheal intubation under general anesthesia were studied. A 7.0-mm internal diameter nasal right angle endotracheal (RAE) tube and 6.5-mm internal diameter nasal RAE tube were inserted into men and women, respectively. Complications were considered to have developed in cases in which insertion of the tube into the nasal cavity failed or epistaxis occurred. The tube was inserted into the other nostril for insertion failures and hemostasis was performed in cases of epistaxis. The degree of nasal septal deviation was determined from posteroanterior skull radiographs or panoramic radiographs; the incidence of complications was compared depending on the direction of the septal deviation and the intubated nostril. Results The radiographs of 390 patients were readable; 94 had nasal septum deviation. The incidence of complications for cases without nasal septum deviation was 16.9%, that for cases in which the tube was inserted into the nostril on the opposite side of the deviation was 18.5%, and that for cases in which the tube was inserted into the nostril with the deviation was 35.0%, showing a high incidence of complications when intubation is performed through the nostril with septum deviation (chi-square test, P < 0.05 ). Conclusions Although there were no differences in the incidence rates of complications between intubation through the left nostril and that through the right nostril, radiological findings indicated that incidence of complications significantly increased when the tube was inserted into the nostril with the septum deviation.

Factor XI deficiency and orthognathic surgery: a case report on anesthesia management

Factor XI deficiency (Hemophilia C) is a very rare autosomal recessive bleeding disorder. Patients with factor XI deficiency do not typically show any spontaneous bleeding or specific symptoms. Sometimes those who have this disorder are identified during special situations such as trauma or surgery. Orthognathic surgery is particularly associated with a high bleeding risk. Therefore, great care must be taken when treating patients with bleeding disorders such as factor XI deficiency. There are a few reports that address the management of patients with bleeding disorders during orthognathic surgery. The current report describes a patient with factor XI deficiency who underwent Le Fort I osteotomy together with bilateral sagittal split osteotomy. The patients condition was assessed using both rotation thromboelastometry (ROTEM™) and noninvasive measurements of total hemoglobin (SpHb) using Masimo Radical 7 (Masimo Co. CA, USA).