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Psychosedation in clinical dental treatment involves controlling the central nervous system to the degree that the patient does not lose consciousness. This psychosedation eliminates the risk of systemic accidents or aggravation of underlying disease following a stress reaction in dental treatment. Propofol is commonly used for conscious sedation and can produce a dense anterograde amnesia. In this study, to investigate the effect of sedation on visual and memory processing in humans, we investigated the effect of the sedative agent propofol on the BOLD contrast signal obtained during visual stimulation using functional magnetic resonance imaging (fMRI).
Ten healthy adult male volunteers were studied (age : 24–46 yrs (30.9 ± 9.2 yrs), height : 167.1 ± 5.8 cm, weight : 59.5 ± 8.1 kg). The task paradigm was the visual subject load. Each subject performed three cycles of 30 sec of visual subject load and 30 sec of rest. The task paradigm was performed in control, infusion, recovery-10 and recovery-30 periods. In the control period, a resting-state scan and activation fMRI scan were imaged before sedation. In the infusion period, an fMRI scan was imaged on the same task paradigm after propofol was administered and maintained to keep the calculated intracerebral concentration at 1.2 µg/ml. In the recovery-10 period, the recovery-state scans were imaged 10 min after administration was stopped. In the recovery-30 period, the recovery-state scans were imaged 30 min after administration was stopped.
1. In the control period, visual stimulation resulted in a bilateral increase in BOLD signals in the visual cortex (Fig. 2a).
The locations of the most significant foci of activation for these regions are primary/secondary visual cortex (BA17/ 19), middle (BA9)/inferior (BA44) frontal gyrus, precentral gyrus (BA44), superior parietal lobule (BA7), precuneus, cingulate gyrus (BA31) and thalamus (Table 1).
2. In the sedation period, visual stimulation resulted in a bilateral increase in BOLD signals in the visual cortex (Fig. 2b). The signal increased in the secondary visual cortex (BA19), superior frontal gyrus (BA9), middle occipital gyrus and culmen (Table 2).
3. In the recovery-10 period, visual stimulation resulted in a bilateral increase in BOLD signals in the visual cortex (Fig. 2c).
The signal increased in the secondary visual cortex (BA19), cuneus, declive, lingual gyrus and middle occipital gyrus (Table 3).
4. In the recovery-30 period, visual stimulation resulted in a bilateral increase in BOLD signals in the visual cortex (Fig. 2d). The signal increased in the secondary visual cortex (BA18), lingual gyrus, cuneus (BA18), inferior frontal gyrus (BA47) and superior frontal gyrus (Table 4).
5. In the sedation period, changes in the signal intensity in Brodmann area 17/18 fell significantly and there was a significant difference between the control period and sedation period (Fig. 4, ,55).
In conclusion, the results of this study suggest that visual information is suppressed by propofol in the pathway of primary visual input to the visual cortex (V1) and in the course from V1 to the secondary visual cortex (V2).
We report a case of Brugada syndrome with implantable cardioverter-defibrillator (ICD), who happened to be diagnosed by 12-lead electrocardiogram (ECG) during frequent dental treatment under intravenous anesthesia.
The subject was a 26-year-old man who had no specific medical history including family history, current use of drugs, episodes of palpitation, or loss of consciousness. His teeth had been left untreated and not looked after due to extreme dental phobia and gag reflex, so intravenous anesthesia was scheduled for his dental treatment.
He underwent extirpation of pulp and root canal treatment under intravenous anesthesia with a combination of midazolam and propofol eight times. Monitoring ECG (II leads) during anesthesia showed a wide S wave suggesting a right bundle branch block. At the level of anesthesia required to effectively suppress the gag reflex during dental treatment, it was difficult to maintain his upper airway to avoid oxygen desaturation. General anesthesia was considered as an alternative method to secure airway management for extraction of the third molar in the right mandible, so an ECG examination was performed as a routine pre-anesthetic screening. The 12-lead ECG revealed Brugada syndrome and so an ICD was implanted immediately.
However, after the treatment, a malfunction was detected in his ICD response to atrial fibrillation several times, so the ICD was repaired and adjusted, and the patient was also prescribed an arrhythmic drug (bepridil hydrochloride, 100 mg a day), and was prohibited from using adrenergic agents including adrenalin in order to avoid proximal atrial fibrillation.
A further eight dental treatments were performed using 3% propitocaine hydrochloride with 0.03 U felypressin under intravenous anesthesia.
Brugada syndrome sometimes causes sudden death, which may be the first symptom without a history of fainting attacks or ventricular fibrillation. It is strongly recommended that patients with a bundle branch block should be examined by using 12-lead ECG, even if they have had no specific previous medical or family history.
Intravenous sedation (IVS) is increasingly being used during dental treatment because of the multi-modality of compromised diseases and patients' demand for comfort and safety. We retrospectively studied IVS for patients undergoing oral surgery or dental treatment from 2005 to 2009 at the Department of Dental Anesthesiology in the Kyushu Dental College Hospital. Clinicostatistical observations were made on 1,309 cases of IVS during a five-year period. IVS cases showed an overall uptrend. There were more females than males undergoing IVS in each of the years (Fig. 1). IVS cases were managed in the outpatient clinic of the Department of Dental Anesthesiology (Dental Anesthesia), outpatient clinic of the Department of Dentistry for the Handicapped (Dentistry for the Handicapped) and operating room. More patients underwent IVS in Dental Anesthesia than in any other department. The number of handicapped patients undergoing IVS for dental procedures has recently increased markedly (Table 1). The number of patients over 80 years old, children less than 19 years old and adults between 20 and 39 years old has tended to increase (Fig. 2). Patients over sixty years old comprised about half of the patients in the operating room. On the other hand, patients between 20 and 39 years old comprised 51.5% of the patients in Dentistry for the Handicapped (Fig. 3). IVS is thus used over a broad age range. The mean age of all patients showed a decreasing tendency every year. The mean age of patients was the highest in the operating room, being 55.8 years old (Table 2). Patients with risk factors have become more common over the years and recently accounted for half of patients receiving IVS (Fig. 4). Many patients indicated for IVS in 2005 were oral surgery patients, but the types of indicated patients have diversified since then (Table 3). Previously, a majority of patients undergoing IVS were under the care of the Department of Oral Surgery, but IVS has recently become more commonplace elsewhere and is now used routinely in many other departments (Table 4). The duration of surgery was most commonly 30 min or less, and almost all patients underwent surgery within 120 min. The mean duration of surgery was longest in the operating room, at 54.3 min (Fig. 5). Propofol was used in about 80% of patients in 2005, while midazolam was the most common choice for handicapped patients. Many operating room patients received one of these drugs in combination with an analgesic (Table 5). A midazolam-propofol combination was used in about 60% of patients in 2009 because it has good anti-anxiety and amnesic effects (Fig. 6). Complications during surgery affected 241 of the 1,309 patients (18.4%), with respiratory depression as the most common complication (Table 6). There were no serious incidents during IVS. We expect that IVS will be used in increasingly diverse situations. This diversification will necessitate anesthetic management suited to the individual patient.
Gender has been reported to be a factor influencing the pharmacokinetics of benzodiazepines. In the present study, we classified patients who underwent intravenous sedation with midazolam by age into a young group (group Y; age, 15 to 29 years; n = 57) and an elderly group (group E; age, 65 to 79 years; n = 60), and investigated gender differences in the effects of midazolam. Age, height, weight, duration of procedure and anesthesia, the number of treated teeth, and midazolam does were investigated based on anesthesia records. The results showed that among background factors, height and weight were greater for male (p < 0.05) in both groups (Table 1). Although no significant gender differences in the duration of procedure and anesthesia were seen in group Y (44.2 vs 39.9 min/73.0 vs 75.8 min), the duration was significantly longer (p < 0.05) for male in group E (50.9 vs 35.5 min/81.3 vs 64.0 min) (Table 2). Male in group E also had a greater number of treated teeth (2 vs 1 teeth, p < 0.05) (Table 2). As for midazolam dose, in group Y male had a lower dose per body weight than female (0.06 vs 0.09 mg/kg, p < 0.05), while no gender differences were observed in group E (0.05 vs 0.05 mg/kg) (Table 2). The difference observed in group Y was attributed to the fact that the activity of CYP3A4, a metabolic enzyme widely distributed in the liver that metabolizes midazolam, is greater in female due to interactions with female sex hormones, and a greater dose was therefore necessary to achieve the same level of sedation in female. In addition, this difference in midazolam dose may have been absent in group E due to age-related decreases in female sex hormone levels. These results indicate that gender and age must be considered in sedation with midazolam during dental procedure.