Age differences in pain sensitivity and effect of topical lidocaine on the tongue in healthy female subjects.

PURPOSE: To assess the sensitivity and the effect of topical lidocaine on the tongue by quantitative sensory testing, comparing healthy middle-aged female subjects with healthy young female subjects. METHODS: Sixteen healthy female subjects including eight in their fifties and eight in their twenties participated. They participated in two sessions at a 2-week interval in randomized order: lidocaine (experimental session) or placebo gel (placebo session) was applied on the tongue tip for 5min. The following parameters were taken on the tongue tip before and after application of the gel in each session: tactile detection threshold (TDT), filament-prick pain detection threshold (FPT), and numerical rating scale (NRS). RESULTS: An increase of both TDT and FPT and a decrease of NRS were found after lidocaine application in both middle-aged and young female subjects. In the elder females, an increase of TDT, FPT, and NRS was also found after placebo gel application. However, the changes were not statistically significant, except for FPT in middle-aged subjects. CONCLUSION: The reactions found after lidocaine application in middle-aged female subjects could be due to habituation as well as to the post-application effect of placebo gel. Placebo-induced changes appeared more pronounced in the elder females.

A Case Report of Burning Mouth Syndrome with Dry Mouth Managed by Kampo Medicine.

The patient was a 56-year-old woman who complained of chronic pain involving her tongue. We diagnosed her with burning mouth syndrome (BMS) based on exclusion of any local factors or systemic conditions. The patient not only had tongue pain but also had other signs and symptoms like scalloped tongue, dry mouth, and headache. To manage these additional issues, we used Goreisan, an herbal Kampo medicine, as a complementary alternative medicine (CAM) approach along with cognitive behavioral therapy (CBT). The patient's BMS was successfully managed with the combination of CAM and CBT, which may suggest that the pathophysiology for BMS might be nociplastic pain rather than purely nociceptive or neuropathic.

Examination of pain relief effect of Goreisan for glossodynia.

BACKGROUND: Pain in glossodynia may be severe; it may prevent patients from working, interfere with daily life activities, and necessitate a patient's visit to a medical institution for consultation and treatment. The pain may be described as persistent and burning (tingling, tingling) or stinging. Patients may complain of dry mouth (dryness), which is thought to cause inflammation of the tongue and gingival mucous membranes and increased pain. Medications are prescribed based on the symptoms of glossodynia, and the therapeutic effect is confirmed. However, each drug has side effects, for example, pain may reduce, but drowsiness and dizziness may occur; further, there is always a tendency of drowsiness.On the other hand, Goreisan, a Chinese herbal medicine, has already been used by physicians to treat pain in the oral and maxillofacial regions resulting from rapid changes in air pressure. However, the lack of high-quality clinical research has been of concern, and a randomized clinical trial to investigate the efficacy and safety of Goreisan for treatment of pain in glossodynia is warranted. METHODS/DESIGN: This multicenter, randomized, controlled study will involve patients treated for glossodynia-related pain. In the experimental group, Goreisan will be taken for 12 weeks in combination with conventional treatment. Participants in the control group will not take any Kampo medicine; only the standard treatment will be taken. Subsequently, the degree of pain will be assessed, and saliva tests of all the patients on their first visit will be performed. Goreisan will be taken at a dose of 7.5 g/d (minute 3) for 12 consecutive weeks. Twelve weeks later, the degree of pain of each patient will be assessed. DISCUSSION: The purpose of this study is to investigate the efficacy of Goreisan for pain reduction in patients undergoing treatment for glossodynia-related pain. If pain in glossodynia patients can be reduced by the administration of Goreisan, its candidacy as an alternative treatment for pain in glossodynia can be further supported by more reliable research. TRIAL REGISTRATION: The study was registered in the jRCTs071200017. URL https://jrct.niph.go.jp/latest-detail/jRCTs071200017.

The effect of midazolam administration for the prevention of emergence agitation in pediatric patients with extreme fear and non-cooperation undergoing dental treatment under sevoflurane anesthesia, a double-blind, randomized study.

Background: Sevoflurane is generally the preferred anesthetic agent for general anesthesia in pediatric patients, due to its rapid induction and recovery characteristics. However, it has been recognized that a major complication is emergence agitation when awakening from general anesthesia. The aim of this study was to evaluate the occurrence rate of emergence agitation in the operating room and postoperative recovery area following intraoperative administration of midazolam to pediatric patients under general anesthesia. Patients and methods: One hundred and twenty pediatric patients undergoing dental treatment under sevoflurane anesthesia were enrolled in this study. The patients were divided into three groups (n=40 each in the 0.1 mg/kg midazolam, 0.05 mg/kg midazolam, and control with saline groups). Midazolam or saline was injected intravenously approximately 30 minutes before the end of the dental treatment. We used the Richmond Agitation and Sedation Scale (RASS) to assess the level of sedation and drowsiness at emergence phase in the operating room. We also used the Pediatric Anesthesia Emergence Delirium Scale (PAED) to assess the level of agitation and delirium at the full recovery phase from anesthesia in the recovery area. Results: At the emergence phase, the incidence of emergence agitation in the 0.1 mg/kg midazolam group was significantly lower than in the other groups (p=0.0010). At the recovery phase, there was no significant difference among the three groups. The odds ratio between PAED score and RASS score was 4.0 using logistic regression analysis. The odds ratio between PAED score and Disability was 2.5. Conclusion: Administration of a single dose of 0.1 mg/kg midazolam dose significantly decreases the incidence of severe emergence agitation at the emergence after sevoflurane anesthesia, but not at the recovery phase. Furthermore, the evaluation of sedative and agitation condition using RASS score at emergence from anesthesia is useful to predict occurrence of agitation in the recovery phase.

Effect of 8% lidocaine spray on the sensory and pain thresholds of the skin of the face and hands evaluated by quantitative sensory testing.

BACKGROUND: Recently, we examined the effects of 2% lidocaine gel on the tactile sensory and pain thresholds of the face, tongue and hands of symptom-free individuals using quantitative sensory testing (QST); its effect was less on the skin of the face and hands than on the tongue. Consequently, instead of 2% lidocaine gel, we examined the effect of 8% lidocaine spray on the tactile sensory and pain thresholds of the skin of the face and hands of healthy volunteers. METHODS: Using Semmes-Weinstein monofilaments, QST of the skin of the cheek and palm (thenar skin) was performed in 20 healthy volunteers. In each participant, two topical sprays were applied. On one side, 0.2 mL of 8% lidocaine pump spray was applied, and on the other side, 0.2 mL of saline pump spray was applied as control. In each participant, QST was performed before and 15 min after each application. Pain intensity was measured using a numeric rating scale (NRS). RESULTS: Both the tactile detection threshold and filament-prick pain detection threshold of the cheek and thenar skin increased significantly after lidocaine application. A significant difference between the effect of lidocaine and saline applications was found on the filament-prick pain detection threshold only. NRS of the cheek skin and thenar skin decreased after application of lidocaine, and not after application of saline. CONCLUSION: The significant effect of applying an 8% lidocaine spray on the sensory and pain thresholds of the skin of the face and hands can be objectively scored using QST.

Effect of nasal high-flow oxygen therapy on the swallowing reflex: an in vivo volunteer study.

OBJECTIVE: The advantages of nasal high-flow oxygen therapy (NHF) include not only allowing talking, but also eating and drinking, during the therapy. However, the effect of NHF on the swallowing reflex remains unclear. In the present study, we aimed to assess the effects of NHF on the swallowing reflex. METHODS: Nine healthy adult Japanese male volunteers with no history of dysphagia or diseases that may cause dysphagia, such as stroke or Parkinson's disease, were evaluated. Participants received one of four levels of NHF intervention (0 (control), 15, 30 and 45 L/min of oxygen) with the NHF system through the nasal cannula. Swallowing was induced by the administration of a bolus injection of 5 mL of distilled water over 3 s through a polyethylene catheter at each level of oxygen flow. The primary end-point was the latency period of the swallowing reflex after bolus injection, which was defined as the time from the start of the bolus injection to the onset of the electromyogram (EMG) burst of the first swallow. RESULTS: Mean latency times of the swallowing reflex with 15 (9.8 ± 2.9 s), 30 (9.0 ± 2.7 s) and 45 (8.5 ± 3.0 s) L/min of NHF were significantly shorter than those under control conditions (11.9 ± 3.7 s; P < 0.05). CONCLUSIONS: Our study demonstrates that NHF may enhance swallowing function with increasing levels of NHF by reducing the latency of the reflex. CLINICAL RELEVANCE: NHF may allow continuation of oral intake without aspiration during oxygen therapy.

Effect of topical lidocaine in the oral and facial regions on tactile sensory and pain thresholds.

OBJECTIVE: The aim of the present study was to examine the effect of lidocaine application to the face, tongue and hand on sensory and pain thresholds of symptom-free subjects. DESIGN: Eighteen females (mean age 25.7 years, range 22-38) participated. Using Semmes-Weinstein monofilaments, the tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) were measured on the cheek skin (CS), tongue tip (TT) and palm side of the thenar skin (TS). Subjects were tested in 2 sessions at a 1week interval in randomised order. Lidocaine (session A) or placebo gel (session B) was applied for 5min. The TDT and FPT were measured before and after application. RESULTS: The TDT at all sites in session A significantly increased after 5min, but a significant session effect on the TDT was only found at the TT (P<0.01). On the other hand, there were significant session effects on the FPT at all sites (P<0.01). CONCLUSION: These results indicate that the pain threshold (FPT) is more susceptible to local anesthetics than the sensory threshold (TDT), but further study is needed to use topical lidocaine for the control of oral and facial pain in the clinic.

A pilot study of upper airway management using a remote-controlled artificial muscle device during propofol anesthesia.

STUDY OBJECTIVE: To test the hypothesis that the jaw closure using a pneumatic actuator device affect airway collapsibility and resistance during propofol anesthesia. DESIGN: Prospective, randomized study. SETTING: University-affiliated hospital. PATIENTS: Six male subjects were included in the present study. INTERVENTION: We used pressure-flow relationships to evaluate critical closing pressure (PCRIT) and upper airway resistance in different conditions of body and head position. Anesthesia was induced and maintained with a propofol infusion, targeting a constant blood concentration of 1.5 to 2.0µg/mL to establish an adequate depth of anesthesia, with patients breathing spontaneously through a nasal mask. An air-inflatable pneumatic actuator was used to achieve jaw closure. Nasal mask pressure was intermittently reduced to evaluate upper airway collapsibility (passive PCRIT) and upstream resistance under 4 different conditions: (1) neutral occlusion at 0-cm head elevation (baseline), (2) jaw closure at 0-cm head elevation, (3) neutral occlusion at 6-cm head elevation, and (4) jaw closure at 6-cm head elevation. PCRIT and upstream resistance under each condition were compared using 1-way analysis of variance. P<.05 was considered significant. MEASUREMENTS: The pressure and inspiratory flow at the subjects' nose mask were recorded. Polysomonographic parameters (electroencephalograms, electrooculograms, submental electromyograms, and plethysmogram) were also recorded. MAIN RESULTS: The combination of 6-cm head elevation with jaw closure using the pneumatic actuator decreased upper airway collapsibility (PCRIT≈-3.0 cm H2O) compared to the baseline position (PCRIT≈-1.2 cm H2O; P=.0003). CONCLUSION: We demonstrated that jaw closure using an air-inflatable pneumatic actuator device can produce substantial decreases in upper airway collapsibility and maintain upper airway patency during propofol anesthesia.

Comparison of the hemodynamic effects of propofol and ketamine as anesthetic induction agents during high-dose remifentanil administration: a single-center retrospective comparative study.

BACKGROUND: We hypothesized that ketamine, when administered as the anesthetic induction agent, may prevent cardiovascular depression during high-dose remifentanil administration, unlike propofol. To test our hypothesis, we retrospectively compared the hemodynamic effects of ketamine, during high-dose remifentanil administration, with those of propofol. METHODS: Thirty-eight patients who underwent oral surgery at the Nagasaki University Hospital between April 2014 and June 2015 were included in this study. Anesthesia was induced by the following procedure: First, high-dose remifentanil (0.3-0.5 µg/kg/min) was administered 2-3 min before anesthesia induction; next, the anesthetic induction agent, either propofol (Group P) or ketamine (Group K), was administered. Mean arterial pressure (MAP) and the heart rate were recorded by the automated anesthesia recording system at four time points: immediately before the administration of high-dose remifentanil (T1); immediately before the administration of propofol or ketamine (T2); 2.5 min (T3), and 5 min (T4) after the administration of the anesthetic induction agent. RESULTS: In Group P, the MAP at T3 (75.7 ± 15.5 mmHg, P = 0.0015) and T4 (68.3 ± 12.5 mmHg, P < 0.001) were significantly lower than those at T1 (94.0 ± 12.4 mmHg). However, the MAP values in the K group were very similar (P = 0.133) at all time points. The heart rates in both Groups P (P = 0.254) and K (P = 0.859) remained unchanged over time. CONCLUSIONS: We showed that ketamine, when administered as the anesthetic induction agent during high-dose remifentanil administration, prevents cardiovascular depression.

Management of post-hyperventilation apnea during dental treatment under monitored anesthesia care with propofol.

Although hyperventilation syndrome generally carries a good prognosis, it is associated with the risk of developing severe symptoms, such as post-hyperventilation apnea with hypoxemia and loss of consciousness. We experienced a patient who suffered from post-hyperventilation apnea. A 17-year-old female who suffered from hyperventilation syndrome for several years developed post-hyperventilation apnea after treatment using the paper bag rebreathing method and sedative administration during a dental procedure. We subsequently successfully provided her with monitored anesthesia care with propofol. Monitored anesthesia care with propofol may be effective for the general management of patients who have severe hyperventilation attacks and post-hyperventilation apnea. This case demonstrates that appropriate emergency treatment should be available for patients with hyperventilation attacks who are at risk of developing post-hyperventilation apnea associated with hypoxemia and loss of consciousness.

Upside-down mask ventilation technique for a patient with a long and narrow mandible.

Mask ventilation, along with tracheal intubation, is one of the most basic skills for managing an airway during anesthesia. Facial anomalies are a common cause of difficult mask ventilation, although numerous other factors have been reported. The long and narrow mandible is a commonly encountered mandibular anomaly. In patients with a long and narrow mandible, the gaps between the corners of the mouth and the lower corners of the mask are likely to prevent an adequate seal and a gas leak may occur. When we administer general anesthesia for these patients, we sometimes try to seal the airway using several sizes and shapes of commercially available face masks. We have found that the management of the airway for patients with certain facial anomalies may be accomplished by attaching a mask upside down.

Effects of chewing efforts on the sensory and pain thresholds in human facial skin: a pilot study.

The aim of this study was to examine the effect of chewing efforts on sensory and pain thresholds of the orofacial skin of symptom-free subjects. Fourteen healthy volunteers were recruited. Using a stair-case method, the tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) on the cheek skin (CS) and the skin overlying the palm side of the thenar skin (TS) were measured before and after chewing gum for 5 min (Time 1: T1) and keeping the jaw relaxed for 5 min (Time 2: T2) as a control. Both for the test and control situation, the TDT was higher in all measurement sites after 5 min. As for the FPT, the reactions between T1 and T2 were quite opposite: the FPT increased and/or remained stable in T1, while, it decreased at all sites in T2. There were significant session effects (T1-T2) on the FPT at the left CS (P<0.01), right CS (P<0.05) and TS (P<0.05). The increase of TDT after chewing/no chewing could be due to habituation, while the decrease of FPT observed in the control situation might be due to sensitization, respectively. This potential sensitization, however, was not observed after chewing efforts. Further studies are needed to clarify the modulating effect of masticatory function on the trigeminal sensory system.

The effect of nonfunctional tooth contact on sensory and pain perception in patients with myofascial pain of the jaw muscles.

PURPOSE: The aim of this study was to examine the effect of nonfunctional tooth contact on sensory threshold (tactile detection threshold: TDT) and pain thresholds (filament-prick pain detection threshold: FPT; pressure pain threshold: PPT) in the orofacial region of patients with myofascial pain of the jaw muscles. METHODS: The study was performed on 36 subjects: 20 normal subjects and 16 patients. Using a stair-case method, TDT and FPT were measured by Semmes-Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5 min (session 1) and keeping the jaw relaxed for 5 min (session 2) as a control. RESULTS: There were significant effects of experimental condition (before-after 5 min) on the TDT and FPT at several sites: after 5 min, TDT was higher in all measurement sites except the left CS of the patients in session 2. As for the FPT, the reactions between CS and TS were quite opposite in both sessions: after 5 min, the FPT at the CS decreased and/or remained, but the FPT at the TS increased and/or remained. Significant session effects (session 1-session 2) were only found on the FPT at the CS in patients. CONCLUSION: Sensitivity to FPT was more susceptible to tooth contact condition, especially in the patients.

The involvement of brain-derived neurotrophic factor in the pattern generator of mastication.

Brain-derived neurotrophic factor (BDNF) is a family of neurotrophins that plays crucial roles in neural development, survival, maintenance and regeneration both in central and peripheral nervous systems. To examine the effects of BDNF on mastication, jaw movement trajectories and masticatory muscle activities were electrophysiologically investigated in BDNF-deficient mice, compared with those of littermate wild-type mice. BDNF-deficient mice showed less number of chewing strokes and more irregular chewing pattern during mastication than wild-type mice. Masseter muscle activities of BDNF-deficient mice exhibited smaller values than those of wild-type mice. No significant difference in the cycle duration existed between these two types of the mice. These results indicate that the burst pattern is more susceptible to peripheral sensory inputs than the timing and suggest the involvement of BDNF in the control of jaw movement.