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Kentaro Nogami,Yozo Manabe, Shigeru Iwamoto, Yoshihisa Katoh* and Shogo Taniguchi
Dexmedetomidine (DEX) is a highly selective α2-adrenergic receptor agonist; its sedative and analgesic effect in clinical settings has been reported. There have been some reports on a transient vasoconstriction upon the administration of DEX to humans. It is known that peripheral vasoconstriction is one of the factors responsible for the prolongation of the analgesic effect. The addition of clonidine to local anesthetics for spinal or epidural anesthesia has been reported to prolong this effect. However, the prolongation of the analgesic effect when DEX is added to local anesthetics has not been confirmed.
We investigated the effect of DEX that had been added to normal saline or local anesthetics as a vasoconstrictor. Six healthy young adult volunteers were enrolled in this study (Table 1). The following baseline measurements were obtained after 30 minutes stabilization period. Each subject was administered 0.3 ml of normal saline containing 0.25 µg/ml, 2.5 µg/ml, 25 µg/ml DEX (ND 0.25, ND 2.5, ND 25) as a hypodermic injection on the forearm. The regional blood flow (RBF) was measured using a non contact type laser tissue rheometer at 1, 3, 5, 7, 10, 20, 30, 60 minutes after the injection. The probes of non contact type laser tissue rheometer were placed at a distance of 1 cm from the skin of the forearm (Fig. 1). During the study period, the hemodynamic changes (blood pressure and heart rate) were also recorded using a Korotkoff sound graph, and the sedative level was assessed by the Richmond Agitation-Sedation Scale (RASS). Statistical analyses were performed using analysis of variance (ANOVA). If the F value was found to be significant, Scheffe's test for multiple comparisons was employed. P<0.01 was considered to be statistically significant.
There was no significant difference in the hemodynamic values between the groups. Throughout this examination, the value of RASS was “0” in all subjects. The results of the study indicated that the concentration of DEX independently enhanced the vasoconstriction (Fig. 2). Furthermore, we also examined the effect of 2% lidocaine (L), 2% lidocaine containing 1/80,000 adrenaline (LA) and 2% lidocaine containing 2.5 µg/ml DEX (LD) on the RBF. The RBF at 5, 7 and 10 minutes after the LD injection was significantly lower than that after the L injection (Fig. 3).
We believe that in this study, the DEX added to the local anesthetic attenuated the vasodilatating effect of lidocaine in the forearm surface tissue without changing the hemodynamics and the level of consciousness.
Section of Anesthesiology, Department of Diagnostics & General Care, Fukuoka Dental College
* Section of Dentistry for the Disabled, Department of Oral Growth and Development, Fukuoka Dental College
Hiroko Yamamura, Satoru Sakurai, Nobuyuki Matsuura, Yukiko Matsuki,Tatsuya Ichinohe and Yuzuru Kaneko
Endotracheal intubation is usually accomplished using a conventional laryngoscope (LS). However, in some situations, the insertion process of a tracheal tube may be difficult or impossible when using LS for nasotracheal intubation. This may be due to the fact that a tracheal tube might get stuck on the anterior wall of the trachea just beyond the vocal cord. This difficult intubation has not been found when Pentax-AWS® (AWS is a new intubation device) is used. Therefore, we compared the difference of laryngeal axis when LS or AWS was used during nasotracheal intubation.
After obtaining institutional research ethics board approval and written informed consent, 20 patients (18–51 years old) requiring nasotracheal intubation for elective surgery were enrolled in this prospective study. After complete muscular paralysis was obtained, confirmed by a peripheral nerve stimulator, a nasotracheal tube was inserted into the naris. Digital photographs of the lateral view of the head and neck of subjects were taken under the following conditions in all patients : simple neck extension (the head was maximally extended), the stick was placed at a point where the tracheal tube appears from nasopharynx. laryngoscopy using LS (the LS was inserted and placed to achieve Cormack grade I view). laryngoscopy using AWS (the AWS was inserted and placed to achieve Cormack grade I view), and when the stick was placed at the point that the tracheal tube appears from the nasopharynx. Tracheal intubation was performed with LS (LS group ; n = 10) or the AWS (AWS group ; n = 10).
Anatomical landmarks (eyebrows, the ala nasi, earlob, mandibular mentum, laryngeal incisure, suprasternal notch, armpit, A : point that the tracheal tube appears from nasopharynx, B : tip of the LS or AWS blade corresponding to the base of the tongue, C : cricoid cartilage, and D : point of the extension laryngeal axis that connects the point B and the point C) were identified and connected for the purpose of angle and distance measurements as illustrated in the photograph. Paired t-test or unpaired t-test, Fisher Exact Test, Yates m × n Chi square tests were used where appropriate, and p<0.05 considered significant.
Reducing the distraction force of the anterior neck tissues (in order to avoid getting stuck to the anterior wall of the trachea) was not necessary for any patient in the AWS group, while it was required in 70% of the subjects in the LS group. As for measurements of craniofacial dimensions, the angle ABD and angle ACD using AWS (angle ABD : 22° ± 11, angle ACD : 17° ± 8, respectively) was significantly smaller than using LS (angle ABD : 40° ± 13, angle ACD : 26° ± 8, respectively), p<0.0001.
These results suggest that one can intubate nasally without getting stuck to the anterior wall of the trachea when using AWS, as one can confirm the process by which the tracheal tube proceeded. We conclude that AWS is a useful intubation device for smooth and safe nasotracheal intubation.
Department of Dental Anesthesiology,Tokyo Dental College
Yozo Manabe, Shigeru Iwamoto,Yuko Tsuru, Mayumi Miyasada,Yumiko Tanaka,Tomoko Ichiyama, Tatsuya Katoh, Kentarou Nogami, Shinji Tominaga and Shogo Taniguchi
Nasotracheal intubation is often indicated in oral and maxillofacial surgery. An alternative orotracheal intubation technique using a lightwand device Trachlight™ (TL; Laerdal Medical, Armork, NY) has been reported to facilitate tracheal intubation in patients with difficult airways. However, there is no report about nasotracheal intubation using TL. A method for grading intubation difficulty based on laryngoscopic view has been suggested by Cormack and Lehane. It is believed that tracheal intubation by direct laryngoscopy is difficult in the case of grades 3 and 4. This study was designed to determine the relationship between the grade of laryngeal view and the ease of nasotracheal intubation by TL.
Three hundred forty four patients (ASA 1 or 2) scheduled for elective oral and maxillofacial surgery under general anesthesia requiring nasotracheal intubation were included in this study. Each patient was routinely monitored during the entire procedure. A rapid-acting anesthetic was administered intravenously, mask ventilation was ensured, and vecuronium bromide (0.08–0.1 mg/kg) was administered. Glottis visualization during laryngoscopy was assessed by using the Cormack and Lehane classification by an attending anesthesiologist with at least 300 cases of anesthesia experience. According to this classification, the patients were subdivided to two groups : Group E (grade 1 and 2), Group D (grade 3 and 4). Then TL intubation was performed by one anesthesiologist with 20-years experience. Three attempts were permitted, with ventilation interposed. If the TL intubation was unsuccessful after three attempts, it was defined as a “Failure” and intubation was carried out using direct laryngoscopy. The total intubation time, and the success or failures of the TL intubation were recorded by another anesthesiologist. The total intubation time was defined as the sum of the durations of all intubation attempts. There were no significant differences among the groups in terms of ratio of gender, height or weight, while the age was significantly high in Group D (Table 1). The total intubation time was not significantly different among the groups (Table 3). There was no significant difference in the success rate among the groups (Table 4).
TL is an effective alternative for patients who require nasotracheal intubation. We found no relationship between the ease of intubation using the TL and glottic visualization. Thus, it is recommended that anesthesiologists become skilled in intubation using TL as well.
Section of Anesthesiology, Department of Diagnostics & General Care, Fukuoka Dental College
Asuka Taguchi, Shuichiro Oka, Kou Fujiwara, Kenji Seki*, Atsushi Endo*, Atsuko Abe, Rikuo Masuda** and Setsu Yoshimura
We report 2 cases of airway stenosis in which the bronchoscope mode of 3 Dimensional Computed Tomography (3D-CT) was used for evaluating the degree of stenosis. 3D-CT obtained from helical computed tomography shows similar airway images to the view during bronchoscopy. This method is mainly used by physicians to diagnose lung cancer, and there are few reports on the use of 3D-CT for upper airway assessment in the field of anesthesiology. In cases where upper airway patency is poor, difficult mask ventilation may occur during rapid induction process. Therefore, we usually choose awake bronchoscopic intubation. But, in these cases, severe adverse airway outcomes may occur when consciousness is depressed by sedation, and in cases where it is not possible to visualize any portion of vocal cords after multiple attempts of bronchoscopy, a tracheotomy is often indicated.
Case 1 ; 64-year-old man (weight, 55 kg ; height, 162 cm) suffering from neck lymph node metastasis of tongue cancer with severe trismus and moderate difficulty in breathing at supine position was scheduled for general anesthesia and extirpation of lymph node (Fig. 1).
Case 2 ; 26-year-old man (weight, 55 kg ; height, 172 cm) suffered from submandibullar phregmon with severe trismus and moderate difficulty in breathing at supine position was scheduled for general anesthesia and drainage of pus (Fig. 3).
In both cases, the images of VB (Virtual Brochoscopy) structured by 3D-CT showed airway stenosis, but they were not so severe and the epiglottis and vocal codes could be identified (Fig. 2, ,4).4). Clinical status and axial CT images indicated some degree of airway stenosis, but the VB images gave us considerable visual feedback on making decision of awake bronchoscopic intubation with intravenous sedation, and finally nasal intubations could be performed with only one attempt without airway obstruction in both cases. The image of VB structured by 3D-CT is an effective non-invasive method and with this method, even a high-grade stenosis can be passed, enabling evaluation of the distal airways. It is suggested that this method not only enables anesthetists to decide the safest strategies for managing airway, but also prepares them psychologically. In conclusion, the VB imaging is a recommended tool for anesthetist to evaluate the degree of airway stenosis and for planning bronchoscopic intubation.
Department of Dental Anesthesia, School of Dentistry, Showa University Dental Hospital
*Department of Radiology, Showa University School of Dentistry
**Department of Anesthesia, Showa University Northren Yokohama Hospital.
Takashi Goto, Asako Ninomiya, Junko Yumura*, Masataka Kasahara, Tatsuya Ichinohe and Yuzuru Kaneko
The aim of this study was to investigate the effect of remifentanil (R) continuous infusion and fentanyl (F) bolus injection on sleeping time during induction of anesthesia. Thirty-nine consenting patients (20 males and 19 females, ASA physical status I or II) scheduled for general anesthesia undergoing oral and maxillofacial surgery participated in this study. Patients were randomly allocated in one of two groups. In the R groups, 0.3 µg/kg/min of R was infused at induction of anesthesia. In the F group, 2 µg/kg of F was injected at induction of anesthesia. One minute after the administration of R or F, we started continuous infusion of 1% propofol to achieve the effect-site concentration (EC) of 4 µg/ml using target controlled infusion technique. After that, we confirmed verbal contact every 10 seconds until the patient lost consciousness. Sleeping time was defined as the duration between the start of R or F administration and the loss of consciousness. We compared propofol EC (µg/ml) and bispectral index (BIS) value at the time of loss of consciousness.
There were no significant differences in the patient background and characteristics. Sleeping in the R group took longer time than that in the F group (R group : 180 ± 38 sec, F group : 152 ± 29 sec). Propofol EC in the F group was lower than that of the R group (R group : 1.5 ± 0.4 µg/ml, F group : 1.2 ± 0.2 µg/ml). BIS value in the R group was lower than that of the F group (R group : 65 ± 14, F group : 73 ± 20).
The results of this study suggest that sleeping time during 0.3 µg/kg/min R infusion was longer than after 2 µg/kg F bolus injection, and R at this dose was not able to give sufficient hypnotic adjuvant effects comparable to F.
Department of Dental Anesthesiology,Tokyo Dental College
* Department of Anesthesiology, Ichikawa General Hospital, Tokyo Dental College
Hiroshi Kawahara, Nozomu Harano, Masahito Nunomaki, Shunji Shiba,Teppei Sagou, Mari Okada,Takaki Nakashima, Kouji Watanabe and Osamu Nakanishi
The Airway Scope® (AWS) is an auxiliary instrument for oral intubation performed by inserting the Intlock® (ITL, a polycarbonate blade) into the undersurface of the epiglottis. The form of the anterior head of the ITL is similar to that of the anterior Macintosh blade. However, when using AWS, the head of the blade is not located at the epiglottic vallecula, as with the Macintosh blade. AWS is designed to enable oral intubation of a tube attached to ITL to guide the tracheal tube through by aligning the glottides with a target mark on a liquid-crystal display, while elevating the epiglottis by inserting ITL into the undersurface of the epiglottis. Although AWS has been used for nasotracheal intubation in patients with trismus, we experienced cases in which nasotracheal intubation using AWS was possible with ITL located at the epiglottic vallecula. The current study was performed prospectively to examine nasotracheal intubation with AWS with ITL located at the epiglottic vallecula (Fig. 1). The subjects were 50 patients with an aperture size of 18 mm or larger, which was sufficient for oral intubation of AWS, and a height of 135 cm or higher. The subjects were selected from patients who were scheduled for nasotracheal intubation in an operating room at Hospital of Kyushu Dental College.
Nasotracheal intubation was performed successfully with ITL located at the epiglottic vallecula in 49 of the 50 patients. It was not possible to perform this intubation in one patient. Visualization of the glottides and epiglottis on AWS liquid crystal display showed that 35 patients were in Grade 1 of the Cormack classification, 15 were in Grade 2, and none were in Grades 3 and 4. Among the 15 patients in Grade 2, 11 were categorized as Grade 2a and 4 as Grade 2b in the modified Cormack classification. In 48 of the 49 patients who underwent nasotracheal intubation with ITL located at the epiglottic vallecula, intubation was performed by adjusting the rotational direction of the tracheal tube head by rotating the end of the tube bilaterally. For the other patient, intubation was performed by lowering the cephalic presentation by approx. 5 cm. Parapharyngeal space cellulitis was present in the patient in whom nasotracheal intubation could not be performed. This patient showed favorable results on visual observation that indicated Grade 1 in the Cormack classification, but nasotracheal intubation was not possible when ITL was inserted into the undersurface of the epiglottis, and thus oral intubation was performed using AWS.
Our results suggest that nasotracheal intubation with AWS can be successfully performed for almost all patients by locating ITL at the epiglottic vallecula and rotating the end of the tracheal tube bilaterally.
Division of Dental Anesthesiology, Department of Control of Physical Functions, Science of Physical Function, Kyushu Dental College
Aya Akao, Hiroko Fujino, Seiko Kitahara, Atsuya Yoshida, Keiji Kubo,Yoshimi Ikemoto* and Ai Nakamura**
We report the pre-anesthetic evaluation and general anesthetic management of a patient who underwent oral surgery prior to an aortic arch replacement for thoracic aortic aneurysm, although the latter had been planned. In general, maxillo-facial oral surgeries are avoided in patients with cardiac diseases in poor condition. It is rarely that oral surgery for maxillo-facial region malignant cancer, for example, is given priority over a chest aortic aneurysm operation. However, the priority of the operation should be decided based on the underlining severity of the disease. If the cardiac condition is acceptable, we can provide general anesthesia safely.
We performed general anesthesia according to “The Guidelines for Perioperative Cardiovascular Evaluation and Management for Noncardiac Surgery”. The pre-anesthetic evaluation was made carefully taken in consideration the surgical risk, and a detailed anesthetic plan was made prior to the procedure. We explained the risks to the patient and his family carefully.
On the day of the operation, we inserted a transcutaneous pacemaker from the left subclavian vein in the event of tachycardia or bradycardia. We tried to minimize changes in blood pressure at the induction of anesthesia and during the operation by continuously administering nitroglycerin. However, the blood pressure declined and the rate pressure product (RPP) went down below 4,000. So, we managed the heart rate using the pacemaker.
After the operation, the tracheal tube was removed and the patient was sent to the intensive care unit. Hemodynamics and vital signs were stable throughout the day, so the pacemaker was safely removed on the following day.
Department of Dental Anesthesiology, Faculty of Dental Science, Kyushu University
* Professor Emeritus, Kyushu University/Hisatsune Hospital
** Department of Dentistry and Oral Surgery, Iizuka Hospital
Nobuyuki Matsuura*,**,Tatsuya Ichinohe*,**, Eiji Kawada** and Yuzuru Kaneko*
Cardiopulmonary resuscitation using a simulator has been reported to be an effective method for educational and training purposes. However, despite its effectiveness, education using CPR simulation systems were lacking objectivity and reproducibility, so repetitive training was necessary in order to achieve and maintain basic skills. Therefore, we developed a new system, which enabled acquiring and evaluating the skills by visible and objective targets with IT support. This system uses a PC skill reporting system with the cardiopulmonary resuscitation simulator Resusci® Anne (Laerdal®), and unifies real time resuscitation data (wave form) obtained from the mannequin and audio-visual data from a video camera (Fig. 2). Incorrect hand position of the sternal pressure and the correction of errors in palpation of the common carotid artery are indicated on a schema. Also, this system is able to generate evaluation sheets and store records of skill evaluation in each step with timing information. In addition, after the cardiopulmonary resuscitation training session, output of the evaluation sheet including the results of visualized comprehensive evaluation can be printed. Because all of this data is integrated and recorded by a PC, the software can replay the recorded basic technique of the trainee, and is verifiable. Reproducibility and objectivity are improved by this system, and effective feedback becomes possible, not only for the individual but also for trainee groups.
This system is based on 2005 guidelines for CPR and ECC of AHA, and is based on the data of Laerdal®. Future changes in the guidelines can be implemented by changing some setup parameters. Our IT-based training system enables effective CPR training and evaluation, and it may be useful in dental anesthesiology education.
* Department of Dental Anesthesiology,Tokyo Dental College
** Dental Education Development Center,Tokyo Dental College
Kenichi Harada,Tetsuya Nagoh, Nozomi Yamada, Kimito Sano and Tomio Kanri
This study examined the changes in plasma adrenaline and noradrenaline concentrations and hemodynamic parameters after preadministration of local infiltration anesthesia with 2% lidocaine with 1 80,000 adrenaline alone or pre-administration of 3% prilocaine + 0.03 IU felypressin, followed by the main local anesthetic/catecholamine infiltration of 4.0 ml of 2% lidocaine with 1 80,000 adrenaline.
The study subjects consisted of 50 adult male volunteers (mean age, 23.8 ± 1.6 years : mean body weight, 67.1 ± 3.2 kg) who were divided into five groups. Then the anesthetic mixture was injected into the left maxillary first premolar gingivobuccal fold. Group I received a single administration of 4.0 ml of 2% lidocaine + 1 80,000 adrenaline. Groups II and III received a preadministration of 2% lidocaine + 1 80,000 adrenaline (0.5 ml and 1.0 ml respectively), followed by the main local anesthetic dose of 4.0 ml of 2% lidocaine + 1 80,000 adrenaline, 3 min later. Groups IV and V received preadministration of 3% prilocaine with 0.03 IU felypressin (0.5 ml and 1.0 ml, respectively), followed by the main local anesthetic dose of 4.0 ml of 2% lidocaine + 1 80,000 adrenaline, 3 min later.
Group I exhibited significant increase in plasma adrenaline concentrations at 1 to 5 min after administration of the main local infiltration anesthesia (Fig. 2). No significant difference was observed among Groups II, III, IV and V. Groups II, III, IV and V showed significantly lower plasma adrenaline concentrations at 2, 3, 4 and 5 min as compared to Group I. Significant elevation of the plasma noradrenaline concentration was observed in Group I at 15 and 20 min (Fig. 3). No significant changes of the systolic blood pressure were noted in any of the five groups (Fig. 4). Although transient increase was noted, the diastolic blood pressure remained significantly reduced from 2 to 5 min in Group I, and from 1 to 10 min in Groups II, III, IV and V (Fig. 5). In Group I, significant increase of the heart rate was observed from 2 to 10 min (Fig. 6).
Preadministration of local anesthetic combined with a vasoconstrictor inhibited the steep rise in plasma adrenaline concentration associated with main local infiltration of 2% lidocaine and 1 80,000 adrenaline, and thereby reduced the associated hemodynamic changes.
Department of Anesthesiology, Nippon Dental University, School of Life Dentistry at Niigata
Akiko Shiki,Yukio Ishikura and Katsuya Ogata
Use of a combination of low-dose propofol and sevoflurane anesthesia is expected to provide smooth emergence from anesthesia and postoperative antiemetic effect. We assessed the effectiveness of this technique for dental treatment in patients who were severely disabled both mentally and physically. In this study, the dose of propofol was about half of the normal dose because of its potent peripheral vasodilating effect which may cause decrease in blood pressure.
Thirty three patients (aged 6 years or older) who underwent general anesthesia for dental treatment were studied (Table 1). Anesthesia was induced with nitrous oxide-oxygen-sevoflurane (3–5%), followed by intravenous propofol (1 mg/kg). After nasotracheal intubation facilitated with 0.08 mg/kg vecuronium bromide, the concentration of sevoflurane was reduced and fixed at 0.6%. Propofol was maintained at a dose of 6 mg/kg/hr initially and adjusted within a dose of 4 or 2 mg/kg/hr. Sevoflurane concentration was increased to 1–2% for about 30 minutes when the patient coughed or moved. We measured the changes in blood pressure, heart rate and oxygen saturation after the start of propofol, and also examined the recovery time of spontaneous breathing from vecuronium bromide, body movement, extubation time and postoperative vomiting.
The changes in blood pressure and heart rate are shown in Table 2. The systolic blood pressure was significantly decreased at 30 minutes (p<0.01) and 60 minutes (p<0.05) after the administration of the induction dose of propofol. The values of mean arterial pressure (MAP) at these points were 57 mmHg and 60 mmHg. respectively. Diastolic blood pressure and heart rate did not change significantly. Oxygen saturation did not change significantly either, and was stable at a value of 98% (Table 3). Mean recovery time of spontaneous breathing after the administration of vecuronium bromide was 51.8 ± 14.7 minutes. The success rate of immobilization was 79.4% (27/34). The success in keeping patients motionless was shown to be independent from the effect of tooth extraction by the chi test (Table 4). Mean extubation time was 14.2 ± 4.8 minutes. Postoperative vomiting occurred once in 1 case.
Our results suggest that an anesthesia method using low-dose of propofol combined with sevoflurane could be useful for dental treatment in patients who are severely disabled both mentally and physically, with respect to the respiratory condition, emergence from anesthesia and prevention of postoperative nausea/vomiting. However, there are two concerns regarding hemodynamic problems : a) Decrease in blood pressure (MAP below 60 mmHg) and b) Reflex coughing or body movement during the operation, which occurred in about 20% of the cases. It is suggested that further studies with a lower dose of propofol and a higher concentration of sevoflurane than those used in this study be considered to assess if improvement of these conditions can be made using this method of anesthesia.
Ogata Dental Clinic