This double-blind, placebo-controlled, randomized cross-over clinical experimental study tested the reliability, validity, and sensitivity to change of punctuate pain thresholds and self-reported pain on needle penetration. Female subjects without orofacial pain were tested in 2 sessions at 1- to 2-week intervals. The test site was the mucobuccal fold adjacent to the first upper right premolar. Active lidocaine hydrochloride 2% (Dynexan) or placebo gel was applied for 5 minutes, and sensory testing was performed before and after application. The standardized quantitative sensory test protocol included mechanical pain threshold (MPT), pressure pain threshold (PPT), mechanical pain sensitivity (MPS), and needle penetration sensitivity (NPS) assessments. Twenty-nine subjects, mean (SD) age 29.0 (10.2) years, completed the study. Test-retest reliability intraclass correlation coefficient at 10-minute intervals between examinations was MPT 0.69, PPT 0.79, MPS 0.72, and NPS 0.86. A high correlation was found between NPS and MPS (r = 0.84; P < .001), whereas NPS and PPT were not significantly correlated. The study found good to excellent test-retest reliability for all measures. None of the sensory measures detected changes in sensitivity following lidocaine 2% or placebo gel. Electronic von Frey assessments of MPT/MPS on oral mucosa have good validity.
Lidocaine; Mechanical pain threshold; Pressure pain threshold; Reliability; Topical anesthesia; Validity
We previously modified the i-gel airway to enable its use in the field of oral and maxillofacial surgery and reported its fabrication methods. In general, the standard i-gel airway is quick to insert and has a high success rate, but the modified i-gel airway has yet to be assessed for these attributes. We, therefore, set out to compare the ease of insertion of the modified i-gel airway with the LMA Flexible to investigate the usefulness of the modified i-gel airway. The study participants, who included 20 new interns with no experience using either the LMA Flexible or the modified i-gel airway, inserted each device 3 times into an intubation practice manikin. The variables measured in this study were insertion time and rate of successful insertions. Mean insertion time over 3 attempts was significantly shorter for the modified i-gel™ airway (18.9 ± 4.7 seconds) than the LMA Flexible (24.9 ± 5.1 seconds, P < .001). The rate of successful insertions as a total of all 3 attempts was significantly higher for the modified i-gel airway (56/60 times, 93.3%) than the LMA Flexible (45/60 times, 75%; P = .012). When used by an inexperienced operator, the modified i-gel™ airway is faster and has a higher success rate than the LMA Flexible, suggesting that it can be easily manipulated during insertion.
Oral and maxillofacial surgery; Supraglottic airway device; Modified i-gel™ airway
Adrenaline (epinephrine) is included in dental local anesthesia for the purpose of vasoconstriction. In Japan, adrenaline is contraindicated for use in patients receiving antipsychotic therapy, because the combination of adrenaline and an antipsychotic is considered to cause severe hypotension; however, there is insufficient evidence supporting this claim. The purpose of the present study was to clarify the changes in hemodynamics caused by drug interaction between adrenaline and an antipsychotic and to evaluate the safety of the combined use of adrenaline and an antipsychotic in an animal study. Male Sprague-Dawley rats were anesthetized with sodium pentobarbital. A catheter was inserted into the femoral artery to measure blood pressure and pulse rate. Rats were pretreated by intraperitoneal injection of chlorpromazine or chlorpromazine and propranolol, and after 20 minutes, saline or 1 of 3 different doses of adrenaline was administered by intraperitoneal injection. Changes in the ratio of mean arterial blood pressure and pulse rate were measured after the injection of adrenaline. Significant hypotension and tachycardia were observed after the injection of adrenaline in the chlorpromazine-pretreated rats. These effects were in a dose-dependent manner, and 100 μg/kg adrenaline induced significant hemodynamic changes. Furthermore, in the chlorpromazine and propranolol–pretreated rats, modest hypertension was induced by adrenaline, but hypotension and tachycardia were not significantly shown. Hypotension was caused by a drug interaction between adrenaline and chlorpromazine through the activation of the β-adrenergic receptor and showed a dose-dependent effect. Low-dose adrenaline similar to what might be used in human dental treatment did not result in a significant homodynamic change.
Local anesthesia; Drug interaction; Adrenaline; Epinephrine; Antipsychotics
In this study, a mechanical model was applied in order to replicate potential surgical fire conditions in an oxygen-enriched environment with and without high-volume suction typical for dental surgical applications. During 41 trials, 3 combustion events were measured: an audible pop, a visible flash of light, and full ignition. In at least 11 of 21 trials without suction, all 3 conditions were observed, sometimes with an extent of fire that required early termination of the experimental trial. By contrast, in 18 of 20 with-suction trials, ignition did not occur at all, and in the 2 cases where ignition did occur, the fire was qualitatively a much smaller, candle-like flame. Statistically comparing these 3 combustion events in the no-suction versus with-suction trials, ignition (P = .0005), audible pop (P = .0211), and flash (P = .0092) were all significantly more likely in the no-suction condition. These results suggest a possible significant and new element to be added to existing surgical fire safety protocols toward making surgical fires the “never-events” they should be.
Surgical fires; Oxygen-enriched environments; High-volume suction.
Acute angle-closure glaucoma (AACG) is a rare complication of general anesthesia. The coexistence of individual risk factors for postoperative AACG and factors associated with intraocular hypertension are considered to be required for postoperative AACG to develop. We present a case of AACG after general anesthesia for oral bone grafting in a patient with no preoperative eye symptoms. In this case, several factors such as postoperative care in a darkened room, psychological stress, and postoperative hypertension may have precipitated the event in this patient, who may have had preexisting undiagnosed elevated intraocular pressure. The interval between the earliest appearance of symptoms at 9 hours and the ultimate diagnosis was 36 hours. In the postoperative period following general anesthesia, any patient is at risk for AACG. It is important that a postoperative diagnosis of AACG should be considered and a timely consultation with an ophthalmologist be considered if a postoperative patient complains of red eyes, visual disorder, eye pain, headache, and nausea.
Acute angle-closure glaucoma; General anesthesia; Postoperative ophthalmological emergency
IMAGe syndrome (OMIM 300290) is a rare multisystem disorder that has a broad phenotypic presentation. Though variable, this disorder mainly consists of Intrauterine growth retardation, Metaphyseal dysplasia, Adrenal hypoplasia congenita, and Genital abnormalities. Patients with IMAGe syndrome present as an uncommon yet important challenge for dentists and anesthesiologists due to their wide range of dysmorphic facial features, adrenal insufficiency, electrolyte imbalances, and need for steroid replacement. The purpose of this case report is to describe the successful anesthetic management of a pediatric patient diagnosed with IMAGe syndrome who presented for full mouth dental rehabilitation.
IMAGe syndrome; Adrenal hypoplasia; General anesthesia; Dental rehabilitation
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.
Airway management; Facemask; Ventilation
The risk for complications while providing dental procedures is greatest when caring for patients having significant medical compromise. It is comforting that significant adverse events can generally be prevented by careful preoperative assessment, along with attentive intraoperative monitoring and support. Nevertheless, the office team must be prepared to manage untoward events should they arise. This continuing education article will address basic emergency drugs that should be available in all dental practices and additional agents that become essential for those practices providing various levels of procedural sedation or general anesthesia.
Medical emergencies; Sedation; Anesthesia; Complications
Please see the pdf version for the Continuing Education Program Answer Sheet.
Globins are small heme proteins that play an important role in oxygen supply, but may also have other functions. Globins offer a unique opportunity to study the functional evolution of genes and proteins. We have characterized the globin repertoire of two different turtle species: the Chinese softshell turtle (Pelodiscus sinensis) and the western painted turtle (Chrysemys picta bellii). In the genomes of both species, we have identified eight distinct globin types: hemoglobin (Hb), myoglobin, neuroglobin, cytoglobin, globin E, globin X, globin Y, and androglobin. Therefore, along with the coelacanth, turtles are so far the only known vertebrates with a full globin repertoire. This fact allows for the first time a comparative analysis of the expression of all eight globins in a single species. Phylogenetic analysis showed an early divergence of neuroglobin and globin X before the radiation of vertebrates. Among the other globins, cytoglobin diverged first, and there is a close relationship between myoglobin and globin E; the position of globin Y is not resolved. The globin E gene was selectively lost in the green anole, and the genes coding for globin X and globin Y were deleted in chicken. Quantitative real-time reverse transcription polymerase chain reaction experiments revealed that myoglobin, neuroglobin, and globin E are highly expressed with tissue-specific patterns, which are in line with their roles in the oxidative metabolism of the striated muscles, the brain, and the retina, respectively. Histochemical analyses showed high levels of globin E in the pigment epithelium of the eye. Globin E probably has a myoglobin-like role in transporting O2 across the pigment epithelium to supply in the metabolically highly active retina.
gene duplication; globins; neuroglobin; oxygen; retina
Klippel-Feil syndrome (KFS) is a rare disease characterized by a classic triad comprising a short neck, a low posterior hairline, and restricted motion of the neck due to fused cervical vertebrae. We report repeated anesthetic management for orthognathic surgeries for a KFS patient with micrognathia. Because KFS can be associated with a number of other anomalies, we therefore performed a careful preoperative evaluation to exclude them. The patient had an extremely small mandible, significant retrognathia, and severe limitation of cervical mobility due to cervical vertebral fusion. As difficult intubation was predicted, awake nasal endotracheal intubation with a fiberoptic bronchoscope was our first choice for gaining control of the patient's airway. Moreover, the possibility of respiratory distress due to postoperative laryngeal edema was considered because of the surgeries on the mandible. In the operating room, tracheotomy equipment was always kept ready if a perioperative surgical airway control was required. Three orthognathic surgeries and their associated anesthetics were completed without a fatal outcome, although once the patient was transferred to the intensive care unit for precautionary postoperative airway management and observation. Careful preoperative examination and preparation for difficult airway management are important for KFS patients with micrognathia.
Klippel-Feil syndrome; Micrognathia; Orthognathic surgeries; General anesthesia
Difficulties with airway management are often caused by anatomic abnormalities due to previous oral surgery. We performed general anesthesia for a patient who had undergone several operations such as hemisection of the mandible and reconstructive surgery with a deltopectoralis flap, resulting in severe maxillofacial deformation. This made it impossible to ventilate with a face mask and to intubate in the normal way. An attempt at oral awake intubation using fiberoptic bronchoscopy was unsuccessful because of severe anatomical abnormality of the neck. We therefore decided to perform retrograde intubation and selected the cuffed oropharyngeal airway (COPA) for airway management. We inserted the COPA, not through the patient's mouth but through the abnormal oropharyngeal space. Retrograde nasal intubation was accomplished with controlled ventilation through the COPA, which proved to be very useful for this difficult airway management during tracheal intubation even though the method was unusual.
Cuffed oropharyngeal airway; Difficult airway management
Hair tourniquet syndrome is a condition where a hair becomes entangled around an appendage. In some cases a knot will form and the resulting tightened noose will slowly strangulate the appendage. Rarely, this condition will affect the oral cavity, but even more rarely, this condition will affect a dental structure.
Hair; Tourniquet; Dental; Tooth; Oral; Cavity
Offices and outpatient dental facilities must be properly equipped with devices for airway management, oxygenation, and ventilation. Part 1 in this series on emergency airway management focused on basic and fundamental considerations for supplying supplemental oxygen to the spontaneously breathing patient and utilizing a bag-valve-mask system including nasopharyngeal and oropharyngeal airways to deliver oxygen under positive pressure to the apneic patient. This article will review the evolution and use of advanced airway devices, specifically supraglottic airways, with the emphasis on the laryngeal mask airway, as the next intervention in difficult airway and ventilation management. The final part of the series (part 3) will address airway evaluation, equipment and devices for tracheal intubation, and invasive airway procedures.
Airway management; Ventilation; Devices; Supraglottic airways; Laryngeal mask airways
Please see the pdf version for the Continuing Education Program Answer Sheet.
In this study, by measuring bispectral index (BIS), we tested the hypothesis that intravenous adenosine 5′-triphosphate (ATP) infusion would deepen the level of midazolam-induced sedation. Ten healthy volunteers underwent 2 experiments with at least 2 weeks' interval: immediately after intravenous bolus administration of midazolam (0.04 mg/kg), they received continuous infusion of either ATP infusion (100 μg/kg/min) or placebo (saline) for 40 minutes in a double-blind, randomized, crossover manner. Changes in BIS values and responsiveness to verbal command as well as cardiorespiratory variables were observed throughout the study periods. Administration of midazolam alone reduced BIS value from control: 97 ± 1 to 68 ± 18 at 25 minutes, which was accompanied by significant cardiopulmonary depressant effects, while maintaining responsiveness to verbal command (consciousness) throughout the study period. Coadministration of ATP with midazolam further reduced BIS value to 51 ± 13, associated with complete loss of consciousness without adverse effect on the cardiorespiratory systems. We conclude that the addition of ATP infusion to midazolam significantly enhances midazolam sedation without disturbing cardiorespiratory functions.
Midazolam sedation; ATP; Central adenosine receptors
This was judged to be the first place winning submission for the American Dental Society of Anesthesiology Student Essay Award.
Acetaminophen is an old drug that is now available in an intravenous formulation. Its advantages and disadvantages are reviewed, including its potential role in multimodal postoperative pain therapy.
Intravenous acetaminophen; Postoperative pain control; Multimodal analgesia
The purpose of this study was to determine the relationship between the head position and the subsequent ease of nasotracheal intubation by using the lightwand device Trachlight (TL). Patients requiring nasotracheal intubation were subdivided into 3 groups according to the intubated head position (group S: sniffing position; group E: extension position; and group N: neutral position). The number of attempts, the total intubation time, and the failures of the TL intubation were recorded. Intubation difficulty by means of TL was assessed by the ordinal 6-point scale. Of the 300 patients enrolled in the study, TL intubation was successful in 91.3% of them. There was no significant difference in the success rate of the first attempt between the groups. No correlation between the ordinal scale and the head position was observed. The total intubation time and the ratio of “unsuccessful” cases were not significantly different among the 3 groups. TL is an effective alternative for patients who require nasotracheal intubation. Our study did not determine the most favorable head position for nasotracheal intubation with the TL, so we recommend that nasotracheal intubation with TL be started with the head in the neutral position and then changed to a more appropriate position, if necessary, on an individual basis.
Nasotracheal intubation; Lightwand device (Trachlight); Appropriate head position.
Many patients undergoing major surgery have more fear of the general anesthesia than the procedure. This appears to be reversed with oral surgery. Therefore, patients need to be as well informed about this aspect as the surgical operation.
It has been reported that the action of infiltration anesthesia on the jawbone is attenuated significantly by elevation of the periosteal flap with saline irrigation in clinical studies; however, the reason is unclear. Therefore, the lidocaine concentration in mandibular bone after subperiosteal infiltration anesthesia was measured under several surgical conditions. The subjects were 48 rabbits. Infiltration anesthesia by 0.5 mL of 2% lidocaine with 1 : 80,000 epinephrine (adrenaline) was injected into the right mandibular angle and left mandibular body, respectively. Under several surgical conditions (presence or absence of periosteal flap, and presence or absence of saline irrigation), both mandibular bone samples were removed at a fixed time after subperiosteal infiltration anesthesia. The lidocaine concentration in each mandibular bone sample was measured by high-performance liquid chromatography. As a result, elevation of the periosteal flap with saline irrigation significantly decreased the lidocaine concentration in the mandibular bone. It is suggested that the anesthetic in the bone was washed out by saline irrigation. Therefore, supplemental conduction and/or general anesthesia should be utilized for long operations that include elevation of the periosteal flap with saline irrigation.
Periosteal flap; Lidocaine concentration; Jawbone; Infiltration anesthesia.