Cardiovascular effects of felypressin (FEL) were studied in Wistar rats. Heart rate and mean arterial pressure measurements were taken in awake rats treated with vasopressin (AVP), FEL, or epinephrine (EPI). Each group received either an intravenous (IV) or an intracerebroventricular V1 receptor antagonist, saline, area postrema removal, or sham surgery. Analysis of variance and Student-Newman-Keuls (P < .05) were applied. Felypressin and AVP induced a pressor effect, and bradycardia was inhibited by IV V1 antagonist. Intracerebroventricular V1 antagonist and area postrema removal enhanced their pressor effects. Epinephrine induced a higher pressor effect and a similar bradycardia that was not affected by the treatments. It was concluded that FEL depends on V1 receptors to induce pressor and bradycardic effects, and that it produces a high relationship between bradycardia and mean arterial pressure variation depending on area postrema and central V1 receptors. These effects are potentially less harmful to the cardiovascular system than the effects of EPI.
Anesthesia, local; Vasoconstrictor agents; Blood pressure; Baroreflex; Vasopressin
The purpose of this prospective, randomized, single-blinded, crossover study was to compare the pain of a traditional 1-stage inferior alveolar nerve (IAN) block injection to a 2-stage IAN block technique. Using a crossover design, 51 subjects randomly received, in a single-blinded manner, either the traditional IAN block or the 2-stage IAN block in 2 appointments spaced at least 1 week apart. For the 2-stage injection, the needle was inserted submucosally and 0.4 mL of 2% lidocaine with epinephrine was slowly given over 1 minute. After 5 minutes, the needle was reinserted and advanced to the target site (needle placement), and 1.8 mL of 2% lidocaine with epinephrine was deposited. For the traditional IAN block, following needle penetration, the needle was advanced while depositing 0.4 mL of 2% lidocaine with epinephrine (needle placement) and then 1.8 mL of 2% lidocaine with epinephrine was deposited at the target site. A Heft-Parker visual analogue scale was used to measure the pain of needle insertion, needle placement, and anesthetic solution deposition. There were no significant differences, as analyzed by Wilcoxon matched-pairs signed-ranks test, between needle insertion and solution deposition for the 2 techniques in men or women. However, there was significantly less pain with the 2-stage injection for needle placement in women. In conclusion, the 2-stage injection significantly reduced the pain of needle placement for women when compared to the traditional IAN technique.
Injection pain; Inferior alveolar nerve block; Lidocaine
The fundamental principles that govern drug therapy are often overlooked by the busy clinician. This disregard frequently results in the use of particular drugs and regimens that may be less than ideal for the clinical situation being managed. By convention, these principles are categorized as pharmacokinetic and pharmacodynamic. Pharmacokinetic processes include drug absorption, distribution, biotransformation (metabolism), and elimination, essentially reflecting the influence of the body on the drug administered. Pharmacodynamics deals with the actual mechanisms of action and the effects a drug produces on the patient. This latter topic will be addressed in a future continuing education article.
Drug therapy; Pharmacokinetics; Dental pharmacology
The authors, using a crossover design, randomly administered, in a single-blind manner, inferior alveolar nerve blocks using 36 mg of lidocaine with 18 μg of epinephrine or a combination of 36 mg of lidocaine with 18 μg epinephrine plus 36 mg meperidine with 18 μg of epinephrine, at 2 separate appointments, to 52 subjects. An electric pulp tester was used to test for anesthesia, in 4-minute cycles for 60 minutes, of the molars, premolars, and central and lateral incisors. Anesthesia was considered successful when 2 consecutive 80 readings were obtained within 15 minutes and the 80 reading was continuously sustained for 60 minutes. Using the lidocaine solution, successful pulpal anesthesia ranged from 8 to 58% from the central incisor to the second molar. Using the lidocaine/meperidine solution, successful pulpal anesthesia ranged from 0 to 17%. There was a significant difference (P < .05) between the lidocaine and lidocaine/meperidine solutions for the lateral incisors through the second molars. We conclude that the addition of meperidine to a standard lidocaine solution does not increase the success of the inferior alveolar nerve block.
Meperidine; Inferior alveolar nerve block; Lidocaine
It is impossible to provide effective dental care without the use of local anesthetics. This drug class has an impressive history of safety and efficacy, but all local anesthetics have the potential to produce significant toxicity if used carelessly. The purpose of this review is to update the practitioner on issues regarding the basic pharmacology and clinical use of local anesthetic formulations.
Local anesthetic pharmacology
The role of temperature in the action of local anesthetics was studied in 20 healthy young volunteers with plain 3% mepivacaine injected periapically twice in their maxillary first premolar, the first time with the solution at a temperature of 20°C and the second time at 4°C. The pulpal response was measured with a pulp tester every minute. The onset of pulp anesthesia was found to be of no statistical difference between 20°C and 4°C. On the other hand, mepivacaine at a temperature of 4°C was found to have a statistically significant longer duration of action. Our conclusion is that the drop in temperature of mepivacaine from 20°C to 4°C provides a longer duration of pulpal anesthesia.
Temperature; Mepivacaine; Local anesthesia; Mechanism of action, onset, duration
The aim of this study was to compare both the behavioral and physiological effects of 2 drug regimens in children: chloral hydrate (CH), meperidine (M), and hydroxyzine (H) (regimen A) versus midazolam (MZ), M, and H (regimen B). Patients between 24 and 54 months of age were examined by crossover study design. Behavior was analyzed objectively by the North Carolina Behavior Rating System and subjectively through an operator and monitor success scale. Physiological data were recorded every 5 minutes and at critical points throughout the appointment. Sixteen patients completed this study. No significant differences in behavior were noted by the North Carolina Behavior Rating System or the operator and monitor success scale. A quiet or annoyed behavior was observed 93% and 90% of the time for regimen A and regimen B, respectively. Using the operator and monitor success scale, 63% of regimen A and 56% of regimen B sedations were successful. No statistically significant differences were noted in any of the physiological parameters between the 2 regimens. Ten episodes of hemoglobin desaturation were detected with regimen A sedations. There were no differences between the sedative drug regimens CH/M/H and MZ/M/H for behavioral outcomes or physiological parameters.
Conscious sedation; Midazolam; Chloral hydrate; Children
A 62-year-old man visited our clinic for dental implantation under intravenous sedation. He demonstrated increased psychomotor activity and incomprehensible verbal contact during intravenous sedation. Although delirium caused by midazolam or propofol in different patients has been reported, the present case represents a delirium that developed from both drugs in the same patient, possibly because of the patient's smaller tolerance to midazolam and propofol.
Delirium; Midazolam; Propofol; Dental treatment
The anti-inflammatory effects of ibuprofen and tramadol were investigated by measuring C-reactive protein concentrations after removal of an impacted lower third molar. Forty-five American Society of Anesthesiologists Class I patients were randomly categorized into 3 equal groups according to postoperative analgesic medication. The first group received tramadol (100 mg every 8 hours), the second group received ibuprofen (400 mg every 8 hours), and the last group received half doses of both drugs in combination (50 mg tramadol every 8 hours and 200 mg ibuprofen every 8 hours). C-reactive protein was measured before surgery to exclude the presence of any preexisting inflammatory condition that might interfere with the study. C-reactive protein was also determined immediately after surgery and 72 hours postoperatively. At 72 hours, C-reactive protein had increased over postsurgery baseline by 123% in the tramadol group (P < .001), 84% in the ibuprofen group (P < .001), and only 37% in the combined analgesic group (P = .078). These results suggest that tramadol may produce supra-additive anti-inflammatory effects with ibuprofen after third-molar extractions.
C-reactive protein; Ibuprofen; Tramadol; Dentistry; Oral surgery
The purpose of this follow-up study was to assess and compare the quantity and quality of dental undergraduate teaching in conscious sedation with comparisons to a previous study conducted in 1998. Questionnaires were designed to collect information about undergraduate sedation education from teaching staff and final-year dental undergraduates at the 15 dental schools in the United Kingdom and Ireland. Staff responses from 9 schools (60%) and student responses from 11 schools (73%) were received. From the students' responses, the mean (range) number of cases observed in inhalational sedation was 7 (0–17) and the mean (range) number performed in inhalational sedation was 4 (0–8). The mean (range) number of cases observed in intravenous sedation was 9 (2–19), and the mean (range) number performed was 5 (0–8). There has been an increase in didactic teaching. There has been a decrease in the observing of inhalational cases, but an increase in the hands-on performance of this type of sedation. There is an increase in the hands-on teaching of intravenous sedation.
Sedation; Education; Dentistry
Clonidine is a preferential alpha-2 agonist drug that has been used for over 35 years to treat hypertension. Recently, it has also been used as a preoperative medication and as a sedative/anxiolytic drug. This randomized, double-blind, placebo-controlled crossover clinical trial characterized the effects of oral clonidine pretreatment on intravenous catheter placement in 13 patients. Parameters measured included the bispectral index (BIS), Observer's Assessment of Alertness/Sedation Scale (OAA/S), frontal temporal electromyogram (EMG), 30-Second Blink Count (Blink), Digit Symbol Substitution Test (DSST), State Anxiety Inventory (SAI), fingertip versus forearm skin temperatures, and multiple questionnaires. Oral clonidine significantly decreased SAI scores, OAA/S, EMG, and Blink, but did not cause statistically significant BIS or DSST reductions. Subjects preferred oral clonidine pretreatment prior to venipuncture compared to placebo. Questionnaires also indicated that clonidine provided minimal sedation, considerable anxiolysis, and some analgesia. Fingertip versus forearm skin temperature differentials were decreased. Reduced fingertip versus forearm temperature differentials suggest increased peripheral cutaneous blood flow prior to venous cannulation. Oral clonidine pretreatment not only helped control patient anxiety and pain but also provided cardiovascular stability.
Clonidine; Venous cannulation; BIS; SAI; DSST
A healthy young male patient was scheduled for dental care under nasotracheal intubated general anesthesia. The presence of a plastic calculator key complicated the intubation. This case report describes the event and reviews some possible techniques for coping with an airway that becomes obstructed by a foreign object.
Foreign body obstruction; Intubation
The use of dynamic electrocardiogram (ECG) monitoring is regarded as a standard of care during general anesthesia and is strongly encouraged when providing deep sedation. Although significant cardiovascular changes rarely if ever can be attributed to mild or moderate sedation techniques, the American Dental Association recommends ECG monitoring for patients with significant cardiovascular disease. The purpose of this continuing education article is to review basic principals of ECG monitoring and interpretation.
Electrocardiography; Patient monitoring; Continuing education
This study was conducted on 72 American Society of Anesthesiologists class 1 patients scheduled for extraction of a mandibular third molar after inferior alveolar nerve block. Each patient was randomly administered one of the following ropivacaine concentrations: 0.75%, 0.5%, 0.375%, or 0.25% (18 patients per group). Onset of block (mean ± SD) was rapid for both 0.75% (1.4 ± 0.4 minutes) and 0.5% (1.7 ± 0.5 minutes) ropivacaine but significantly slower for the 0.375% (4.2 ± 2.5 minutes) and 0.25% (10.7 ± 3.0 minutes) concentrations. Tooth extraction was performed successfully with the 0.5% and 0.75% concentrations, and supplemental injections were not required. Second injections, however, were required with 0.375% ropivacaine. Anesthesia was unsuccessful in 13 patients given 0.25% ropivacaine even after 3 injections. The mean durations of soft tissue anesthesia were 3.3 ± 0.3 hours and 3.0 ± 0.3 hours for the 0.75% and 0.5% concentrations, but significantly shorter with more dilute concentrations. The duration of analgesia showed a similar pattern, with the 0.75% and 0.5% concentrations producing prolonged analgesia of 6.0 ± 0.4 hours and 5.6 ± 0.4 hours. These results indicate that 0.5% and 0.75% concentrations were effective for intraoral nerve blockade, with both a rapid onset and prolonged duration of pain control.
Ropivacaine; Local anesthesia; Local anesthetics; Dentistry; Oral surgery
A 57-year-old male with a documented history of obstructive sleep apnea with loud snoring received deep intravenous sedation with midazolam, fentanyl, ketamine, and propofol infusion and a left interscalene brachial plexus nerve block for a left biceps tendon repair. Loud snoring during the case was noted. On the second postoperative day, he was observed to have significant uvular edema. After due consideration of the various elements in the differential diagnosis, it was concluded that negative pressure trauma from deep snoring during the sedation was the most likely etiology.
Uvular edema; Obstructive sleep apnea; Deep sedation; Negative pressure edema
The aim of this study is to assess the difference in duration of action after infiltration anesthesia when elevation of a periosteal flap (EPF) was accomplished with water or saline irrigation versus nonelevation of a periosteal flap (NEPF). The 57 patients in this study were under conscious sedation. A long treatment time of more than 1 hour was used. Instances where peripheral nerve block or opioids were administered and infiltration anesthesia over 2 fields were excluded before the study. Patients were included in either an EPF group (n = 29) or an NEPF group (n = 28). Statistically significant differences were detected in the initial dose of anesthetic (EPF: 4.3 ± 1.4 mL, NEPF: 1.8 ± 0.9 mL), the time until initial supplemental anesthesia (EPF: 38 ± 26 minutes, NEPF: 65 ± 27 minutes), and the frequency of anesthesia administration (EPF: 2.5 ± 1.2 times, NEPF: 1.3 ± 0.7 times). These results suggest that the duration of anesthesia action in EPF decreases to half compared with NEPF, even if the anesthetic was infiltrated in double the amount. Although supplemental anesthesia is required frequently in EPF, it is not efficacious. We speculated that the residual anesthetics in tissue were washed out by irrigation and hemorrhage and that supplemental anesthesia became ineffective because of leakage from the opened flap. Elevation of a periosteal flap reduces the effect of infiltration anesthetics.
Infiltration anesthesia; Local anesthesia; Lidocaine; Epinephrine; Oral surgery; Periosteal flap
This case involves a possible complication of excessive bleeding or rupture of hemangiomas. Problems and anesthetic management of the patient are discussed. A 35-year-old man with Sturge-Weber syndrome was to undergo teeth extraction and gingivectomy. Hemangiomas covered his face and the inside of the oral cavity. We used intravenous conscious sedation with propofol and N2O-O2 to reduce the patient's emotional stress. It was previously determined that stress caused marked expansion of this patient's hemangiomas. Periodontal ligament injection was chosen as the local anesthesia technique. Teeth were extracted without excessive bleeding or rupture of hemangiomas, but the planned gingivectomies were cancelled. Deep sedation requiring airway manipulation should be avoided because there are possible difficulties in airway maintenance. Because this was an outpatient procedure, propofol was selected as the sedative agent primarily because of its rapid onset and equally rapid recovery. Periodontal ligament injection with 2% lidocaine containing 1 : 80,000 epinephrine was chosen for local anesthesia. Gingivectomy was cancelled because hemostasis was challenging. As part of preoperative preparation, equipment for prompt intubation was available in case of rupture of the hemangiomas. The typically seen elevation of blood pressure was suppressed under propofol sedation so that expansion of the hemangiomas and significant intraoperative bleeding was prevented. Periodontal ligament injection as a local anesthetic also prevented bleeding from the injection site.
Sturge-Weber syndrome; Hemangioma; Mental retardation; Anesthetic management; Oral surgery