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jtitle_s:("anesti Prog")
1.  Effect of supplemental gases on end-tidal CO2 and oxygen saturation in patients undergoing fentanyl and midazolam outpatient sedation. 
Anesthesia Progress  1997;44(1):1-4.
Forty-six American Society of Anesthesiologists Class I and II adults were randomly assigned to one to two study groups. Each subject received 0.7 microgram/kg of fentanyl and a titrated dose of midazolam. One group received 100% supplemental oxygen (O2) while another group received 50% nitrous oxide (N2O) and 50% O2. End-tidal carbon dioxide (EtCO2) and O2 saturation (SpO2) were measured at 5-min intervals throughout the procedure. We conclude that there was no significant difference in EtCO2 or O2 saturation between the two groups.
PMCID: PMC2148865  PMID: 9481973
2.  Comparison of psychomotor performance after intravenous and rectal diazepam. 
Anesthesia Progress  1997;44(1):5-10.
Twenty-four healthy subjects participated in a triple crossover study in which some of the widely used psychomotor tests were applied as indicators of psychomotor ability. Diazepam was administered in doses of 10 mg intravenously, 10 mg rectally, and 35 mg rectally. Plasma levels of diazepam and performance decrement in the Trieger dot test (DOT), the perceptual speed test (PST), the digit symbol substitution test (DSST), and continuous reaction time were measured up to 12 hr after administration. The psychomotor effects were quite similar after administration of 10 mg diazepam intravenously and rectally. When the 35-mg rectal administration was compared to the 10-mg administrations, performance was still affected at 12 hr.
PMCID: PMC2148863  PMID: 9481974
3.  Stability of parenteral midazolam in an oral formulation. 
Anesthesia Progress  1997;44(1):17-22.
Midazolam is increasingly being used for oral sedation in pediatric dentistry. Unfortunately, it is available only as a parenteral formulation in Canada and the United States. Preparation of the parenteral solution for oral use is not uniform and leads the clinician to question the stability of this drug when used in conjunction with these vehicles. Therefore, the purpose of this study was to investigate the chemical stability of parenteral midazolam as an oral formulation to determine its expiry date. This was evaluated using a validated stability-indicating liquid chromatographic method. Midazolam was diluted in orange-flavored syrup to yield concentrations of 0.35, 0.64, and 1.03 mg/ml and then stored at room temperature. Samples were drawn on each of 9 study days (0, 1, 2, 6, 7, 9, 13, 21, and 102) and chromatographed. On each study day, solutions were inspected visually for changes in color, clarity, and appearance of particulate matter. Midazolam concentrations were considered within acceptable limits if they were not less than 90% of the initial concentration. Over the 102-day study period, there was no significant change in concentration in any of the solutions. On day 102, the remaining midazolam was within 7% of the day zero concentration. Therefore, these formulations of midazolam are stable at room temperature for a period of 102 days and would be suitable for clinical use.
PMCID: PMC2148861  PMID: 9481976
4.  Avoidance of nitrous oxide and increased isoflurane during alfentanil based anesthesia decreases the incidence of postoperative nausea. 
Anesthesia Progress  1997;44(1):27-31.
Postoperative nausea and vomiting have been associated with the use of nitrous oxide. Alfentanil, when combined with nitrous oxide, also results in a high incidence of postoperative nausea and vomiting. To further define this emesis-potentiating effect of N2O, 119 patients were chosen for study and divided into two groups: group A (n = 59) was administered a mixture of alfentanil, N2O, and O2 with 0.25% isoflurane, group B (n = 60) was administered a mixture of oxygen, room air, isofluorane, and alfentanil. The incidence of postoperative nausea and vomiting was ascertained by a blinded observer in the recovery room. All 119 patients were scheduled for extra-abdominal procedures (excluding thoracotomial, intracranial, ophthalmologic, and middle ear surgery). Patients with a previous history of nausea and vomiting, hiatal hernias, reflux esophagitis, or morbid obesity were excluded. The incidence of vomiting was 5% (3/60) in group B and 15% (8/59) in group A (P = 0.067). Forty-four percent (26/59) of the patients in group A and 20% (12/59) in group B were nauseated postoperatively (P = 0.005). Our data suggest that elimination of N2O from alfentanil-based anesthetics lessens the incidence of nausea.
PMCID: PMC2148860  PMID: 9481978
5.  Analgesic effectiveness of ketorolac compared to meperidine in the rat formalin test. 
Anesthesia Progress  1997;44(1):11-16.
The rat formalin test is an analgesic behavioral observation assessment method that demonstrates two phases of nociceptive behavior. The test consists of injecting the right hind paw with a 5% formalin solution and then observing the animal for specific nociceptive behavior. The phases represent two different types of pain. Phase 1 is pain produced by direct nerve stimulation and phase 2 is an inflammation-induced pain. The nociceptive behavior measured in this experiment was licking and biting the injected paw. A comparison of nociceptive behavior was made when ketorolac and meperidine were injected (i.p.) 10 min prior to formalin injection. As expected, a biphasic pattern of licking and biting the injected paw ensued. It was found that ketorolac had no significant reduction in licking and biting, while meperidine dramatically reduced the nociceptive response in phase 1. In phase 2, both ketorolac and meperidine caused a reduction in licking and biting; however, meperidine reduced the nociceptive response to a greater extent. This experiment demonstrates that ketorolac, when compared to meperidine, is less effective in treating pain from inflammatory origin and is not effective in treating pain from direct nerve stimulation.
PMCID: PMC2148858  PMID: 9481975
6.  Pharmacokinetics of EMLA cream 5% application to oral mucosa. 
Anesthesia Progress  1997;44(1):32-37.
Plasma concentrations of lidocaine and prilocaine were measured following the application of a 5% eutectic mixture of local anesthetics (EMLA) topical anesthetic cream to the oral mucosa of twelve subjects. For each subject, a total of 8 g of EMLA was occluded to 18 cm2 of buccal mucosa for 30 min. Analysis was carried out by high-pressure liquid chromatography, and results showed peak concentrations at 40 min for lidocaine and prilocaine. The maximum concentration measured in any subject was 418 ng/ml for lidocaine and 223 ng/ml for prilocaine, well below known toxic levels. No adverse local effects were observed from a 30-min application of EMLA. A follow-up pilot study assessing the clinical efficacy of EMLA for achieving sufficient analgesia for restorative procedures showed that the cream was successful in 75% of subjects tested.
PMCID: PMC2148857  PMID: 9481979
7.  Intraoperative Damage and Correction of Pilot Balloon During Orthognathic Surgery 
Anesthesia Progress  1997;44(1):38-39.
A case of intraoperative damage to the nasotracheal tube pilot balloon and its correction is discussed.
PMCID: PMC2148856  PMID: 9481980
Maxillofacial; Surgery; Nasotracheal tube
8.  Editorial 
Anesthesia Progress  1997;44(1):ii.
PMCID: PMC2148855
9.  Is measurement of end-tidal CO2 through a nasal cannula reliable? 
Anesthesia Progress  1997;44(1):23-26.
When using a nasal cannula to sample gases expired by a patient, air from the room may dilute the sample. For this reason, the accuracy of the partial pressure of end-tidal carbon dioxide (ETCO2) measurements is questionable. We experimentally examined the reliability of ETCO2 measurements through a nasal cannula and found that they depended on both biological factors (tidal volume and respiratory rates) and mechanical factors (the diameter and the length of the cannula and the diameter of the prongs). These results suggest that the correct use of an appropriate sampling cannula will provide reliable ETCO2 measurements without clinical problems.
PMCID: PMC2148854  PMID: 9481977
10.  The efficacy of nonopioid analgesics for postoperative dental pain: a meta-analysis. 
Anesthesia Progress  1997;44(4):119-126.
The evidence for the efficacy of nonopioid analgesics in the dental pain model was examined by conducting a meta-analysis. Studies were obtained by searching the literature from August 1996 back to 1975 using the terms pain, analgesics, and dentistry. This led to the review of 294 articles, of which 33 studies met the inclusion criteria. Pain scale results were transformed into a common percent scale and converted to N-weighted means with differences in efficacy considered significant using a 95% confidence interval. Collectively, therapeutic doses of the nonsteroidal anti-inflammatory drugs (NSAIDs) commonly used in dentistry were significantly more efficacious than the combination of acetaminophen (600 or 650 mg) with codeine (60 mg). Similarly, specific doses of each of diflunisal, flurbiprofen, ibuprofen, and ketorolac were significantly more efficacious than the commonly used acetaminophen-codeine combination. These quantitative results show that particular NSAIDs may be more efficacious than the acetaminophen-codeine combination for relief of postoperative dental pain.
PMCID: PMC2148941  PMID: 9481955
11.  The incidence of complications associated with local anesthesia in dentistry. 
Anesthesia Progress  1997;44(4):132-141.
Local anesthetics are frequently administered in dentistry and thus can be expected to be a major source of drug-related complications in the dental office. Additionally, the dentist will more often be confronted with the treatment of risk patients; thus, the incidence of side effects can be expected to rise. In this study, 2731 patients receiving dental anesthesia were evaluated by questionnaire for risk factors, type and dosage of local anesthetic applied, type and duration of treatment, and complications associated with the administration of the local anesthetic. Of all patients, 45.9% had at least one risk factor in their medical histories, with cardiovascular diseases and allergies being the most frequent. The overall incidence of complications was 4.5%. It was significantly higher in risk patients (5.7%) than in nonrisk patients (3.5%). The most frequently observed complications (dizziness, tachycardia, agitation, nausea, tremor) were transient in nature and did not require treatment. Severe complications (seizure, bronchospasm) occurred in only two cases (0.07%). Articaine was found to be administered in over 90% of all dental anesthesias in Germany despite the great variety of local anesthetics available. Articaine 1:100,000 caused more sympathomimetic side effects than did articaine 1:200,000. Additionally, doses of local anesthetics proved not to be strictly determined according to body weight, especially for patients weighing less than 50 kg. In summary, it can be stated that dental local anesthesia can be considered safe. Nevertheless, the incidence of complications due to dental anesthesia can be expected to be further reduced if (a) patients are routinely evaluated for risk factors with an adequate medical history prior to dental treatment, (b) doses of local anesthetics are strictly determined according to body weight, (c) anesthetics with low concentrations of epinephrine are used, and (d) the concept of a differentiated dental anesthesia is applied.
PMCID: PMC2148940  PMID: 9481957
13.  Timing and side effects of flumazenil for dental outpatients receiving intravenous sedation with midazolam. 
Anesthesia Progress  1997;44(4):127-131.
We studied the timing and side effects of flumazenil treatment for 10 healthy volunteers and 46 dental outpatients who received intravenous sedation with midazolam. For the volunteers, vital signs were monitored before and after intravenous injection of midazolam and flumazenil. In addition, grip strength, signs and symptoms, and performance on the Romberg's test and addition tests were evaluated 30 min and 60 min after midazolam injection as well as after flumazenil injection. There were no significant changes in vital signs before, immediately after, or 50 min after injection of flumazenil, the latter time corresponding to the half-life of the drug. Thus, awakening from sedation was associated with no effects on the cardiovascular or respiratory systems. Distinct effects of flumazenil were demonstrated by the Romberg's test and the assessment of sedation status. Flumazenil had no effect on the outcome of the addition test. For the outpatients, sedation status and signs and symptoms were studied in patients undergoing procedures lasting 30 min or less (group S) and those undergoing procedures lasting 31 to 60 min (group L). Three patients in group S and one in group L had signs and symptoms of resedation. After treatment with flumazenil, abnormalities such as excitability and nausea were reported by only two patients in group L. One patient in group S had drowsiness that did not resolve after injection of flumazenil and continued until the following day. Our results indicate that flumazenil should be given at least 60 min after intravenous sedation with midazolam in dental outpatients. Moreover, caution should be exercised with regard to the potential side effects of flumazenil.
PMCID: PMC2148936  PMID: 9481956
14.  Violent emergence from anesthesia: is it a pharmacological or psychological reaction? 
Anesthesia Progress  1997;44(4):142-143.
A violent emergence from deep sedation is an uncommon reaction in the daily practice of anesthesia in the oral and maxillofacial surgery office. We present a case of a 22-yr-old male with a severe violent emergence from deep sedation that we attribute to a psychological rather than a pharmacological cause. A differential diagnosis is discussed, as are methods of treatment.
PMCID: PMC2148935  PMID: 9481958
15.  Regulation of Pediatric Oral Conscious Sedation 
Anesthesia Progress  1997;44(4):117-118.
PMCID: PMC2148934  PMID: 19598713
16.  The effects of idazoxan combined with 30% nitrous oxide on the jaw-opening reflex in the rat. 
Anesthesia Progress  1997;44(3):96-100.
In rats, the jaw-opening reflex is elicited by activation of a nociceptive receptor by the electric stimulation of the tooth pulp. This study was undertaken to assess the effects of 30% nitrous oxide and 30% nitrous oxide with idazoxan, an alpha 2-adrenergic antagonist, on this reflex. Each rat received electric stimulation for the jaw-opening reflex at 3, 5, 7, 10, 15, and 20 min after both the start of inhalation and the withdrawal of 100% oxygen or 30% nitrous oxide in oxygen. Idazoxan, 400 micrograms/ kg, was administered intravenously at the start of the inhalation period. Amplitudes significantly decreased during inhalation of nitrous oxide, but they returned gradually to control levels after cessation of nitrous oxide inhalation. In the cases of 100% oxygen, 100% oxygen with idazoxan, and 30% nitrous oxide in oxygen with idazoxan, amplitudes did not change from controls during and after 30% nitrous oxide inhalation. The latency remained unchanged irrespective of the treatment. Since in rats the degree of inhibition by 30% nitrous oxide in oxygen is partially diminished by administration of idazoxan, we conclude that nitrous oxide affects an alpha 2-adrenergic receptor in the central nervous system.
PMCID: PMC2148931  PMID: 9481969
17.  Plasma potassium changes in hypertensive patients undergoing oral surgery with local anesthetics containing epinephrine. 
Anesthesia Progress  1997;44(3):106-109.
Blood pressure, heart rate, and plasma potassium concentration were measured before and 10 min following the injection of 4.4 ml of 2% lidocaine with 1:80,000 epinephrine in 14 patients receiving treatment for hypertension. Patients were divided into two groups. Group 1 was receiving treatment with non-potassium-sparing diuretics and group 2 was being treated with nonselective beta-adrenergic antagonists. No significant changes in systolic or diastolic blood pressures were detected between groups at 10 min. The change in heart rates from the preinjection value differed between groups at 10 min (P < 0.02). Ten minutes following the injection of the local anesthetic, plasma potassium concentration was significantly reduced in group 1 patients compared to both baseline and the change in group 2 patients (P < 0.05).
PMCID: PMC2148929  PMID: 9481971
18.  Comparison of lidocaine with and without bupivacaine for local dental anesthesia. 
Anesthesia Progress  1997;44(3):83-86.
The purpose of this study was to investigate the effectiveness of a combination of bupivacaine and lidocaine and that of lidocaine alone for local dental anesthesia. First, on different days, healthy volunteers were given 2% lidocaine with 1/80,000 epinephrine or 2% lidocaine with 1/80,000 epinephrine + 0.5% bupivacaine, after which pain was produced with a pulp tester. No difference was found in the time until onset of anesthetic effect between the preparations. However, the duration of anesthetic effect was longer with both lidocaine and bupivacaine than with lidocaine alone. Next, patients undergoing dental surgery were given one of the anesthetic preparations, after which serum concentrations of the anesthetics and epinephrine were measured. The maximal serum concentration of lidocaine was higher and was reached sooner after injection in patients receiving lidocaine alone (1.74 microgram/ml after 5 min) than in patients receiving both anesthetics (0.85 microgram/ml after 3 min). The mean maximal serum concentration of lidocaine was higher in patients receiving lidocaine alone (1.77 +/- 0.03 microgram/ml) than in those receiving both anesthetics (0.99 +/- 0.45 microgram/ml). Furthermore, the mean plasma concentration of epinephrine 1 min after injection was significantly higher in patients receiving lidocaine alone (0.671 ng/ml) than in patients receiving both lidocaine and bupivacaine (0.323 ng/ml). The results of this study suggest that the combination of lidocaine with epinephrine and bupivacaine produces lower systemic levels of the anesthetic and epinephrine and a longer duration of activity than lidocaine with epinephrine alone for local dental anesthesia.
PMCID: PMC2148928  PMID: 9481966
19.  The effectiveness of topical anesthesia and vibration in alleviating the pain of oral injections. 
Anesthesia Progress  1997;44(3):87-89.
The goal of the research was to compare the effectiveness of vibration with that of a topical anesthetic in reducing the pain of local anesthetic injections. Injections were given adjacent to maxillary premolars in four locations in 61 patients. Before injection, sites received either placebo or topical anesthetic with or without vibration. Patients rated the injection pain on a five-point scale. The topical anesthetic caused a statistically significant decrease in pain values; however, the amount of decrease was of questionable clinical significance.
PMCID: PMC2148927  PMID: 9481967
20.  Peripheral opioid analgesia in teeth with symptomatic inflamed pulps. 
Anesthesia Progress  1997;44(3):90-95.
The purpose of this study was to investigate the ability of low-dose fentanyl to produce analgesia when administered via the periodontal ligament injection in teeth with symptomatic, inflamed pulps. All subjects presented for emergency treatment with moderate to severe pain and had a posterior tooth with a clinical diagnosis of irreversible pulpitis. Twenty subjects randomly received either 10 micrograms fentanyl citrate or saline placebo via the periodontal ligament injection in a double-blind manner. The subjects rated their pain prior to injection and rated pain intensity and pain half gone for 59 min postinjection. Low-dose fentanyl delivered via the periodontal ligament injection in inflamed teeth provided significantly greater analgesia than the saline placebo (P < 0.05). Since the dose of fentanyl used was less than the dose required to provide analgesia by a central mechanism, the results of this study may be consistent with a peripheral opioid mechanism of action.
PMCID: PMC2148926  PMID: 9481968
21.  Effects of block analgesia on attenuating intraoperative stress responses during oral surgery. 
Anesthesia Progress  1997;44(3):101-105.
Surgical intervention affects cardiorespiratory function and deteriorates the homeostatic mechanisms. The aim of this study was to evaluate the effect of block analgesia, which may minimize the intraoperative stress responses during oral surgery. In addition, we evaluated whether block analgesia could lessen the anesthetic requirements. Twenty-eight operative patients were randomly allocated to one of four groups: group 1, 1.3MAC without block analgesia; group 2, 1.6MAC without block analgesia; group 3, 1.0MAC with block analgesia; and group 4, 1.3MAC with block analgesia. Systolic blood pressure (SBP), heart rate (HR), and plasma norepinephrine levels (NE) were measured and compared. Results showed that the increases in SBP, HR, and NE in groups 1 and 2 were greater than those in groups 3 and 4. SBP elevation in group 1 was the greatest among all groups. These results suggest that block analgesia appears to be effective for preventing hyperreactivity of the sympathetic nervous and endocrine systems. In conclusion, general anesthesia combined with block analgesia assures safer anesthesia for patients with cardiovascular diseases or elderly patients who require cardiovascular stability during surgery.
PMCID: PMC2148925  PMID: 9481970
22.  Pulmonary edema following postoperative laryngospasm: case reports and review of the literature. 
Anesthesia Progress  1997;44(3):110-116.
Pulmonary edema that follows upper airway obstruction may occur in a variety of clinical situations. The predominant mechanism is forced inspiration against a closed or occluded glottis, inducing large intrapleural and transpulmonary pressure gradients favoring the transudation of fluid from the pulmonary capillaries into the interstitium. Postanesthetic laryngospasm has been implicated as the most frequent cause of this syndrome in adults. Risk factors for development of postlaryngospasm pulmonary edema include difficult intubation; nasal, oral, or pharyngeal surgical site; and obesity with obstructive apnea. The syndrome is recognized by development of hypoxia shortly (1-90 min) after a laryngospasm. A chest radiograph will reveal a symmetric bilateral infiltrate with normal heart size. Cardiogenic pulmonary edema and aspiration must be ruled out. Treatment is directed at correction of hypoxia with supplemental oxygen and use of diuretics (furosemide). Occasionally patients may require intubation.
PMCID: PMC2148924  PMID: 9481972
23.  The Training of Operator-Anesthetists 
Anesthesia Progress  1997;44(3):81-82.
PMCID: PMC2148932  PMID: 19598712
24.  The influence of meperidine and nitrous oxide on respiratory depression in rats. 
Anesthesia Progress  1997;44(2):45-48.
Narcotic sedation is commonly accomplished with nitrous oxide (N2O) coadministration. Concerns regarding respiratory morbidity and mortality with drug combinations have been reported in the literature, particularly in patients not receiving supplemental oxygen (O2). The purpose of this investigation was to determine the effect of meperidine alone and in combination with N2O on respiration in laboratory rats by evaluating cardiovascular and arterial blood gas data. Fifty-four Sprague-Dawley rats were assigned to one of six groups (nine per group). Groups were allocated based upon the dosage of meperidine administered (0, 4.0, or 8.0 mg/kg intraperitoneally [i.p.]) and exposure to N2O (50% with oxygen) or O2 (100%). Following meperidine administration, animals were placed into a sealed chamber through which flowed either N2O or O2. Arterial blood was obtained, at baseline and at 15-min intervals, from a femoral artery catheter and pH, O2, CO2 (mm Hg), and oxygen saturation (%) were determined. Plasma samples were analyzed using a System 1306 pH/blood gas analyzer. Group comparisons demonstrated that: (a) N2O coadministration, in animals pretreated with meperidine, did not result in increased arterial CO2 levels, and (b) as expected, arterial O2 levels in all groups increased significantly from preexposure baseline values (P < 0.05). This investigation demonstrated that the coadministration of N2O to meperidine-sedated animals did not enhance respiratory depression.
PMCID: PMC2148837  PMID: 9481959
25.  Epinephrine at doses used in dentistry deteriorates platelet retention rate. 
Anesthesia Progress  1997;44(2):59-63.
Epinephrine promotes platelet aggregation through alpha 2 receptor-mediated mechanisms. In this study, the change in the platelet retention rate (PRR) was investigated before and after submucosal epinephrine injection with or without lidocaine in oral surgical patients during isoflurane-nitrous oxide anesthesia. Thirty-nine consenting patients participated in this study. Subjects were allocated in one of five groups depending on the solution injected, the diclofenac supplement, and the patients' age. PRR was measured immediately before and 5 min after epinephrine injection using a modified form of Saltzman's method. Injection of epinephrine with lidocaine deteriorated PRR, although epinephrine without lidocaine produced no PRR change. Epinephrine at doses used in routine dental practices may activate the platelet aggregating function. Dentists should keep in mind that epinephrine elicits both hemodynamic and platelet-activating effects. The latter may be of clinical importance in some situations.
PMCID: PMC2148836  PMID: 9481962

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