布比卡因和利多卡因肿胀液在局麻吸脂术中的应用效果比较

目的:结合在局麻吸脂术使用布比卡因的经验探讨肿胀液中布比卡因的安全使用、组成及其有效性。方法:选择2013年6月-2019年2月135例不同部位进行局麻负压吸脂的患者为研究对象,肿胀液主要成分为布比卡因和利多卡因,评估应用含布比卡因和利多卡因肿胀液在吸脂术中的药物组成、用量、疗效和安全性。结果:局麻吸脂中含布比卡因结合利多卡因的肿胀液适合于吸脂量低于4800ml的患者,仅含布比卡因一种麻醉药物的肿胀液在吸脂量为3600ml,布比卡因总用量为252mg(文献值为150mg)时未显示毒性;含布比卡因肿胀液组镇痛效果好于利多卡因组,术中起效快,术后1~4d无痛苦、恢复快、愈合好、并发症少、住院时间缩短一半。结论:布比卡因及布比卡因结合利多卡因的肿胀液在局麻吸脂中具有镇痛效果好、手术安全等优点,为其进一步应用提供了宝贵经验。证明布比卡因、尤其是布比卡因结合利多卡因作为肿胀液的麻醉药物值得进一步推广。     

Comparison of Ropivacaine and Lidocaine for Intravenous Regional Anesthesia in Volunteers: A Preliminary Study on Anesthetic Efficacy and Blood Level

Background: Ropivacaine may be useful for intravenous regional anesthesia, but its anesthetic effectiveness and toxicity have not been evaluated.

Methods: Two doses of ropivacaine (1.2 and 1.8 mg/kg) and one dose of lidocaine (3 mg/kg) were compared for intravenous regional anesthesia in 15 volunteers. An arm tourniquet was inflated for 30 min after injection and then deflated in two cycles. Sensory block was measured by response to touch, cold, pinprick, and transcutaneous electric stimulation, and motor function was measured by hand grip strength and muscle power. Median, ulnar, radial, and musculocutaneous nerve functions were tested before local anesthetic injection and then at 5-min intervals until blocks resolved. The plasma ropivacaine and lidocaine concentrations were determined from arterial and venous blood samples drawn from the unanesthetized arm.

Results: Sensory and motor blocks were complete within 25 min and 30 min, respectively, in all three treatment groups. However, recovery of sensory and motor block after tourniquet release was slowest in the high-dose ropivacaine group. Anesthesia to pinprick and transcutaneous electric stimulation was sustained in all the volunteers in the high-dose ropivacaine group for 55 min and 85 min, respectively, whereas complete recovery was observed in the lidocaine group (P = 0.008) and partial recovery in the low-dose ropivacaine group (P < 0.05) during the same period. Motor block also was sustained in the high-dose ropivacaine group for 70 min, which was significantly longer than in the lidocaine group (P < 0.05). All volunteers (five of five) given lidocaine and one volunteer given high-dose ropivacaine reported light-headedness and hearing disturbance during tourniquet release when the arterial plasma lidocaine and ropivacaine concentrations were 4.7 +/- 2.1 [micro sign]g/ml (mean) and 2.7 [micro sign]/ml, respectively.     

Modifying the Baricity of Local Anesthetics for Spinal Anesthesia by Temperature Adjustment: Model Calculations

Background: Although local anesthetics (LAs) are hyperbaric at room temperature, density drops within minutes after administration into the subarachnoid space. LAs become hypobaric and therefore may cranially ascend during spinal anesthesia in an uncontrolled manner. The authors hypothesized that temperature and density of LA solutions have a nonlinear relation that may be described by a polynomial equation, and that conversion of this equation may provide the temperature at which individual LAs are isobaric.

Methods: Density of cerebrospinal fluid was measured using a vibrating tube densitometer. Temperature-dependent density data were obtained from all LAs commonly used for spinal anesthesia, at least in triplicate at 5[degrees], 20[degrees], 30[degrees], and 37[degrees]C. The hypothesis was tested by fitting the obtained data into polynomial mathematical models allowing calculations of substance-specific isobaric temperatures.

Results: Cerebrospinal fluid at 37[degrees]C had a density of 1.000646 +/- 0.000086 g/ml. Three groups of local anesthetics with similar temperature (T, [degrees]C)-dependent density ([rho]) characteristics were identified: articaine and mepivacaine, [rho]1(T) = 1.008-5.36 E-06 T2 (heavy LAs, isobaric at body temperature); L-bupivacaine, [rho]2(T) = 1.007-5.46 E-06 T2 (intermediate LA, less hypobaric than saline); bupivacaine, ropivacaine, prilocaine, and lidocaine, [rho]3(T) = 1.0063-5.0 E-06 T2 (light LAs, more hypobaric than saline). Isobaric temperatures ([degrees]C) were as follows: 5 mg/ml bupivacaine, 35.1; 5 mg/ml L-bupivacaine, 37.0; 5 mg/ml ropivacaine, 35.1; 20 mg/ml articaine, 39.4.     

Possible Mechanism of Irreversible Nerve Injury Caused by Local Anesthetics: Detergent Properties of Local Anesthetics and Membrane Disruption

Background: Irreversible nerve injury may result from neural membrane lysis due to the detergent properties of local anesthetics. This study aimed to investigate whether local anesthetics display the same properties as detergents and whether they disrupt the model membrane at high concentrations.

Methods: Concentrations at which dodecyltrimethylammonium chloride and four local anesthetic (dibucaine, tetracaine, lidocaine, and procaine) molecules exhibit self-aggregation in aqueous solutions were measured using an anesthetic cation-sensitive electrode. Light-scattering measurements in a model membrane solution were also performed at increasing drug concentrations. The concentration at which drugs caused membrane disruption was determined as the point at which scattering intensity decreased. Osmotic pressures of anesthetic agents at these concentrations were also determined.

Results: Concentrations of dodecyltrimethylammonium chloride, dibucaine, tetracaine, lidocaine, and procaine at which aggregation occurred were 0.15, 0.6, 1.1, 5.3, and 7.6%, respectively. Drug concentrations causing membrane disruption were 0.09% (dodecyltrimethylammonium chloride), 0.5% (dibucaine), 1.0% (tetracaine), 5.0% (lidocaine), 10.2% (procaine), and 20% (glucose), and osmotic pressures at these concentrations were 278, 293, 329, 581, 728, and 1,868 mOsm/kg H2O, respectively.     

腰奇穴麻醉与腰俞穴麻醉、局部麻醉临床对比试验研究

为探索一种安全可靠用于肛门会阴和直肠下段手术较理想的穴位麻醉方法,采用随机单盲分组系统观察了腰奇穴麻醉试验组100例,腰俞穴麻醉（对照1组）与局部麻醉（对照2组）各100例,应用于肛肠科手术麻醉。结果试验组与对照l组比较在同等用药剂量下其麻醉效果前者优于后者,与对照2组比较则局部麻醉痛苦大（多次穿刺）,且不宜用于高位脓肿和肛瘘根治术的麻醉。结果表明,腰奇穴麻醉具有选穴定位准确,操作简便容易掌握,用药量少,麻醉时间长,毒副作用小,使用安全的优点,是用于肛肠科手术较理想的麻醉方法。     

Hypoxic Contraction of Isolated Rabbit Mesenteric Veins: Contribution of Endothelium and Attenuation by Volatile Anesthetics

Background: Acute systemic hypoxia induces mesenteric venoconstriction in intact rabbits in part because of an increase in chemoreflex-mediated sympathetic efferent nerve activity. Inhaled anesthetics attenuate this reflex response. The direct effects of hypoxia on mesenteric veins are unknown. The purpose of the current study was to examine the effects of hypoxia on isolated rabbit mesenteric capacitance veins and to determine the effects of halothane, isoflurane, and enflurane on the responses to hypoxia.

Methods: Isometric tension was measured before, during, and after 10 min of hypoxia in the rings of either quiescent or norepinephrine contracted veins, with or without endothelium. Effects of various pharmacologic agents and volatile anesthetics on the responses to hypoxia were examined.

Results: Hypoxia augmented contractions to norepinephrine and phenylephrine only in endothelium-intact veins. The hypoxic response was inhibited by phentolamine (alpha-adrenoceptor antagonist) and abolished in the absence of extracellular Calcium2+. There were no effects of propranolol (beta-adrenoceptor antagonist), ryanodine (a sarcoplasmic reticulum Calcium2+ depleter), indomethacin (cyclooxygenase inhibitor), or nordihydrogualaretic acid (lipoxygenase inhibitor), L-NAME an inhibitor of nitric oxide synthase) enhanced basal sensitivity of veins to norepinephrine but had no effect on the response to hypoxia. Nicardipine (a blocker of voltage-gated calcium channels) depressed the hypoxic contraction by 86 plus/minus 5%, phosphoramidon (an inhibitor of endothelin-converting enzyme) by 82 plus/minus 8%, and BQ-123 (a specific endothelin-1 receptor antagonist) by 47 + 10%. Volatile anesthetics (1.0 MAC) inhibited responses to hypoxia in the absence as well as presence of L-NAME.     

The Efficacy of Liposomal Bupivacaine Over Traditional Local Anesthetics in Periarticular Infiltration and Regional Anesthesia During Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BackgroundSince its Food and Drug Administration approval in 2011 as a local anesthetic for postsurgical analgesia, liposomal bupivacaine (LB) has been incorporated into the periarticular injection (PAI) of many knee surgeons. The slow release of this medication from vesicles should significantly extend the duration of its analgesic effect, but current evidence has not clearly demonstrated this benefit.MethodsWe systematically searched electronic databases including PubMed, MEDLINE, Cochrane Library, EMBASE, ScienceDirect, and Scopus, as well as the Journal of Arthroplasty web page for relevant articles. All calculations were made using Review Manager 5.3.ResultsWe identified 42 studies that compared LB to an alternate analgesic modality. Seventeen of these studies were controlled trials that were included in meta-analysis. Significant differences were seen in pain scores with LB over a peripheral nerve block (mean difference = 0.45, P = .02) and LB over a traditional PAI (standard mean difference = ?0.08, P = .004).ConclusionWhile LB may offer a statistically significant benefit over a traditional PAI, the increase in pain control may not be clinically significant and it does not appear to offer a benefit in reducing opioid consumption. However, there is no standardization among current studies, as they vary greatly in design, infiltration technique, and outcome measurement, which precludes any reliable summarization of their results. Future independent studies using a standardized protocol are needed to provide clear unbiased evidence.     

The Effect of Anesthesia on Intraoperative and Postoperative Bleeding during Abdominal Prostatectomies: A Comparison of Neurolept Anesthesia, Halothane Anesthesia and Epidural Anesthesia

Intraoperative blood loss was measured during abdominal prostatectomies in 213 patients anesthetized with neurolept anesthesia, halothane anesthesia and epidural anesthesia. In 55 of these patients, postoperative bleeding was also measured. The average intraoperative blood loss with neurolept anesthesia was 8.2 ± 5 ml/min, with halothane anesthesia 6.6 ± 6.3 ml/min and with epidural anesthesia 3.8 ± 2.3 ml/min. The difference of blood loss in the epidural group and in the groups receiving general anesthesia is highly significant.
Average systolic and diastolic blood pressures were lower during operation in the epidural group than in the other two groups. Statistical analyses failed, however, to show a significant correlation between blood pressures and blood loss in the individual patient. Thus, the ultimate explanation for the diminished bleeding associated with epidural anesthesia is not definitely ascertained. The average postoperative bleeding was not significantly different among the three anesthetic groups.     

Laryngeal Mask Airway in Pediatric Practice: A Prospective Study of Skill Acquisition by Anesthesia Residents

Background: A prospective study was conducted to determine the rate of skill acquisition with the laryngeal mask airway in pediatric anesthesiology practice. The aim of the study was to provide information about the amount of supervised training required before satisfactory levels of skill were achieved.

Methods: Eight anesthesia residents in their third year of training with no prior experience using the laryngeal mask airway were observed using the device in 75 pediatric patients each (600 patients in total). Residents were given standardized guidelines for laryngeal mask airway usage in accordance with the manufacturer's recommendations and followed a predetermined protocol for anesthetic management. Induction was achieved with propofol followed by either a propofol infusion or isoflurane and either controlled or spontaneous ventilation as clinically indicated. Predefined major and minor problems were documented during the induction, maintenance, and recovery phases of anesthesia by a randomly selected supervising consultant trained in the study protocol and problem definitions.

Results: The total number of problems was 189 occurring in 121 children. Fifty-five children had one problem, sixty-four children had two problems, and two children had three problems. Of the problems, 77 were major and 112 were minor. The problem rate per patient for overall, major, and minor problems was 31.5%, 12.8%, and 18.7%, respectively. The problem rate comparing the first to last epochs of 15 uses decreased from 62% to 2% for overall problems, 23% to 2% for major problems, and 39 to 1% for minor problems. The residents with the most problems in the final epoch had problem rates of less than 10% after 60 uses. There was a significant decrease in the overall problem rate for induction, maintenance, and recovery (P < 0.05). The major problem rate decreased significantly for induction and maintenance (p < 0.05), but not for recovery. The minor problem rate decreased significantly for induction and recovery (P < 0.05).     

Sciatic Nerve Blockade in Infant, Adolescent, and Adult Rats: , A Comparison of Ropivacaine with Bupivacaine

Background: Ropivacaine is a newly introduced local anesthetic. anesthetic. No data are available regarding its safety, efficacy, or sensory-selectivity in children. The sciatic block duration and systemic toxicity of bupivacaine and ropivacaine were compared compared among infant, adolescent, and adult rats.

Methods: Infant, adolescent, and adult rats received blocks with ropivacaine or bupivacaine. Nociceptive, proprioceptive, and motor blockade were assessed. Systemic effects (contralateral leg analgesia, seizures, respiratory distress, apnea) were quantified. Plasma local anesthetic concentrations were measured at terminal apnea.

Results: Nerve blockade for a given absolute dose lasted longer in infants than in older rats for both drugs. Block duration duration from ropivacaine generally was the same as or slightly shorter than bupivacaine. There was no difference in sensory-selectivity between the drugs. Doses required to induce all systemic toxicity indices were inversely related to age (e.g., the lethal dose in 50% of animals [LD50] of ropivacaine in infants is 155 mg/kg; in adults it is 54 mg/kg). All indices of toxicity occurred at higher doses per kilogram for ropivacaine than bupivacaine, at all ages (e.g., the LD50 of bupivacaine in infants is 92 mg/kg; in adults it is 30 mg/kg). Plasma concentrations at terminal apnea were higher for ropivacaine than for bupivacaine at all ages, and were higher in infants than in older rats.     

Skeletal Muscle Oxygen Pressure Fields in Rats: A Study of the Normal State and the Effects of Local Anesthetics, Local Trauma and Hemorrhage

The MDO (Mehrdraht Dortmund Oberflache) oxygen electrode was used for studies of oxygen pressure fields in rat skeletal muscle. With this multiwire oxygen electrode, the three-dimensional oxygen pressure field was measured and presented as a two-dimensional frequency distribution, i.e. a histogram. Statistical analysis of the histograms was carried out with the two-sample Kolmogorov-Smirnov test. This eliminated the influence of mean values, since these do not always represent the actual biological situation. The oxygen pressure fields in skeletal muscle of anesthetized normal rats breathing air spontaneously were investigated. When the oxygen pressure in the inspired gas was changed (50% and 95%), changes were seen in muscle oxygen pressure curves. The normal oxygen pressure field histograms were compared with those obtained after local anesthesia, after local trauma to the muscle and after hemorrhage. After local anesthesia the histograms were unchanged. Significant changes in the distribution types of the histograms were found after trauma in all rats studied. After hemorrhage significant changes, similar to those seen after trauma, were found in 15 of the 23 rats studied. Local blood flow was also measured with the ¹³³xenon-clearance method in the hemorrhage experiments. No correlation was found between the changes in the mean oxygen tension values and the changes in ¹³³xenon-clearance.     

Interscalene Brachial Plexus Block: Area of Analgesia, Complications and Blood Concentrations of Local Anesthetics

In a prospective clinical study including 100 patients, the consequences of using the interscalene approach to block the brachial plexus were investigated according to the area of analgesia, complications and blood concentrations of local anesthetics. Sufficient analgesia of the shoulder and the upper part of the arm was obtained in 98–99% of the cases, whilst the area of analgesia in the forearm and the hand was more variable. In two groups, with 10 patients in each group, the blood concentration was measured during the first 50 mill after injection in the neurovascular sheath by either the interscalene or the axillary approach. The peak values were at the same level in the two groups, but there was a much more rapid rise in concentration in the interscalene group. No toxic reactions were seen. The complications were in accordance with those reported in other publications.