Density of spinal anaesthetic solutions of bupivacaine, levobupivacaine, and ropivacaine with and without dextrose

Background. Spread of intrathecal local anaesthetics is determinedprincipally by baricity and position of the patient. Hypobaricsolutions of bupivacaine are characterized by an unpredictablespread of sensory block whereas addition of dextrose 80 mg ml^–1provides a predictable spread but to high thoracic levels. Incontrast, dextrose concentrations between 8 and 30 mg ml^–1have shown reliable and consistent spread for surgery. Hence,the aim of this study was to determine the density of bupivacaine,levobupivacaine, and ropivacaine with and without dextrose atboth 23 and 37°C before embarking on clinical studies. Methods. Density (mg ml^–1) was measured using the methodof mechanical oscillation resonance, accurate to five decimalplaces on 1250 samples. 500 density measurements were performedin a randomized, blind fashion at 23 and 37°C on 10 plainsolutions of bupivacaine (2.5, 5, and 7.5 mg ml^–1) levobupivacaine(2.5, 5, and 7.5 mg ml^–1) and ropivacaine (2, 5, 7.5,and 10 mg ml^–1). Following this, 750 density measurementswere taken at 23 and 37°C on the 5 mg ml^–1 solutionsof bupivacaine, levobupivacaine, and ropivacaine with addeddextrose (10, 20, 30, 50, and 80 mg ml^–1). Results. There was a linear relationship between density anddextrose concentration for all three local anaesthetics (R²=0.99)at 23 and 37°C. The mean density of levobupivacaine 5 mgml^–1 was significantly greater than the densities of bupivacaine5 mg ml^–1 and ropivacaine 5 mg ml^–1 after adjustingfor dextrose concentration using analysis of covariance. Thisdifference existed both at 23 and 37°C. The mean (SD) densityof levobupivacaine 7.5 mg ml^–1 was 1.00056 (0.00003) mgml^–1, the lower 0.5% percentile (1.00047 mg ml^–1)lying above the upper limit of hypobaricity for all patientgroups. Conclusions. The density of local anaesthetics decreases withincreasing temperature and increases in a linear fashion withthe addition of dextrose. Levobupivacaine 5 mg ml^–1 hasa significantly higher density compared with bupivacaine 5 mgml^–1 and ropivacaine 5 mg ml^–1 at 23 and 37°Cboth with and without dextrose. Levobupivacaine 7.5 mg ml^–1is an isobaric solution within all patient groups at 37°C. Br J Anaesth 2004; 92: 547–51     

Reconstruction of a real-world car-to-pedestrian collision using geomatics techniques and numerical simulations

The aim of this study is to provide an improved method for traffic accident reconstruction based on geomatics techniques and numerical simulations. A combination of various techniques was used. First, an unmanned aerial vehicle (UAV), laser scanner and structured-light scanner were used to obtain information on the accident scene, vehicle and victim. The collected traces provided detailed initial impact conditions for subsequent numerical simulations. Then, multi-body system (MBS) simulations were conducted to reconstruct the kinematics of the car-to-pedestrian collision. Finally, a finite element (FE) simulation using the THUMS model was performed to predict injuries. A real-life vehicle-pedestrian collision was used to verify the feasibility and effectiveness of this method. The reconstruction result revealed that the kinematic and injury predictions of the numerical simulations effectively conformed to the surveillance video and investigation of the actual accident. UAV photogrammetry was demonstrated to be more efficient in accident data collection than hand sketch and measurement, and 3D laser scanning enabled an easier and more accurate modeling process of vehicle. The present study shows the feasibility of this method for use in traffic accident reconstruction.     

靶向Wnt10b的小干扰RNA抑制胚胎皮肤毛囊发育的初步研究

目的 利用小干扰RNA(siRNA)抑制皮肤Wnt10b基因的表达,观察Wnt10b基因沉默能否抑制毛囊的发育并探讨其潜在机制.方法 化学合成siRNA-Wnt10b,将siRNA转染体外培养的胎鼠背部皮肤,荧光定量PCR检测转染后不同时间段皮肤组织Wnt10b和p-连环蛋白(β-catenin) mRNA的表达,Western blot检测转染后72 h皮肤组织的Wnt10b和β-catenin蛋白含量.将转染后72 h的皮肤组织石蜡包埋、切片,HE染色,镜下观察各组毛囊发育情况并做统计学处理.结果 siRNA-Wnt10b转染后的24、48 h,胎鼠背部皮肤Wnt10b mRNA的表达呈不同程度下降;但β-catenin mRNA表达未随Wnt10b mRNA水平的起伏而明显波动;转染后72 h,Wnt10b蛋白和β-catenin的蛋白表达同时减少,新形成毛囊数量也随之减少(t=3.254,P=0.002).结论 在体外器官培养的环境中,siRNA-Wnt10b能够抑制胎鼠背部皮肤组织Wnt10b蛋白的表达,减少新形成毛囊的数量;Wnt10b可能只在蛋白水平上调控细胞β-catenin的表达.     

不同程度急性胆管炎患者的胆汁细菌培养

目的 分析不同程度急性胆管炎患者术中胆汁细菌培养的阳性率和细菌谱差异.方法 回顾分析自2008年1月至2011年10月期间该院急性胆管炎患者241例,根据日本东京指南标准将患者分为不同等级,全部患者均经手术治疗,术中常规取胆汁送细菌培养,记录胆汁培养结果,数据经SPSS 16.0软件分析统计分析.结果 该组细菌培养阳性率75.1％,共培养出细菌244株,其中革兰氏阳性菌139株,阴性菌99株,酵母菌6株.前五位细菌分别是大肠埃希菌、粪肠球菌、铅黄肠球菌、铜绿假单胞菌、肺炎克雷伯菌.轻度与重度胆管炎的感染阳性率差异有统计学意义(P＜0.05),但轻度与中度(P=0.141)、中度与重度(P=0.647)急性胆管炎阳性率差异无统计学意义.革兰氏阴性菌在中、重度胆管炎患者分布较革兰氏阳性菌普遍(P＜0.05).在中、重度急性胆管炎中,多重细菌感染比例较高(P＜0.05).结论 胆道感染细菌仍以大肠杆菌及肠球菌为主,重型急性胆管炎较轻型急性胆管炎细菌培养阳性率高.革兰氏阴性菌在中、重度患者中的分布较阳性菌广,重型急性胆管炎中多重细菌感染较普遍.     

Role of Breast Surgery in BRCA Mutation Carriers

BRCA mutation carriers have a life-long breast cancer risk between 55 and 85% and a high risk of developing breast cancer at a very young age, depending on the type of mutation. The risk of developing contralateral breast cancer after a first breast cancer is elevated up to 65%, especially in case of BRCA1 mutation and young age at the first breast cancer. Since bilateral prophylactic mastectomy is associated with a risk reduction of 90–95% of developing primary or contralateral breast cancer, this option is a key point within the counseling process for patient information and shared decision-making of mutation carriers. Although the local control after breast-conserving therapy in mutation carriers seems to be comparable to that of sporadic breast cancer patients, individual patient information and counseling should include all alternative procedures of oncologically adequate mastectomy techniques and immediate reconstruction. Excellent cosmetic results, high levels of life quality, and good patient acceptance can be achieved with the recent developments in reconstructive surgery of the breast.     

Anaesthetic management of a parturient with pulmonary stenosis and aortic incompetence for Caesarean section

Anaesthetic management of Caesarean section in a parturientwith severe pulmonary stenosis and aortic regurgitation is described.The valvular sequelae resulted from previous unsuccessful surgicalcorrection (Ross procedure) of congenital aortic stenosis. Thiscase demonstrates the importance of multi-disciplinary assessmentand careful anaesthetic planning, to avoid deterioration inperioperative cardiac performance in parturients with complexvalvular disease. Br J Anaesth 2003; 90: 241–3     

Haemodynamic changes during high spinal anaesthesia in children having open heart surgery

BACKGROUND: This prospective series examined the haemodynamic effects of high spinal anaesthesia in combination with light general anaesthesia in infants and children undergoing open heart surgery who were candidates for immediate or early postoperative extubation. METHODS: After midazolam premedication and sevoflurane inhalation induction, 30 patients, aged 7 months to 13 years, who were undergoing open heart surgery, received spinal anaesthetics with 0.5% tetracaine D10 mixed with morphine. The spinal blocks were placed at the L2,3 or L3,4 interspace with cephalad spread being promoted by positioning the patient in 30 degrees of Trendelenburg for a minimum of 10 min. Maintenance of anaesthesia was with isoflurane 0.2-0.5% in 70% nitrous oxide to maintain heart rate and blood pressure within 20% of postinduction baseline values. Haemodynamic values were recorded at predetermined timed intervals and intraoperative events up to and including aortic cannulation. For analysis of the data, patients were divided into four age groups (< 1 years, 1-3 years, 4-6 years and > 7 years). RESULTS: Haemodynamic stability was demonstrated in all four age groups. Statistically significant slowing of the heart rate did occur in the groups older than 1 year at 25 min, although clinically significant bradycardia requiring treatment never occurred. Hypotension did occur during specific surgical manipulations but recovered spontaneously. Atropine, fluid boluses and vasopressors were never used. At the conclusion of surgery, all patients met extubation criteria and could move all four extremities. CONCLUSIONS: High spinal anaesthesia with hyperbaric tetracaine and morphine in combination with light general anaesthesia is well tolerated haemodynamically by the paediatric population studied.     

Hemodynamic and catecholamine responses during tracheal intubation using a lightwand device (Trachlight) in elderly patients with hypertension

Purpose.Tracheal intubation using a lightwand device (Trachlight) should minimize hemodynamic change by avoiding direct-vision laryngoscopy. We evaluated hemodynamic and catecholamine responses during tracheal intubation using a Trachlight in elderly patients with hypertension.Methods.Twenty-six hypertensive patients aged over 65 years undergoing orthopedic surgery were randomly divided into two groups, group L (n = 13) and group T (n = 13). Anesthesia was induced with fentanyl (2g·kg^–1) and propofol (1.5mg·kg^–1), and then muscle relaxation was obtained with vecuronium (0.15mg·kg^–1). The trachea was intubated with either a Macintosh laryngoscope (group L) or a Trachlight (group T). Hemodynamics, plasma catecholamine concentrations, and arterial blood gases were measured before the induction of anesthesia (T0), before tracheal intubation (T1), immediately after tracheal intubation (T2), and 3min after tracheal intubation (T3).Results.The intubation time was shorter in group T than in group L (12.6 ± 1.7 vs 23.5 ± 2.9s, mean ± SE; P 0.01). Compared with the preinduction (T0) value, systolic blood pressure (SBP) showed a significant decrease at T1 and T3 in group L and at T1, T2, and T3 in group T. The heart rate (HR) and plasma norepinephrine (NE) concentration showed no change in either group throughout the time course, whereas the plasma epinephrine (E) concentration showed a significant decrease at T2 and T3 in both groups. The mean values of the rate-pressure product (RPP: HR × SBP) were less than 15 000 after tracheal intubation in both groups. There was no significant difference in hemodynamic or catecholamine responses between groups at any point. No patient had ischemic ST-T changes in either group.Conclusion.A lightwand has no advantage over a laryngoscope in terms of hemodynamic and plasma catecholamine responses to tracheal intubation in elderly patients with hypertension, despite a shorter intubation time.     

Imprint cytology versus frozen section: intraoperative analysis of sentinel lymph nodes in breast cancer

Background: Intraoperative analysis of the sentinel node status in breast cancer adds the benefit of proceeding to axillary dissection at the same time as the primary breast operation, without the need for a second trip to theatre. However, the method of intra­operative analysis must be both rapid and accurate for use in this setting. Methods: A prospective series of 20 consecutive patients in one hospital who underwent sentinel node biopsy was performed. Intraoperative evaluation by imprint cytology and frozen section was compared with the final histopathological results. The time taken for both procedures was recorded. Results: A total of 21 sentinel node procedures was performed. The sentinel node was found in 20 procedures (95%). The average time to perform intraoperative pathological analysis was 17 min (range: 5?35 min). Of the eight positive sentinel nodes, five were positive on imprint cytology alone and five were positive on frozen section alone (62.5% accuracy). The statistical false negative rate was 18.8% and the ‘false reassurance rate’ (patients with an initially negative node that was subsequently positive on formal histology who required a second trip to theatre for axillary dissection) was 37.5%. All patients with a negative sentinel node had a negative axilla. Conclusions: Intraoperative analysis of sentinel lymph nodes in breast cancer can be performed quickly. Imprint cytology and frozen section show comparable accuracy in predicting sentinel node status.     

Bacterial contamination of epidural needles after multiple skin passes

Background. Infection and epidural abscess are important complicationsof epidural analgesia. Difficult insertion may be associatedwith an increased risk of bacterial contamination of the epiduralneedle or catheter. Methods. Bacterial contamination of epidural needles and trocarsafter difficult epidural insertion, defined as two or more skinpasses, was assessed in 38 obstetric and ten gynaecologicalpatients. Results. There was no bacterial growth on any of the 48 epiduralneedles or trocars despite the mean (range) insertion time being20 (10–30) min and the number of insertion attempts being3 (2–4). Conclusions. Difficult epidural insertion is not associatedwith an increased risk of needle contamination and is thereforean unlikely source of epidural infection. Br J Anaesth 2002; 89: 922–4