超声引导椎管内麻醉穿刺在剖宫产术的应用

目的 评估超声技术在产科椎管内麻醉中的临床应用价值.方法 选择单胎足月择期行剖宫产手术的产妇纳入本研究.纳入标准:年龄20～35岁,美国麻醉医师协会麻醉风险评分(ASA)Ⅰ级,均无脊柱疾病、中枢神经系统疾病等椎管内麻醉禁忌证;剔除标准:术中改变麻醉方式者.结果 本研究共纳入69例产妇,其中超声组35例,传统组34例.超声组穿刺时间为47.5 (38.0,72.8)s,传统组穿刺时间为56.5(41.0,140.5)s,差异无统计学意义(P=0.087);穿刺次数比较,超声组明显少于传统组(P＜0.05);传统组麻醉后并发症发生率为8.6％,超声组无麻醉后并发症发生;超声测得腰椎(L)3-4椎间隙黄韧带至皮肤距离为(5.0±0.9)cm,实际操作测得硬膜外深度为(5.3±0.8)cm,两者呈正相关(r=0.899,P＜0.01).结论 临床应用超声引导产妇椎管内麻醉穿刺能指导实际操作,减少穿刺时间,提高一次穿刺成功率,并减少麻醉后并发症的发生.     

基础加骶管麻醉在小儿腹部手术中的应用

目的探讨基础麻醉 骶管麻醉在小儿腹部手术中的应用效果。方法对43例小儿腹部手术进行基础麻醉 骶管麻醉,对麻醉效果进行评价。结果麻醉效果满意,无严重并发症发生。结论基础麻醉 骶管麻醉是小儿腹部手术的有效麻醉方法。     

老年患者局部麻醉下施行无张力疝修补术

目的 总结65岁以上老年患者局部麻醉下施行无张力疝修补术治疗腹股沟疝的临床经验。方法 对161例老年腹股沟疝患者临床资料进行回顾性分析。结果 麻醉效果满意，手术时间20～50min，术后24h内可以下床活动，平均住院时间7．6天，术后约4％患者出现尿潴留等并发症。随访1个月～2年未见复发病例。结论 局部麻醉下施行无张力疝修补术具有操作简单、患者痛苦小、恢复快、手术并发症明显降低及住院时间缩短等优点，提高了手术安全性，拓宽了手术适应证，适合老年患者。     

A ventilation strategy during general anaesthesia to reduce postoperative atelectasis

Background. Atelectasis is common during and after general anaesthesia. We hypothesized that a ventilation strategy, without recruitment manoeuvres, using a combination of continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP) and a reduced end-expiratory oxygen fraction (F_ETO₂) before ending mask ventilation with CPAP after extubation would reduce the area of postoperative atelectasis.

Methods. Thirty patients were randomized into three groups. During induction and emergence, inspiratory oxygen fractions (F_IO₂) were 1.0 in the control group and 1.0 or 0.8 in the intervention groups. No CPAP/PEEP was used in the control group, whereas CPAP/PEEP of 6 cmH₂O was used in the intervention groups. After extubation, F_IO₂ was set to 0.30 in the intervention groups and CPAP was applied, aiming at F_ETO₂ < 0.30. Atelectasis was studied by computed tomography 25 min postoperatively.

Results. The median area of atelectasis was 5.2 cm² (range 1.6–12.2 cm²) and 8.5 cm² (3–23.1 cm²) in the groups given F_IO₂ 1.0 with or without CPAP/PEEP, respectively. After correction for body mass index the difference between medians (2.9 cm²) was statistically significant (confidence interval 0.2–7.6 cm², p = 0.04). In the group given F_IO₂ 0.8, in which seven patients were ex- or current smokers, the median area of atelectasis was 8.2 cm² (1.8–14.7 cm²).

Conclusion. Compared with conventional ventilation, after correction for obesity, this ventilation strategy reduced the area of postoperative atelectasis in one of the intervention groups but not in the other group, which included a higher proportion of smokers.     

Seton drainage and fibrin glue injection for complex anal fistulas

Objective The study aimed to evaluate the efficacy of fibrin glue in the treatment of complex anal fistula. Method Thirty consecutive patients with a complex anal fistula underwent glue instillation after an 8 week period of seton drainage. Cure was defined as complete closure of any secondary opening, absence of fistula seepage, and no abscess formation. Results The mean age of the patients (15 males) was 40.5 (range, 22.8–69.1) years. The mean duration of follow‐up was 11.7 (range, 0.2–33.5) months. Complete closure of the fistula was achieved in 17 patients at 1 month but in two patients a delayed abscess occurred. At the end of follow‐up, 15 (50%) patients were considered to have been cured. The success rate was no different in cases of Crohn’s disease or when postoperative antibiotic therapy was given. There was, however, a significant difference in success following regional vs general anaesthesia (68.4 vs 18.2% success, P = 0.02). Conclusion Fibrin glue cured 50% of our first 30 patients, and regional anaesthesia was predictive of success.     

Subpectoral implantation of a cardioverter defibrillator under local anaesthesia

Objective—To evaluate patient acceptability of submuscular implantation of a cardioverter defibrillator (ICD) under local anaesthesia with conscious sedation.
Design—Retrospective review. Patient acceptability in the second half of the study was routinely assessed within 24 hours.
Setting—Regional cardiac centre.
Patients—45 consecutive patients with either aborted sudden death or haemodynamically unstable ventricular tachycardia were referred for ICD im- plantation.
Interventions—A subpectoral implantation technique was employed. Twelve procedures were performed under general anaesthesia. Thirty three patients were sedated with midazolam and diamorphine, and local anaesthesia was achieved with bupivicaine. Ventricular fibrillation for defibrillation threshold testing was induced by alternating current, T wave shock, or ultrarapid burst pacing. Patients were contacted after the procedure to assess acceptability.
Results—32 patients having implantation under local anaesthesia did not recall the surgical procedure. One patient described an awareness of "pushing" as the generator was positioned in the pocket. Seven patients said that the procedure was painless but recalled a test shock, four describing it as mildly uncomfortable. All 33 patients stated that they would be willing to have a second implant under local anaesthesia. Twelve patients who had the implant performed under general anaesthesia had no recollection of the procedure. Mean (SD) total procedure duration was significantly longer in those who had general anaesthesia (93 (16) v 67 (17) minutes; p = 0.0009).
Conclusions—Subpectoral implantation of ICDs may be performed safely with patient acceptability under local anaesthesia with conscious sedation.

Keywords: cardioverter defibrillator;  subpectoral implantation;  local anaesthesia;  pacing     

Pharmacokinetic–pharmacodynamic modelling in anaesthesia

Anaesthesiologists adjust drug dosing, administration system and kind of drug to the characteristics of the patient. They then observe the expected response and adjust dosing to the specific requirements according to the difference between observed response, expected response and the context of the surgery and the patient.The approach above can be achieved because on one hand quantification technology has made significant advances allowing the anaesthesiologist to measure almost any effect by using noninvasive, continuous measuring systems. On the other the knowledge on the relations between dosing, concentration, biophase dynamics and effect as well as detection of variability sources has been achieved as being the benchmark specialty for pharmacokinetic–pharmacodynamic (PKPD) modelling.The aim of the review is to revisit the most common PKPD models applied in the field of anaesthesia (i.e. effect compartmental, turnover, drug–receptor binding and drug interaction models) through representative examples. The effect compartmental model has been widely used in this field and there are multiple applications and examples. The use of turnover models has been limited mainly to describe respiratory effects. Similarly, cases in which the dissociation process of the drug–receptor complex is slow compared with other processes relevant to the time course of the anaesthetic effect are not frequent in anaesthesia, where in addition to a rapid onset, a fast offset of the response is required. With respect to the characterization of PD drug interactions different response surface models are discussed. Relevant applications that have changed the way modern anaesthesia is practiced are also provided.     

Nerve stimulator for regional anaesthesia procedures with automatic interactive closed-loop control

Abstract

Peripheral nerve stimulators have widespread among anaesthesiologists and remain a popular technique. However, in commercial devices, the user has to manually adjust stimulus intensity. Thus, the aim of this study is to propose a method that allows automating the current intensity control. An earlier nerve stimulator prototype was modified to add an accelerometer and an sEMG module. The choice of these two sensors is aimed at the possibility of observing the mechanical and electrical responses of the muscle contraction evoked by the stimulation. The tests were performed in two steps. The first step was to observe how the sensors behave during stimulation and muscle contraction. The second step was to implement a control algorithm and to validate the automation technique. Comparing the two methods, no significant differences were found on procedure time (manual: 12.5?±?2.3; automatic: 11.6?±?1.9; ρ?=0.380) and blockade latency time (manual: 11.6?±?1.1; automatic: 11.9?±?1.2; ρ?=0.524). Comparing needle-nerve distance in manual or automatic mode, no significant differences were found for 1.0?mA, 0.8?mA, 0.5?mA and 0.3?mA. We conclude that the technique for automating the current intensity update, using accelerometer and/or electromyography, is satisfactory. Furthermore, we conclude that the use of the accelerometer alone is sufficient for detection of muscle contraction.     

The value of surveys in obstetric anaesthesia

BackgroundThe Obstetric Anaesthetists’ Association (OAA) has facilitated national surveys in obstetric anaesthesia since 1998. We wanted to examine trends in OAA-approved surveys since this time.MethodsOAA-approved surveys performed between January 1998 and December 2012 were examined for the year they were carried out, the format (postal or electronic), the target group and the response rate. We determined whether each survey was presented or published. For each survey published as a substantive paper, we identified the number of times the publication had been cited. We also surveyed lead obstetric anaesthetists and expert witnesses practising in obstetric anaesthesia on the perceived usefulness of OAA-approved surveys.ResultsOne hundred and thirty-five surveys approved by the OAA were carried out between 1998 and 2012. Response rates have fallen over the years, reaching a current plateau of 65%. Response rates varied with the target group. Seventy-eight percent of surveys were presented and 83% were published in some form. For surveys published as substantive papers (n=34, 25%), the median [IQR (range)] number of citations was 6 [3–11 (0–36)] per publication. Our survey of lead obstetric anaesthetists had a response rate of 62%. Those who replied rated OAA surveys a median [IQR (range)] of 6 [5–7 (1–9)] on a 0–10 scale of usefulness to their clinical practice.ConclusionsResponse rates to OAA-approved surveys have declined but remain acceptable despite an increase in the number of surveys performed. Most surveys were presented or published in some form.