Larsen's syndrome: anaesthetic implications. Six case reports

Six cases were examined to review the important anaesthetic implications of Larsen's syndrome. Potential problems arising in these patients are highlighted and emphasis placed on cervical spine and airway/respiratory management.     

全凭静脉麻醉老龄大鼠海马tau蛋白磷酸化水平与认知功能的关系

目的 探讨咪唑安定、芬太尼、丙泊酚联用对老龄大鼠认知功能的影响以及这种影响是否与海马tau蛋白磷酸化水平有关.方法 雄性18月龄SD大鼠40只,随机分成全麻组和对照组,每组20只.每组分别于处理后第1和第7天各断头处死10只,HE染色光镜下观察海马神经元结构,免疫组化染色法检测海马tall蛋白Thr231和Ser404位点磷酸化蛋白的表达水平.其中后处死大鼠于处理后第1周行水迷宫实验.结果 处理后第1天,全麻组大鼠寻找平台的时间明显长于对照组(P＜0.01),但第2～7天与对照组比较差异无统计学意义.处理后第1天,全麻组海马tau蛋白Thr231位点的磷酸化水平高于对照组(P＜0.05).第7天,两组Thr231、Ser404位点的磷酸化水平差异无统计学意义.光镜下各组大鼠海马神经元结构未见明显异常.结论 咪唑安定、芬太尼、丙泊酚联用可引起老龄大鼠麻醉后第1天出现短暂的认知功能减退,海马tau蛋白Thr231位点的过度磷酸化可能与其有关.     

Patients' desire for information about anaesthesia: Danish attitudes

Background : Patients' desire for information about anaesthesia has been examined in a number of Commonwealth countries but not in Scandinavia. A questionnaire was distributed to form a basis for giving Danish patients more appropriate preoperative information.
Methods : 201 preoperative patients in Denmark were asked to complete a questionnaire. The patients were divided into subgroups according to: age, gender, residential origin, ASA group, educational level, type of anaesthesia planned and number of previous anaesthetics.
Results : Patients from a city area required significantly more information than patients from a rural/urban area about pre-medication drugs, drips/catheters, pain/pain relief and complications. Men more than women preferred to know about dangerous complications. Information about pain /pain relief, duration of anaesthesia, and influence of anaesthesia on daily activities such as eating, drinking, mobilisation was given the highest priority, while unpleasant information such as about complications and needles was given the lowest priority. Meeting the anaesthetist and information about alternative methods of anaesthesia and premedication drugs were given only moderate priority. Ranking information in Denmark was significantly correlated with Scotland, Canada and Australia, despite profound differences in priority. More often than Danish patients, Australian patients felt they had right to know, and especially about complications.
Conclusion : Patients from a city area required more information than patients from a rural/urban area. Information about the influence on daily activities was preferred to unpleasant information. Ranking information in Denmark was correlated with a number of Commonwealth countries.     

Effect of minimizing preoperative fasting on perioperative blood glucose homeostasis in children

Two hundred healthy, unpremedicated children, ages 1–10 years, scheduled for elective outpatient surgery were studied in order to examine the effect of minimizing preoperative fasting on perioperative blood glucose concentrations in paediatric patients. None of the patients ingested solids after midnight. On the day of surgery, the children were assigned to one of two groups. Group A children (n= 113) were not allowed any liquids for at least 6 h prior to surgery (NPO). Children in Group B (n= 87) ingested 10 ml·kg^?1 of apple juice 2–4 h prior to the induction of anaesthesia. All patients received lactated Ringer's solution intraoperatively, unless BG at induction was < 50 mg·dl^?1 (2.8 m·mol·l^?1) in which case dextrose 2.5% in lactated Ringer's solution was administered. None of the patients who received apple juice was hypoglycaemic during induction of anaesthesia. However, two children in the NPO group had blood glucose values ± 50 mg·dl^?1 (2.8 m·mol·l^?1) at the time of induction of anaesthesia. Thirteen (11%) patients in Group A and 6 (7%) patients in Group B showed either no change or a further decrease in their postoperative BG concentration as compared with their induction values. Two of 43 patients in Group A and 2 of 41 patients in Group B had gastric fluid volumes > 0.4 ml/kg. All patients in both groups had gastric pH < 2.5. This study shows that gastric fluid volume and pH following a 2–4 h fast are not different from the values measured in children who were subjected to a traditional fasting period of 6 h or longer. Moreover, apple juice consumed 2–4 h prior to surgery neither buffers gastric pH nor does it modify intraoperative glucose homeostasis in children.     

The effectiveness of sub-Tenon's infiltration of local anaesthesia for cataract surgery

Purpose: To determine if adequate anaesthesia and akinesia could be obtained using an inferonasal quadrant sub-Tenons anaesthesia for cataract surgery.
Methods: The sub-Tenons method of local anaesthesia was used in 50 patients undergoing extracapsular cataract extraction and lens implantation. The technique followed was that described by JD Stevens in his study of 50 patients. Posterior sub-Tenons space was approached through a conjunctival incision in the inferonasal quadrant and the anaesthetic solution delivered by an irrigating cannula. The patients were assessed for residual ocular movements just before surgery. Effectiveness of anaesthesia was assessed during surgery using a verbal pain rating score. Scoring was based on the concept of a visual analogue pain score chart.
Results: Total akinesia was obtained in 20% patients and total anaesthesia in 24% patients. The remainder of the patients had adequate akinesia and anaesthesia to proceed with and complete the surgery.
Conclusion: This method provides satisfactory anaesthesia for cataract surgery.     

Fetal anaesthesia for intrauterine treatment

Fetal anaesthesia was performed 5 times in 1 patient to treat pleural effusions, obtain fetal blood sampling, provide albumin infusion, and establish and replace a pleuro-amniotic indwelling shunt catheter under ultrasound guidance. A maternal epidural catheter was placed and used for epidural anaesthesia for the first 4 anaesthetics. Fetal administration of pancuronium 0.15 mg·kg^?1 via the umbilical vein or 0.25 mg·kg^?1 intramuscularly was enough to produce immobilization without maternal effect. However, maternal pretreatment with intravenous diazepam and fentanyl was required for fetal sedation and analgesia, which was necessary for accurate and safe injection, and for suppression of fetal stress.     

The mechanisms of sodium current inhibition by benzocaine in the squid giant axon

(1) The effects of benzocaine on the ionic currents in the voltage-clamped squid giant axon have been examined under various conditions; intact axons internally perfused with CsF and axons dialysed with tetraethyl-ammonium ions were used. (2) Both the steady state outward (potassium) current and the early transient (sodium) current were reduced by ca. 50% by benzocaine (1 mM). (3) Plots of the changes produced by benzocaine (1 mM) in the Hodgkin-Huxley parameters for the steady state activation (m), the steady state inactivation (h) and the time constants (_m and _h) for activation and inactivation of the sodium current are shown. Them andh curves are shifted in positive and negative directions respectively on the voltage axis. The time constants are not greatly affected. (4) In axons in which the sodium current inactivation had been largely removed by treatment with chloramine T, the sodium current was still reduced by ca. 50% by 1 mM benzocaine and the positive shift in activation remained unchanged. (5) The dependence on benzocaine concentration (for2mM) of the peak sodium current reduction and the shift in steady state inactivation have been determined. (6) It is concluded that in the squid axon the effects on inactivation are not the main reason for the reduction of the sodium current by benzocaine and that, in common with many other neutral anaesthetics, there are at least two sites at which benzocaine acts.     

一氧化氮对异丙酚麻醉作用影响的实验研究

目的　了解一氧化氮(NO)对异丙酚麻醉作用的影响。方法　昆明种小白鼠40只,分为两组组Ⅰ,20只,雌雄不拘,随机分为实验组Ⅰ(n=10)腹腔注射(ip)左旋精氨酸(L-Arg)600mg/kg;对照组Ⅰ(n=10)ip生理盐水0.3ml/10g,30min后,两组分别ip异丙酚120mg/kg。组Ⅱ,20只,雄性,随机分为实验组Ⅱ(n=10)ipN-硝基-左旋精氨酸甲酯(L-NAME)50mg/kg;对照组Ⅱ(n=10)ip生理盐水0.3ml/10g,30min后,分别ip异丙酚110mg/kg。测定各组动物翻正反射消失的起效时间和维持时间。结果　各实验组与对照组翻正反射的消失率(实验组Ⅰ80%,对照组Ⅰ80%,实验组Ⅱ90%,对照组Ⅱ80%)及起效时间(实验组Ⅰ3.3±0.7min,对照组Ⅰ2.7±0.6min,实验组Ⅱ4.8±0.8min,对照组Ⅱ4.7±0.8min)无明显差别。实验组Ⅰ的维持时间(44.0±22.5min)明显短于对照组Ⅰ(70.1±28.1min,P＜0.05),实验组Ⅱ(61.4±20.9min)明显长于对照组Ⅱ(35.5±26.9min,P＜0.05)。结论　改变NO的产量可以影响异丙酚的麻醉维持时间,提示异丙酚的全麻机制可能与NO有关。     

Selection of baseline blood pressure to guide management of hypotension during spinal anaesthesia for caesarean section

IntroductionRecommendations on vasopressor management during caesarean section under spinal anaesthesia suggest maintaining systolic arterial pressure ≥90% of an accurately measured baseline value. The baseline is often taken as the first reading in the operating room. We hypothesise that this reading may not reflect an accurate baseline value.MethodsA retrospective case note review of 300 non-hypertensive women undergoing caesarean section with neuraxial anaesthesia, including spinal anaesthesia for elective delivery (n=100), and spinal (n=100) and epidural top-up anaesthesia (n=100) for emergency delivery. Systolic arterial pressure values recorded at various time points between the last antenatal visit and the first blood pressure value recorded in the operating room were compared.ResultsThere was a stepwise and significant increase in systolic arterial pressure over three time points (last antenatal clinic, morning of surgery, operating room) before elective caesarean section (all P <0.001). In women having emergency caesarean under spinal anaesthesia, a stepwise increase over four time points (last antenatal clinic, first reading in labour, final reading in labour, operating room) was observed. A similar trend was seen over these time points for women having emergency caesarean under epidural top-up, although the systolic blood pressure did not rise during labour.ConclusionsUsing the initial blood pressure reading in the operating room as the baseline value may lead to unnecessary vasopressor use and hypertension. Prospective research is required to clarify which reading represents the most accurate baseline to maintain homeostasis and reduce the hypotensive sequelae of neuraxial anaesthesia for both the mother and fetus.