老年病人的术后认知功能障碍

术后认知功能障碍（POCD）定义为术后通过反复多次神经心理测试,患者的基本认知功能出现不同程度的损害。而早期术后认知功能及精神障碍更多见于老年患者。虽然POCD多见于心脏手术术后，但非心脏手术后发生POCD亦不少见，老年患者（年龄大于65岁）行心脏手术或非心脏手术，术后1周POCD的发生率分别为50%及26%。POCD的高危因素包括：高龄、术前认知受损以及酗酒等。POCD影响生活质量，加重社会负担并干扰药物治疗效果，延长患者住院周期。有必要深入的研究POCD的病因和神经功能保护的策略。     

自动麻醉记录系统

该研究将通过M icrosoft V isua l C 6.0和V isua l B as ic 6.0为主要的开发工具,SQL Server为数据库,采用客户端/服务器结构,设计出基于W indow s操作系统,网络环境下运行的应用程序,并将它们用于自动麻醉记录。该自动记录系统负责处理麻醉全过程中的相关病人信息,对医护现场的多种医疗设备:如监护仪、静脉输液泵、麻醉机等进行数据的实时自动采集、加工以及集成等,并在综合病人相关信息及生理参数的基础上自动输出麻醉记录单。该记录系统不仅提高了临床医师的工作效率,减低了麻醉医师的劳动强度,而且使麻醉记录更加准确和完整。     

双相气道正压无创机械通气上呼吸道影像分析

目的应用多层螺旋CT对患者不同通气状态下上呼吸道放射性成像,证实在全身麻醉无自主呼吸的条件下,双相气道正压(bi-level positive airway pressure,BiPAP)无创机械通气能克服上呼吸道阻力,实施有效的机械通气。方法选择拟实施全身麻醉的择期手术患者10例,分别对患者清醒自主呼吸、麻醉诱导后自主呼吸停止、BiPAP无创通气时头颈部正位和侧位作螺旋CT扫描。监测扫描过程的无创血压(NIBP)、脉搏氧饱和度(SpO2)、心率(HR)、自主呼吸频率(RR)。测量上呼吸道各软组织区(软腭后区RP、舌根后区RG、会厌区EPG)的最窄气道横截面左右径、前后径线长度及相应横截面积。结果头部正位麻醉诱导后各软组织区的最窄横截面左右径、前后径线长度及相应横截面积均比清醒时缩小(P<0.05),BiPAP通气时各截面径线和面积与清醒期比较差异仍有统计学意义(P<0.05,P<0.01)。头部侧位BiPAP通气时各径线和截面积与清醒时比较,差异无统计学意义。EPG区和RG区在BiPAP通气期的侧位截面积明显比正位时增大(P<0.05,P<0.01)。诱导期正、侧位SpO2均明显下降(P<0.01);头部正位BiPAP通气时与诱导期的SpO2比较虽有改善,但差异无统计学意义(P>0.05);头部侧位BiPAP通气时SpO2较诱导期明显升高(P<0.01),基本恢复到清醒期水平(P>0.05)。结论麻醉诱导后上呼吸道的通气面积明显减少,气道通畅度下降;头颈部侧位时上呼吸道各软组织区最狭窄处的通气截面积比正位时显著改善,以会厌区最明显。无明显上呼吸道梗阻性病史的成年患者全身麻醉时,头部侧位BiPAP无创通气能克服上呼吸道阻力,实施有效的机械通气,保证通气和氧合正常。     

Respiratory chemoreflexes and effects of cortical activation state in urethane anesthetized rats

Urethane anesthetized (< 1 .3 g/kg), Sprague-Dawley (SD) rats spontaneously cycled between a cortically desynchronized state (State I) and a cortically synchronized state (State III), which were very similar to awake and slow wave sleep (SWS) states in unanesthetized animals, based on EEG criteria. These low levels of urethane anaesthesia did not cause significant respiratory depression or reductions in sensitivity to hypoxia (10% O2 in nitrogen) or hypercapnia (5% CO2 in air) in rats in either State I or State III. Thus, breathing frequency (fR), tidal volume (VT) and total ventilation (VTOT) all increased on cortical activation in urethane-anaesthetized rats whether breathing air, the hypoxic or the hypercapnic gas mixture, in a manner that was very similar to that observed in unanaesthetized animals. The relative sensitivity to hypoxia was greater in State III than State I, the relative sensitivity to CO2, overall, was equal in both states, State III occurred less often during hypoxia and hypercapnia, and hypoxic, urethane-anaesthetized rats sighed frequently, particularly in State I. This is also similar to the situation seen in unanesthetized rats. Given the similarities seen between urethane anesthetized rats in the present study and literature values for unanesthetized rats, the data suggest that urethane-anaesthetized rats provide a good model system for studying respiratory patterns and chemoreflexes as a function of cortical activation state.     

臂内侧入路臂丛阻滞麻醉的解剖学基础

目的：为臂内侧入路臂丛阻滞麻醉提供解剖学基础。方法：①尸体解剖观测臂内侧血管神经鞘；②模拟注射造影剂后X线造影和CT扫描观察造影剂扩散范围；③选择合适病例临床应用。结果：①臂内侧血管神经鞘与腋鞘相通；②臂内侧血管神经鞘注射有色液体后，鞘内各主要神经干均被染色；③造影剂可以于臂内侧鞘内向上、向下扩散；④临床应用225例，成功211例，成功率93．8％。结论：臂内侧人路臂丛阻滞麻醉具有操作简便，成功率高，无严重并发症的优点，特别适用于前臂及手部手术麻醉。     

Post-traumatic epidural hematoma in two patients with long-standing “arrested” hydrocephalus

The occurrence of a post-traumatic epidural hematoma in two patients with long-standing arrested hydrocephalus is reported. There was a relatively long interval between the head injury and the onset of symptoms. The large hematoma was accommodated by the decrease in size of the markedly dilated ventricles. This report stresses the possibility of the presence of an epidural hematoma in the management of head injury in patients with long-standing arrested hydrocephalus.     

Arterial hypertension associated with the use of a tourniquet with either general or regional anaesthesia

A hypertensive patient with left cardiac enlargement developed marked hypertension under general anaesthesia, during which time a tourniquet was applied around his thigh. When the tourniquet was released, severe hypotension ensued which responded to therapy. The patient, however, died 16 h later of a myocardial infarction. Because of this incident, the anaesthetic and haemodynamic data of 699 patients who underwent limb surgery with a pneumatic tourniquet inflated for at least an hour were retrospectively examined using multivariate analysis. A 30% increase in systolic and/or diastolic arterial blood pressure occurred in 27% of the total patient material and in 67% of those who had had a general anaesthetic. There was a higher frequency of the occurrence of "tourniquet hypertension" with older age, longer operations and the operation site being the lower rather than the upper limb. Tourniquet hypertension rarely occurred in patients with spinal anaesthesia (2.7%) and brachial plexus blockade (2.5%), while those with intravenous regional anesthesia had a higher incidence (19%) of hypertension.     

Spread of epidural analgesia following a constant pressure injection

(1) The spread of epidural analgesia following injection of 15ml of 2% mepivacaine was 17.3 ± 0.6, 14.3 ± 0.4, and 13.3 ± 0.7 spinal segments in cervical, thoracic, and lumbar epidural analgesia, respectively. The patients age showed significant correlation with the spread of epidural analgesia in cervical (r = 0.5776, p < 0.001), thoracic (r = 0.3758, p < 0.01), and lumbar area (r = 0.8195, p < 0.001). The spread of cervical epidural analgesia was more caudad than cephalad (p < 0.05), but in lumbar epidural analgesia it was more cephalad than caudad (p < 0.05). There was no difference between the cephalad and caudad spread in thoracic epidural analgesia.(2) The epidural pressure immediately after injection of 15ml of 2% mepivacaine into the lumbar epidural space at a constant pressure (80mmHg) correlated to the patients age (r = –0.5714, p < 0.001) and the spread of analgesia (r = –0.3904, p < 0.05). The lower epidural pressure associated with higher age, the wider spread of analgesia. There was no significant correlation between the residual pressure at 60 seconds and the age or the spread of analgesia.(Hirabayashi Y et al.: Spread of epidural analgesia following a constant pressure injection: an investigation of relationships between locus of injection, epidural pressure and spread of analgesia. J Anesth 1: 44–50, 1987)     

Epidural pressure and its relation to spread of epidural analgesia

The relationships between the epidural pressures following the injection of local anesthetic solution and the spread of epidural analgesia were investigated. In 46 patients, 15ml of 2% mepivacaine was injected into the lumbar epidural space at a constant rate (1ml/sec) using an electropowered syringe pump. Injection pressures and residual pressures were recorded and the spread of analgesia to pinprick was assessed. The changes of the epidural pressures during and following the injection of a volume of local anesthetic solution in old subjects were significantly smaller than those in young subjects (P < 0.05). The spread of analgesia closely correlated with the epidural pressures during and following the injection of local anesthetic solution. The most close correlation was found between the epidural pressure immediately after the completion of injection and the spread of analgesia (r = –0.5659, P < 0.001). In conclusion, the lower the terminal injection pressure and the residual pressures associated with higher age, the wider the spread of epidural analgesia.(Hirabayashi Y, Matsuda I, Inoue S et al.: Epidural pressure and its relation to spread of epidural analgesia. J Anesth 1: 168–172, 1987)     

Monitoring, past, present, future

Summary A little over 40 years ago, anesthesiology in the United States became recognized as a specialty. At that time, its practice was largely that of an art, the science of which was yet to come. A finger on the pulse, observation of color, skin turgor, perspiration, and perhaps a blood pressure cuff in adults, and an estimation of the reflex signs of anesthesia were the standards for the assessment of the patient status and the depth of anesthesia. How far have we come in the intervening years? The journey, as reflected in the experience of one physician, will be held up to the looking-glass; easily as astounding as that through which Alice passed.Caught as we are in the socio-economic climate of the present, how shall we react? Has the gadgetry and electronics of this day given us a meaningful cost-effective handle on a decreased morbidity and mortality? What impact is there on decision-making and outcome? What indeed is the contribution of the machine versus the newer agents, techniques, and the advanced educational milieu.The first attempts at monitoring were clearly directed toward the cardiovascular system. The devices developed were simple and non-invasive. The Riva-rocci method of measuring blood pressure was first applied in anesthesia by Harvey Cushing at the turn of the century. But it was 40 years before the electrocardiogram was introduced as an instrument of potential importance. It took another 25 years for it to have general acceptance, and even later for the anesthesiologist to become comfortable with it as a diagnostic tool. In the early 40s, Peterson, at Pennsylvania, began the applications of invasive blood pressure monitoring for clinical purposes. Subsequently, the use of the central venous catheter, and finally the Swan-Ganz catheter, became acceptable. The application for the technology of cardiac output was a long time in gaining clinical credence. However, this last link surely depended on the computer to make it a clinically useful instrument. The measurement of the cardiovascular system was first, because the means were there.The assessment of respiratory function was more cumbersome, and while the pneumotachygraph was available 40 years ago, its vagaries made it a research tool. Meters for respiration also were available, but too cumbersome for clinical use. The integration of respiratory measurements and blood gas analysis have gone hand-in-hand, the latter far outstripping the former in clinical utility. Shall it be invasive or non-invasive, what is the price? Lastly, our technology has introduced the means for what is a meaningful clinical measurement of neurological and neuromuscular activity. Nerve-muscle stimulators, electromyography, processed electroencephalogram, and the evoked potential as devices for assessment are only the beginning. In all this technological advance there is the black box and the electronic marvels that are part of this age. While invasive techniques surely have a place, the utilization of non-invasive techniques like the measurement of oxygen, carbon dioxide, and all the agents that we employ have changed forever the nature of our practice. Finally, the need to document the anesthesia course objectively will, and has already begun, to impact on our practice. How did we get where we are and where are we going will be explored in this personal journey.