腹腔镜手术对小儿心率变异性的影响

目的观察腹腔镜手术下小儿心率变异性（Heart rate variability，HRV）的变化，为小儿术中及术后心血管的康复提供依据。方法选择ASAⅠ或Ⅱ级择期行腹腔镜手术的患儿20例，全部采用静吸复合全麻，气管内插管，呼吸机行间歇正压通气。分别于麻醉前、气腹前、气腹5min、气腹20min、气腹30min和放气腹5min观察心率变异性指标总功率（TP）、高频功率（HF）、低频功率（LF）、低频标准化值（LFNU）、高频标准化值（HFNU）和低频高频功率比（LF／HF）的变化。结果与气腹前比较，TP、LF、LFNU和LF／HF显著升高（P〈0．01），Hk，无明显变化（P〉0．05）。结论腹腔镜手术气腹后小儿交感神经占优势。HRV可作为麻醉循环监测的敏感指标，动态反映小儿自主神经的变化。     

异丙酚和七氟烷麻醉对心率变异性的不同影响

目的 观察异丙酚和七氟烷麻醉对心率变异性的不同影响.方法 选择择期行妇科腹腔镜手术病人40例,随机分为两组,异丙酚组（P组,20例）术中以异丙酚麻醉维持,七氟烷组（S组,20例）术中以七氟烷麻醉维持.记录麻醉前、麻醉诱导后、插管后、切皮后、气腹形成后、关气腹、拔管后10min七个时点的心率（HR）、平均动脉压（MAP）、BIS和低频（LF）、高频（HF）、低高频比值（LF/HF）、心率变异指数（HRV）等心率变异性指标.结果 麻醉诱导后两组病人的HR、MAP、BIS、HRV、HF、LF、LF/HF均显著性下降（ P〈0.05）,两组间无显著差异.在麻醉维持过程中P组LF值显著降低,HF值不降低甚至略有升高,LF/HF值显著下降;S组LF及HF均显著降低,与P组相比LF降低更明显（ P〈0.05）,S组LF/HF值无明显变化,与P组有显著性差异（ P〈0.05）.结论 异丙酚对交感神经系统抑制明显,异丙酚麻醉自主神经系统向副交感神经占优势的方向转变;七氟烷对迷走神经系统和交感神经系统均有抑制,对自主神经系统的平衡性无明显影响.     

高血压患者腹腔镜手术CO2气腹过程中自主神经功能的变化

目的 探讨高血压患者在腹腔镜手术CO2气腹过程中自主神经功能的变化.方法 应用心率变异性(HRV)分析法对25例择期高血压患者腹腔镜手术(Ⅰ组)和25例无高血压腹腔镜手术患者(Ⅱ组)麻醉前、气管插管结束后15 min、腹腔内CO2充气完成后的心率变异性改变进行分析.结果 麻醉诱导及插管15min后Ⅰ组低频(LF)、高频(HF)、低频与高频的比值(LF/HF)及总功率(TP)显著降低(P＜0.05),Ⅱ组LF、LF/HF、11P亦显著降低(P＜0.05),而HF未见明显改变.腹腔CO2充气完成后两组HRV值均显著升高(P＜0.05).组间比较显示,插管15min后Ⅰ组HF和TP显著低于Ⅱ组,LF和LF/HF组间差异无统计学意义;气腹后Ⅰ组HF和TP亦显著低于Ⅱ组.而LF/HF显著高于Ⅱ组,LF组间差异仍无统计学意义.结论 高血压患者迷走神经活性厦总自主神经张力显著低于非高血压患者,迷走神经对心脏窦房结的调控作用严重受损.     

达芬奇机器人手术中气腹、体位对老年冠心病患者心电图QT离散度的影响

目的观察达芬奇机器人手术中CO2气腹及头高位对老年冠心病患者心电图QT离散度（QTd）、QT间期（QTc）和心率变异性（HRV）的影响。方法选择择期行达芬奇机器人肝胆胰手术的老年患者30例,全身麻醉,气腹压12 mm Hg,头高15°位。记录并分析麻醉前（T0）、麻醉后5 min（T1）、气腹后1 min（T2）、5 min（T3）、10 min（T4）、头高位后1 min（T5）、5 min（T6）、10 min（T7）时的QTd、QTc、HRV。结果与T1时比较,CO2气腹后QTd、QTc明显增加（P〈0.05）,HRV低频功率（LF）、低频与高频功率之比（LF/HF）显著增高（P〈0.05）。与T4时比较,头高位后QTd、QTc增加明显（P〈0.05）,而LF、LF/HF变化不显著（P〉0.05）。结论达芬奇机器人手术中CO2气腹和头高位可引起心交感活性升高、心血管系统功能改变,增加心血管事件发生率,尤其对老年冠心病患者必须引起足够的重视。     

老年冠心病患者腹腔镜胆囊切除术中CO2气腹对心率变异性的影响及星状神经节阻滞对气腹的干预作用

【目的】观察老年冠心病患者在腹腔镜胆囊切除术（TVLC）中CO2气腹对心率变异性的影响以及术前经右侧星状神经节阻滞对CO2气腹的干预作用。【方法】选择2008年5月至2008年12月择期在全麻下行TVLC的老年冠心病患者60例。随机分为两组,对照组和右侧星状神经节阻滞组（R-SGB组）各30例。分别于麻醉后SGB前（T0）、SGB后（T1）、气腹后10min（T2）、20min（T3）和30min（T4）记录HR、MAP并分析患者的心率变异性（heart rate variability,HRV）。HRV通过功率谱分析：低频率（LF）,高频率（HF）,LF／HF比率,总能量（TP）。【结果】CO2气腹后老年冠心病患者LF、LF／HF、TP均升高（P〈0．05）。R-SGB组气腹后各时点LF、LF／HF、TP升高低于对照组（P〈0．05）。两组HF未见明显改变（P〉0．05）。【结论】CO2气腹使老年冠心病患者交感神经活性显著升高,右侧星状神经节阻滞可减轻CO2气腹时的心血管反应,维持CO2气腹时的交感／迷走神经张力的均衡。     

胆囊切除术中心率变异性的动态观察

目的观察胆囊切除术过程中心率变异性的变化和其临床意义。方法选择择期手术患者66例,年龄25～75岁,ASAⅠ～Ⅱ级,选择全凭静脉麻醉（TIVA）,气管内插管,机控通气。分别于胆囊牵拉前5min（T0）、牵拉时（T1）、牵拉5min（T2）、牵拉10min（T3）观察心率变异性指标低频标准化值（LFnu）、高频标准化值（HFnu）、低频高频功率比（LF/HF）、总功率（TP）的变化。结果牵拉瞬间,LFnu、HFnu、LF/HF值较牵拉前比较差异均无统计学意义,而TP值降低（P〈0.05）。牵拉5min时,HFnu较牵拉前和牵拉时降低,差异有统计学意义（P〈0.01）,且LF/HF比值较其他时间点降低（P〈0.05）。牵拉10min时,TP较牵拉前降低,差异有统计学意义（P〈0.05）。结论牵拉胆囊5min时对心脏自主神经的张力影响最大,主要表现在反映心脏迷走神经的HF值显著升高。     

依托咪酯和丙泊酚对急诊脑血管介入手术患者全麻诱导期心率变异性的影响

目的：观察依托咪酯和丙泊酚对急诊颅脑介入手术患者全麻诱导插管时心率变异性的影响。方法：选择急诊颅脑介入手术的清醒患者30例,随机分为丙泊酚组（A组15例）和依托咪酯组（B组15例）,采用丙泊酚或依托咪酯、罗库溴铵、芬太尼进行快速序贯诱导,分别于诱导前5min（T0）、插管前即刻（T1）和插管后5min（T2）记录和比较患者的血压、心率、外周氧饱和度（SpO2）、心率变异性（HRV）的变化。结果：①T1时A组收缩压（SAP）和舒张压（DAP）较B组均显著下降（P〈0.05）;T2时A组SAP较B组SAP显著下降（P〈0.05）,DAP则无显著差异;2组心率（HR）在T1、T2时均无显著差异。②A组在T1、T2时低频（LF）、高频（HF）、LF/HF、总功率谱（TP）均较T0有显著下降（P〈0.05）;B组在T1时LF、HF、TP较T0有显著下降（P〈0.05）,但LF/HF与T0比较,差异无统计意义;组间比较,在T2时A组LF、LF/HF较B组有显著降低（P〈0.05）。结论：依托咪酯在急诊颅脑介入手术全麻快速序贯诱导过程中虽然抑制心率变异性,但在保持植物神经功能和血流动力学的相对稳定性方面优于丙泊酚。     

腹腔镜胆囊切除术中CO_2气腹对心率变异性的影响

目的:探讨腹腔镜胆囊切除术中CO2气腹对心率变异性的影响。方法:选择ASA分级Ⅰ～Ⅱ级择期行腹腔镜胆囊切除手术病人40例,利用心率变异功率谱分析技术(HRV-PSA)和脑电(electroencephalogram,EEG)双频谱指数技术(bispectralindex,BIS)对40例病人CO2人工气腹后心率变异性(HRV)指标低频功率(LF)、高频功率(HF)、低频高频比(LF/HF)、总功率(TP)的变化进行分析。结果:CO2人工气腹后LF、LF/HF、TP均明显升高,HF未见明显改变。结论:腹腔镜胆囊切除术中CO2人工气腹使交感神经系统活性显著升高。     

右美托咪定对支撑喉镜手术心率变异性的影响

目的研究右美托咪定对支撑喉镜手术心率变异性的影响。方法选择ASA分级Ⅰ~Ⅱ支撑喉镜手术患者60例,随机分成两组,D组在全麻诱导前15 min给予右美托咪定0.6μg/kg,C组以等容量的0.9%氯化钠溶液输注,两组采用相同的麻醉诱导维持用药、复苏方法。分别记录两组诱导前15 min(T0)、插管时(T1)、手术操作时(T2)、拔除气管导管时(T3)、拔除气管导管5 min后(T4)的心率变异性(HRV)频域分析指标低频功率(LF)和高频功率(HF),计算低频功率与高频功率的比值(LF/HF)。结果与T0比较,D组T2~T4时点HF值明显升高(P0.05),LF变化不明显,LF/HF明显降低(P0.05),与C组比较T2~T4时点HF值明显升高(P0.05),LF变化不明显,LF/HF明显降低(P0.05)。结论支撑喉镜手术中,单次应用右美托咪定能改变HRV,达到交感与迷走调节的均衡性,稳定心血管反应。     

不同剂量右美托咪定对老年LC患者围术期血流动力学及心率变异性的影响

[目的]探讨不同剂量右美托咪定(Dex)对老年腹腔镜胆囊切除术(LC)患者围术期血流动力学及心率变异性(HRV)的影响.[方法]90例行LC的老年患者,均行气管插管全麻,随机分为三组,每组30例,分别于麻醉诱导前15 min泵注10 mL的Dex,0.25 μg/kg(A组)、0.5 μg/kg(B组)和等量生理盐水(对照组,C组).比较三组患者麻醉诱导前(T0)、建立气腹后5 min(T1)、10 min(T2)、20 min(T3)、放气腹后5 min(T4)时的平均动脉压(MAP)、心率(HR)、脉搏血氧饱和度(SpO2)、低频功率(LF)、高频功率(HF)和LF/HF比值.[结果]三组患者术中输液量、麻醉时间及手术时间比较差异均无显著性(P>0.05);A组、C组T1-4时刻的MAP、HR均明显高于T0时刻(P<0.05);B组T1-4时刻的MAP、HR均明显低于A组和C组(P<0.05);B组T1-4时刻的HF明显高于A组和C组,LF/HF明显低于A组和C组(P<0.05);A组和C组患者T0-4时刻的LF、HF、LF/HF比较差异均无显著性(P>0.05);B组拔管后躁动发生率明显低于C组(P<0.05).[结论]0.5 μg/kg Dex更有利于维持老年LC患者围术期血流动力学稳定,且未增加不良反应的发生.     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.