硬膜外麻醉中用异丙酚镇静目标控制输注系统的性能及测评

目的：研究硬膜外阻滞时异丙酚目标控制输注镇静系统的性能。方法：12例中、低位硬膜外腔阻滞择期手术病人,选用Marsh的药代动力学参数进行异丙酚目标控制输注镇静。目标血药浓度设定范围1．5－3．0mg.L^-1,由麻醉医师根据镇静需要调整目标浓度,笨一病例的目标浓度可调整1－2次,以高效液相色谱法检测异丙酚血药浓度。计算偏离不性、不准确度等性能评价指标,分析系统性能。结果：多数实测血药浓度低于预计浓度,偏离性（MDPE）为－16．14％。偏离性和不准确确度与硬膜外阻滞范围无相关。结论：采用Marsh参数作目标控制镇静,血浆异丙酚目标浓度与实测浓度的偏离性较大,应用时需进行校正。     

异丙酚复合氯胺酮用于小儿眼科手术麻醉的临床观察

目的:观察异丙酚复合氯胺酮用于小儿眼科手术的麻醉效果.方法:选择ASA Ⅰ级小儿眼科手术40例,随机分为异丙酚组(A组,n＝20)和安定组(B组,n=20).A组肌注氯胺酮4 mg/kg负荷量,加异丙酚、氯胺酮复合液4ml/(kg@h)连续输注,B组肌注氯胺酮4 mg/kg负荷量,加静注安定0.2 mg/kg,以0.1%氯胺酮4 mg/(kg@h)连续输注.分别观察两组MBP、HR、SpO2变化、术毕清醒时间、氯胺酮使用总量及不良反应.结果:A组心血管反应轻微,术毕清醒时间短,不良反应少,与B组比较差异有显著性(P＜0.01);A组氯胺酮使用总量比B组少(P＜0.05).结论:异丙酚复合氯胺酮用于小儿眼科麻醉效果确切,安全可靠.     

老年人急性心肌梗死82例临床分析

目的：总结老年人急性心肌梗塞（ＡＭＩ）静脉溶栓治疗经验。方法：对８２例老年人ＡＭＩ的临床资料及其中７５例的溶栓治疗资料进行分析。结果：老年人ＡＭＩ时,无胸痛史达５４．９％,入院心电图ＳＴ－Ｔ缺乏典型改变占４５．３％。经静脉溶栓治疗,梗塞动脉开通率为６２．９％,与７０岁以下ＡＭＩ组溶栓开通率比较（６５％）,无统计学差异。结论：老年人ＡＭＩ发病时,临床表现及心电图改变常不典型,应引起重视。在本文条件下     

Modulation of immunoglobulin production and cytokine mRNA expression in peripheral blood mononuclear cells by intravenous immunoglobulin

Intravenous immunoglobulin (IVIG) has the potential to regulate Ig production, but the mechanism(s) responsible for this effect is unknown. In experiments reported here, we examined the ability of IVIG to regulate Ig production in human peripheral blood mononuclear cells (PBMCs) stimulated with pokeweed mitogen (PWM). IVIG (2–10 mg/ml) showed a potent (80–85%) inhibition of PWM-stimulated IgG, IgM, and IgA production. To determine more precisely how IVIG mediated the inhibition of Ig production, we studied Ig promoting cytokine gene expression after PWM stimulation with or without IVIG (2 and 10 mg/ml) using dot-blot techniques. RNA was isolated from PBMCs at predetermined time points and probed with cDNAs specific for human cytokines (IL-1-, IL-2, IL-2R, IL-4, IL-5, IL-6, -IFN, and TNF-). IL-6 mRNA accumulation was maximal at 4.5 hr post-PWM stimulation and was inhibited 64–75% when IVIG (10 mg/ml) was present. -IFN mRNA levels peaked at 72 hr poststimulation and were also 68–75% inhibited by IVIG. IL-2 mRNA levels peaked at 4.5 hr and were 23–46% inhibited by IVIG. The inhibitory effect of IVIG on production of these cytokines (IL-6 and -IFN) was also observed at the protein level in sonicated PBMCs after incubation with PWM and IVIG. The mRNA levels for other cytokines were not or only minimally inhibited by IVIG. Addition of IL-6, -IFN, or IL-2 partially restored Ig production in IVIG-treated PWM-stimulated cultures, suggesting that inhibition of other cytokines or another mechanism(s) independent of cytokine inhibition might also be involved, although inhibition of IL-6, -IFN, and IL-2 may be one of the critical factors in the suppression of Ig production by IVIG.     

Optimizing sedation following major vascular surgery: a double-blind study of midazolam administered by continuous infusion

A randomized, double-blind study was undertaken to determine the dose requirements, recovery characteristics, and pharmacokinetic variables of midazolam given by continuous infusion for sedation in patients following abdominal aortic surgery. Thirty subjects, 50–75 yr, scheduled to undergo aortic reconstructive surgery, entered the study. Following a nitrous oxide-isoflurane-opioid anaesthetic technique, patients were randomly allocated to receive one of three loading doses (0.03, 0.06 or 0.1 mg · kg^?1) and initial infusion rates (0.5, 1.0 or 1.5 μg · kg^?1 · min^?1) of midazolam, corresponding to groups low (L), moderate (M) and high (H). The infusion of midazolam was adjusted to maintain sedation levels of “3, 4 or 5,“ which permitted eye opening in response to either verbal command or a light shoulder tap, using a seven-point scale ranging from “0” (awake, agitated) to “6” (asleep, non-responsive). Additionally, morphine was given in increments of 2.0 mg iv prn for analgesia. On the morning after surgery, midazolam was discontinued, and the tracheas were extubated when patients were awake. Blood samples were taken during, and at increasing intervals for 48 hr following discontinuation of the infusion, and analyzed by gas chromatography. The desired level of sedation was maintained during more than 94% of the infusion period in all three groups, with a maximum of three dose adjustments per patient, for treatment which lasted 16.3 ± 0.6 hr. There was, however, an increase in both the infusion rates and mean plasma concentrations from Group L to Group H (P < 0.05), which corresponded to an inverse relationship of morphine requirements during the period of sedation (P < 0.05, Group H vs Group L). Optimal midazolam infusion rates and resulting plasma concentrations at the times the infusions were discontinued (in parentheses) were as follows — Group L: 0.60 ± 0.18 μg · kg^?1 min^?1 (76 ± 32 ng · mL^?1), Group M: 0.90 ± 0.52 μg · kg^?1 · min^?1 (133 ± 71 ng · mL^?1), and Group H: 1.34 ± 0.69 μg · kg^?1 · min^?1 (206 ± 106 ng · mL^?1). Times to awakening were longer in Group H: 3.1 ± 3.4 hr, than in Group L: 1.1 ± 0.8 h, P < 0.05. Pharmacokinetic variables were found to be dose- independent over the range of infusion rates. Mean values were t_1/2β = 4.4 ± 1.5 hr, CL = 5.94 ± 1.69 mL · min^?1 · kg^?1, Vd = 3.13 ± 1.07 L · kg^?1. It is concluded that midazolam, infused between 0.6–0.9 μg · kg^?1 · min^?1, provides a stable level of sedation, when administered in conjunction with intermittent iv morphine following AAS. This sedation technique, which costs $1.65 ± 0.73 hr^?1 ($Can), is associated with rapid recovery and minimal side effects.     

Estimating the human immunodeficiency virus infection curve of intravenous drug users in Lombardia,Italy

We present a model to estimate the infection curve of the human immunodeficiency virus in intravenous drug users in Lombardia. We based estimates on AIDS incidence data, according to a backcalculation model accounting for therapy and changes in the surveillance definition of AIDS.     

异丙酚复合芬太尼维持麻醉对脑代谢的影响

观察异丙酚复合芬太尼维持麻醉对脑代谢的影响。方法： 择期手术病人８ 例, 芬太尼、硫贲妥钠、维库溴铵诱导插管, 静脉联接Ｇｒａｓｅｂｙ 微泵异丙酚８ ｍｇ／ （ｋｇ·ｈ） , 芬太尼１ μｇ／ （ｋｇ·ｈ）维持麻醉。连续监测ＭＡＰ、心电图、脉搏氧饱和度和呼气末二氧化碳分压, 同步采集动脉血和颈内静脉血作血气分析, 计算动－ 静脉氧含量差（Ｄａ － ｖＯ２） 和脑氧摄取率（ＥＲＯ２） 。结果： 异丙酚麻醉维持平稳, Ｄａ － ｖＯ２ 和ＥＲＯ２ 在给药３０ ｍｉｎ 、６０ ｍｉｎ 较气管插管后５ ｍｉｎ 无明显改变, 有平均动脉压下降和心动过缓。结论： 异丙酚复合芬太尼维持麻醉可保持脑氧供需平衡稳定。     

The use of chemical restraint in helicopter transport

Introduction: Helicopter transport of the combative patient is a major safety hazard facing air medical teams. Although physical restraints alone are helpful, the addition of chemical restraint (CR) often is necessary to control these patients while in flight.

Methods: A survey was conducted to determine the current practices of using nonparalyzing CR in air medical transport programs nationwide. The survey consisted of 24 questions on the use of CR during transport. Each U.S. program belonging to the Association of Air Medical Services was contacted by telephone, and a flight nurse or paramedic provided answers based on personal experience and statistics compiled by his or her individual program.

Results: Of the 100 programs responding, benzodiazepines were used most commonly to control agitation with 51% using midazolam. Patients with a head injury required CR more frequently than any other condition (73%). Crews flying larger aircraft reported less need for CR. A physician order was required by only 30% of the programs, but delays infrequently endangered the patient (2%). Only 7% of the responding programs had a patient whose condition deteriorated because of CR.

Conclusion: CR is necessary in air medical transport. Most programs use short-acting benzodiazepines. Crews in smaller aircraft use CR more frequently, and head injury is the most common condition requiring such restraint.     

Preliminary UK experience of dexmedetomidine, a novel agent for postoperative sedation in the intensive care unit

Dexmedetomidine, a highly selective and potent alpha2-adrenergic agonist, has a potentially useful role as a sedative agent in patients requiring intensive care. As part of a larger European multicentre trial, a total of 119 postoperative cardiac and general surgical patients requiring ventilation and sedation in an intensive care unit were enrolled in four centres in the United Kingdom. One hundred and five patients were randomly allocated to receive either dexmedetomidine or placebo with rescue sedation and analgesia provided by midazolam and morphine, respectively. Compared with the control group, intubated patients receiving dexmedetomidine required 80% less midazolam [mean 4.9 (5.8) microg.kg-1.h-1 vs. 23.7 (27.5) microg.kg-1.h-1, p < 0.0001], and 50% less morphine [11.2 (13.4) microg.kg-1.h-1 vs. 21.5 (19.4) microg.kg-1.h-1,p = 0.0006]. Cardiovascular effects and adverse events could be predicted from the known properties of alpha-2 agonists. In conclusion, dexmedetomidine is a useful agent for the provision of postoperative analgesia and sedation.     

Self-administration of cocaine increases the release of acetylcholine to a greater extent than response-independent cocaine in the nucleus accumbens of rats

  Rationale: The neurochemical effects of psychostimulant exposure may depend on how these drugs are encountered. A useful method for examining this issue is to compare neurotransmitter release following response-dependent, or self-administered, drug exposure and response-independent exposure. Objectives: This experiment examined the effect of active and passive cocaine administration on acetylcholine (ACh) efflux in the shell region of the nucleus accumbens (NAc) in rats. Methods: One group of rats (CSA: cocaine self-administration) was trained to lever-press for intravenous infusions of cocaine (0.42 mg/kg per infusion) on a fixed-ratio-1 schedule of reinforcement. Cocaine infusions were accompanied by the onset of a stimulus light that signaled a 20-s time-out period. Control rats received intravenous cocaine (cocaine non-contingent: CNC) or saline (SAL) in a manner that was not contingent upon their behavior. Drug infusions in these groups were determined by the lever-press behavior of the animals in the CSA group, i.e. they were yoked to rats in the self-administration group such that CNC animals received equal amounts of cocaine as CSA rats. Animals received cocaine or saline in 3-h sessions for 13 consecutive days before testing. On day 14, extracellular ACh was measured in 15-min intervals before, during and after a 3-h session of cocaine exposure using unilateral microdialysis probes located in the NAc shell coupled with HPLC. Results: ACh efflux was significantly increased above baseline in both groups of rats that received cocaine but CSA rats had significantly higher ACh levels during the self-administration period compared to their yoked counterparts. In addition, ACh efflux remained elevated longer in CSA animals relative to CNC rats following cessation of cocaine exposure. Conclusions: These results demonstrate that ACh interneurons in the NAc shell are responsive to cocaine exposure. In addition, these findings suggest that the manner in which the drug is administered (i.e. either by active self-administration or passive exposure) may be relevant to the magnitude of the neural response. Received: 28 April 1998 / Final version: 4 November 1998