Multitasking: association between poorer performance and a history of recurrent falls

OBJECTIVES: To examine the association between poorer performance on concurrent walking and reaction time and recurrent falls. DESIGN: Cross-sectional analysis. SETTING: Community. PARTICIPANTS: Three hundred seventy-seven older community-dwelling adults (mean age+/-standard deviation 78+/-3). MEASUREMENTS: Reaction times on push-button and visual-spatial decision tasks were assessed while seated and while walking a 20-m course (straight walk) and a 20-m course with a turn at 10 m (turn walk). Walking times were recorded while walking only and while performing a reaction-time response. Dual-task performance was calculated as the percentage change in task times when done in dual-task versus single-task conditions. A history of recurrent falls (> or = 2 vs < or = 1 falls) in the prior 12 months was self-reported. Multivariate logistic regression models were used to predict the standardized odds ratios (ORs) of recurrent falls history. The standardized unit for dual-task performance ORs was interquartile range/2. RESULTS: On the push-button task during the turn walk, poorer reaction time response (slower) was associated with 28% lower (P=.04) odds of recurrent fall history. On the visual-spatial task, poorer walking-time response (slower) was associated with 34% (P=.02) and 42% (P=.01) higher odds of recurrent falls history on the straight and turn walks, respectively. CONCLUSION: These findings suggest that walking more slowly in response to a visual-spatial decision task may identify individuals at risk for multiple falls. Prospective studies are needed to confirm the prognostic value of poor walking responses in a dual-task setting for multiple falls.     

005 2000年国际心肺复苏指南简介

近年来,有关心肺复苏(CPR)基础研究及临床试验领域研究十分活跃,为此美国心脏协会在汇同了各大洲权威复苏委员会意见后,于2000年8月首次拟定并公布了国际心肺复苏指南.本文拟就该新指南中的若干重要进展简介如下. 1 2000年国际CPR指南更注重以科学、循证为据 新指南的重要标志在于,参照大量随机对照试验(RCT)结果,依科学、循证医学为据,对既往指南进行了全面、公正、客观的论证与评价,摒弃了地区和国界的差异,且不拘泥于某学术权威、机构或国家的各自标准,首次由跨国度、洲际的权威机构共同撰写而成,乃是全体专家智慧与实践的结晶. 2 2000年国际CPR指南建议取消检测脉搏有无来判定心脏聚停 新指南的另一重要标志在于删除了复苏前检核脉搏.认为检测脉搏并不可靠.实践证明,对于现场救助者尤其是非医务人员,检测脉搏不仅手法往往不规范,且耗时较久,结果使之不能及时实施CPR和电除颤.此外,据统计,由现场非专业救助者因触及患者脉搏自身的细微自颤,而作出其心脏并未真正停搏的假阴性漏诊率高达10%,终至此类患者在事发现场由于漏诊而丧失或延误了室贵的抢救时间,而不幸生物死亡.故新指南建议,取消现场检测脉搏,认为在决定实施胸外按压前,无需检测脉搏,只需结合患者意识丧失、呼吸停止、以及对咳嗽、触动等刺激的反应来综合判定即可. 3 2000年国际CPR指南更强调现场急救与早期除颤 新指南再次强调,对于心脏骤停者,事发现场应争分夺秒,全力抢救.认为现场急救的成败与生存链(chain of survival)的建立息息相关.该生存链包括早期通路、早期CPR、早期除颤与早期高级生命支持4链环节,亦即在心脏骤停事发现场,均应立即通知医疗部门,同时实施CPR,尽早除颤和高级生命支持.并建议应尽早使用紧急自动体外除颤(AED). 4 2000年国际CPR指南建议简化胸外按压与人工呼吸频度 新指南建议,将CPR时的胸外按压频度由既往的80～100次/min上调至100次/min,调幅达25%;并建议无论单、双人复苏,胸外按压/人工呼吸比均统一为15∶2(原指南中双人复苏按压/呼吸比为5∶1,单人复苏按压/呼吸比15∶2).实践证明,高频按压能获得更有效的前向血流;而按压/呼吸15∶2配合比,既可减少胸外按压中断间期,又能获得更大的胸腔内压;且每次中断胸外按压而行人工呼吸后,均需多次按压才能恢复先前按压所维持的血流,而许多复苏者按压频率往往过低.故新指南减少了每次按压之间的间隔,而增加了每分钟按压频率.从而保证了在等同时间内,既增加前向血流,又提高胸腔内压,且操作更有节律,更简便易行. 5 2000年国际CPR指南建议CPR时实施二阶段ABCD四步复苏 新指南建议,抢救心脏骤停者时,实施CPR可按以下二阶段ABCD四步进行.第1个ABCD四步包括:A开放气道,B正压通气,C胸外按压,D如为室速/室颤则应立即除颤;第2个ABCD四步包括:A进一步气道控制,B评估气管内插管是否充分、正压通气,C建立液路及给药,D鉴别处理一切可逆转病因. 6 2000年国际CPR指南认为CPR时面罩给氧等效于气管内插管给氧 新指南认为,抢救实施CPR时,口对口人工呼吸给氧效果较差.而选择气囊一面罩给氧,较气管插管给氧更简捷且等效,建议在现场及转运途中亦不应中断.据晚近的1项RCT结果证明,气囊一面罩给氧与气管插管给氧一样能有效提高CPR成功率.是否行气管插管最好依据患者情况和救助者经验而定. 7 2000年国际CPR指南建议CPR时的辅助用药 新指南建议,抢救心脏骤停者,如属室速/室颤,可首先连续3次电除颤.对3次除颤仍无效者,选用肾上腺素1mg静注,每3～5min可复行,或/和单剂加压素40U静注,继之再电除颤数次;如为非室速/室颤,建议仅用肾上腺素1mg静注,每3～5min可重复,暂不主张电除颤.对于顽固性室速/室颤,实践证明只有胺碘酮才显示了它有益的治疗前景,而其它传统药物如利多卡因、Bretyhium、普鲁卡因酰胺等的抗室速/室颤作用,均未能得到RCT的证实,且疗效均差. 8 2000年国际CPR指南建议CPR时的液体选择 新指南建议,CPR宜选用生理盐水,不宜再用糖水,因后者可在缺氧条件下代谢成乳酸,而加重酸中毒;且晶体液尚有助于使浓缩的血液稀释,益于循环重建. 9 2000年国际CPR指南中CPR其它相关建议 新指南建议,进一步普及CPR规范抢救方法,建议在各公共场所增设或更新先进的便携式AED仪,尽快建全全球急救网络网站及CPR专门机构. (袁志敏石延华摘)     

The Reinforcing Effects of Ethanol Are Altered by the Endogenous Neurosteroid, Allopregnanolone

We examined the effect of systemic administration of the endog-enously occurring progesterone metabolite, allopregnanolone, on oral self-administration of ethanol by male rats. Rats were trained to perform an operant response for presentation of 0.1 ml of a solution of 10% ethanol in water using the sucrose fading technique. After acquisition of stable lever-press responding on a fixed-ratio 4 schedule, subjects received subcutaneous injections of 1,3, or 10 mg/kg of allopregnanolone, or vehicle, 20 min prior to the self-administration session. Pretreatment with 3 mg/kg, but not 1 or 10 mg/kg, increased the mean total number of lever press responses made to obtain ethanol, and therefore increased the mean total number of ethanol presentations. The number of responses and response rate were examined as a function of the number of “runs” within the 30-min session; a “run” was defined as a series of consecutive responses with an interresponse interval of <1 min. The increase in total responses after 3 mg/kg was due in part to an increased number of responses for the first run of the session, with no effect on response rates. However, the higher dose of 10 mg/kg decreased response rates within the first run. Thus, allopregnanolone alters ethanol-reinforced responding at concentrations lower than those that depress rates of responding. The effects of administration of the ben-zodiazepene, diazepam, were determined for comparison with those of the neurosteroid. The subcutaneous injection of 0.3, 1.0, or 3.0 mg/kg of diazepam did not produce any clear dose-dependent changes in measures of ethanol-reinforced operant responding, supporting the suggestion of differences in the contribution of the benzodiazepene and neurosteroid binding sites to GABA_A receptor function. The results indicate that exogenous administration of allopregnanolone dose-dependently alters ethanol-reinforced operant responding, and suggest that this endogenously occurring neurosteroid could mediate some of the reinforcing effects of ethanol.     

2009 Survey Results: Surgeon Practice Patterns Regarding Arthroscopic Surgery

A survey was conducted to collect information on the surgical management and practice preferences of the audience members at a recent continuing medical education conference. Participants were polled on a variety of surgical topics, and their responses were recorded using a wireless audience response system. The answers were tabulated and are presented in this report. The majority of respondents preferred an arthroscopic repair for rotator cuff tears (52%) and shoulder instability (71%). Most (50%) perform single-row repair; 33% perform double-row repair. For simple knee arthroscopy, most use preoperative antibiotics (85%), no tourniquet (53%), and no chemical anticoagulation or only compression boots (69%). For cruciate ligament reconstruction, the majority preferred only a preoperative antibiotic (67%), no chemical anticoagulation or only compression boots (56%), and single-bundle reconstruction (88%) using a transtibial femoral tunnel (78%). Most (47%) prefer an all inside suture-based meniscus repair device.