心肺复苏胸外按压的生物力学研究

目的 通过对人体尸体标本的生物力学测试,研究人体胸廓在外力作用下的应力、应变特点,探讨胸外按压时胸廓受力变形的机制.方法 成年男性尸体标本1具,使用MTS材料试验机和引伸仪,采用O～200 N载荷,分别模拟人体按压时胸廓所承受的负重工况,测试垂直加压情况下胸廓的位移和应变.结果 测试得出静态加压和动态加压时胸廓的载荷-位移关系和载荷-应变关系数据并得出统计曲线.结论 通过人体胸廓生物力学测试发现了胸外按压时人体胸廓下压深度与按压力量的关系,并提出初步的计算公式.     

Pit-Crew心肺复苏模式对胸外按压质量效果的影响

目的:观察以Pit-Crew心肺复苏（cardiopulmonary resuscitation, CPR）模式的团队复苏对胸外按压质量改善的效果。方法:采用对照研究的方法,将64名重症医学科和急诊科医护人员按照医护比例分成角色分工组与未角色分工组,每组各8队,每队4人。角色分工组每队指定一名队长组织协调整个CPR流程...     

胸外心脏按压人员不同报数方式对心肺复苏质量的影响

目的 比较胸外心脏按压时采用不同报数方式的按压有效率及人体疲劳程度,以建立更为规范和适当的报数方法.方法 随机抽取48名经正规基本生命支持(BLS)与高级生命支持(ALS)训练的急诊科专业住院医师与护士,用抛硬币方式随机确定报数方式的先后顺序,两种方式间隔30 min,在心肺复苏(CPR)训练模型上进行单人连续3 min的胸外按压;记录按压总次数、有效按压次数、受试者最大心率以及达最大心率所用时间.按压结束后受试者填写视觉模拟量表(VAS),以记录其主观疲劳及不适程度.结果 按压人员采用从1数到10重复3次的报数方式,3min内有效按压总次数、有效按压比例及平均按压深度均明显大于采用从1连续数到30的报数方式[(202.40±6.52)次比(173.50±5.68)次,(67.48±2.00)%比(57.81±2.00)%,(4.45±0.34)cm比(4.05±0.21)cm,均P＜0.01],VAS得分明显低于采用从1连续数到30的报数方式[(22.15±3.09)分比(31.10±4.09)分,P＜0.01],受试者达到最大心率所用时间也明显长于采用从1连续数到30的报数方式[(124.88±5.40)s比(106.15±6.80)s,P＜0.01].两种报数方式之间受试者最大心率比较则无明显差异.结论 CPR过程中采用从1数到10重复3次的报数方式进行胸外按压具有更高的按压有效率.也更能节省按压人员的体力,由此在一定程度上提高了CPR质量.     

心肺复苏胸外按压深度控制器的研究

目的 研究设计出一种装置,使医务人员在心肺复苏时能够明确胸外按压的有效深度,以减少按压不足或按压过度,有利于提高心肺复苏效果.方法 采用自主研制的胸外按压深度控制器,结合心肺复苏模拟人系统,随机挑选具有心肺复苏经验的医务人员进行操作实验,同时设立对照组,对两组胸外按压有效率进行比较分析.结果 实验组胸外按压有效率高于对照组(P<0.01).结论 胸外按压深度控制器能够提高医务人员心肺复苏时胸外按压的有效率.     

心肺复苏中胸外按压作用及研究进展

心肺复苏(CPR)中基础生命支持(BLS)是整个复苏过程的基础和关键,胸外按压在BLS的地位越来越受到重视,有关胸外按压的频率问题、胸外按压与呼吸比例的问题以及胸外按压确切机制一直是急诊医学界关注的焦点,我国心肺复苏的基础研究应该进一步的加强。     

心肺复苏仪胸外心脏按压对心肺复苏成功的影响

目的:探讨心肺复苏仪胸外心脏按压对心肺复苏成功的影响。方法:将42例心跳呼吸骤停患者随机分为徒手胸外心脏按压组(A组)和心肺复苏仪胸外心脏按压组(B组)。二组均进行无创动脉血压、心电、经皮氧饱和度sPO2等监测。结果:B组的自主循环恢复率和24小时存活率均明显高于A组(P<0.05和P<0.01),但二组的出院存活率无显著性差异。B组的经皮氧饱和度明显高于A组(P<0.05),而自主循环恢复时间则明显短于后者(P<0.01);二组的平均动脉压无显著性差异。结论:心肺复苏仪胸外心脏按压在提高自主循环率,缩短自主循环恢复时间,改善患者生存机会等方面明显优于徒手胸外心脏按压。     

单纯胸外按压心脑复苏研究进展

目击者所实施的传统心肺复苏(CPR)包括胸外按压和口对口通气,是"生存链"抢救的主要部分,但迄今只有不到1/3的心脏骤停者被实施传统的CPR.近来,不少试验研究结果提示,单纯胸外按压心脑复苏(CCR)与传统的CPR相比有相似或更优的生存率与神经学预后,尤其是CCR在现场急救方面更具操作性.     

与胸外心脏按压同时和非同时机械通气对心肺复苏影响的比较

目的：探讨与胸外心脏按压同时和非同时机械通气在心肺复苏中应用的效果。方法：将12例心跳呼吸骤停患者随机分为与胸外心脏按压同时控制机械通气组和与胸外按压非同时手控机械通气组。采用控制通气模式机械通气与持续循手胸外心脏按压同时进行;后者采用手控通气模式机械通气（MAMV）与间断徒手胸外心脏按压非同时配配合进行心肺复苏,胸外心脏按压每5次后暂停1次,在暂停间期给予MAMV1次,之后通气与按压依此比例进行。2组均进行无创动脉血压、心电、经皮氧饱和度（SpO2)、潮气量（VT)、气道峰压（Ppeak)等监测。结果：与胸外心脏按压非同时手控机械通气组的SpO2、VT均明显高于与胸外心脏按压同时模式通气组的SpO2和VT,P均＜0．05;而peak则明显低于后者,P＜0．05;2组的平均动脉压无显著差别。结论：与胸外心脏按压非同时手控机械通气在提高SpO2、VT,降低Ppeak,恢复窦性心律及提高心肺复苏成功率等方面明显优于与胸外心脏按压同时控制机械通气。     

自动心肺复苏机胸外按压在心跳骤停患者中的应用进展

自动心肺复苏机是一种全自动的、同步胸外心脏按压、间歇正压通气的仪器。自2005年心肺复苏指南进一步强调有效按压是建立人工循环的关键以来[1],已有许多研究比较自动心肺复苏胸外按压仪在临床的优势,如早期就有报道自动心肺复苏机可     

细化心肺复苏流程对胸外按压中断时间的影响

目的探讨细化心肺复苏（ CPR）流程,对CPR的除颤期及气管插管期胸外按压中断时间的影响。方法依据2010 CPR指南,制定细化CPR的除颤期及气管插管期的CPR流程,缩短CPR过程中胸外按压中断时间。选择2012-08～2013-11间124例心脏骤停患者为试验组,实施细化的除颤期及气管插管期CPR流程。选择2011-04～2012-07间122例心脏骤停患者为对照组,实施常规CPR流程。对两组患者CPR胸外按压中断时间、自主循环恢复时间、自主循环恢复率、72 h生存率及28 d生存率、28 d神经功能预后CPC评分进行回顾性对比分析。结果两组患者CPR的除颤期胸外按压中断时间及气管插管期胸外按压中断时间、自主循环恢复时间、自主循环恢复率、28 d生存率及28 d神经功能预后CPC评分各项指标比较均差异有统计学意义（P＜0.05）。两组患者72 h生存率比较差异无统计学意义（P＞0．05）。结论细化CPR流程,可缩短CPR的除颤期及气管插管期胸外按压中断时间,有效提高CPR成功率。     

The impact of chest compression rates on quality of chest compressions - a manikin study

Purpose

Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables.

Methods

Twenty healthcare professionals performed 2 min of continuous compressions on an instrumented manikin at rates of 80, 100, 120, 140 and 160 min⁻¹ in a random order. An electronic metronome was used to guide compression rate. Compression data were analysed by repeated measures ANOVA and are presented as mean (SD). Non-parametric data was analysed by Friedman test.

Results

At faster compression rates there were significant improvements in the number of compressions delivered (160(2) at 80 min⁻¹ vs. 312(13) compressions at 160 min⁻¹, P < 0.001); and compression duty-cycle (43(6)% at 80 min⁻¹ vs. 50(7)% at 160 min⁻¹, P < 0.001). This was at the cost of a significant reduction in compression depth (39.5(10) mm at 80 min⁻¹ vs. 34.5(11) mm at 160 min⁻¹, P < 0.001); and earlier decay in compression quality (median decay point 120 s at 80 min⁻¹ vs. 40 s at 160 min⁻¹, P < 0.001). Additionally not all participants achieved the target rate (100% at 80 min⁻¹ vs. 70% at 160 min⁻¹). Rates above 120 min⁻¹ had the greatest impact on reducing chest compression quality.

Conclusions

For Guidelines 2005 trained rescuers, a chest compression rate of 100–120 min⁻¹ for 2 min is feasible whilst maintaining adequate chest compression quality in terms of depth, duty-cycle, leaning, and decay in compression performance. Further studies are needed to assess the impact of the Guidelines 2010 recommendation for deeper and faster chest compressions.     

Poor chest compression quality with mechanical compressions in simulated cardiopulmonary resuscitation: a randomized, cross-over manikin study

Introduction

Mechanical chest compression devices are being implemented as an aid in cardiopulmonary resuscitation (CPR), despite lack of evidence of improved outcome. This manikin study evaluates the CPR-performance of ambulance crews, who had a mechanical chest compression device implemented in their routine clinical practice 8 months previously. The objectives were to evaluate time to first defibrillation, no-flow time, and estimate the quality of compressions.

Methods

The performance of 21 ambulance crews (ambulance nurse and emergency medical technician) with the authorization to perform advanced life support was studied in an experimental, randomized cross-over study in a manikin setup. Each crew performed two identical CPR scenarios, with and without the aid of the mechanical compression device LUCAS. A computerized manikin was used for data sampling.

Results

There were no substantial differences in time to first defibrillation or no-flow time until first defibrillation. However, the fraction of adequate compressions in relation to total compressions was remarkably low in LUCAS-CPR (58%) compared to manual CPR (88%) (95% confidence interval for the difference: 13–50%). Only 12 out of the 21 ambulance crews (57%) applied the mandatory stabilization strap on the LUCAS device.

Conclusions

The use of a mechanical compression aid was not associated with substantial differences in time to first defibrillation or no-flow time in the early phase of CPR. However, constant but poor chest compressions due to failure in recognizing and correcting a malposition of the device may counteract a potential benefit of mechanical chest compressions.     

Chest compressions by ambulance personnel on chests with variable stiffness: abilities and attitudes

INTRODUCTION: Quality of cardiopulmonary resuscitation (CPR) performed by professionals is reported to be substandard even with automated corrective feedback. We hypothesised that lack of quality is not due to physical capabilities. MATERIALS AND METHODS: Eighty ambulance personnel from the same services where the quality of clinical CPR was investigated, performed two-rescuer CPR with similar corrective feedback for 5min on each of four manikins with different chest stiffness. The personnel also scored their agreement with statements on clinical CPR performance. RESULTS: All study subjects performed CPR well within Guidelines recommendations on all four manikins with mean compression depth 44+/-3mm, compression rate 101+/-3min(-1), and 7+/-2 ventilations per minute. Three quarters stated that during CPR on patients their personal sense of correct depth and force determined their performance. Fifty-five percent believed that too deep chest compressions could cause serious injury to the patient, and 39% that compressing to Guidelines recommended depth may often result in severe patient injury. A quarter felt that the potential benefits of compressing to the Guidelines depth could not justify the injuries it would cause. Breaking ribs made 54% feel very uncomfortable. CONCLUSIONS: Ambulance personnel were physically capable of consistently compressing to the Guidelines depth even on the stiffest chest. These laboratory results cannot be directly compared to the clinical out-of-hospital ALS situation, but strongly indicate that the inadequate chest compressions found in our clinical study were not due to lack of physical capability. We speculate that this may at least partly be explained by their fear of causing patient injury and trust in their own opinion of what is the correct compression depth and force in preference to the feedback.     

Resuscitation great. A history of mechanical devices for providing external chest compressions

The importance of providing good quality chest compressions with limited interruptions has been emphasised by the Resuscitation Guidelines 2005. The difficulties of providing consistent, good quality, chest compressions manually are well documented and attempts have been made to devise mechanical means to achieve this. Many see the development of mechanical devices as a new phenomenon; however, as with many other components of resuscitation science, they have in fact been available for a number of years. This paper provides a brief historical review of some of the mechanical devices which have been invented over the last 45 years in order to deliver external chest compressions. It also suggests some reasons why these devices failed to become a regular part of resuscitation practice.     

The quality of chest compressions by trained personnel: the effect of feedback, via the CPREzy, in a randomized controlled trial using a manikin model

Even after training, the ability to perform effective cardiac compressions has been found to be poor and to decrease rapidly. We assessed this ability with and without a non-invasive feedback device, the CPREzy, during a 270s CPR session in an unannounced, single-blinded manikin study using 224 hospital employees and staff chosen at random and using a non-cross over design. The two groups self-assessed their knowledge and skills as adequate. However, the control group (N=111) had significantly more difficulty in delivering chest compressions deeper than 4 cm (25 versus 1 candidate in the CPREzy group), P=0.0001. The control group compressed ineffectively in 36% (+/-41%) of all compressions as opposed to 6+/-13% in the CPREzy group (N=112, P=0.0001). If compressions were effective initially, the time until >50% of compressions were less than 4 cm deep was 75+/-81s in the control group versus 194+/-87 s in the CPREzy group (P=0.0001 [-180 to -57.5]). After a few seconds of training in its use, our candidates used the CPREzy effectively. Against the background knowledge that estimation of compression depth by the rescuer or other team members is difficult, and that performing effective compressions is the cornerstone of any resuscitation attempt, our data suggests that a feedback device such as the CPREzy should be used consistently during resuscitation.     

The effect on quality of chest compressions and exhaustion of a compression--ventilation ratio of 30:2 versus 15:2 during cardiopulmonary resuscitation--a randomised trial

BACKGROUND: Recent cardio pulmonary resuscitation (CPR) guidelines changed the compression:ventilation ratio in 30:2. OBJECTIVE: To compare the quality of chest compressions and exhaustion using the ratio 30:2 versus 15:2. METHODS: A prospective, randomised crossover design was used. Subjects were recruited from the H.-Hart hospital personnel and the University College Katho for nurses and bio-engineering. Each participant performed 5min of CPR using either the ratio 30:2 or 15:2, then after a 15min rest switched to the other ratio. The data were collected using a questionnaire and an adult resuscitation manikin. The outcomes included exhaustion as measured by a visual analogue scale (VAS) score, depth of chest compressions, rates of chest compressions, total number of chest compressions, number of correct chest compressions and incomplete release. Data were compared using the Wilcoxon Signed Ranks Test. The results are presented as medians and interquartile ranges (IQR). RESULTS: One hundred and thirty subjects completed the study. The exhaustion-score using the VAS was 5.9 (IQR 2.25) for the ratio 30:2 and 4.5 (IQR 2.88) for the ratio 15:2 (P<0.001). The compression depth was 40.5mm (IQR 15.75) for 30:2 and 41mm (IQR 15.5) for 15:2 (P=0.5). The compression rate was 118beats/min (IQR 29) for 30:2 and 115beats/min (IQR 32) for 15:2 (P=0.02). The total number of compressions/5min was 347 (IQR 79) for 30:2 and 244compressions/5min (IQR 72.5) for 15:2 (P<0.001). The number of correct compression/5min was 61.5 (IQR 211.75) for 30:2 and 55.5 (IQR 142.75) for 15:2 (P=0.001). The relative risk (RR) of incomplete release in 30:2 versus 15:2 was 1.087 (95% CI=0.633-1.867). CONCLUSIONS: Although the 30:2 ratio is rated to be more exhausting, the 30:2 technique delivers more chest compressions and the quality of chest compressions remains unchanged.     

Metronome improves compression and ventilation rates during CPR on a manikin in a randomized trial

Aim

We hypothesized that a unique tock and voice metronome could prevent both suboptimal chest compression rates and hyperventilation.

Methods

A prospective, randomized, parallel design study involving 34 pairs of paid firefighter/emergency medical technicians (EMTs) performing two-rescuer CPR using a Laerdal SkillReporter Resusci Anne^® manikin with and without metronome guidance was performed. Each CPR session consisted of 2 min of 30:2 CPR with an unsecured airway, then 4 min of CPR with a secured airway (continuous compressions at 100 min⁻¹ with 8-10 ventilations/min), repeated after the rescuers switched roles. The metronome provided “tock” prompts for compressions, transition prompts between compressions and ventilations, and a spoken “ventilate” prompt.

Results

During CPR with a bag/valve/mask the target compression rate of 90-110 min⁻¹ was achieved in 5/34 CPR sessions (15%) for the control group and 34/34 sessions (100%) for the metronome group (p < 0.001). An excessive ventilation rate was not observed in either the metronome or control group during CPR with a bag/valve/mask. During CPR with a bag/endotracheal tube, the target of both a compression rate of 90-110 min⁻¹ and a ventilation rate of 8-11 min⁻¹ was achieved in 3/34 CPR sessions (9%) for the control group and 33/34 sessions (97%) for the metronome group (p < 0.001). Metronome use with the secured airway scenario significantly decreased the incidence of over-ventilation (11/34 EMT pairs vs. 0/34 EMT pairs; p < 0.001).

Conclusions

A unique combination tock and voice prompting metronome was effective at directing correct chest compression and ventilation rates both before and after intubation.     

交换按压手对胸外按压质量和疲劳的影响

目的 研究心肺复苏(cardiopulmonary resuscitation,CPR)时交换按压手的按压方式对胸外按压质量及操作者疲劳的影响.方法 177名经标准基础生命支持培训的医学生,用抽签方式随机确定按压方式(交换按压手即上下手交换的方式或传统按压方式)的先后顺序,两种方式间隔7d,分别在模拟人上进行10个循环的标准成人单人CPR;记录按压质量、CPR前后操作者的生理参数、主观疲劳指标.计量资料用均数±标准差(x(-)±s)表示,两组均数比较用成组t检验,两组率的比较用x2检验,不感到疲劳的概率用Kaplan-Meier方法评估,以P＜0.05为差异具有统计学意义.结果 在以优势手为初始按压手的操作者中,交换按压手组和传统按压组按压质量均差异无统计学意义(P＞0.05),CPR后Borg疲劳评分差异无统计学意义(13.17 ±1.62 vs.13.41 ±2.11,P=0.437),出现疲劳的循环数也差异无统计学意义(P =0.127).在以非优势手为初始按压手的操作者中,交换按压手组比传统按压组按压深度更深[(39±10) mm vs.(38±9) mm,P=0.015],CPR后Borg疲劳评分更低(12.67 ±2.03 vs.13.33 ±1.95,P=0.011),出现疲劳的循环数更晚(P =0.041).结论 CPR中交换按压手的按压方式能延缓以非优势手为初始按压手的操作者的疲劳,改善胸外按压质量.