调度员指导的心肺复苏对院前心脏骤停生存率影响的Meta分析北大核心CSCD

目的评价第一目击者在对院前心脏骤停(out-of-hospital cardiac arrest,OHCA)患者进行心肺复苏(cardiopulmonary resuscitation,CPR)时是否接受调度员指导(dispatcher-assisted cardiopulmonary resuscitation,DA-CPR)对OHCA患者结局是否有影响。方法通过检索在中文及英文各大数据库公开发表的临床研究,筛选出关于对院前心脏骤停患者心肺复苏时是否进行DA-CPR的文献,按照Cochrane Handbook5.1.0标准,对纳入文献质量进行评价,并提取出相关有效数据,应用Review Manager 5.3软件,对三个结局指标(自主循环恢复、存活至出院、神经功能良好)分别进行Meta分析。结果共纳入21项研究,共计349822例患者,其中DA-CPR组182125人,CPR-Only组167697人。分析结果显示:在美国、日本、韩国,DA-CPR相比CPR-Only未能提高OHCA停患者的ROSC率,RR=1.10,95%CI:0.94~1.29,P=0.24;未能提高OHCA患者的出院存活率,RR=1.10,95%CI:0.90~1.34,P=0.34;未能提高OHCA患者的神经功能良好率,RR=1.01,95%CI:0.79~1.28,P=0.97。而在中国,DA-CPR相比CPR-Only,能提高OHCA患者的ROSC率,RR=2.61,95%CI:1.53~4.46,P=0.0005;能提高OHCA患者的出院存活率,RR=6.08,95%CI:1.84~20.04,P=0.003;能提高OHCA患者的神经功能良好率,RR=9.76,95%CI:1.87~51.02,P=0.007。结论DA-CPR在世界总体范围内的效果无统计学意义。但因发现DA-CPR在不同国家的效果差别较大,所以需具体而言:在发达国家,DA-CPR与无调度员指导的BCPR相比,不能明显提高OHCA患者的ROCS率、出院生存率和神经功能良好率。而在提高我国OHCA患者的ROCS率、出院生存率和神经功能良好率方面,DA-CPR优于无调度员指导的BCPR,有统计学意义。     

心脏骤停患者心肺复苏抢救中的影响因素分析

目的 探讨心脏骤停患者心肺复苏抢救中的影响因素.方法 回顾性收集2015年9月-2018年9月急救中心收治的304例成年心脏骤停患者的临床数据,包括患者基本人口学信息、现场心肺复苏(cardio-pulmonary resuscitaion,CPR)情况[包括是否有目击者、目击者是否实施CPR、胸部按压分数(chest...     

心源性心脏骤停心肺复苏成功的分析

目的分析影响心源性心脏骤停患者心肺复苏成功的临床因素。方法选择该院收治的心源性心脏骤停患者共58例,根据复苏成功与否分成心肺复苏成功组(成功组)22例和心肺复苏失败组(失败组)36例。分析两组患者的临床资料,探讨与心肺复苏成功的相关因素。结果两组患者性别比和发病种类比较,差异无统计学意义(P0.05);成功组患者的年龄和入院时间明显低于失败组,院前给予抢救的比例明显高于失败组,差异均有统计学意义(P0.05)。成功组患者的心脏停搏时间、抢救时间、心肺复苏循环平均次数、肾上腺素剂量和电除颤次数明显低于失败组,应用辅助机械通气的比例明显高于失败组,差异均有统计学意义(P0.05)。结论心肺复苏成功的因素可能与发病年龄、入院时间、院前给予抢救的比例、心脏停搏时间、抢救时间、心肺复苏循环次数、肾上腺素剂量、平均电除颤次数和应用辅助机械通气有关。     

心脏骤停后心肺复苏和心肺脑复苏成功病例的对比分析

目的 探讨影响心脏骤停患者成功脑复苏的相关因素.方法 回顾对比分析心脏骤停后成功心肺脑复苏(A组,n=38)和仅心肺复苏成功(B组,n=42)患者之间的相关指标,包括性别、年龄、原发疾病、心脏骤停原因、心脏骤停环境、心脏骤停相关时间和心肺复苏后相关治疗持续时间.结果 两组性别比和平均年龄比较差异无统计学意义(P＞0.05).原发疾病:A组以外科为主(78.9%),B组以内科为主(61.9%),两组比较差异有统计学意义(P＜0.005).心脏骤停原因:A组31例(81.6%)为急性缺氧、低血压、内脏神经反射和单纯心脏疾患, B组30例(71.4%)为慢性缺氧和慢性心脏病,两组比较差异有统计学意义(P＜0.005).心脏骤停环境:A组24例(63.2%)发生在手术室和ICU,B组22例(52.4%)发生在普通病房,两组比较差异有统计学意义(P＜0.005).心脏骤停相关时间:A组心脏骤停持续时间(8.2±8.7)min,自主心跳恢复时间(6.7±8.4)min,脑缺血缺氧时间(1.5±1.3)min,均明显短于B组[分别为(30.8±26.2)min、(27.7±24.9)min和(3.1±3.1)min,P＜0.001或P＜0.005].心肺复苏后相关治疗持续时间:A组亚低温持续时间(4.0±2.6)d,呼吸机持续时间(11.1±19.7)d,与B组[(5.9±3.8)d和(15.4±29.3)d]比较差异无统计学意义(P＞0.05).Logistic多因素回归分析显示,原发疾病(OR=6.22,95%CI 1.64～23.46)、心脏骤停持续时间(OR=1.11,95%CI 1.04～1.19)和心脏骤停发生环境(OR=4.51,95%CI 1.22～16.61)与成功脑复苏的关系更密切,成为三个独立影响因素.结论 没有明显慢性疾病,在手术室和ICU以急性缺氧、低血压和单纯心脏原因发生的心脏骤停,抢救及时有效,复苏后处理恰当、合理,尽早实施全面脑保护是成功脑复苏的有利因素.     

体外心肺复苏对成人心脏骤停患者预后影响的荟萃分析

目的 评价体外心肺复苏(ECPR)与传统心肺复苏(CCPR)对成人心脏骤停患者的生存和神经功能预后的影响.方法 计算机检索PubMed,Web of science等数据库在1980年1月到2015年1 1月公开发表的相关文献,并对获得文献进行严格的筛选和质量评价,提取相关数据,使用Review Manager 5.0软件进行统计分析.结果 纳入8个研究,共计2 718例,其中ECPR组462例,传统心肺复苏(CCPR)组2 256例.Meta分析结果显示:与CCPR比较,ECPR可以提高成人心脏骤停患者的出院存活率(OR=2.92,95％CI:2.24～3.81,P＜0.01),长期存活率(OR=2.97,95％CI:2.11 ～4.19,P＜0.01)和神经功能状态(OR=3.50,95％CI:2.36～5.81,P＜0.01.在纳入的8项研究中,4项建立了倾向评分匹配的队列,其中ECPR组与CCPR组各182例.Meta分析结果表明:在提高成人心脏骤停患者的自主循环恢复率、出院存活率、长期存活率和神经功能状态方面,ECPR均具有较为显著的优势.结论 ECPR可以改善成人心脏骤停患者的自主循环恢复率、出院存活率、长期存活率和神经功能预后,效果优于CCPR.     

ICU心脏骤停患者心肺复苏的相关临床因素分析

目的 分析影响ICU心脏骤停患者心肺复苏的相关因素.方法 收集ICU心脏骤停并行心肺复苏抢救病例131例,分为自主循环恢复(ROSC)组与未恢复(Non-ROSC)组,分析患者临床资料及影响ROSC的相关因素.结果 单因素分析显示,ROSC 组和Non-ROSC 组有统计学意义的项目:原发病(χ2=11.015,P=0.026)、心脏骤停形式(χ2=7.048,P=0.029)、目击察觉(χ2=15.886,P＜0.001),无统计学意义的项目:性别、年龄及心脏骤停时间点等.Logistic回归分析显示,原发病为心血管疾病(OR=0.129,P=0.003)、脑血管疾病(OR=7.818,P=0.002)、严重多发伤(OR=0.141,P=0.014),心脏骤停形式为心脏停搏或无脉电活动(OR=4.573,P=0.006),目击察觉(OR=0.078,P=0.000)是影响ICU心脏骤停患者心肺复苏的重要因素.结论 原发病、心脏骤停形式及目击察觉是影响ICU心脏骤停患者心肺复苏的重要因素.     

体外心肺复苏应用于心脏骤停患者神经功能预后的系统评价和Meta分析

目的 通过系统评价探讨体外膜肺氧合(ECMO)辅助下心肺复苏(CPR)对心脏骤停(CA)患者神经功能预后的影响。方法 检索从建库至2023年2月PubMed、Web of Science、Ovid、Cochrane Library、中国知网、万方数据库、中华医学期刊全文数据库、中国生物医学文献数据库等。根据文献纳入和排除标准进行文献筛选、质量评价和资料提取,应用RevMan 5.3软件进行统计分析。结果 共纳入9项研究,共计2 694例患者,其中体外心肺复苏(ECPR)组717例患者,传统心肺复苏(CCPR)组1 977例。Meta分析结果显示,与CCPR相比,ECPR可以提高CA患者短期(出院或1个月内)神经功能预后[OR=2.93,95%CI(1.76,4.87),P<0.000 1]及长期神经功能预后[OR=0.12,95%CI(0.07,0.17),P<0.000 01]。亚组分析表明,在院内心脏骤停(IHCA)和院外心脏骤停(OHCA)患者中实施ECPR对改善出院时的神经功能预后方面异质性较大(组内I²≥50%,P<0.05),而在改善...     

A quality improvement initiative to optimize use of a mechanical chest compression device within a high-performance CPR approach to out-of-hospital cardiac arrest resuscitation

BackgroundMinimizing the chest compression pause associated with application of a mechanical CPR device is a key component of optimal integration into the overall resuscitation process. As part of a multi-agency implementation project, Anchorage Fire Department deployed LUCAS CPR devices on BLS and ALS fire apparatus for initiation early in resuscitation efforts. A 2012 report identified the pause interval for device application as a key opportunity for quality improvement (QI). In early 2013 we began a QI initiative to reduce device application time interval and optimize the overall CPR process. To assess QI initiative effectiveness, we compared key CPR process metrics from before to during and after its implementation.MethodsWe included all cases of EMS-treated out-of-hospital cardiac arrest during 2012 and 2013 in which a mechanical CPR device was used and the defibrillator electronic record was available. Continuous ECG and impedance data were analyzed to measure chest compression fraction, duration of the pause from last manual to first mechanical compression, and duration of the longest overall pause in the resuscitation effort.ResultsCompared to cases from 2012 (n = 61), median duration of the pause prior to first mechanical compression for cases from 2013 (n = 71) decreased from 21 (15, 31) to 7 (4, 12) s (p < 0.001), while median chest compression fraction increased from 0.90 (0.88, 0.93) to 0.95 (0.93, 0.96) (p < 0.001). Median duration of the longest pause decreased from 25 (20, 35) to 13 (10, 20) s (p < 0.001), while the proportion of cases where the longest pause was for mechanical CPR application decreased from 74% to 31% (p < 0.001).ConclusionsOur QI initiative substantially reduced the duration of the pause prior to first mechanical compression. Combined with the simultaneous significant increase in compression fraction and significant decrease in duration of the longest pause, this finding strongly suggests a large improvement in mechanical CPR device application efficiency within an overall high-performance CPR process.     

Continuous mechanical chest compression during in-hospital cardiopulmonary resuscitation of patients with pulseless electrical activity

Survival after in-hospital pulseless electrical activity (PEA) cardiac arrest is poor and has not changed during the last 10 years. Effective chest compressions may improve survival after PEA. We investigated whether a mechanical device (LUCAS™-CPR) can ensure chest compressions during cardiac arrest according to guidelines and without interruption during transport, diagnostic procedures and in the catheter laboratory.

Methods

We studied mechanical chest compression in 28 patients with PEA (pulmonary embolism (PE) n = 14; cardiogenic shock/acute myocardial infarction; n = 9; severe hyperkalemia; n = 2; sustained ventricular arrhythmias/electrical storm; n = 3) in a university hospital setting.

Results

During or immediately after CPR, 21 patients underwent coronary angiography and or pulmonary angiography. Successful return of a spontaneous circulation (ROSC) was achieved in 27 out of the 28 patients. Ten patients died within the first hour and three patients died within 24 h after CPR. A total of 14 patients survived and were discharged from hospital (13 without significant neurological deficit). Interestingly, six patients with PE did not have thrombolytic therapy due to contraindications. CT-angiography findings in these patients showed fragmentation of the thrombus suggesting thrombus breakdown as an additional effect of mechanical chest compressions. No patients exhibited any life-threatening device-related complications.

Conclusion

Continuous chest compression with an automatic mechanical device is feasible, safe, and might improve outcomes after in-hospital-resuscitation of PEA. Patients with PE may benefit from effective continuous chest compression, probably due to thrombus fragmentation and increased pulmonary artery blood flow.     

新型大鼠心跳骤停和复苏的机械装置

目的研发由电磁阀系统总控制、压缩气体驱动的新型大鼠电刺激诱发心跳骤停和复苏的机械装置,并探讨其有效性和安全性。方法选用Sprague-Dawley雄性大鼠20只,应用自主开发研制的心跳骤停和复苏机械装置,持续交流电经右心室内膜致颤。在6min心室颤动后,开始给予6min的机械胸外按压和同步机械通气,随后双向波经胸体外除颤。结果15只大鼠复苏成功,自主循环恢复率为75%。电刺激后所有大鼠立刻出现心室颤动,3min的电刺激停止后动物持续表现为室颤而没有自发转复心律现象。心肺复苏期间恢复自主循环组其冠状动脉灌注压恒定在24mmHg左右,显著高于未能恢复自主循环组。结论本新型大鼠心跳骤停和心肺复苏装置的有效性和安全性高,可最大限度减少实验的误差,具有一定的推广应用前景。     

吸气阻力阀联合心肺复苏术对心脏骤停患者疗效的Meta分析

目的系统评价应用吸气阻力阀（ITD）联合心肺复苏术（CPR）对心脏骤停患者的疗效。 方法计算机检索PubMed、ISI WOK平台数据库、Science Online、Nature、中文生物医学文献库（CMCC）、万方数据资源、CNKI中国知网、维普电子资源数据库中关于应用ITD和未使用ITD进行CPR的临床对照研究,检索时间为2000年至2015年6月。由2名研究者按照纳入及排除标准独立进行文献筛选、资料提取和质量评估后,采用Revman 5.3软件对数据进行Meta分析。 结果共纳入8项研究,共包括138 992例心脏骤停患者,其中应用ITD组（ITD组）患者7 056例,未应用ITD（对照组）患者6 936例。Meta分析结果显示,自主循环恢复率两组间比较差异无统计学意义[OR=1.03,95%CI（0.96,1.11）,Z=0.93,P=0.35],复苏后改良Rankin评分≤ 3的比例ITD组明显优于对照组[OR=1.74,95%CI（1.11,2.73）,Z=2.40,P=0.02],复苏后存活出院率ITD组优于对照组[OR=1.40,95%CI（1.04,1.91）,Z=2.18,P=0.03]。亚组分析结果显示,应用ITD联合主动胸外按压-减压心肺复苏术（ACD-CPR）（ITD + ACD-CPR）组的自主循环恢复率[OR=1.13,95%CI（1.01,1.26）,Z=2.11,P=0.03]、复苏后改良Rankin评分≤ 3的比例[OR=1.53,95%CI（1.22,1.93）,Z=3.67,P<0.001]及复苏后存活出院率[OR=1.25,95%CI（1.04,1.49）,Z=2.38,P=0.02]均明显优于对照组。 结论应用吸气阻力阀联合ACD-CPR可以提高心脏骤停患者心肺复苏成功率。     

Comparison of chest compression only and standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest in Singapore

OBJECTIVE: Chest compression only cardiopulmonary resuscitation (CC-CPR) without ventilation has been proposed as an alternative to standard cardiopulmonary resuscitation (CPR) for bystanders. However, there has been controversy regarding the relative effectiveness of both of these techniques. We aim to compare the outcomes of cardiac arrest patients in the cardiac arrest and resuscitation epidemiology study who either received CC-CPR, standard CPR or no bystander CPR. METHODS: This prospective cohort study involved all out-of-hospital cardiac arrest (OHCA) patients attended to by emergency medical service (EMS) providers in a large urban centre. The data analyses were conducted secondarily on these collected data. The technique of bystander CPR was reported by paramedics who arrived at the scene. RESULTS: From 1 October 2001 to 14 October 2004, 2428 patients were enrolled into the study. Of these, 255 were EMS-witnessed arrests and were excluded. 1695 cases did not receive any bystander CPR, 287 had standard CPR and 154 CC-CPR. Patient characteristics were similar in both the standard and CC-CPR groups except for a higher incidence of residential arrests and previous heart disease sufferers in the CC-CPR group. Patients who received standard CPR (odds ratio (OR) 5.4, 95% confidence interval (CI) 2.1-14.0) or CC-CPR (OR 5.0, 95% CI 1.5-16.4) were more likely to survive to discharge than those who had no bystander CPR. There was no significant difference in survival to discharge between those who received CC-CPR and standard CPR (OR 0.9, 95% CI 0.3-3.1). CONCLUSION: We found that patients were more likely to survive with any form of bystander CPR than without. This emphasises the importance of chest compressions for OHCA patients, whether with or without ventilation.     

Active compression-decompression cardiopulmonary resuscitation (CPR) versus standard CPR for cardiac arrest patients: a meta-analysis

BACKGROUND:

Active compression-decompression cardiopulmonary resuscitation (ACDCPR) has been popular in the treatment of patients with cardiac arrest (CA). However, the effect of ACD-CPR versus conventional standard CPR (S-CRP) is contriversial. This study was to analyze the efficacy and safety of ACD-CPR versus S-CRP in treating CA patients.

METHODS:

Randomized or quasi-randomized controlled trials published from January 1990 to March 2011 were searched with the phrase “active compression-decompression cardiopulmonary resuscitation and cardiac arrest” in PubMed, EmBASE, and China Biomedical Document Databases. The Cochrane Library was searched for papers of meta-analysis. Restoration of spontaneous circulation (ROSC) rate, survival rate to hospital admission, survival rate at 24 hours, and survival rate to hospital discharge were considered primary outcomes, and complications after CPR were viewed as secondary outcomes. Included studies were critically appraised and estimates of effects were calculated according to the model of fixed or random effects. Inconsistency across the studies was evaluated using the I2 statistic method. Sensitivity analysis was made to determine statistical heterogeneity.

RESULTS:

Thirteen studies met the criteria for this meta-analysis. The studies included 396 adult CA patients treated by ACD-CPR and 391 patients by S-CRP. Totally 234 CA patients were found out hospitals, while the other 333 CA patients were in hospitals. Two studies were evaluated with high-quality methodology and the rest 11 studies were of poor quality. ROSC rate, survival rate at 24 hours and survival rate to hospital discharge with favorable neurological function indicated that ACD-CPR is superior to S-CRP, with relative risk (RR) values of 1.39 (95% CI 0.99–1.97), 1.94 (95% CI 1.45–2.59) and 2.80 (95% CI 1.60–5.24). No significant differences were found in survival rate to hospital admission and survival rate to hospital discharge for ACD-CPR versus S-CRP with RR values of 1.06 (95% CI 0.76–1.60) and 1.00 (95% CI 0.73–1.38).

CONCLUSION:

Quality controlled studies confirmed the superiority of ACD-CPR to S-CRP in terms of ROSC rate and survival rate at 24 hours. Compared with S-CRP, ACD-CPR could not improve survival rate to hospital admission or survival rate to hospital discharge.KEY WORDS: Active compression-decompression, Cardiopulmonary resuscitation, Cardiac arrest, Meta-analysis     

Mechanical chest compression does not seem to improve outcome after out-of hospital cardiac arrest. A single center observational trial

AimRecently three large post product placement studies, comparing mechanical chest compression (cc) devices to those who received manual cc, found equivalent outcome results for both groups. Thus the question arises whether those results could be replicated using the devices on a daily routine.MethodsWe prospectively enrolled 948 patients over a 12 months period. Chi-Square test and Mann–Whitney-U test were used to assess differences between “manual” and “mechanical” cc subgroups. Uni- and multivariate Cox regression hazard analysis were used to assess the influence of cc type on survival.ResultsA mechanical cc device was used in 30.1% (n = 283) cases. Patients who received mechanical cc had a significantly worse neurological outcome – measured in cerebral performance category (CPC) – than the manual cc group (56.8% vs. 78.6%, p = 0.009). Patients receiving mechanical cc were significantly younger, more were male and were more likely to have bystander CPR and an initially shock-able ECG rhythm. There was no difference in the quality of CPR that might explain the worse outcome in mechanical cc patients.ConclusionEven with high quality CPR in both, manual and mechanical cc groups, outcome in patients who received mechanical cc was significantly worse. The anticipated benefits of a higher compression ratio and a steadier compression depth of a mechanical cc device remain uncertain. In this study selection for mechanical cc was not standardized, and was non-random. This merits further investigation. Further research on how mechanical cc is chosen and used should be considered.Clinical trial registration: https://ekmeduniwien.at/core/catalog/2013/ (EK-Nr:1221/2013)     

Transthoracic impedance for the monitoring of quality of manual chest compression during cardiopulmonary resuscitation

Objective

The quality of cardiopulmonary resuscitation (CPR), especially adequate compression depth, is associated with return of spontaneous circulation (ROSC) and is therefore recommended to be measured routinely. In the current study, we investigated the relationship between changes of transthoracic impedance (TTI) measured through the defibrillation electrodes, chest compression depth and coronary perfusion pressure (CPP) in a porcine model of cardiac arrest.

Methods

In 14 male pigs weighing between 28 and 34 kg, ventricular fibrillation (VF) was electrically induced and untreated for 6 min. Animals were randomized to either optimal or suboptimal chest compression group. Optimal depth of manual compression in 7 pigs was defined as a decrease of 25% (50 mm) in anterior posterior diameter of the chest, while suboptimal compression was defined as 70% of the optimal depth (35 mm). After 2 min of chest compression, defibrillation was attempted with a 120-J rectilinear biphasic shock.

Results

There were no differences in baseline measurements between groups. All animals had ROSC after optimal compressions; this contrasted with suboptimal compressions, after which only 2 of the animals had ROSC (100% vs. 28.57%, p = 0.021). The correlation coefficient was 0.89 between TTI amplitude and compression depth (p < 0.001), 0.83 between TTI amplitude and CPP (p < 0.001).

Conclusion

Amplitude change of TTI was correlated with compression depth and CPP in this porcine model of cardiac arrest. The TTI measured from defibrillator electrodes, therefore has the potential to serve as an indicator to monitor the quality of chest compression and estimate CPP during CPR.     

Mechanical cardiopulmonary resuscitation for patients with cardiac arrest

BACKGROUND:

Although modern cardiopulmonary resuscitation (CPR) substantially decreases the mortality induced by cardiac arrest, cardiac arrest still accounts for over 50% of deaths caused by cardiovascular diseases. In this article, we address the current use of mechanical devices during CPR, and also compare the CPR quality between manual and mechanical chest compression.

METHODS:

We compared the quality and survival rate between manual and mechanical CPR, and then reviewed the mechanical CPR in special circumstance, such as percutaneous coronary intervention, transportation, and other fields.

RESULTS:

Compared with manual compression, mechanical compression can often be done correctly, and thus can compromise survival; can provide high quality chest compressions in a moving ambulance; enhance the flow of blood back to the heart via a rhythmic constriction of the veins; allow ventilation and CPR to be performed simultaneously.

CONCLUSION:

Mechanical devices will be widely used in clinical practice so as to improve the quality of CPR in patients with cardiac arrest.KEY WORDS: Cardiopulmonary resuscitation, Manual compression, Mechanical compressionCardiopulmonary resuscitation (CPR), also called basic life support, is an emergency medical procedure performed to restore blood flow (circulation) and breathing. The goal of CPR is to provide oxygen quickly to the brain, heart, lungs, and other organs until normal function of the heart and lung is restored. CPR can help prevent brain damage and death in children.[1] It is reported that approximately 600 000 individuals suffer from cardiac arrest and receive cardiopulmonary resuscitation in the United States and Europe each year.[2,3] Although modern CPR substantially decreases the mortality induced by cardiac arrest, cardiac arrest still accounts for over 50% of deaths caused by cardiovascular diseases.[4]The success rate of CPR ranging widely from 5% to 10% is based on many factors such as (1) causes of cardiac or respiratory arrest; (2) underlying health conditions of victims; (3) time elapse between arrest and CPR; and (4) techniques for CPR.[5,6] The survival rate is affected not only by CPR but more importantly by its quality. Effective CPR can contribute more blood flow to the brain, heart and other organs, and thus increase the survival rate of patients with cardiac arrest.[7] In November 2005 the AHA revised CPR guidelines to emphasize chest compression and its effect on blood pressure.[8] Studies[7,9,10] showed that by taking fewer breaks between compressions, rescuers can keep blood pressure higher, which helps to pump blood to the brain and other vital organs. However, during CPR even with the best manual chest compressions, cardiac output is approximately 20% to 30% of normal value, and performer''s fatigue may also reduce the quality of the compressions. Besides, chest compressions can not be performed during the transportation of patients, which prolong the time between the arrest and CPR, and also increase the difficulty of resuscitation.[11,12] Therefore, to avoid or reduce these negative factors and to improve the CPR quality, mechanical devices are frequently used.In this article we address the current use of mechanical devices during CPR, and also compare the CPR quality between manual and mechanical chest compression.

Comparison of quality between manual and mechanical CPR

In 1961, Harrison-Paul[13] applied the electric pneumatic device clinically, and then Kouwenhoven et al[14] introduced closed chest cardiac massage for CPR in 1969. The Kouwenhoven technique has been shown repeatedly its clinically inefficacy. Although this technique can clearly save lives, its inherent inefficiency and the challenges related to teaching and retaining the skills needed to perform the technique correctly have limited its overall effectiveness. This has prompted us to develop new life-saving CPR techniques and devices.At present, the most commonly used mechanical chest-compression devices include LUCASTM, Autopluse, Lifebelt, Thumper and Brunswick-TM HLR R30. Compared with manual compression, mechanical compression can: (1) often be done correctly, and thus can compromise survival; (2) potentially improve the quality of chest compression with automatic mechanical devices, which can potentially apply compression more consistently than manually; (3) can provide high quality chest compressions in a moving ambulance, which is very difficult to accomplish with manual CPR; (4) allow a reduction in a number of emergency medical systems (EMS) personnel needed to perform resuscitation;[15] (5) allow ventilation and CPR to be performed simultaneously; (6) enhance the flow of blood back to the heart via a rhythmic constriction of the veins.[16]Autopulse can markedly increase the mean systolic blood pressure from 72 mmHg to 106 mmHg, and the average diastolic blood pressure from 17 mmHg to 23 mmHg as compared with manual compression (P<0.05). In addition, Autopulse can obviously improve coronary perfusion, and generate approximately 36% of the normal blood flow, which is much higher than that generated by manual compression (13%).[17] But before and after use of Autopulse, there is no significant difference in the pressure of end tidal carbon dioxide (PETCO₂), which serves as an important parameter for evaluating cardiac output and pulmonary blood flow.[18] Axelsson et al[5] reported that in 126 patients who participated in the study, 64 were enrolled in a mechanical chest compression group and 62 in a control group. The group receiving mechanical ACD-CPR showed highest PETCO₂ values in contrast to the average (P=0.04), initial (P=0.01) and minimum (P=0.01) values. There was no significant difference in the maximum values between the two groups. This indicated that chest compression can increase blood supply to the heart and lung.

Comparison of survival rate

Although mechanical CPR can increase cardiac output, coronary and cerebral blood flow, arterial blood pressure, and PETCO₂, whether mechanical CPR can increase the survival rate of patients with cardiac arrest is still in debate. Skogvoll et al[19] reported that there were no significant differences between mechanical and manual CPR compression (survival rates 13% vs. 12%) in 302 patients with cardiac arrest. Another prospective trial showed that the survival rate of patients after hospitalization for 24, 48, and 72 hours and the number of patients who had reestablished spontaneous circulation was increased in the mechanical compression group, but no differences were observed between the mechanical and manual CPR compression groups.[18] In a prospective randomized trial conducted by Kouwenhoven[14], 1410 patients received mechanical CPR and 1456 received manual CPR. The survival rate of the mechanical CPR group was significantly higher than that of the manual CPR group (23.8% vs. 20.6%, P< 0.05). Ong et al[17] also reported that mechanical CPR increased the survival rate of patients. But Skogvoll et al[19] described in their randomized clinical trial that mechanical CPR increased the mortality of patients. Thus further clinical studies or animal experiments are needed to confirm this finding.

Mechanical CPR in special circumstance

Percutaneous coronary intervention (PCI)

In most cases, cardiopulmonary arrest is derived from the heart. Myocardial ischemia caused by acute coronary occlusion can lead to the development of ventricular fibrillation. PCI was thought to be useful in patients with acute ST elevation myocardial infarction (STEMI),[20,21] and it was also beneficial to patients after recovery of spontaneous circulation.[22] Sunde et al[23,24] found that the mortality of patients treated with PCI (n=12) was significantly lower than that of patients treated conservatively (n=20) (17% vs. 70%). However, PCI is seldom used in patients with cardiac arrest.[25] CPR is still required to perform PCI during cardiac arrest, but it is very difficult to simultaneously perform manual CPR and PCI. Mechanical chest compression allows for continued PCI despite ongoing cardiac or circulatory arrest with artificially sustained circulation. A study[25] reported that in 3058 patients treated with PCI for ST-elevation myocardial infarction (STEMI), 118 were in cardiogenic shock and 81 required defibrillation. LUCAS was used in 38 patients, 1 underwent a successful pericardiocentesis, and 36 were treated with PCI. Eleven of these patients were discharged alive in good neurological conditions. Similarly, other studies have shown that that it is feasible to perform mechanical CPR during PCI.[26–29]

Transportation

During ambulance transport to hospital, it may not be possible to perform manual CPR, while mechanical devices may play an important role in maintaining circulation.

Other fields

Mechanical devices have been used in imaging diagnosis. Agostoni et al[30] evaluated both CT image quality in a phantom study and feasibility in an initial case series using automated chest compression (A-CC) devices for cardiopulmonary resuscitation (CPR), and they found under CPR conditions multidetector CT diagnostics supports either focused treatment or the decision to terminate efforts.

Limitations of mechanical CPR

Delayed time-elapse between arrest and CPR

Device use may delay the time-elapse between arrest and CPR. Ong et al[31] reported that LUCAS device delayed CPR for 2.9±2.1 minutes when compared with manual compression. Another study showed that the median no-flow time, defined as the sum of all pauses between compressions longer than 1.5 seconds, during the first 5 minutes of resuscitation, was manual CPR 85 seconds (interquartile range [IQR] 45 to 112 seconds) versus mechanical CPR 104 seconds (IQR 69 to 151 seconds). The mean no-flow ratio, defined as no-flow time divided by segment length, was manual 0.28 versus mechanical CPR 0.40 (difference=−0.12; 95% confidence interval −0.22 to −0.02). However, from 5 to 10 minutes into the resuscitation, the median no-flow time was manual 85 seconds (IQR 59 to 151 seconds) versus mechanical CPR 52 seconds (IQR 34 to 82 seconds) and the mean no-flow ratio manual 0.34 versus mechanical CPR 0.21 (difference=0.13; 95% confidence interval 0.02 to 0.24). The average time to apply mechanical CPR during this period was 152 seconds. This suggests that in the first 5 minutes, the quality of manual CPR is higher than that of mechanical CPR; while during 5-10 minutes, the quality of mechanical CPR was improved. Hallstrom et al[19] reported that use of an automated LDB-CPR device as used in this study was associated with worse neurological outcomes and a trend toward worse survival than manual CPR. These factors might partly explain the varied outcomes treated with mechanical CPR.

Injuries associated with mechanical CPR

Mechanical chest compression can also cause injuries in patients. Hallstrom et al[32,33] reported that fracture was present in 10/47 in the manual group and in 11/38 in the LUCAS group (P=0.46), and there were multiple rib fractures (> or =3 fractures) in 13/47 in the manual group and in 17/38 in the LUCAS group (P=0.12). Bleeding in the ventral mediastinum was noted in 2/47 and 3/38 in the manual and LUCAS groups respectively (P=0.65), retrosternal bleeding in 1/47 and 3/38 (P=0.32), epicardial bleeding in 1/47 and 4/38 (P=0.17), and hemopericardium in 4/47 and 3/38 (P=1.0), respectively. This finding indicates that mechanical chest compression with the LUCAS device appears to be associated with the same variety and incidence of injuries as manual chest compression. For the injuries caused by mechanical CPR, we still need further clinical studies.In conclusion, mechanical devices will be widely used in clinical practice so as to improve the quality of CPR in patients with cardiac arrest.     

Adrenaline for out-of-hospital cardiac arrest resuscitation: A systematic review and meta-analysis of randomized controlled trials

Introduction

The evidence for adrenaline in out-of-hospital cardiac arrest (OHCA) resuscitation is inconclusive. We systematically reviewed the efficacy of adrenaline for adult OHCA.

Methods

We searched in MEDLINE, EMBASE, and Cochrane Library from inception to July 2013 for randomized controlled trials (RCTs) evaluating standard dose adrenaline (SDA) to placebo, high dose adrenaline (HDA), or vasopressin (alone or combination) in adult OHCA patients. Meta-analyses were performed using random effects modeling. Subgroup analyses were performed stratified by cardiac rhythm and by number of drug doses. The primary outcome was survival to discharge and the secondary outcomes were return of spontaneous circulation (ROSC), survival to admission, and neurological outcome.

Results

Fourteen RCTs (n = 12,246) met inclusion criteria: one compared SDA to placebo (n = 534), six compared SDA to HDA (n = 6174), six compared SDA to an adrenaline/vasopressin combination (n = 5202), and one compared SDA to vasopressin alone (n = 336). There was no survival to discharge or neurological outcome differences in any comparison group, including subgroup analyses. SDA showed improved ROSC (RR 2.80, 95%CI 1.78–4.41, p < 0.001) and survival to admission (RR 1.95, 95%CI 1.34–2.84, p < 0.001) compared to placebo. SDA showed decreased ROSC (RR 0.85, 95%CI 0.75–0.97, p = 0.02; I² = 48%) and survival to admission (RR 0.87, 95%CI 0.76–1.00, p = 0.049; I² = 34%) compared to HDA. There were no differences in outcomes between SDA and vasopressin alone or in combination with adrenaline.

Conclusions

There was no benefit of adrenaline in survival to discharge or neurological outcomes. There were improved rates of survival to admission and ROSC with SDA over placebo and HDA over SDA.