体外心肺复苏技术在成人心搏骤停抢救中的应用

目的 回顾性总结应用体外心肺复苏(E-CPR)技术救治成人心搏骤停患者的临床经验.方法 2005年7月至2009年7月,有11例心源性心搏骤停成人患者(男7例,女4例,年龄24～71岁)经常规心肺复苏(CPR)抢救10～15 min无法有效恢复自主循环,而采用E-CPR技术抢救.7例心脏手术后患者在CPR抢救同时自原胸骨切口先建立升主动脉-右心房常规体外循环辅助,再转为体外膜肺氧合(ECMO)辅助;4例患者在CPR抢救同时直接经股动、静脉置管建立ECMO辅助.结果 11例患者CPR时间30～90 min,平均(51±14)min,10例患者可恢复自主心律.11例患者ECMO辅助时间2～223 h,中位时间126 h.6例患者成功撤离ECMO辅助,但存活出院率为36.4%(4/11).2例患者在ECMO辅助的同时加用主动脉内球囊反搏术(IABP),1例存活.3例患者因合并肾功能衰竭而需血液滤过治疗.结论 E-CPR为抢救危重的心搏骤停患者提供了一个新的手段.如何有效评估和选择病例,及时开始救治以提高成功率,值得进一步研究.     

Extracorporeal cardiopulmonary resuscitation for blunt cardiac rupture

Extracorporeal cardiopulmonary resuscitation (ECPR) followed by operating room sternotomy, rather than resuscitative thoracotomy, might be life-saving for patients with blunt cardiac rupture and cardiac arrest who do not have multiple severe traumatic injuries.A 49-year-old man was injured in a vehicle crash and transferred to the emergency department. On admission, he was hemodynamically stable, but a plain chest radiograph revealed a widened mediastinum, and echocardiography revealed hemopericardium. A computed tomography scan revealed hemopericardium and mediastinal hematoma, without other severe traumatic injuries. However, the patient's pulse was lost soon after he was transferred to the intensive care unit, and cardiopulmonary resuscitation was initiated. We initiated ECPR using femorofemoral veno-arterial extracorporeal membrane oxygenation (ECMO) with heparin administration, which achieved hemodynamic stability. He was transferred to the operating room for sternotomy and cardiac repair. Right ventricular rupture and pericardial sac laceration were identified intraoperatively, and cardiac repair was performed. After repairing the cardiac rupture, the cardiac output recovered spontaneously, and ECMO was discontinued intraoperatively. The patient recovered fully and was discharged from the hospital on postoperative day 7.In this patient, ECPR rapidly restored brain perfusion and provided enough time to perform operating room sternotomy, allowing for good surgical exposure of the heart. Moreover, open cardiac massage was unnecessary. ECPR with sternotomy and cardiac repair is advisable for patients with blunt cardiac rupture and cardiac arrest who do not have severe multiple traumatic injuries.     

Managing cardiac arrest with refractory ventricular fibrillation in the emergency department: Conventional cardiopulmonary resuscitation versus extracorporeal cardiopulmonary resuscitation

AimRefractory ventricular fibrillation, resistant to conventional cardiopulmonary resuscitation (CPR), is a life threatening rhythm encountered in the emergency department. Although previous reports suggest the use of extracorporeal CPR can improve the clinical outcomes in patients with prolonged cardiac arrest, the effectiveness of this novel strategy for refractory ventricular fibrillation is not known. We aimed to compare the clinical outcomes of patients with refractory ventricular fibrillation managed with conventional CPR or extracorporeal CPR in our institution.MethodThis is a retrospective chart review study from an emergency department in a tertiary referral medical center. We identified 209 patients presenting with cardiac arrest due to ventricular fibrillation between September 2011 and September 2013. Of these, 60 patients were enrolled with ventricular fibrillation refractory to resuscitation for more than 10 min. The clinical outcome of patients with ventricular fibrillation received either conventional CPR, including defibrillation, chest compression, and resuscitative medication (C-CPR, n = 40) or CPR plus extracorporeal CPR (E-CPR, n = 20) were compared.ResultsThe overall survival rate was 35%, and 18.3% of patients were discharged with good neurological function. The mean duration of CPR was longer in the E-CPR group than in the C-CPR group (69.90 ± 49.6 min vs 34.3 ± 17.7 min, p = 0.0001). Patients receiving E-CPR had significantly higher rates of sustained return of spontaneous circulation (95.0% vs 47.5%, p = 0.0009), and good neurological function at discharge (40.0% vs 7.5%, p = 0.0067). The survival rate in the E-CPR group was higher (50% vs 27.5%, p = 0.1512) at discharge and (50% vs 20%, p = 0. 0998) at 1 year after discharge.ConclusionsThe management of refractory ventricular fibrillation in the emergency department remains challenging, as evidenced by an overall survival rate of 35% in this study. Patients with refractory ventricular fibrillation receiving E-CPR had a trend toward higher survival rates and significantly improved neurological outcomes than those receiving C-CPR.     

Assessment of outcomes and differences between in- and out-of-hospital cardiac arrest patients treated with cardiopulmonary resuscitation using extracorporeal life support

Aim

Cardiopulmonary resuscitation (CPR) using extracorporeal life support (ECLS) for in-hospital cardiac arrest (IHCA) patients has been assigned a low-grade recommendation in current resuscitation guidelines. This study compared the outcomes of IHCA and out-of-hospital cardiac arrest (OHCA) patients treated with ECLS.

Methods

A total of 77 patients were treated with ECLS. Baselines characteristics and outcomes were compared for 38 IHCA and 39 OCHA patients.

Results

The time interval between collapse and starting ECLS was significantly shorter after IHCA than after OHCA (25 (21-43) min versus 59 (45-65) min, p < 0.001). The weaning rate from ECLS (61% versus 36%, p = 0.03) and 30-day survival (34% versus 13%, p = 0.03) were higher for IHCA compared with OHCA patients. IHCA patients had a higher rate of favourable neurological outcome compared to OHCA patients, but the difference was not statistically significant (26% versus 10%, p = 0.07). Kaplan-Meier analysis showed improved 30-day and 1-year survival for IHCA patients treated with ECLS compared to OHCA patients who had ECLS. However, multivariate stepwise Cox regression model analysis indicated no difference in 30-day (odds ratio 0.94 (95% confidence interval 0.68-1.27), p = 0.67) and 1-year survival (0.99 (0.73-1.33), p = 0.95).

Conclusion

CPR with ECLS led to more favourable patient outcomes after IHCA compared with OHCA in our patient group. The difference in outcomes for ECLS after IHCA and OHCA disappeared after adjusting for patient factors and the time delay in starting ECLS.     

Comparing the survival between extracorporeal rescue and conventional resuscitation in adult in-hospital cardiac arrests: Propensity analysis of three-year data

Aim

Extracorporeal cardiopulmonary resuscitation (ECPR) has been shown to have survival benefit over conventional CPR (CCPR) in patients with in-hospital cardiac arrest of cardiac origin. We compared the survival of patients who had return of spontaneous beating (ROSB) after ECPR with the survival of those who had return of spontaneous circulation (ROSC) after conventional CPR.

Methods

Propensity score-matched cohort of adults with in-hospital prolonged CPR (>10 min) of cardiac origin in a university-affiliated tertiary extracorporeal resuscitation center were included in this study. Fifty-nine patients with ROSB after ECPR and 63 patients with sustained ROSC by CCPR were analyzed. Main outcome measures were survival at hospital discharge, 30 days, 6 months, and one year, and neurological outcome.

Results

There was no statistical difference in survival to discharge (29.1% of ECPR responders vs. 22.2% of CCPR responders, p = 0.394) and neurological outcome at discharge and one year later. In the propensity score-matched groups, 9 out of 27 ECPR patients survived to one month (33.3%) and 7 out of 27 CCPR patients survived (25.9%). Survival analysis showed no survival difference (HR: 0.856, p = 0.634, 95% CI: 0.453-1.620) between the groups, either at 30 days or at the end of one year (HR: 0.602, p = 0.093, 95% CI: 0.333-1.088).

Conclusions

This study failed to demonstrate a survival difference between patients who had ROSB after institution of ECMO and those who had ROSC after conventional CPR. Further studies evaluating the role of ECMO in conventional CPR rescued patients are warranted.     

Eleven years of experience with extracorporeal cardiopulmonary resuscitation for paediatric patients with in-hospital cardiac arrest

Purpose

The study aims to describe 11 years of experience with extracorporeal cardiopulmonary resuscitation (ECPR) for in-hospital paediatric cardiac arrest in a university affiliated tertiary care hospital.

Methods

Paediatric patients who received extracorporeal membrane oxygenation (ECMO) during active extracorporeal cardiopulmonary resuscitation (ECPR) at our centre from 1999 to 2009 were included in this retrospective study. The results from three different cohorts (1999–2001, 2002–2005 and 2006–2009) were compared. Survival rates and neurological outcomes were analysed. Favourable neurological outcome was defined as paediatric cerebral performance categories (PCPC) 1, 2 and 3.

Results

We identified 54 ECPR events. The survival rate to hospital discharge was 46% (25/54), and 21 (84%) of the survivors had favourable neurological outcomes.The duration of CPR was 39 ± 17 min in the survivors and 52 ± 45 min in the non-survivors (p = NS). The patients with pure cardiac causes of cardiac arrest had a survival rate similar to patients with non-cardiac causes (47% (18/38) vs. 44% (7/16), p = NS).The non-survivors had higher serum lactate levels prior to ECPR (13.4 ± 6.4 vs. 8.8 ± 5.1 mmol/L, p < 0.01) and more renal failure after ECPR (66% (19/29) vs. 20% (5/25), p < 0.01).The patients resuscitated between 2006 and 2009 had shorter durations of CPR (34 ± 13 vs. 78 ± 76 min, p = 0.032) and higher rates of survival (55% (16/29) vs. 0% (0/8), p = 0.017) than those resuscitated between 1999 and 2002.

Conclusions

In our single-centre experience with ECPR for paediatric in-hospital cardiac arrest, the duration of CPR has become shorter and outcomes have improved in recent years. Higher pre-ECPR lactate levels and the presence of post-ECPR renal failure were associated with increased mortality. The presence of non-cardiac causes of cardiac arrest did not preclude successful ECPR outcomes. The duration of CPR was not significantly associated with poor outcomes in this study.     

Extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest: A review of the Japanese literature

Aim

Although favourable outcomes in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest have been frequently reported in Japanese journals since the late 1980s, there has been no meta-analysis of ECPR in Japan. This study reviewed and analysed all previous studies in Japan to clarify the survival rate of patients receiving ECPR.

Material and methods

Case reports, case series and abstracts of scientific meetings of ECPR for out-of-hospital cardiac arrest written in Japanese between 1983 and 2008 were collected. The characteristics and outcomes of patients were investigated, and the influence of publication bias of the case-series studies was examined by the funnel-plot method.

Results

There were 1282 out-of-hospital cardiac arrest patients, who received ECPR in 105 reports during the period. The survival rate at discharge given for 516 cases was 26.7 ± 1.4%. The funnel plot presented the relationship between the number of cases of each report and the survival rate at discharge as the reverse-funnel type that centred on the average survival rate. In-depth review of 139 cases found that the rates of good recovery, mild disability, severe disability, vegetative state, death at hospital discharge and non-recorded in all cases were 48.2%, 2.9%, 2.2%, 2.9%, 37.4% and 6.4%, respectively.

Conclusions

Based on the results of previous reports with low publication bias in Japan, ECPR appears to provide a higher survival rate with excellent neurological outcome in patients with out-of-hospital cardiac arrest.     

体外心肺复苏启动前因素对患者预后的影响

目的:分析体外心肺复苏（extracorporeal cardiopulmonary resuscitation,ECPR）启动前因素对患者预后的影响,以探讨ECPR的干预时机和改进策略。方法:回顾性分析2018年7月至2021年4月在湖南师范大学附属第一医院（湖南省人民医院）行ECPR的29例患者。按患者是否存活出院分为生存组( n=13)及死亡组( n=16),分析两组常规心肺复苏（conventional cardiopulmonary resuscitation,CCPR）时间（开始心肺复苏到体外膜肺氧合运转的时间）、ECPR前初始心律、院外及院内心搏骤停的构成比、外院转运病例构成比。按CCPR时间分为≤45 min组、45~60 min组及>60 min组分别比较其出院存活率及持续自主循环恢复（sustained return of spontaneous circulation,ROSC）率。本院院内心搏骤停患者按心搏骤停（cardiac arrest,CA）发生地点分为本科室亚组和其他科室亚组,比较其存活率。 结果:29例患者总体生存率44.83%,体外膜肺氧合（extracorporeal membrane oxygenation,ECMO）平均辅助时长114（33.5,142.5） h,CCPR平均时长60（44.5,80） min。生存组ECMO辅助时间（140.15±44.80）h较死亡组长（ P=0.001）,生存组CCPR时间明显低于死亡组（ P=0.010）。初始心律为可除颤心律组生存率更高（ P=0.010）。OHCA较IHCA患者病死率高（ P=0.020）。外院转运病例病死率高于本院病例（ P=0.025）。CCPR时间≤45min、45~60 min、>60 min三组患者出院生存率依次递减（ P=0.001）,ROSC率依次递减（ P=0.001)。本院院内心搏骤停患者,CA发生地点在本科室（急诊医学科）组与其他科室组生存率差异无统计学意义（ P=0.54）。 结论:ECPR出院存活率高于国内外报道的CCPR存活率,ECPR对难治性心搏骤停是有效的。ECPR的预后跟CCPR时间、CA初始心律、CA发生地点明显相关,提高ECPR存活率需加强宣教及团队建设。     

体外膜肺氧合在抢救危重心脏病患者心搏骤停中的作用

目的观察体外膜肺氧合对危重心脏患者心搏骤停后常规心肺复苏困难者的治疗效果。方法本院自2005年9月至2006年5月行体外膜肺氧合(ECMO)治疗危重心脏病患者37例,回顾性分析其中11例发生心搏骤停实施常规心肺复苏无效或复苏后持续低心排而行ECMO循环辅助患者的病历资料。结果5例为心脏术后患者,其中3例心肺复苏(CPR)的同时紧急建立体外循环再次手术,之后因低心排而行ECMO。7例患者床旁建立ECMO,ECMO支持治疗(134．0±113．0)h。8例顺利停机,6例存活出院,其中2例经心脏移植后出院。3例不能顺利脱机者由于ECMO辅助期间循环功能恶化,并最终死于多器官功能衰竭。ECMO期间出现的并发症包括出血、神经精神系统异常、肢体缺血坏死和多脏器功能不全。结论ECMO可以为心搏骤停的患者提供最快的心肺功能支持,为赢得抢救时机和提高抢救质量提供了又一途径,在危重患者心肺复苏中具有良好的疗效。     

RESCUE transesophageal echocardiography for monitoring of mechanical chest compressions and guidance for extracorporeal cardiopulmonary resuscitation cannulation in refractory cardiac arrest

There is a growing interest in using point-of-care transesophageal echocardiography (TEE) during cardiac arrest. TEE is effective at identifying the etiology of sudden cardiovascular collapse and guiding management during the resuscitation. In selected patients with refractory cardiac arrest, extracorporeal cardiopulmonary resuscitation (ECPR) can be considered. ECPR requires percutaneous vascular access for the implantation of veno-arterial extracorporeal membrane oxygenation circuit. We present a case of prolonged cardiac arrest in which rescue TEE was pivotal in narrowing the differential diagnosis, monitoring of mechanical chest compression performance, and guiding cannulation for ECPR.     

体外膜肺氧合治疗用于心肺复苏的临床研究

目的 总结体外膜肺氧合（ECMO）治疗对于常规心肺复苏（CPR）困难患者的临床治疗经验。方法 自2005-09-2006-05我院进行ECMO治疗37例患者，其中11例心脏骤停后实施电除颤和心脏按压等CPR措施无效或自主循环恢复后持续低心排而行ECMO循环辅助。结果 8例顺利停机，6例存活恢复出院，其中2例行心脏移植后康复出院。3例不能顺利撤机者在ECMO辅助期间由于循环功能恶化，最终因多器官功能衰竭死亡。顺利撤机和存活出院的患者治疗前乳酸水平较低。ECMO治疗后乳酸清除率较快（P〈0．05）。ECMO期间出现的并发症包括出血、神经精神系统异常、肢体缺血坏死和多脏器功能不全。4例患者因膜肺出现血浆渗漏而更换膜肺。结论 ECMO可为危重心脏病患者心脏骤停后复苏困难时提供心肺功能支持，提高危重心脏病患者CPR的存活率。CPR后动脉血乳酸值和ECMO治疗后乳酸清除率可以预测患者预后。     

Comparison of extracorporeal and conventional cardiopulmonary resuscitation: A meta-analysis of 2 260 patients with cardiac arrest

BACKGROUND: This meta-analysis aimed to determine whether extracorporeal cardiopulmonary resuscitation (ECPR), compared with conventional cardiopulmonary resuscitation (CCPR), improves outcomes in adult patients with cardiac arrest (CA).     

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。     

山莨菪碱对心脏骤停患者氧化应激及心肺复苏效果的影响

目的:探讨山莨菪碱对心脏骤停患者氧化应激及心肺复苏效果的影响。方法:选择急诊科抢救的心脏骤停患者119例,骤停时间≤10min,随机分为对照组和干预组。两组均按照美国心脏学会心肺复苏指南进行标准的心肺复苏,干预组在标准心肺复苏基础上静脉注射山莨菪碱,比较两组患者自主循环恢复(ROSC)率及复苏后24h存活率;分别在自主循环恢复后和复苏24h后测定血清总超氧化物岐化酶(T-SOD)活力、总抗氧化力(T-AOC)和丙二醛(MDA)含量,比较两组间差别。结果:干预组患者自主循环恢复率与对照组比较差异无统计学意义(P>0.01);复苏24h后,干预组患者存活率显著高于对照组(P<0.01);自主循环恢复后及复苏24h后,干预组T-SOD活力和T-AOC显著高于对照组,MDA含量显著低于对照组(P<0.01)。结论:早期应用山莨菪碱可能会减轻心脏骤停患者体内氧化应激,可能有助于提高复苏后24h存活率,但对于短期自主循环的恢复可能没有明显改善。     

Hemodynamic-directed cardiopulmonary resuscitation during in-hospital cardiac arrest

Cardiopulmonary resuscitation (CPR) guidelines assume that cardiac arrest victims can be treated with a uniform chest compression (CC) depth and a standardized interval administration of vasopressor drugs. This non-personalized approach does not incorporate a patient's individualized response into ongoing resuscitative efforts. In previously reported porcine models of hypoxic and normoxic ventricular fibrillation (VF), a hemodynamic-directed resuscitation improved short-term survival compared to current practice guidelines. Skilled in-hospital rescuers should be trained to tailor resuscitation efforts to the individual patient's physiology. Such a strategy would be a major paradigm shift in the treatment of in-hospital cardiac arrest victims.     

Refractory Anaphylactic Shock Requiring Emergent Venoarterial Extracorporeal Membrane Oxygenation in the Emergency Department: A Case Report

Venoarterial extracorporeal membrane oxygenation is a viable salvage intervention for patients who experience cardiopulmonary arrest or profound shock from any cause. Acute anaphylactic shock is a rare cause of cardiac arrest. We present a case of a 35-year-old male who experienced cardiac arrest owing to anaphylactic shock while receiving general anesthesia for a routine outpatient surgical procedure. Traditional advanced cardiac life support therapies were provided by paramedics en route to the emergency department of a suburban, community-based hospital. Maximal medical management including endotracheal intubation, intravenous steroids, intravenous crystalloid fluid administration, intravenous vasoactive medications, and high-quality cardiopulmonary resuscitation was provided. Although return of spontaneous circulation was achieved, profound cardiogenic shock persisted. Venoarterial extracorporeal membrane oxygenation was initiated by the emergency department provider and nursing team. The patient survived, was neurologically intact, had full recovery, and was discharged home several days later. We have extensive experience with venoarterial extracorporeal membrane oxygenation, and this case exemplifies the value of an established emergency department extracorporeal membrane oxygenation program in managing all causes of cardiac arrest or refractory shock.     

Chest compression-only cardiopulmonary resuscitation performed by lay rescuers for adult out-of-hospital cardiac arrest due to non-cardiac aetiologies

Objective

Bystander CPR improves survival in patients with out-of-hospital cardiac arrest (OHCA). For adult sudden collapse, bystander chest compression-only CPR (COCPR) is recommended in some circumstances by the American Heart Association and European Resuscitation Council. However, adults who arrest from non-cardiac causes may also receive COCPR. Because rescue breathing may be more important for individuals suffering OHCA secondary to non-cardiac causes, COCPR is not recommended for these cases. We evaluated the relationship of lay rescuer COCPR and survival after OHCA from non-cardiac causes.

Methods

Analysis of a statewide Utstein-style registry of adult OHCA, during a large scale campaign endorsing COCPR for OHCA from presumed cardiac cause. The relationship between lay rescuer CPR (both conventional CPR and COCPR) and survival to hospital discharge was evaluated.

Results

Presumed non-cardiac aetiologies of OHCA accounted for 15% of all cases, and lay rescuer CPR was provided in 29% of these cases. Survival to hospital discharge occurred in 3.8% after conventional CPR, 2.7% after COCPR, and 4.0% after no CPR (p = 0.85). The proportion of patients receiving COCPR was much lower in the cohort of OHCA from respiratory causes (8.3%) than for those with presumed cardiac OHCA (18.0%; p < 0.001).

Conclusions

In the setting of a campaign endorsing lay rescuer COCPR for cardiac OHCA, bystanders were less likely to perform COCPR on OHCA victims who might benefit from rescue breathing.     

Different roles of nitric oxide synthase isoforms in cardiopulmonary resuscitation in pigs

The purpose of the present study was to identify the roles of the three nitric oxide synthase (NOS) isoforms on whole body ischemia-reperfusion injury during cardiopulmonary resuscitation (CPR) with periodic acceleration (pGz) in pigs. Thirty-two anesthetized pigs (27.6+/-3.4 kg) were monitored for hemodynamics and selected echocardiographic variables. Twenty minutes after NOS inhibition or placebo administration, ventricular fibrillation (VF) was induced and remained untreated for 3 min, followed by CPR with pGz for 15 min, plus 3 min of manual chest compressions and defibrillation attempt. Four groups were studied: (1) saline control; (2) L-NAME (non-selective NOS inhibitor); (3) aminoguanidine (inducible NOS inhibitor); (4) TRIM (neuronal NOS inhibitor). Return of spontaneous circulation (ROSC) to 180 min occurred in 6/8 controls, 4/8 L-NAME, 7/8 aminoguanidine, and 2/8 TRIM animals. The L-NAME group had significantly lower organ blood flow, impaired cardiac function, but higher vascular tone than control group. The aminoguanidine group had the highest organ blood flows and survival rate. Six out of eight TRIM treated animals had initial return of heartbeat; however, with impaired heart contractility and could not survive more than 20 min of ROSC. This study reveals the differential role of endogenous NO produced from the three NOS isoforms during pGz-CPR. Both endothelial and neuronal NOS derived NO show predominantly protective effects while inducible NOS derived NO plays a detrimental role in pGz-CPR. The present study has shown that cardiac arrest and resuscitation appears to be associated with a different expression of NOS isoforms which appear to affect resuscitation outcomes differently.     

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.