Who Gets Bystander Cardiopulmonary Resuscitation in a Witnessed Arrest?

Objective: To identify characteristics associated with provision of bystander CPR in witnessed out-of-hospital cardiac arrest cases.
Methods: An observational, prospective, cohort study was performed using cardiac arrest cases as identified by emergency medical services (EMS) agencies in Oakland County, MI, from July 1, 1989, to December 31, 1993. All patients who sustained a witnessed arrest prior to arrival of EMS personnel were reviewed.
Results: Of the 927 patients meeting entry criteria, the 229 patients receiving bystander CPR were younger: 60.9 ± 14.7 vs 67.9 ± 14.7 years (p < 0.01). Most (76.6%) cardiac arrests occurred in the home. In a multivariate logistic model, only the location of arrest outside the home was a significant predictor of receiving bystander CPR [odds ratio (OR) 3.8; 99% CI 2.5, 5.9]. Arrests outside the home were associated with significantly improved outcome, with 18.2% of out-of-home and 8.2% of in-home victims discharged from the hospital alive (OR 2.5; 99% CI 1.4, 4.4).
Conclusion: Patients who have had witnessed cardiac arrests outside the home are nearly 4 times more likely to receive bystander CPR, and are twice as likely to survive. This observation emphasizes the need for CPR training of family members in the authors' locale. This phenomenon may also represent a significant con-founder in studies of out-of-hospital cardiac arrest and resuscitation.     

Predictive Factors of Successful Telephone-assisted Cardiopulmonary Resuscitation

Background

Our emergency medical service developed a telephone (phone)-assisted cardiopulmonary resuscitation (PACPR) procedure.

Objectives

To describe this procedure and study the factors modulating its implementation.

Methods

We conducted a single-center prospective study of telephone calls to our emergency medical communication center for cardiac arrest, for which PACPR was initiated.

Results

Thirty-eight patients were included in the study. In six cases, cardiopulmonary resuscitation (CPR) had been started before the call. When PACPR was initiated, CPR was performed until the rescue team arrived in 27 cases. One-third (n = 9) of the bystanders in these cases knew first-aid interventions, and all of these bystanders continued CPR until the rescue team arrived. The absence of a familial relationship between bystander and patient facilitated the continuation of CPR (100% vs. 37% with family ties, p = 0.01). CPR was continued more often if the bystander immediately agreed to PACPR than when he or she did not agree at first (88% vs. 45%, respectively, p = 0.01). When an obstacle to performing CPR was encountered, CPR was then performed in 57% of cases vs. 100% of cases with no obstacle (p = 0.003). These obstacles were associated with either the bystander (panic, apprehension, feelings of inadequacy, physical inability, indirect witness, tiredness) or the victim (morphotype, physical position). The presence of an obstacle, compared to no obstacle, associated with the bystander lowered the CPR performance rate (58% vs. 94%, respectively, p = 0.01). The presence of an obstacle, compared to no obstacle, associated with the victim also lowered CPR performance rate (50% vs. 85%, respectively, p = 0.04).

Conclusion

Our study demonstrates the feasibility of PACPR. The results may lead to a better understanding of facilitating factors and obstacles to telephone-assisted CPR, with the goal of improving its implementation. Good command of communication tools, identification of an appropriate bystander, and appropriate victim positioning are three fundamental factors of success.     

The Evolution of Abdominal Compression in Cardiopulmonary Resuscitation

Objective: To review the history of external abdominal compression as an adjunct to cardiopulmonary resuscitation (CPR), tracking the development of five major themes over the course of the 20th century: 1) augmentation of peripheral resistance by physical means, 2) risk of hepatic injury with abdominal compression, 3) counterpulsation vs sustained compression, 4) the abdominal pump mechanism, and 5) contact compression techniques.
Methods: Literature retrieved from successive MEDLINE English-language searches was reviewed with a special emphasis on work and concepts highlighted by participants at the First Purdue Conference on Interposed Abdominal Compression-CPR, September 1992.
Results: External abdominal compression of one form or another has been studied as a means of resuscitation by many investigators throughout the 20th century. Experimental and clinical studies have shown generally consistent evidence of hemodynamic augmentation by abdominal compression during various forms of CPR. Recent advances include a modified theoretical understanding of hemodynamic mechanisms and demonstration of clinical potential in humans. Inconsistencies in published results may be due to differences in mechanical techniques of abdominal compression. Based on these studies, a modified manual technique for "contact compression" of the abdominal aorta is recommended.
Conclusions: A technique for left-of-center, angled compression of the abdominal aorta against the crest of the spine is recommended. Further well-supervised and controlled clinical trials using this standardized technique are warranted as a prelude to more widespread clinical application of abdominal compression in CPR.     

Chest Compression and Ventilation Rates during Cardiopulmonary Resuscitation: The Effects of Audible Tone Guidance

Objectives: To determine: 1) whether chest compressions during CPR are being performed according to American Heart Association (AHA) guidelines during cardiac arrest; and 2) the effect of an audio prompt to guide chest compressions on compliance with AHA guidelines and hemodynamic parameters associated with successful resuscitation. Methods: An observational clinical report and laboratory study was conducted. A research observer responded to a convenience sample of cardiac arrests within a 300-bed hospital and counted the rate of chest compressions and ventilations during CPR. To evaluate the effect of an audio prompt on CPR, health care providers performed chest compression without guidance using a porcine cardiac arrest model for 1 minute, followed by a second minute in which audio guidance was added. Chest compression rates, arterial and venous blood pressures, end-tidal CO₂ (ETCO₂) levels, and coronary perfusion pressures were measured and compared for the two periods. Results: Twelve in-hospital cardiac arrests were observed in the clinical part of the study. Only two of 12 patients had chest compressions performed within AHA guidelines. No patient had respirations performed within AHA guidelines. In the laboratory, 41 volunteers were tested, with 66% performing chest compressions outside the AHA standards for compression rate without audible tone guidance. With guided chest compressions, the mean (± SD) chest compression rate increased from 74 ± 22 to 100 ± 3/min (p < 0.01). End-tidal CO₂ levels increased from 15 ± 7 to 17 ± 7 torr (p < 0.01). Coronary perfusion pressure increased minimally with audible tone-guided chest compressions. Conclusions: The majority of Basic Cardiac Life Support-certified health care professionals did not perform CPR according to AHA-recommended guidelines. The use of audible tones to guide chest compression resulted in significantly higher chest compression rates and ETCO₂ levels.     

血管加压素联合肾上腺素抢救心脏骤停的临床观察

目的:研究血管加压素联合肾上腺素对心脏骤停的疗效。方法:64例呼吸心跳骤停患者随机分为肾上腺素组(对照组)和血管加压素联合肾上腺素组(治疗组)各32例,观察自主心律恢复时间、1h有效率、24h有效复苏成功率。结果:对照组、治疗组自主心律恢复时间分别为(20.5±4.5)min、(8.5±3.5)min、1h有效率分别为38%、72%;24h有效复苏成功率分别为13%、44%。治疗组的自主心律恢复时间明显短于对照组,1h有效率、24h有效复苏成功率明显高于对照组。结论:对心脏骤停患者,在标准心肺复苏(CPR)中,联合应用血管加压素和肾上腺素,可有效缩短自主心律恢复时间,提高1h有效率和24h有效复苏成功率。     

Electroencephalography during Out-of-hospital Cardiopulmonary Resuscitation

Background

At the present time there is no parameter that can estimate the quality of cerebral perfusion and possible success of cerebral resuscitation during advanced cardiac life support (ACLS) efforts. In recent years, various attempts have been made to use electroencephalography (EEG)-based cerebral neuromonitoring to assess the effectiveness of cardiopulmonary resuscitation (CPR).

Objectives

The Cerebral State Monitor M3 (Danmeter A/S, Odense, Denmark) is a portable, single-channel EEG monitor that provides the user with different EEG-based parameters and the raw waveform EEG to measure cerebral activity.

Case Report

We report two cases of out-of-hospital CPR with single-channel EEG monitoring conducted parallel to ACLS with external chest compressions. We demonstrate an artifact in waveform EEG recordings that is caused by the external chest compressions, and that leads to a miscalculation of the Burst Suppression Ratio and Cerebral State Index.

Conclusion

These cases suggest that digitally processed EEG-monitoring is not a useful tool during CPR.     

Theoretically Optimal Duty Cycles for Chest and Abdominal Compression during External Cardiopulmonary Resuscitation

Objective: To use an electronic model of human circulation to compare the hemodynamic effects of different durations of chest compression during external CPR, both with and without interposed abdominal compression (IAC).
Methods: An electrical analog model of human circulation was studied on digital computer workstations using SPICE, a general-purpose circuit simulation program. In the model the heart and blood vessels were represented as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in IAC-CPR, was simulated by the alternate application of damped rectangular voltage pulses, first between intrathoracic vascular capacitances and ground, and then between intra-abdominal vascular capacitances and ground. With this model compression frequencies of 60, 80, and 100 cycles/min and duty cycles ranging from 10% to 90%, both with and without IAC, were compared.
Results: There was little difference in hemodynamics when the overall compression frequency was varied between 60 and 100 cycles/min, but the effects of duty cycle were substantial. During both standard CPR and IAC-CPR, total flow and coronary flow were greatest at chest compression durations equal to 30% of cycle time. Interposed abdominal compression substantially improved simulated systemic blood flow and perfusion pressure at all duty cycles, compared with standard CPR without abdominal compression. Mean arterial pressure > 75 mm Hg and artificial cardiac output > 2.0 L/min could be generated by 30% duty cycle compression with IAC. Coronary perfusion in the model is clearly optimized at 30% chest compression (i.e., high-impulse chest compression technique).
Conclusion: Combined high-impulse chest compressions and IACs maximize blood flow during CPR in the electrical analog model of human circulation.     

“Push as Hard as You Can” Instruction for Telephone Cardiopulmonary Resuscitation: A Randomized Simulation Study

Background

The medical priority dispatch system (MPDS®) assists lay rescuers in protocol-driven telephone-assisted cardiopulmonary resuscitation (CPR).

Objective

Our aim was to clarify which CPR instruction leads to sufficient compression depth.

Methods

This was an investigator-blinded, randomized, parallel group, simulation study to investigate 10 min of chest compressions after the instruction “push down firmly 5 cm” vs. “push as hard as you can.” Primary outcome was defined as compression depth. Secondary outcomes were participants exertion measured by Borg scale, provider's systolic and diastolic blood pressure, and quality values measured by the skill-reporting program of the Resusci^® Anne Simulator manikin. For the analysis of the primary outcome, we used a linear random intercept model to allow for the repeated measurements with the intervention as a covariate.

Results

Thirteen participants were allocated to control and intervention. One participant (intervention) dropped out after min 7 because of exhaustion. Primary outcome showed a mean compression depth of 44.1 mm, with an inter-individual standard deviation (SD_b) of 13.0 mm and an intra-individual standard deviation (SD_w) of 6.7 mm for the control group vs. 46.1 mm and a SD_b of 9.0 mm and SD_w of 10.3 mm for the intervention group (difference: 1.9; 95% confidence interval −6.9 to 10.8; p = 0.66). Secondary outcomes showed no difference for exhaustion and CPR-quality values.

Conclusions

There is no difference in compression depth, quality of CPR, or physical strain on lay rescuers using the initial instruction “push as hard as you can” vs. the standard MPDS^® instruction “push down firmly 5 cm.”     

126例心跳骤停心肺复苏临床分析

目的：探讨急诊抢救心跳骤停的程序及方法，以便提高心肺复苏成功率。方法：回顾性分析126例在急诊抢救心跳骤停患者的临床资料，分析抢救程序及方法对心肺复苏的影响。结果：126例患者中31例复苏成功，63例复苏有效，32例复苏无效。结论：心肺复苏抢救成功与开始抢救时间、胸外按压方法、抢救药物及仪器的合理应用有密切关系。     

Sex-Based Disparities in Receiving Bystander Cardiopulmonary Resuscitation by Location of Cardiac Arrest in Japan

Objective

To assess whether sex-based disparities occur by location of arrest in out-of-hospital cardiac arrest (OHCA) victims receiving bystander cardiopulmonary resuscitation (BCPR).

心脏猝死高危者家属心肺复苏知识与技能培训的重点和难点

目的 通过对心脏猝死高危者家属进行心肺复苏知识与技能的培训,以探讨公众掌握心肺复苏知识与技能的重点和难点.方法 应用方便取样方法,选取首都医科大学附属宣武医院、中国医学科学院阜外心血管病医院住院的心脏猝死(sudden cardiac death.SCD)高危人群的家属集中进行心肺复苏(cardiopulmonary resuscitation,CPR)培训.培训结束后对研究对象进行CPR知识和技能测试.结果 培训后即刻对受训家属进行知识与技能的测试,98.4%的家属CPR知识测试通过,但是只有34.3%的家属技能测试合格,65.7%都需要多次反复指导才能做到技能达标.结论 公众对CPR知识与技能的掌握程度不一致,CPR技能是公众CPR培训的重点与难点.     

Hemodynamics, Survival Benefits, and Complications of Interposed Abdominal Compression during Cardiopulmonary Resuscitation

Objective: To review and describe the hemodynamics and mechanism of benefit of interposed abdominal compression cardiopulmonary resuscitation (IAC-CPR) as well as the current complications and survival data withtheuseoflAC-CPR.
Methods: Critical review of selected, published English-language studies analyzing IAC-CPR. Overview of hemodynamic effects, complications, and survival data of IAC-CPR vs standard CPR.
Results: Several investigators have demonstrated improvements in coronary perfusion pressure, carotid and cerebral blood flows, and augmented venous return using IAC-CPR compared with standard CPR. Recently, IAC-CPR has been shown to improve survival from in-hospital cardiac arrest. To date, there has been no increase in complications seen with the use of abdominal compression during CPR.
Recommendations: IAC-CPR should be considered an adjunct to standard CPR for adult patients experiencing in-hospital cardiac arrest, after an adequate airway has been secured. More research is needed before IAC-CPR can be recommended for out-of-hospital cardiac arrest, for patients who have not been intubated, or for children.     

Discordant Cardiopulmonary Resuscitation and Code Status at Death

ContextOne fundamental way to honor patient autonomy is to establish and enact their wishes for end-of-life care. Limited research exists regarding adherence with code status.ObjectivesThis study aimed to characterize cardiopulmonary resuscitation (CPR) attempts discordant with documented code status at the time of death in the U.S. and to elucidate potential contributing factors.MethodsThe Cerner Acute Physiology and Chronic Health Evaluation (APACHE) outcomes database, which includes 237 U.S. hospitals that collect manually abstracted data from all critical care patients, was queried for adults admitted to intensive care units with a documented code status at the time of death from January 2008 to December 2016. The primary outcome was discordant CPR at death. Multivariable logistic regression models were used to identify patient-level and hospital-level associated factors after adjustment for age, hospital, and illness severity (APACHE III score).ResultsA total of 21,537 patients from 56 hospitals were included. Of patients with a do-not-resuscitate code status, 149 (0.8%) received CPR at death, and associated factors included black race, higher APACHE III score, or treatment in small or nonteaching hospitals. Of patients with a full code status, 203 (9.0%) did not receive CPR at death, and associated factors included higher APACHE III score, primary neurologic or trauma diagnosis, or admission in a more recent year.ConclusionAt the time of death, 1.6% of patients received or did not undergo CPR in a manner discordant with their documented code statuses. Race and institutional factors were associated with discordant resuscitation, and addressing these disparities may promote concordant end-of-life care in all patients.     

Hemodynamics of Interposed Abdominal Compression during Human Cardiopulmonary Resuscitation

Objective: Clinical studies of interposed abdominal compression CPR (IAC-CPR) have had diverse outcomes. This study compared the hemodynamics of standard CPR and IAC-CPR in humans.
Methods: A 24-month prospective nonrandomized analysis of hemo-dynamic parameters was performed in a convenience cohort of 20 adults who had had out-of-hospital, nontraumatic, normothermic cardiac arrests. The study took place in the resuscitation unit of a large urban hospital. Thoracic aortic and right atrial catheters were inserted and pressures were recorded during standard CPR and IAC-CPR. Coronary perfusion pressures (CPPs) were determined during standard CPR and IAC-CPR. The patients were separated into two groups based upon their responses to IAC-CPR. Responders had increases in CPP during IAC-CPR; nonresponders had decreases or no change in CPP during IAC-CPR. Aortic relaxation, right atrial relaxation, aortic compression, and right atrial compression phase pressures were compared between the two groups.
Results: CPPs increased in 13 patients and decreased in seven patients. The mean change in CPP with IAC-CPR was an increase of 5.8 ± 15.1 torr. An elevated right atrial compression phase pressure (RaComp) during standard CPR was predictive of an increase in CPP during IAC-CPR (p = 0.047). In those patients who showed improvements in CPP during IAC-CPR, mean aortic relaxation phase pressures (AoRelax) increased by 9.5 ± 14.2 torr (p = 0.026) and mean right atrial relaxation phase pressures (RaRelax) decreased by 2.6 ± 6.2 torr (p = 0.099) during IAC-CPR.
Conclusions: The variable effects of IAC-CPR on CPP appear to be multifactorial. The improvement in CPP that occurred in responders to IAC-CPR was secondary to an increase in AoRelax as well as a decrease in RaRelax.