Haemodynamics of cardiac arrest and resuscitation

Cardiopulmonary Resuscitation: The Importance of the Basics

Cardiac arrest is the loss of organized cardiac activity. Unfortunately, survival to hospital discharge is poor, despite recent scientific advances. The goals of cardiopulmonary resuscitation (CPR) are to restore circulation and identify and correct an underlying etiology. High-quality compressions remain the foundation of CPR, optimizing coronary and cerebral perfusion pressure. High-quality compressions must be performed at the appropriate rate and depth. Interruptions in compressions are detrimental to management. Mechanical compression devices are not associated with improved outcomes but can assist in several situations.

Evaluation of transcutaneous near-infrared spectroscopy for early detection of cardiac arrest in an animal model

Sudden cardiac arrest (SCA) is a leading cause of mortality worldwide. The SCA-to-resuscitation interval is a key determinant of patient outcomes, highlighting the clinical need for reliable and timely detection of SCA. Near-infrared spectroscopy (NIRS), a non-invasive optical technique, may have utility for this application. We investigated transcutaneous NIRS as a method to detect pentobarbital-induced changes during cardiac arrest in eight Yucatan miniature pigs. NIRS measurements during cardiac arrest were compared to invasively acquired carotid blood pressure and partial oxygen pressure (PO₂) of spinal cord tissues. We observed statistically significant decreases in mean arterial pressure (MAP) 64.68 mmHg ± 13.08, p < 0.0001), spinal cord PO₂ (38.16 mmHg ± 20.04, p = 0.0028), and NIRS-derived tissue oxygen saturation (TSI%) (14.50% ± 3.80, p < 0.0001) from baseline to 5 min after pentobarbital administration. Euthanasia-to-first change in hemodynamics for MAP and TSI (%) were similar [MAP (10.43 ± 4.73 s) vs TSI (%) (12.04 ± 1.85 s), p = 0.3714]. No significant difference was detected between NIRS and blood pressure-derived pulse rates during baseline periods (p > 0.99) and following pentobarbital administration (p = 0.97). Transcutaneous NIRS demonstrated the potential to identify rapid hemodynamic changes due to cardiac arrest in periods similar to invasive indices. We conclude that transcutaneous NIRS monitoring may present a novel, non-invasive approach for SCA detection, which warrants further investigation.

Evaluation of abdominal compression-decompression combined with chest compression CPR performed by a new device: Is the prognosis improved after this combination CPR technique?

INTRODUCTION

This study was designed to compare the outcomes of standard cardiopulmonary resuscitation (STD-CPR) and combined chest compression and abdominal compression-decompression cardiopulmonary resuscitation (CO-CPR) with a new device following out-of-hospital cardiac arrest (OHCA). Moreover, we investigated whether patient prognosis improved with this combination treatment.

METHODS

This trial was a single-centre, prospective, randomized trial, and a blinded assessment of the outcomes was performed. A total of 297 consecutive patients with OHCA were initially screened, and 278 were randomized to the STD-CPR group (n = 135) or the CO-CPR group (n = 143). We compared the proportions of patients who achieved a return of spontaneous circulation (ROSC), survived to hospital admission and survived to hospital discharge. In addition, we also performed the Kaplan-Meier analysis with a log-rank test at the end of the follow-up period to compare the survival curves of the two groups.

RESULTS

The differences were not statistically significant in the proportion of patients who achieved ROSC [31/135 (23.0%) versus 35/143 (24.5%)] and survived to hospital admission [28/135 (20.7%) versus 33/143 (23.1%)] between the CO-CPR group and STD-CPR group. However, there was a significant difference in the proportion of patients who survived to hospital discharge [16/135 (11.9%) versus 7/143 (4.9%)] between the two groups. Nine patients (6.7%) in the CO-CPR group and 2 patients (1.4%) in the STD group showed good neurological outcomes according to the cerebral performance category (CPC) scale score, and the difference was statistically significant (P = 0.003). The Kaplan-Meier curves showed that the patients in the CO-CPR group achieved better survival benefits than those in the STD-CPR group at the end of the follow-up period (log-rank P = 0.007).

CONCLUSION

CO-CPR was more beneficial than STD-CPR in terms of survival benefits in patients who have suffered out-of-hospital cardiac arrest. Trial registration Chinese Clinical Trial Registry, registered number: ChiCTR2100049581 . Registered 30 July 2021- Retrospectively registered. http://www.medresman.org.cn/uc/index.aspx .

Point-of-Care Ultrasound Compression of the Carotid Artery for Pulse Determination in Cardiopulmonary Resuscitation

AIM

To identify whether a novel pulse check technique, carotid artery compression using an ultrasound probe, can reduce pulse check times compared to manual palpation (MP).

METHODS

This prospective study was conducted in an emergency department between February and December 2021. A physician applied point-of-care ultrasound-carotid artery compression (POCUS-CAC) and assessed the carotid artery compressibility and pulsatility by probe compression during rhythm check time. Another clinician performed MP of the femoral artery. The primary outcome was the difference in the average time for pulse assessment between POCUS-CAC and MP. The secondary outcomes included the time difference in each pulse check between methods, the proportion of times greater than 5 s and 10 s, and the prediction of return of spontaneous circulation (ROSC) during ongoing chest compression.

RESULTS

25 cardiac arrest patients and 155 pulse checks were analyzed. The median (interquartile range) average time to carotid pulse identification per patient using POCUS-CAC was 1.62 (1.14-2.14) s compared to 3.50 (2.99-4.99) s with MP. In all 155 pulse checks, the POCUS-CAC time to determine ROSC was significantly shortened to 0.44 times the MP time (P < 0.001). The POCUS-CAC approach never exceeded 10 s, and the number of patients who required more than 5 s was significantly lower (5 vs. 37, P < 0.001). Under continuous chest compression, six pulse checks predicted the ROSC.

CONCLUSIONS

We found that emergency physicians could quickly determine pulses by applying simple POCUS compression of the carotid artery in cardiac arrest patients.

Feasibility and Clinical Outcome of Reboa in Patients with Impending Traumatic Cardiac Arrest

BACKGROUND

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may improve Systolic Blood Pressure (SBP) in hypovolemic shock. It has, however, not been studied in patients with impending traumatic cardiac arrest (ITCA). We aimed to study the feasibility and clinical outcome of REBOA in patients with ITCA using data from the ABOTrauma Registry.

METHODS

Retrospective and prospective data on the use of REBOA from 16 centers globally were collected. SBP was measured both at pre- and post-REBOA inflation. Data collected included patients' demography, vascular access technique, number of attempts, catheter size, operator, zone and duration of occlusion, and clinical outcome.

RESULTS

There were 74 patients in this high-risk patient group. REBOA was performed on all patients. A 7-10Fr catheter was used in 66.7% and 58.5% were placed on the first attempt, 52.1% through blind insertion and 93.2% inflated in Zone I, 64.8% for a period of 30 to 60 min, 82.1% by ER doctors, trauma surgeons, or vascular surgeons. SBP significantly improved to 90 mm Hg following the inflation of REBOA. 36.6% of the patients survived.

CONCLUSIONS

Our study has shown that REBOA may be performed in patients with ITCA, SBP can be elevated, and 36.6% of the patients survived if REBOA placement is successful.

Levosimendan Ameliorates Post-Resuscitation Acute Intestinal Microcirculation Dysfunction Partly Independent of Its Effects on Systemic Circulation: A Pilot Study On Cardiac Arrest In A Rat Model

BACKGROUND

Cardiac arrest (CA) is recognized as a life-threatening disease; however, the initial resuscitation success rate has increased due to advances in clinical treatment. Levosimendan has shown potential benefits in CA patients. However, its exact function on intestinal and systemic circulation in CA or post-cardiac arrest syndrome (PCAS) remained unclear. This study preliminarily investigated the link between dynamic changes in intestine and systemic hemodynamics post-resuscitation after levosimendan administration.

METHODS

Twenty-five rats were randomized into three groups: 1) sham control group (n = 5), 2) levosimendan group (n = 10), and 3) vehicle group (n = 10). Intestinal microcirculation was observed using a sidestream dark-field imaging device at baseline and each hour of the return of spontaneous circulation (≤6 h). Systemic hemodynamics, serum indicators of cardiac injury, and tissue perfusion/metabolism were measured by echo-cardiography, a biological signal acquisition system, and an enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

Myocardial injury and global and intestinal perfusion/metabolism were significantly improved by levosimendan treatment. There was no statistically significant difference in the mean arterial pressure values between the vehicle and levosimendan groups (P > 0.05). The intestinal and systemic circulation measurements showed poor correlation (Pearson r-value of variable combinations in the levosimendan group was much less than 0.75; P < 0.01, levosimendan vs. vehicle group).

CONCLUSIONS

Levosimendan significantly reduced the cardiac injury and corrected the metabolic status in an experimental rat model of ventricular fibrillation (VF) induced CA and CPR. Levosimendan may ameliorate PCAS-induced intestinal microcirculation dysfunction, partly independent of its effects on macrocirculation.

State-of-the-Art Review-Endovascular Resuscitation

ABSTRACT

The emerging concept of endovascular resuscitation applies catheter-based techniques in the management of patients in shock to manipulate physiology, optimize hemodynamics, and bridge to definitive care. These interventions hope to address an unmet need in the care of severely injured patients, or those with refractory non-traumatic cardiac arrest, who were previously deemed non-survivable. These evolving techniques include Resuscitative Endovascular Balloon Occlusion of Aorta, Selective Aortic Arch Perfusion, and Extracorporeal Membrane Oxygenation and there is a growing literature base behind them. This review presents the up-to-date techniques and interventions, along with their application, evidence base, and controversy within the new era of endovascular resuscitation.

Randomized blinded trial of automated REBOA during CPR in a porcine model of cardiac arrest

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) reportedly elevates arterial blood pressure (ABP) during non-traumatic cardiac arrest.

OBJECTIVES

This randomized, blinded trial of cardiac arrest in pigs evaluated the effect of automated REBOA two minutes after balloon inflation on ABP (primary endpoint) as well as arterial blood gas values and markers of cerebral haemodynamics and metabolism.

METHODS

Twenty anesthetized pigs were randomized to REBOA inflation or sham-inflation (n = 10 in each group) followed by insertion of invasive monitoring and a novel, automated REBOA catheter (NEURESCUE® Catheter & NEURESCUE® Assistant). Cardiac arrest was induced by ventricular pacing. Cardiopulmonary resuscitation was initiated three min after cardiac arrest, and the automated REBOA was inflated or sham-inflated (blinded to the investigators) five min after cardiac arrest.

RESULTS

In the inflation compared to the sham group, mean ABP above the REBOA balloon after inflation was higher (inflation: 54 (95%CI: 43-65) mmHg; sham: 44 (33-55) mmHg; P = 0.06), and diastolic ABP was higher (inflation: 38 (29-47) mmHg; sham: 26 (20-33) mmHg; P = 0.02), and the arterial to jugular oxygen content difference was lower (P = 0.04). After return of spontaneous circulation, mean ABP (inflation: 111 (95%CI: 94-128) mmHg; sham: 94 (95%CI: 65-123) mmHg; P = 0.04), diastolic ABP (inflation: 95 (95%CI: 78-113) mmHg; sham: 78 (95%CI: 50-105) mmHg; P = 0.02), CPP (P = 0.01), and brain tissue oxygen tension (inflation: 315 (95%CI: 139-491)% of baseline; sham: 204 (95%CI: 75-333)%; P = 0.04) were higher in the inflation compared to the sham group.

CONCLUSION

Inflation of REBOA in a porcine model of non-traumatic cardiac arrest improves central diastolic arterial pressure as a surrogate marker of coronary artery pressure, and cerebral perfusion.

INSTITUTIONAL PROTOCOL NUMBER

2017-15-0201-01371.

The Effect of Chest Compression Location and Aortic Perfusion in a Traumatic Arrest Model

BACKGROUND

Recent evidence demonstrates that closed chest compressions directly over the left ventricle (LV) in a traumatic cardiac arrest (TCA) model improve hemodynamics and return of spontaneous circulation (ROSC) when compared to traditional compressions. Selective aortic arch perfusion (SAAP) also improves hemodynamics and controls hemorrhage in TCA. We hypothesized that chest compressions located over the LV would result in improved hemodynamics and ROSC in a swine model of TCA using SAAP.

MATERIALS AND METHODS

Transthoracic echo was used to mark the location of the aortic root (Traditional location) and the center of the LV on animals (n = 24), which were randomized to receive chest compressions in one of the two locations. After hemorrhage, ventricular fibrillation (VF) was induced to simulate TCA. After a period of 10 min of VF, basic life support (BLS) with mechanical CPR was initiated and performed for 10 min, followed by advanced life support (ALS) for an additional 10 min. SAAP balloons were inflated at min 6 of BLS. Hemodynamic variables were averaged over the final 2 min of the BLS and ALS periods. Survival was compared between this SAAP cohort and a control group without SAAP (No-SAAP) (n = 26).

RESULTS

There was no significant difference in ROSC between the two SAAP groups (P = 0.67). There was no ROSC difference between SAAP and No-SAAP (P = 0.74).

CONCLUSIONS

There was no difference in ROSC between LV and Traditional compressions when SAAP was used in this swine model of TCA. SAAP did not confer a survival benefit compared to historical controls.

Predictors of Successful Weaning From Veno-Arterial Extracorporeal Membrane Oxygenation After Coronary Revascularization for Acute Myocardial Infarction Complicated by Cardiac Arrest: A Retrospective Multicenter Study

AIM

While veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been utilized to resuscitate and stabilize hemodynamics in patients of acute myocardial infarction (AMI) complicated by cardiac arrest (CA), it is essential to predict the possibility of weaning from ECMO to determine further strategies, including use of ventricular assist device. We aimed to determine predictors of successful weaning from VA-ECMO in the early phase of ECMO treatment.

METHODS

We identified consecutive patients of AMI complicated by CA treated with VA-ECMO and percutaneous coronary intervention (PCI). Clinical data within 48 h after ECMO initiation were assessed and multiple logistic regression analysis was performed to determine independent predictors of weaning outcome.

RESULTS

Fifty-five patients were analyzed. While 28 (51%) patients were successfully weaned from VA-ECMO, 27 (49%) failed to wean. Multivariate analysis identified post-PCI thrombolysis in myocardial infarction (TIMI) flow grade (P = 0.046), mean arterial pressure (MAP) at 4 h after ECMO initiation (P = 0.010), and serum lactate at 24 h (P = 0.015) as independent predictors of successful weaning. Left ventricular ejection fraction (LVEF) at 24 and 48 h was significantly greater in the successful weaning group (P = 0.014, P = 0.025, respectively).

CONCLUSIONS

Successful weaning from VA-ECMO was predicted by post-PCI TIMI flow grade, MAP at 4 h, and serum lactate at 24 h after VA-ECMO initiation in patients of AMI complicated by CA. Furthermore, in patients who failed to wean from ECMO, LVEF did not recover within 48 h. In such patients, adjunctive use of other circulatory mechanical devices must be considered.

Does chest compression during cardiopulmonary resuscitation provide sufficient cerebral oxygenation?

Background/aim

Some of the patients suffering from cardiac arrest (CA) remain in a chronic unconscious state in intensive care units (ICUs). The primary aim of this study was to evaluate the efficacy of chest compression (CC) on cerebral oxygenation during cardiopulmonary resuscitation (CPR). As a secondary goal, we attempted to determine the effects of regional cerebral oxygen saturation (rSO2) values on consciousness and the survival rate using the Full Outline of Unresponsiveness (FOUR) scoring method.

Materials and methods

This observational preliminary study was carried out with 20 patients with CA who were hospitalized in ICUs. The rSO2 values measured by near-infrared spectroscopy were recorded during CA. FOUR scoring was used to determine the neurological status, severity of disease, and degree of organ dysfunction in survivors.

Results

Return of spontaneous circulation (ROSC) was gained in 8 (40%) of 20 patients. Maximum rSO2 values were higher in survivors than in nonsurvivors (P = 0.005). The mean FOUR score before CA was 11.50 ± 0.8 in survivors, whereas this value was 7.87 ± 0.7 for 1 week after ROSC (P < 0.0001). There was a significant positive correlation between the minimum and mean rSO2 values and the mean 1-week FOUR scores in survivors (r = 0.811, r = 0.771 and P = 0.015, P = 0.025, respectively).

Conclusion

Our results suggest that the maximum rSO2 values affect ROSC while the minimum and mean rSO2 values affect the post-cardiac arrest neurological outcome.

Cardiac arrests within the emergency department: an Utstein style report, causation and survival factors

BACKGROUND

Emergency Department Cardiac Arrests are typically classified with in-hospital cardiac arrests, but are yet to be well described as a distinct clinical entity. This study provides an Utstein style report on Emergency Department Cardiac Arrests, and identifies factors associated with survival.

PATIENTS AND METHODS

Patients who experienced a cardiac arrest in the Emergency Department of the National University Hospital, Singapore, between January 2010 and August 2012 were studied. Data were collected retrospectively and potential survival factors were assessed with a multivariate logistic regression.

RESULTS

One hundred and six cases were identified for analysis. Most patients were male and 43.4% had a presumed cardiac diagnosis. All arrests were witnessed and received Advanced Cardiac Life Support interventions immediately. Out of the total, 31.1% of arrests occurred during or immediately after intubation. Overall, 48.1% of patients survived to hospital discharge. Patients with a shockable rhythm had the highest survival rate (70.8%), followed by asytole (20.8%) and pulseless electrical activity (15.1%). In all, 91.3% of survivors with a premorbid Cerebral Performance Category score of 1 were discharged with a similar Cerebral Performance Category score.Variables associated with survival to hospital discharge were a shockable initial rhythm (odds ratio 12.1; 95% confidence interval, 3.1-47.6) and a time to return of spontaneous circulation of less than 10 min (odds ratio 4.1; 95% confidence interval, 1.0-16.9).

CONCLUSION

This is the first Utstein style report on Emergency Department Cardiac Arrests. A high survival rate with good neurological outcomes was found in this population. The initial rhythm and time to return of spontaneous circulation have been identified as survival factors and may be used to guide decision-making during resuscitation.

Prognostic indicators of survival and survival prediction model following extracorporeal cardiopulmonary resuscitation in patients with sudden refractory cardiac arrest

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) has been considered in selected candidates with potentially reversible causes during a limited period. Candidate selection and the identification of predictable conditions are important factors in determining outcomes during CPR in the emergency department (ED). The objective of this study was to determine the key indicators and develop a prediction model for survival to hospital discharge in patients with sudden cardiac arrest who received ECPR.

Methods

This retrospective analysis was based on a prospective cohort, which included data on CPR with ECPR-related variables. Patients with sudden cardiac arrest who received ECPR at the ED from May 2006 to June 2016 were included. The primary outcome was survival to discharge. Prognostic indicators and the prediction model were analyzed using logistic regression.

Results

Out of 111 ECPR patients, there were 18.9% survivors. Survivors showed younger age, shorter CPR duration (p < 0.05) and had tendencies of higher rate of initial shockable rhythm (p = 0.055) and higher rate of any ROSC event before ECPR (p = 0.066) than non-survivors. Eighty-one percent of survivors showed favorable neurologic outcome at discharge. In univariate analysis, the following factors were associated with survival: no preexisting comorbidities, initial serum hemoglobin level ≥14 g/dL, and mean arterial pressure ≥60 mmHg after ECPR. Based on multivariate logistic regression, predictors for survival in ECPR were as follows: age ≤56 years, no asystole as the initial arrest rhythm, CPR duration of ≤55 min, and any return of spontaneous circulation (ROSC) event before ECPR. The prediction scoring model for survival had a c-statistic of 0.875.

Conclusions

With careful consideration of differences in the inclusion criteria, the prognostic indicators and prediction scoring model for survival in our study may be helpful in the rapid decision-making process for ECPR implementation during CPR in the ED.

The role of resuscitative endovascular balloon occlusion of the aorta (REBOA) as an adjunct to ACLS in non-traumatic cardiac arrest

Non-traumatic cardiac arrest is a major public health problem that carries an extremely high mortality rate. If we hope to increase the survivability of this condition, it is imperative that alternative methods of treatment are given due consideration. Balloon occlusion of the aorta can be used as a method of circulatory support in the critically ill patient. Intra-aortic balloon pumps have been used to temporize patients in cardiogenic shock for decades. More recently, resuscitative endovascular balloon occlusion of the aorta (REBOA) has been utilized in the patient in hemorrhagic shock or cardiac arrest secondary to trauma. Aortic occlusion in non-traumatic cardiac arrest has the effect of reducing the vascular volume that the generated cardiac output is distributed across. This augments myocardial and cerebral perfusion, increasing the probability of a return to a good quality of life for the patient. This phenomenon has been the subject of numerous animal studies dating back to the early 1980s; however, the human evidence is limited to several small case series. Animal research has demonstrated improvements in cerebral and coronary perfusion pressure during ACLS that lead to statistically significant differences in mortality. Several case series in humans have replicated these findings, suggesting the efficacy of this procedure. The objectives of this review are to: 1) introduce the reader to REBOA 2) review the physiology of NTCA and examine the current limitations of traditional ACLS 3) summarize the literature regarding the efficacy and feasibility of aortic balloon occlusion to support traditional ACLS.

Echocardiography for patients undergoing extracorporeal cardiopulmonary resuscitation: a primer for intensive care physicians

Echocardiography is an invaluable tool in the management of patients with extracorporeal cardiopulmonary resuscitation (ECPR) and subsequent extracorporeal membrane oxygenation (ECMO) support and weaning. At the very beginning, echocardiography can identify the etiology of cardiac arrest, such as massive pulmonary embolism and cardiac tamponade. Eliminating these culprits saves life and may avoid the initiation of extracorporeal cardiopulmonary resuscitation. If the underlying causes are not identified or intrinsic to the heart (e.g., such as those caused by cardiomyopathy and myocarditis), conventional cardiopulmonary resuscitation (CCPR) will continue to maintain cardiac output. The quality of CCPR can be monitored, and if cardiac output cannot be maintained, early institution of extracorporeal cardiopulmonary resuscitation may be reasonable. Cannulation is sometimes challenging for extracorporeal cardiopulmonary resuscitation patients. Fortunately, with the help of ultrasonography procedures including localization of vessels, selecting a cannula of appropriate size and confirmation of catheter tip may become easy under sophisticated hand. Monitoring of cardiac function and complications during extracorporeal membrane oxygenation support can be done with echocardiography. However, the cardiac parameters should be interpreted with understanding of hemodynamic configuration of extracorporeal membrane oxygenation. Thrombus and blood stasis can be identified with ultrasound, which may prompt mechanical and pharmacological interventions. The final step is extracorporeal membrane oxygenation weaning. A number of studies investigated the accuracy of some echocardiographic parameters in predicting success rate and demonstrated promising results. Parameters and threshold for successful weaning include aortic VTI ≥ 10 cm, LVEF > 20-25%, and lateral mitral annulus peak systolic velocity >6 cm/s. However, the effectiveness of echocardiography in ECPR patients cannot be determined in observational studies and requires randomized controlled trials in the future. The contents in this review are well known to echocardiography specialists; thus, it should be used as an educational material for emergency or intensive care physicians. There is a trend that focused echocardiography is performed by intensivists and emergency physicians.

A Novel Nonlinear Mathematical Model of Thoracic Wall Mechanics During Cardiopulmonary Resuscitation Based on a Porcine Model of Cardiac Arrest

Cardiopulmonary resuscitation (CPR) is used widely to rescue cardiac arrest patients, yet some physiological aspects of the procedure remain poorly understood. We conducted this study to characterize the dynamic mechanical properties of the thorax during CPR in a swine model. This is an important step toward determining optimal CPR chest compression mechanics with the goals of improving the fidelity of CPR simulation manikins and ideally chest compression delivery in real-life resuscitations. This paper presents a novel nonlinear model of the thorax that captures the complex behavior of the chest during CPR. The proposed model consists of nonlinear elasticity and damping properties along with frequency dependent hysteresis. An optimization technique was used to estimate the model coefficients for force-compression using data collected from experiments conducted on swine. To track clinically relevant, time-dependent changes of the chest's properties, the data was divided into two time periods, from 1 to 10 min (early) and greater than 10 min (late) after starting CPR. The results showed excellent agreement between the actual and the estimated forces, and energy dissipation due to viscous damping in the late stages of CPR was higher when compared to the earlier stages. These findings provide insight into improving chest compression mechanics during CPR, and may provide the basis for developing CPR simulation manikins that more accurately represent the complex real world changes that occur in the chest during CPR.

Hands-on defibrillation during active chest compressions: eliminating another interruption

After decades of research, effective chest compressions have emerged as a key component of high-quality cardiopulmonary resuscitation (CPR) for cardiac arrest patients. Minimizing interruptions in chest compressions is garnering increasing attention as a method to improve CPR quality and outcomes. Hands-on defibrillation has been suggested as both a safe and effective means of reducing interruptions in chest compressions. This article discusses the safety and efficacy of a novel and controversial method to reduce interruptions: hands-on defibrillation.

Comparing extracorporeal cardiopulmonary resuscitation with conventional cardiopulmonary resuscitation: A meta-analysis

INTRODUCTION

The objective was to determine whether extracorporeal cardiopulmonary resuscitation (ECPR), when compared with conventional cardiopulmonary resuscitation (CCPR), improves outcomes in adult patients, and to determine appropriate conditions that can predict good survival outcome in ECPR patients through a meta-analysis.

METHODS

We searched the relevant literature of comparative studies between ECPR and CCPR in adults, from the MEDLINE, EMBASE, and Cochrane databases. The baseline information and outcome data (survival, good neurologic outcome at discharge, at 3-6 months, and at 1 year after arrest) were extracted. Beneficial effect of ECPR on outcome was analyzed according to time interval, location of arrest (out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA)), and pre-defined population inclusion criteria (witnessed arrest, initial shockable rhythm, cardiac etiology of arrest and CPR duration) by using Review Manager 5.3. Cochran's Q test and I(2) were calculated.

RESULTS

10 of 1583 publications were included. Although survival to discharge did not show clear superiority in OHCA, ECPR showed statistically improved survival and good neurologic outcome as compared to CCPR, especially at 3-6 months after arrest. In the subgroup of patients with pre-defined inclusion criteria, the pooled meta-analysis found similar results in studies with pre-defined criteria.

CONCLUSION

Survival and good neurologic outcome tended to be superior in the ECPR group at 3-6 months after arrest. The effect of ECPR on survival to discharge in OHCA was not clearly shown. As ECPR showed better outcomes than CCPR in studies with pre-defined criteria, strict indications criteria should be considered when implementation of ECPR.

[Veno-arterial extracorporeal membrane oxygenation. Indications, limitations and practical implementation]

Due to the technical advances in pumps, oxygenators and cannulas, veno-arterial extracorporeal membrane oxygenation (va-ECMO) or extracorporeal life support (ECLS) has been widely used in emergency medicine and intensive care medicine for several years. An accepted indication is peri-interventional cardiac failure in cardiac surgery (postcardiotomy low cardiac output syndrome). Furthermore, especially the use of va-ECMO for other indications in critical care medicine, such as in patients with severe sepsis with septic cardiomyopathy or in cardiopulmonary resuscitation has tremendously increased. The basic indications for va-ECMO are therapy refractory cardiac or cardiopulmonary failure. The fundamental purpose of va-ECMO is bridging the function of the lungs and/or the heart. Consequently, this support system does not represent a causal therapy by itself; however, it provides enough time for the affected organ to recover (bridge to recovery) or for the decision for a long-lasting organ substitution by a ventricular assist device or by transplantation (bridge to decision). Although the outcome for bridged patients seems to be favorable, it should not be forgotten that the support system represents an invasive procedure with potentially far-reaching complications. Therefore, the initiation of these systems needs a professional and experienced (interdisciplinary) team, sufficient resources and an individual approach balancing the risks and benefits. This review gives an overview of the indications, complications and contraindications for va-ECMO. It discusses its advantages in organ transplantation and transport of critically ill patients. The reader will learn the differences between peripheral and central cannulation and how to monitor and manage va-ECMO.

Doubling survival and improving clinical outcomes using a left ventricular assist device instead of chest compressions for resuscitation after prolonged cardiac arrest: a large animal study

Introduction

Despite improvements in pre-hospital and post-arrest critical care, sudden cardiac arrest (CA) remains one of the leading causes of death. Improving circulation during cardiopulmonary resuscitation (CPR) may improve survival rates and long-term clinical outcomes after CA.

Methods

In a porcine model, we compared standard CPR (sCPR; n =10) with CPR using an intravascular cardiac assist device without additional chest compressions (iCPR; n =10) following 10 minutes of electrically induced ventricular fibrillation (VF). In a separate crossover experiment, 10 additional pigs were subjected to 10 minutes of VF and 6 minutes of sCPR; the iCPR device was then implanted if a return of spontaneous circulation (ROSC) was not achieved using sCPR. Animals were evaluated in respect to intra- and post-arrest hemodynamics, survival, functional outcome and cerebral and myocardial lesions following CPR. We hypothesized that iCPR would result in more frequent ROSC and better functional recovery than sCPR.

Results

iCPR produced a mean flow of 1.36 ± 0.02 L/min, leading to significantly higher coronary perfusion pressure (CPP) values during the early period of CPR (22 ± 10 mmHg vs. 9 ± 5 mmHg, P ≤0.01, 1 minute after start of CPR; 20 ± 11 mmHg vs. 10 ± 7 mmHg, P =0.03, 2 minutes after start of CPR), resulting in high ROSC rates (100% in iCPR vs. 50% in sCPR animals; P =0.03). iCPR animals showed significantly lower serum S100 levels at 10 and 30 minutes following ROSC (3.5 ± 0.6 ng/ml vs. 7.4 ± 3.0 ng/ml 30 minutes after ROSC; P ≤0.01), as well as superior clinical outcomes based on overall performance categories (2.9 ± 1.0 vs. 4.6 ± 0.8 on day 1; P ≤0.01). In crossover experiments, 80% of animals required treatment with iCPR after failed sCPR. Notably, ROSC was still achieved in six of the remaining eight animals (75%) after a total of 22.8 ± 5.1 minutes of ischemia.

Conclusions

In a model of prolonged cardiac arrest, the use of iCPR instead of sCPR improved CPP and doubled ROSC rates, translating into improved clinical outcomes.

An optimal transition time to extracorporeal cardiopulmonary resuscitation for predicting good neurological outcome in patients with out-of-hospital cardiac arrest: a propensity-matched study

INTRODUCTION

Prolonged conventional cardiopulmonary resuscitation (CCPR) is associated with a poor prognosis in out-of-hospital cardiac arrest (OHCA) patients. Alternative methods can be needed to improve the outcome in patients with prolonged CCPR and extracorporeal cardiopulmonary resuscitation (ECPR) can be considered as an alternative method. The objectives of this study were to estimate the optimal duration of CPR to consider ECPR as an alternative resuscitation method in patients with CCPR, and to find the indications for predicting good neurologic outcome in OHCA patients who received ECPR.

METHODS

This study is a retrospective analysis based on a prospective cohort. We included patients ≥ 18 years of age without suspected or confirmed trauma and who experienced an OHCA from May 2006 to December 2013. First, we determined the appropriate cut-off duration for CPR based on the discrimination of good and poor neurological outcomes in the patients who received only CCPR, and then we compared the outcome between the CCPR group and ECPR group by using propensity score matching. Second, we compared CPR related data according to the neurologic outcome in matched ECPR group.

RESULTS

Of 499 patients suitable for inclusion, 444 and 55 patients were enrolled in the CCPR and ECPR group, respectively. The predicted duration for a favorable neurologic outcome (CPC1, 2) is < 21 minutes of CPR in only CCPR patients. The matched ECPR group with ≥ 21 minutes of CPR duration had a more favorable neurological outcome than the matched CCPR group at 3 months post-arrest. In matched ECPR group, younger age, witnessed arrest without initial asystole rhythm, early achievement of mean arterial pressure ≥ 60 mmHg, low rate of ECPR-related complications, and therapeutic hypothermia were significant factors for expecting good neurologic outcome.

CONCLUSIONS

ECPR should be considered as an alternative method for attaining good neurological outcomes in OHCA patients who required prolonged CPR, especially of ≥ 21 minutes. Younger or witnessed arrest patients without initial asystole were good candidates for ECPR. After implantation of ECPR, early hemodynamic stabilization, prevention of ECPR-related complications, and application of therapeutic hypothermia may improve the neurological outcome.

Perimortem cesarean section for maternal and fetal salvage: concise review and protocol

Cardiopulmonary arrest is a rare event during pregnancy and labor. Perimortem cesarean section has been resorted to as a rare event since ancient times; however, greater awareness regarding this procedure within the medical community has only emerged in the past few decades. Current recommendations for maternal resuscitation include performance of the procedure after five minutes of unsuccessful cardiopulmonary resuscitation. If accomplished in a timely manner, perimortem cesarean section can result in fetal salvage and is also critical for maternal resuscitation. Nevertheless, deficits in knowledge about this procedure are common. We have reviewed publications on perimortem cesarean section and present the most recent evidence on this topic, as well as recommending our "easy-to-access protocol" adapted for resuscitation following maternal collapse.

Role of manual and mechanical chest compressions during resuscitation efforts throughout cardiac arrest

The previously published randomized trials of mechanical versus manual resuscitation of patients with cardiac arrest are inconclusive, but a recent systematic review concluded: "There is no evidence that mechanical cardiopulmonary resuscitation devices improve survival; to the contrary they may worsen neurological outcome." However, in our view, none of the randomized trials to date are definitive as the manual groups with primary cardiac arrest have not been treated optimally; that is, with minimally interrupted manual chest compressions, as advocated with cardiocerebral resuscitation. Since the mechanical chest compression devices work on different principles, it is possible that, while they may not be as effective and may even be worse in some subsets of patients, they may be preferable in others. Nevertheless, there are situations where manual chest compressions are not practical and, in these, mechanical devices may well be preferable. The Thumper® (Michigan Instruments, MI, USA) and the LUCAS™ (Jolife AB, Lund, Sweden) devices produce sternal compressions at 100 per min. By contrast, the AutoPulse® (ZOLL Circulation, CA, USA) produces chest compressions at a rate of only 80 per min. Since chest compression rate, as reviewed in this article, is important, one would guess that the devices that can produce a faster rate would be more effective. On the other hand, it could be that sternal compressions with manual or mechanical devices may be more or less effective depending on the arrested patient's chest configuration. We speculate that in the subset of patients with barrel chests, where sternal compressions are less likely to be operative, the AutoPulse might be more effective, but less effective in thin-chested individuals, where direct cardiac compression is the major mechanism of forward blood flow in the manual, Thumper and LUCAS methods. The original LUCAS device had the potential of active decompression as well as compression. To market in the USA, holes had to be placed in the 'suction cup'. It would be informative to know whether the original LUCAS device is more effective than the device in which the active decompression has been deactivated.

Extracorporeal membrane oxygenation for resuscitation and cardiac arrest management

This article reviews the potential application of extracorporeal membrane oxygenation (ECMO) technology to cardiopulmonary resuscitation for in and out-of-hospital cardiac arrest and discusses the current evidence on the subject. The possible strategies for organ protection during ECMO and the concept of ECMO networks are also reviewed.

Hemodynamic rescue and ECG stability during chest compressions using adenosine and lidocaine after 8-minute asphyxial hypoxia in the rat

INTRODUCTION

Sudden cardiac death generally arises from either ventricular fibrillation or asphyxial hypoxia. In an effort to translate the cardioprotective effects of adenosine and lidocaine (AL) from hemorrhagic shock to cardiopulmonary resuscitation, we examined the effect of AL on hemodynamics and electrocardiogram (ECG) stability in the rat model of asphyxial hypoxia.

METHODS

Male Sprague-Dawley rats were randomly assigned to 1 of 4 groups (n = 8): saline (SAL), adenosine (ADO), lidocaine (LIDO), and AL. Cardiac arrest (mean arterial pressure <10 mm Hg) was induced by clamping the ventilator line for 8 minutes. A 0.5-mL intravenous drug bolus was injected followed by chest compressions (300 min(-1)), which were repeated every 5 minutes for 1 hour.

RESULTS

Return of spontaneous circulation was achieved in 5 SAL (62.6%), 4 ADO (50%), 7 LIDO (87.5%), and 8 AL rats (100%) within 5 minutes but could not be sustained. During chest compressions, mean arterial pressure was consistently higher in the AL-treated rats compared with all groups (P < .05; 35-45 and 55 minutes) followed by the LIDO group and was lowest in the ADO and SAL groups (P < .05). Systolic pressure followed a similar pattern. In addition, diastolic pressure in the AL-treated rats was significantly higher from 25 to 60 minutes than LIDO and ADO alone or SAL, and heart rate was 30% to 40% lower. Improved ECG rhythm and R-R variability were apparent in AL-treated rats during early compressions and hands-off intervals.

CONCLUSIONS

We conclude that a small bolus of 0.9% NaCl AL improved hemodynamics with possible diastolic rescue and ECG stabilization during chest compressions compared with ADO, LIDO, or SAL controls.

Quantifying the effect of cardiopulmonary resuscitation quality on cardiac arrest outcome: a systematic review and meta-analysis

Background- Evidence has accrued that cardiopulmonary resuscitation quality affects cardiac arrest outcome. However, the relative contributions of chest compression components (such as rate and depth) to successful resuscitation remain unclear. Methods and Results- We sought to measure the effect of cardiopulmonary resuscitation quality on cardiac arrest outcome through systematic review and meta-analysis. We searched for any clinical study assessing cardiopulmonary resuscitation performance on adult cardiac arrest patients in which survival was a reported outcome, either return of spontaneous circulation or survival to admission or discharge. Of 603 identified abstracts, 10 studies met inclusion criteria. Effect sizes were reported as mean differences. Missing data were resolved by author contact. Estimates were segregated by cardiopulmonary resuscitation metric (chest compression rate, depth, no-flow fraction, and ventilation rate), and a random-effects model was applied to estimate an overall pooled effect. Arrest survivors were significantly more likely to have received deeper chest compressions than nonsurvivors (mean difference, 2.44 mm; 95% confidence interval, 1.19-3.69 [P<0.001]; n=6 studies; I(2)=0.0%; P for heterogeneity=0.9). Likewise, survivors were significantly more likely to have received chest compression rates closer to 85 to 100 compressions per minute (cpm) than nonsurvivors (absolute mean difference from 85 cpm, -4.81 cpm; 95% confidence interval, -8.19 to -1.43 [P=0.005]; from 100 cpm, -5.04 cpm; 95% confidence interval, -8.44 to -1.65 [P=0.004]; n=6 studies; I(2)<49%; P for heterogeneity >0.2). No significant difference in no-flow fraction (n=7 studies) or ventilation rate (n=4 studies) was detected between survivors and nonsurvivors. Conclusions- Deeper chest compressions and rates closer to 85 to 100 cpm are significantly associated with improved survival from cardiac arrest.

In-hospital cardiac arrest

In-hospital sudden cardiac arrest and resuscitation is distinct from out-of-hospital sudden cardiac arrest (OOHSCA) and warrants specific attention. Sudden cardiac arrest (SCA) is a manifestation of an underlying process rather than a disease itself. The complex, multiorgan system dysfunction common among the inpatient population can precipitate SCA by both similar and very different mechanisms than OOHSCA. The diagnostic and treatment algorithms of SCA remain largely the same between the inpatient and outpatient arenas. The application of complex diagnostic and therapeutic interventions is permissible, but such tools must not interrupt or delay the important basics of cardiac arrest management in the inpatient setting, including adequate chest compressions and timely defibrillation when appropriate.

A trial of an impedance threshold device in out-of-hospital cardiac arrest

BACKGROUND

The impedance threshold device (ITD) is designed to enhance venous return and cardiac output during cardiopulmonary resuscitation (CPR) by increasing the degree of negative intrathoracic pressure. Previous studies have suggested that the use of an ITD during CPR may improve survival rates after cardiac arrest.

METHODS

We compared the use of an active ITD with that of a sham ITD in patients with out-of-hospital cardiac arrest who underwent standard CPR at 10 sites in the United States and Canada. Patients, investigators, study coordinators, and all care providers were unaware of the treatment assignments. The primary outcome was survival to hospital discharge with satisfactory function (i.e., a score of ≤3 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating greater disability).

RESULTS

Of 8718 patients included in the analysis, 4345 were randomly assigned to treatment with a sham ITD and 4373 to treatment with an active device. A total of 260 patients (6.0%) in the sham-ITD group and 254 patients (5.8%) in the active-ITD group met the primary outcome (risk difference adjusted for sequential monitoring, -0.1 percentage points; 95% confidence interval, -1.1 to 0.8; P=0.71). There were also no significant differences in the secondary outcomes, including rates of return of spontaneous circulation on arrival at the emergency department, survival to hospital admission, and survival to hospital discharge.

CONCLUSIONS

Use of the ITD did not significantly improve survival with satisfactory function among patients with out-of-hospital cardiac arrest receiving standard CPR. (Funded by the National Heart, Lung, and Blood Institute and others; ROC PRIMED ClinicalTrials.gov number, NCT00394706.).

Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial

BACKGROUND

Active compression-decompression cardiopulmonary resuscitation (CPR) with decreased intrathoracic pressure in the decompression phase can lead to improved haemodynamics compared with standard CPR. We aimed to assess effectiveness and safety of this intervention on survival with favourable neurological function after out-of-hospital cardiac arrest.

METHODS

In our randomised trial of 46 emergency medical service agencies (serving 2·3 million people) in urban, suburban, and rural areas of the USA, we assessed outcomes for patients with out-of-hospital cardiac arrest according to Utstein guidelines. We provisionally enrolled patients to receive standard CPR or active compression-decompression CPR with augmented negative intrathoracic pressure (via an impedance-threshold device) with a computer-generated block randomisation weekly schedule in a one-to-one ratio. Adults (presumed age or age ≥18 years) who had a non-traumatic arrest of presumed cardiac cause and met initial and final selection criteria received designated CPR and were included in the final analyses. The primary endpoint was survival to hospital discharge with favourable neurological function (modified Rankin scale score of ≤3). All investigators apart from initial rescuers were masked to treatment group assignment. This trial is registered with ClinicalTrials.gov, number NCT00189423.

FINDINGS

2470 provisionally enrolled patients were randomly allocated to treatment groups. 813 (68%) of 1201 patients assigned to the standard CPR group (controls) and 840 (66%) of 1269 assigned to intervention CPR received designated CPR and were included in the final analyses. 47 (6%) of 813 controls survived to hospital discharge with favourable neurological function compared with 75 (9%) of 840 patients in the intervention group (odds ratio 1·58, 95% CI 1·07-2·36; p=0·019]. 74 (9%) of 840 patients survived to 1 year in the intervention group compared with 48 (6%) of 813 controls (p=0·03), with equivalent cognitive skills, disability ratings, and emotional-psychological statuses in both groups. The overall major adverse event rate did not differ between groups, but more patients had pulmonary oedema in the intervention group (94 [11%] of 840) than did controls (62 [7%] of 813; p=0·015).

INTERPRETATION

On the basis of our findings showing increased effectiveness and generalisability of the study intervention, active compression-decompression CPR with augmentation of negative intrathoracic pressure should be considered as an alternative to standard CPR to increase long-term survival after cardiac arrest.

FUNDING

US National Institutes of Health grant R44-HL065851-03, Advanced Circulatory Systems.

A resuscitation "dilemma" theory-practice-ethics. Is there a theory-practice-ethics gap?

The theory-practice-ethics gap - a new paradigm to contemplate. Practices based on tradition, rituals and outdated information are placed into a nonscientific paradigm called the theory-practice gap. Within this paradigm there is often a gap between theoretical knowledge and its application in practice. This theory-practice gap has always existed [Allmark, P., 1995. A classical view of the theory-practice gap in nursing. J. Adv. Nurs. 22 (1), 18-23; Hewison, A. et al., 1996. The theory-practice gap in nursing: a new dimension. J. Adv. Nurs. 24 (4), 754-761]. Its creation is often sited as a culmination of theory being idealistic and impractical, even if practical and beneficial, are often ignored. Most of the evidence relating to the non integration of theory and practice makes the assumption that environmental factors are responsible and will affect learning and practice outcomes, hence the "gap". In fact, it is the author's belief, that to "bridge the gap" between theory and practice an additional component is required, called ethics. A moral duty and obligation ensuring theory and practice integrate. In order to effectively implement new practices, one must deem these practices are worthy and relevant to their role as healthcare providers. Otherwise, we fall victims to providing nothing more than a lip service. This introduces a new concept which the author refers to as the theory-practice-ethics gap. This theory-practice-ethics gap must be considered when reviewing some of the unacceptable outcomes in health care practice. The author believes that there is a crisis of ethics where theory and practice integrate, and as a consequence, malfeasance. We are failing to fulfill our duty as healthcare providers and as patient advocates. One practice of major concern, which the author will endeavor to unfold relates to adult and pediatric resuscitation.

Resuscitation and critical care of neonatal calves

Neonatal morbidity and mortality are major economic concerns in both beef and dairy cattle in the United States. In both beef and dairy most calf death occurs in the early neonatal period, particularly in calves born following dystocia. This article focuses on the resuscitation of calves after delivery and highlights some therapeutic points for the care of critical calves.