Abstract
Advancements in diagnostic and therapeutic approaches have led to a remarkable reduction in the morbidity and mortality rates associated with a variety of diseases. In the context of acute ischemic heart disease, significant milestones have been achieved, beginning with the establishment of cardiac ICUs. These were pivotal in providing specialized care for patients with severe heart conditions. Subsequent to this development, methods to restore blood flow in areas compromised by arterial blockages were introduced. Initially, systemic thrombolysis was the primary method used, but it has since been largely supplanted by primary percutaneous coronary intervention (PCI), also known as primary coronary angioplasty, which is now the preferred treatment due to its effectiveness and safety. The incidence of out-of-hospital cardiac arrest (OHCA) where resuscitation attempts have been made, whether successful or not, is significant and presents a considerable challenge. Unfortunately, the mortality rate among these patients remains distressingly high, and efforts to reduce it are fraught with difficulty. It is crucial to acknowledge that survival from an OHCA does not automatically equate to a favorable clinical outcome, as serious neurological impairments are common sequelae of such events. In addition to mortality rates, the term “survival with favorable neurologic outcome” has emerged as another critical measure of the success of resuscitation efforts. This parameter underscores the importance of not only saving lives but also preserving the quality of life for survivors. The ability to restore both life and cognitive function is a testament to the comprehensiveness of care provided to OHCA patients.
The manuscript titled “Predictors and rate of survival after Out-of-Hospital Cardiac Arrest” presents a retrospective cohort study conducted to assess predictors and rates of survival after out-of-hospital cardiac arrest (OHCA) . Here are some potential drawbacks and limitations, along with suggestions for improvement:
Drawbacks:
- 1.
Retrospective Design :
- ○
Biases : Retrospective studies are prone to selection and recall biases.
- ○
Improvement : Consider conducting a prospective study to mitigate these biases and improve the reliability of the findings.
- ○
- 2.
Single-Center Data :
- ○
Generalizability : Results may not be representative of a broader population.
- ○
Improvement : Collaborate with multiple centers to increase the sample diversity and enhance the external validity of the study.
- ○
- 3.
Lack of Neurological Outcomes :
- ○
Incomplete Data : Important aspects of patient recovery post-OHCA are not covered.
- ○
Improvement : Include assessments of neurological status and quality of life in future studies.
- ○
- 4.
Limited Data on OHCA Circumstances :
- ○
Contextual Factors : Factors like location of arrest, witness presence, and EMS response times are crucial.
- ○
Improvement : Collect comprehensive data on these contextual factors to better understand their impact on outcomes.
- ○
- 5.
Selection Bias in Coronary Angiography :
- ○
Discretionary Decisions : The decision to perform angiography could introduce bias.
- ○
Improvement : Establish clear criteria for patient selection for angiography to reduce bias.
- ○
- 6.
Short-Term Follow-Up :
- ○
Long-Term Insights : The study lacks long-term follow-up data beyond 7.1 years.
- ○
Improvement : Extend the follow-up period to assess long-term survival and outcomes.
- ○
- 7.
Statistical Analysis :
- ○
Depth : The manuscript could benefit from more detailed statistical analysis.
- ○
Improvement : Include subgroup analyses, interaction effects, and use advanced statistical methods to control for confounders.
- ○
- 8.
Small Sample Size :
- ○
Power : A small sample size may limit the ability to detect smaller effect sizes.
- ○
Improvement : Increase the sample size or collaborate with other centers for a larger, multicenter study.
- ○
- 9.
Lack of Long-Term Follow-Up Data :
- ○
Longevity : Insights into long-term survival and health are limited.
- ○
Improvement : Plan for extended follow-up assessments to better understand long-term outcomes.
- ○
Suggestions for Improvement:
- 1.
Expand the Study Design : Transition to a prospective, multicenter study design to enhance the generalizability and reduce biases.
- 2.
Include Neurological Outcomes : Incorporate assessments of neurological function and quality of life in the study outcomes.
- 3.
Collect Comprehensive Data : Ensure that data on the circumstances of OHCA and pre-hospital care are collected and analyzed.
- 4.
Standardize Procedures : Develop standardized protocols for patient selection and treatment to reduce variability and bias.
- 5.
Enhance Statistical Analysis : Perform additional statistical analyses to explore the robustness of the findings and to control for potential confounders.
- 6.
Increase Sample Size : Aim for a larger sample size to increase the power of the study and enable subgroup analyses.
- 7.
Long-Term Follow-Up : Plan for extended follow-up periods to assess long-term survival and outcomes.
- 8.
Interdisciplinary Approach : Involve experts from different fields (e.g., neurology, rehabilitation medicine) to ensure a comprehensive assessment of patient outcomes.
- 9.
Public Health Implications : Discuss the potential public health implications of the findings and suggest practical steps for improving OHCA survival rates.
- 10.
Transparent Reporting : Ensure that the manuscript adheres to the Transparent Reporting of Studies Conducted in Nonhuman Subjects (TROSP) or other relevant reporting guidelines to enhance the transparency and quality of the reporting.
By addressing these limitations and following these suggestions, the manuscript could provide a more comprehensive and robust analysis of predictors and rates of survival after OHCA.
The term OHCA can be somewhat ambiguous, as it may be interpreted to encompass any cardiac arrest event that occurs outside of a hospital setting, regardless of whether it results in death. Consequently, most research papers focus on cases where resuscitation efforts were made, specifically involving patients who experienced cardiac arrest and received attention from EMS. OHCA is intimately connected with the concept of “Sudden Cardiac Death” (SCD), which is characterized as an unexpected demise due to cardiac causes within a brief timeframe, typically within an hour of symptom onset. Given that the majority of OHCAs are attributed to primary cardiac issues, the terms OHCA and SCD are closely related, yet they are not used interchangeably. The key distinction is that OHCA does not always lead to fatality. OHCA is more prevalent among men than women. The majority of these incidents take place in the home, accounting for more than 66 % of cases, with workplaces and public spaces following at approximately 20 %, and other locations making up the remainder. Since the majority of OHCAs are precipitated by coronary atherosclerotic disease, the initial treatment after a successful resuscitation often involves coronary angiography. The criteria for indicating treatment in OHCA patients mirror those for patients with sustained circulation, with clinical suspicion, electrocardiogram (ECG) readings, or laboratory results being the primary indicators.
Improving outcomes for OHCA hinges on reinforcing the chain of survival, which includes the swift application of CPR and the use of automated external defibrillators (AEDs). Despite the critical role these interventions play, the rates of bystander CPR and AED deployment are disappointingly low. This can be attributed to a variety of patient-specific factors, such as inadequate education and socioeconomic barriers, as well as systemic issues like the insufficient availability of AEDs in many communities. Health inequalities refer to the disparities in healthcare access and opportunities for health that different individuals encounter. The community’s immediate response to cardiac arrest is pivotal and hinges on prompt recognition of the event, early bystander CPR, and early defibrillation with an AED. These disparities in pre-hospital care can stem from patient characteristics or the characteristics of the bystanders themselves. Several population characteristics have been identified that influence the delivery of CPR and AED use, including sex, ethnicity, socioeconomic status, and age. Research indicates that patients from lower socioeconomic backgrounds are more prone to the risk factors that can lead to cardiac arrest, and thus are at a higher risk of experiencing OHCA. The socioeconomic background is closely tied to the geographic location, with significant differences observed between urban and rural areas. It is a well-documented fact that EMS response times are generally longer in rural settings compared to urban ones. Bystander CPR has been linked to higher survival rates in urban areas, while its impact in rural areas appears to be less significant, potentially due to the slower EMS response times.
Extracorporeal cardiopulmonary resuscitation (ECPR) is a specialized form of life support that can potentially enhance long-term survival rates by ensuring the continuous delivery of oxygenated blood to vital organs until the heart can effectively resume its function, thus preventing organ failure. This advanced technique not only sustains end-organ perfusion but also buys time for critical diagnostic and therapeutic procedures, such as coronary angiography and percutaneous coronary intervention (PCI), to be conducted on patients with reversible causes of cardiac arrest. While ECPR holds promise for improving outcomes, its widespread adoption and impact on survival rates post-cardiac arrest are still a subject of debate. Observational studies suggest that ECPR might offer superior neurological outcomes and survival rates compared to conventional CPR (C-CPR) in cases of out-of-hospital cardiac arrest (OHCA). ECPR is advised to be considered as a rescue therapy for selecting patients with treatable underlying conditions when standard CPR has been unsuccessful. In essence, ECPR represents a valuable tool in the critical care arsenal, particularly when time is of the essence and the potential for recovery is high. However, its use should be carefully considered on a case-by-case basis, considering the patient’s condition, the availability of resources, and the expertise of the healthcare team.
Despite significant progress in the management of heart conditions, the prognosis for patients who suffer a sudden cardiac arrest remains challenging. Although the application of bystander CPR and the speed at which defibrillation is administered have seen improvements, the demographics of OHCA patients are shifting. CPR is an essential emergency procedure that can potentially double or triple a patient’s chance of surviving an OHCA. The likelihood of survival is also linked to the underlying cause of the sudden cardiac arrest and the first monitored rhythm. It’s noteworthy that about 40 % of OHCA patients are found with initial shockable rhythms, but only 22 % of these patients achieve return of spontaneous circulation (ROSC). This discrepancy highlights the importance of this group as a priority for future interventions aimed at improving ROSC rates and overall survival outcomes for OHCA patients. To enhance survival rates, efforts should be directed towards improving the public’s CPR skills, increasing the accessibility and use of AEDs, and refining EMS response protocols. Additionally, ongoing research into the causes and mechanisms of cardiac arrest, as well as the development of novel therapeutic approaches, will be crucial in the ongoing battle to improve outcomes for OHCA patients.
While we recognize the need to delve deeper into these issues, we extend our congratulations to Anthony Matta and his team for their commendable contributions to the field. Their work highlights the ongoing pursuit of improved treatments and outcomes in the management of acute cardiac conditions, including the complex and multifaceted challenge of OHCA.
Consent for publication
Not applicable.
Ethics approval and consent to participate
This is a review of a recently published article in Current Problems in Cardiology, no ethics approval and consent to participate was required.
Funding
2023 Chengdu Medical Research Project Fund (No.: 2023020 )
Availability of data and materials
Not applicable, please contact author for data requests.
CRediT authorship contribution statement
Jinfeng Li: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Lei Bao: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Validation, Visualization, Writing – original draft, Writing – review & editing. Mengyue Gu: Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Resources, Validation, Visualization, Writing – original draft, Writing – review & editing. Mengmei Wang: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Hui Zhong: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
First two authors contribute equally to this manuscript and should be considered as first co-authors.
References
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
