Elsevier

Resuscitation

Volume 80, Issue 1, January 2009, Pages 30-34
Resuscitation

Clinical paper
Inter-hospital variability in post-cardiac arrest mortality

https://doi.org/10.1016/j.resuscitation.2008.09.001Get rights and content

Summary

Aim

A growing body of evidence suggests that variability in post-cardiac arrest care contributes to differential outcomes of patients with initial return of spontaneous circulation after cardiac arrest. We examined hospital-level variation in mortality of patients admitted to United States intensive care units (ICUs) with a diagnosis of cardiac arrest.

Methods

Patients with a primary ICU admission diagnosis of cardiac arrest were identified in the 2002–2005 Acute Physiology and Chronic Health Evaluation (APACHE) IV dataset, a multicenter clinical registry of ICU patients.

Results

We identified 4674 patients from 39 hospitals. The median number of annual patients was 33 per hospital (range: 12–116). Mean APACHE score was 94 (±38), and overall mortality was 56.8%. Age, severity of illness (acute physiology score), and admission Glasgow Coma Scale were all associated with increased mortality (p < 0.001). There was no survival difference for patients admitted from the emergency department vs. the inpatient floor. Among institutions, unadjusted in-hospital mortality ranged from 41% to 81%. After adjusting for age and severity of illness, institutional mortality ranged from 46% to 68%. Patients treated at higher volume centers were significantly less likely to die in the hospital.

Conclusions

We demonstrate hospital-level variation in severity adjusted mortality among patients admitted to the ICU after cardiac arrest. We identify a volume–outcome relationship showing lower mortality among patients admitted to ICUs that treat a high volume of post-cardiac arrest patients. Prospective studies should identify hospital-level and patient care factors that contribute to post-cardiac arrest survival.

Introduction

Overall survival after cardiac arrest is poor,1, 2 and has remained largely unchanged over time.3, 4 Furthermore, despite international efforts to develop and disseminate cardiac arrest treatment guidelines, significant outcome variability persists among individual emergency medical service (EMS) systems and hospital. Reported rates of survival to hospital discharge range from 1% to 31% after out-of-hospital cardiac arrest2, 5 and 0% to 42% after in-hospital cardiac arrest.6 Although numerous pre-arrest,3, 7, 8 and intra-arrest9, 10, 11, 12, 13, 14, 15 factors contribute to this variability, much less is known about the relative contribution of post-cardiac arrest care.

Post-cardiac arrest care is now recognized as a critical link in the chain of survival.16, 17 Therapeutic hypothermia and formalized post-cardiac arrest treatment protocols decrease morbidity and mortality.18, 19, 20, 21 However, substantial inter-hospital variability in mortality of patients that achieve initial return of spontaneous circulation (ROSC) has been reported.8, 22 Mortality differences have been associated with hospital-based factors as well as patient care factors.23, 24 Although likely to be a universal phenomenon, all of these data are from sites outside the United States (US).

The goal of this study was to examine within the US health care system the variability in mortality of patients that achieve initial ROSC after cardiac arrest. Documenting inter-hospital variability of post-cardiac arrest mortality is the first step in understanding the role of post-cardiac arrest care in the overall chain of survival. Ultimately, identifying the sources of variability is essential to optimize post-cardiac arrest care. This study utilized a large clinical intensive care unit (ICU) database to determine site-dependent variability in adjusted in-hospital mortality and the association between mortality and hospital case volume.

Section snippets

Study design and patients

We conducted a retrospective cohort study using the Acute Physiology and Chronic Health Evaluation (APACHE) IV database (Cerner Corporation, Kansas City, MO). APACHE is an ICU clinical information system used by participating hospitals within the US for benchmarking and quality improvement.25 Patient demographics, admission source, primary admission diagnosis, and detailed laboratory and physiologic variables are collected in the first 24 h of ICU admission. Trained clinical coordinators

Study population

The initial dataset contained 5386 post-arrest patients in 57 hospitals. We excluded 215 patients in 18 very low volume hospitals, resulting in 39 hospitals in the final sample (Table 1). Just over half of the hospitals were academic hospitals (26%) or community hospitals with housestaff (33%). Most hospitals were located in the southeast (44%), west (28%), or midwest (21%). The median number of hospital beds at each facility was 384 (IQR 280–650), and the median number of cardiac arrest

Discussion

We demonstrate inter-hospital variability in severity adjusted post-cardiac arrest mortality in patients admitted to the ICU after successful resuscitation from cardiac arrest. In addition, we observed an inverse relationship between the volume of cardiac arrest patients treated in the ICU and in-hospital mortality. These findings are consistent with previous work that has demonstrated wide variability in post-cardiac arrest mortality outside the US,22, 23, 24 and the relationship between

Conclusions

In-hospital mortality varies significantly among patients admitted to US intensive care units after initial resuscitation from cardiac arrest, and one potential source of outcome variability is patient volume. These results suggest the need for additional research to delineate best-practices and to optimize post-cardiac arrest care. If variability in patient care is found to be causal, then development, dissemination and implementation of comprehensive post-cardiac arrest care guidelines should

Conflict of interest

BGC & JK have no pertinent disclosures. RMM serves on the BLS Subcommittee of the American Heart Association Emergency Cardiac Care Committee as a fellow. AAK is an employee of Cerner Corporation and owns shares of Cerner stock. RWN serves on the ACLS Subcommittee of the American Heart Association Emergency Cardiac Care Committee.

References (40)

  • J. Engdahl et al.

    Is hospital care of major importance for outcome after out-of-hospital cardiac arrest? Experience acquired from patients with out-of-hospital cardiac arrest resuscitated by the same Emergency Medical Service and admitted to one of two hospitals over a 16-year period in the municipality of Goteborg

    Resuscitation

    (2000)
  • W.A. Knaus et al.

    The APACHE III prognostic system. Risk prediction of hospital mortality for critically ill hospitalized adults

    Chest

    (1991)
  • B.S. Abella et al.

    Induced hypothermia is underused after resuscitation from cardiac arrest: a current practice survey

    Resuscitation

    (2005)
  • M.S. Eisenberg et al.

    Cardiac resuscitation

    N Engl J Med

    (2001)
  • W. Rosamond et al.

    Heart disease and stroke statistics—2008 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee

    Circulation

    (2008)
  • J. Herlitz et al.

    Factors associated with survival to hospital discharge among patients hospitalised alive after out of hospital cardiac arrest: change in outcome over 20 years in the community of Goteborg, Sweden

    Heart

    (2003)
  • M. Niskanen et al.

    Outcome from intensive care after cardiac arrest: comparison between two patient samples treated in 1986–87 and 1999–2001 in Finnish ICUs

    Acta Anaesthesiol Scand

    (2007)
  • C. Sandroni et al.

    In-hospital cardiac arrest: incidence, prognosis and possible measures to improve survival

    Intens Care Med

    (2007)
  • M. Holmberg et al.

    Factors modifying the effect of bystander cardiopulmonary resuscitation on survival in out-of-hospital cardiac arrest patients in Sweden

    Eur Heart J

    (2001)
  • V.M. Nadkarni et al.

    First documented rhythm and clinical outcome from in-hospital cardiac arrest among children and adults

    JAMA

    (2006)
  • Cited by (213)

    View all citing articles on Scopus

    A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2008.09.001.

    View full text