Resuscitation 83 (2012) 793 794
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Resuscitation
jo u rn al hom epage : www.elsevier.com/locate/resuscitation
Editorial
Hospital care after resuscitation from out-of-hospital cardiac arrest:
The emperor s new clothes?
The large regional variation in outcome after treatment for out- to hospital, and analyses restricted to cardiac etiology of arrest are
of-hospital cardiac arrest (OHCA)1 has led to efforts to develop susceptible to bias. Thus the revised Utstein approach to comparing
and implement cardiac resuscitation systems of care that include outcomes after OHCA recommended including all treated patients
interconnected community, emergency medical services (EMS) and rather than those with a particular etiology or initial rhythm.8
hospital efforts to measure and improve the process and outcome of In another retrospective analysis published simultaneously as
care for this population.2 Implicit assumptions of these efforts are the CARES work, Ro et al. evaluated the relationship between the
that care provided for patients with OHCA is better at some hos- annual volume of patients received at hospitals and survival to
pitals that receive such patients than others, and that resuscitated discharge after cardiac arrest of non-cardiac etiology in a national
patients should be preferentially transported to higher-performing Korean registry derived from combination of ambulance run sheets
hospitals. with hospital data abstracted by trained reviewers.9 Generalized
In this volume of Resuscitation, two investigations describe additive modeling evaluated for a threshold value that discrimi-
whether the characteristics of receiving hospitals are associated nated between a low and high volume of patients received. Then
with outcome after OHCA. In a retrospective analysis that com- multiple logistic regression analysis evaluated whether there was
bined quality improvement data from the Cardiac Arrest Registry to an association between the volume of patients received and sur-
Enhance Survival (CARES) registry with administrative information vival to discharge. There was a significant and important difference
about hospital characteristics and hospitals self-report of whether in survival to discharge among patients transported to a high vol-
they use hypothermia to assess the relationship, Cudnik et al. eval- ume hospital rather than low volume hospital overall and within
uated whether increasing hospital volume of OHCA patients was specific etiologies of arrest.
associated with improved survival.3 They included adults who had There are several potential explanations why an association
OHCA of presumed cardiac etiology, were treated by EMS, and between patient volume and outcome was not observed in the
were directly transported to a hospital. The analysis used multi- CARES registry but was in the Korean registry. The quality of care
level hierarchical logistic regression to adjust for the interaction may be lower among CARES hospitals than among Korean hospi-
between patient-level factors with hospital characteristics and the tals, but this seems unlikely since overall survival was greater in
association between hospital characteristics within different sites. the former than in the latter. The accuracy of the data in each reg-
A significant relationship was observed between trauma center istry may differ as CARES performs limited data verification at the
designation but not presence of a coronary catheterization labora- source whereas staff of the Korean registry visit participating hos-
tory or the volume of patients received and survival or neurologic pitals and review medical records to identify information related to
outcome among all treated patients or those with a first-recorded covariate and outcome. It seems plausible that bias and confound-
shockable rhythm. ing in CARES data may reduce the likelihood of identifying whether
The hospital factor with the largest treatment effect in this differences in care are associated with differences in survival.
study was self-reported use of hypothermia. Since only a minor- Prior studies provide conflicting evidence regarding the influ-
ity of patients have hypothermia induced at hospitals that report ence of hospital factors on survival after OHCA. A Japanese study
that they use it,4 reported use of hypothermia may be a surro- that included more 10,000 patients showed that OHCA patients
gate marker for other factors that are associated with outcome, transported to critical cardiac care hospitals had improved 1-month
and attenuate the effect of hospital factors upon patient survival to survival compared with patients transported to hospitals without
discharge. specialized facilities (6.7% versus 2.8%, p < 0.001, adjusted odds ratio
This study restricted enrollment to patients with a cardiac etiol- 3.39, p < 0.001).10 A Swedish study of almost 4000 OHCA patients
ogy of arrest. There is a twofold variation in the reported proportion reported marked variability in hospital outcomes after adjusting for
of cardiac arrests of non-cardiac etiology.5 There is poor agreement pre-hospital factors, with survival varying from 14% to 42% in differ-
in attributing cause of heart failure deaths.6 Information from 12- ent centres.11 Similarly a recent Australian study of 2706 patients
lead electrocardiogram does not identify which patients among who were transported to hospital with return of a spontaneous cir-
those resuscitated from OHCA have significant lesions at time of culation found that survival to hospital discharge was significantly
emergency catheterization.7 Assessment of the etiology of arrest is greater in patients transported to hospitals with 24 h interventional
difficult to assess accurately in field. If etiology is determined using cardiology facilities, with the best survival in major trauma-level
hospital information, assessing etiology is conditioned on survival hospitals.12 A US study of 109,739 patients who received intensive
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http://dx.doi.org/10.1016/j.resuscitation.2012.03.034
794 Editorial / Resuscitation 83 (2012) 793 794
care in hospital indicated that hospital teaching status, size and 5. Kuisma M, Alaspaa A. Out-of-hospital cardiac arrests of non-cardiac origin. Epi-
demiology and outcome. Eur Heart J 1997;18:1122 8.
urban location were associated with outcome in patients resusci-
6. Ziesche S, Rector TS, Cohn JN. Interobserver discordance in the classification of
tated from in-hospital and out-of-hospital cardiac arrest.13
mechanisms of death in studies of heart failure. J Card Fail 1995;1:127 32.
Conversely, a North American study of 4087 patients with OHCA 7. Spaulding CM, Joly LM, Rosenberg A, et al. Immediate coronary angiogra-
phy in survivors of out-of-hospital cardiac arrest. N Engl J Med 1997;336:
reported increased rates of survival among patients resuscitated
1629 33.
from OHCA who were treated at larger hospitals capable of inva-
8. Jacobs I, Nadkarni V, Bahr J, et al. Cardiac arrest and cardiopulmonary resus-
sive cardiac procedures but this effect was not independent of
citation outcome reports: update and simplification of the Utstein templates
for resuscitation registries. A statement for healthcare professionals from a task
pre-hospital factors.14
force of the international liaison committee on resuscitation (American Heart
How should variation in outcome after hospitalization for post-
Association, European Resuscitation Council, Australian Resuscitation Council,
resuscitation care be interpreted in the context of factors associated
New Zealand Resuscitation Council, Heart and Stroke Foundation of Canada,
with variations in outcomes of other conditions? Variation in out- InterAmerican Heart Foundation, Resuscitation Council of Southern Africa).
Resuscitation 2004;63:233 49.
comes after hospitalization for acute myocardial infraction has
9. Ro YS, Shin SD, Song KJ, et al. A comparison of outcomes of out-of-hospital cardiac
been associated with hospitals teaching status,15 urban location,16
arrest with non-cardiac etiology between emergency departments with low-
geographic region,17 safety net status,18 and institutional culture.19 and high-resuscitation case volume. Resuscitation 2012;83:855 61.
10. Kajino K, Iwami T, Daya M, et al. Impact of transport to critical care med-
Additional work is necessary to understand and improve the varia-
ical centers on outcomes after out-of-hospital cardiac arrest. Resuscitation
tion in process and outcome after OHCA as has been done for acute
2010;81:549 54.
myocardial infarction. 11. Herlitz J, Engdahl J, Svensson L, Angquist KA, Silfverstolpe J, Holmberg S. Major
differences in 1-month survival between hospitals in Sweden among initial
There are multiple examples throughout the field of medicine
survivors of out-of-hospital cardiac arrest. Resuscitation 2006;70:404 9.
of the positive correlation between greater provider experience or
12. Stub D, Smith K, Bray JE, Bernard S, Duffy SJ, Kaye DM. Hospital characteristics
procedural volume for complex diagnoses or procedures and better are associated with patient outcomes following out-of-hospital cardiac arrest.
Heart 2011;97:1489 94.
patient outcome.20 The relationship between volume and outcome
13. Carr BG, Goyal M, Band RA, et al. A national analysis of the relationship
is complex. Procedural volume is an identifiable surrogate marker
between hospital factors and post-cardiac arrest mortality. Intensive Care Med
for a number of patient, physician, and systems variables that have
2009;35:505 11.
14. Callaway CW, Schmicker R, Kampmeyer M, et al. Receiving hospital character-
an impact on outcome but are difficult to quantify individually.
istics associated with survival after out-of-hospital cardiac arrest. Resuscitation
Despite inconsistent evidence of a relationship between the
2010;81:524 9.
volume of patients a hospital receives after cardiac arrest and
15. Allison JJ, Kiefe CI, Weissman NW, et al. Relationship of hospital teaching status
with quality of care and mortality for Medicare patients with acute MI. JAMA
their subsequent survival, we believe that it would be premature
2000;284:1256 62.
to conclude that implementation of regional cardiac resuscita-
16. Baldwin LM, Chan L, Andrilla CH, Huff ED, Hart LG. Quality of care for myocardial
tion systems of care will not improve process and outcome. We
infarction in rural and urban hospitals. J Rural Health 2010;26:51 7.
recommend that future efforts to evaluate the effect of regional- 17. Krumholz HM, Chen J, Rathore SS, Wang Y, Radford MJ. Regional variation in the
treatment and outcomes of myocardial infarction: investigating New England s
ization in this population should include all patients regardless
advantage. Am Heart J 2003;146:242 9.
of the putative etiology of their arrest, and should be consistent
18. Ross JS, Cha SS, Epstein AJ, et al. Quality of care for acute myocardial infarction
with the Utstein approach. Until such an evaluation has been com- at urban safety-net hospitals. Health Aff (Millwood) 2007;26:238 48.
19. Curry LA, Spatz E, Cherlin E, et al. What distinguishes top-performing hospitals
pleted, it seems reasonable to preferentially transport patients who
in acute myocardial infarction mortality rates? A qualitative study. Ann Intern
have been resuscitated from OHCA to a facility with trauma center
Med 2011;154:384 90.
designation and other facilities to enable use goal-directed ther- 20. Ross JS, Normand SL, Wang Y, et al. Hospital volume and 30-day mortality for
three common medical conditions. N Engl J Med 2010;362:1110 8.
apies including therapeutic hypothermia, primary percutaneous
coronary intervention, together with comprehensive neurological
assessment and therapy regardless of the volume of patients with
Dion Stub
OHCA that the hospital receives annually. Indeed, the emperor is
Alfred Hospital, Baker Heart and Diabetes Institute,
wearing clothes.
Melbourne, Australia
"
Graham Nichol
References
University of Washington-Harborview Center for
Prehospital Emergency Care, Seattle, WA,
1. Nichol G, Thomas E, Callaway CW, et al. Regional variation in out-of-hospital
cardiac arrest incidence and outcome. JAMA 2008;300:1423 31. United States
2. Nichol G, Aufderheide TP, Eigel B, et al. Regional systems of care for out-of-
hospital cardiac arrest: a policy statement from the American Heart Association.
"
Corresponding author.
Circulation 2010;121:709 29.
3. Cudnik MT, Sasson C, Rea TD, et al. Increasing hospital volume is not associ- E-mail address: [e-mail] (G. Nichol)
ated with improved survival in out of hospital cardiac arrest of cardiac etiology.
Resuscitation 2012;83:862 8.
29 March 2012
4. Freese J. Driving toward  cool resuscitation care. Following a successful hospital-
based hypothermia program, New York begins inducing cooling in the field. JEMS
2010;35:9 10.