Resuscitation 81 (2010) 1209–1211

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In-hospital cardiac arrest: Is it time for an in-hospital ‘chain of prevention’?

夽

Gary B. Smith

∗

Department of Critical Care, Queen Alexandra Hospital, Cosham, Portsmouth PO6 3LY, United Kingdom

a r t i c l e i n f o

Article history:
Received 21 February 2010
Received in revised form 11 April 2010
Accepted 15 April 2010

Keywords:
Education
Monitoring
Vital signs
Cardiac arrest
Rapid response system
Medical emergency team
Early warning score
Patient safety
Prevention
European Resuscitation Council
Guidelines

a b s t r a c t

The ‘chain of survival’ has been a useful tool for improving the understanding of, and the quality of the
response to, cardiac arrest for many years. In the 2005 European Resuscitation Council Guidelines the
importance of recognising critical illness and preventing cardiac arrest was highlighted by their inclusion
as the first link in a new four-ring ‘chain of survival’. However, recognising critical illness and preventing
cardiac arrest are complex tasks, each requiring the presence of several essential steps to ensure clinical
success. This article proposes the adoption of an additional chain for in-hospital settings – a ‘chain of
prevention’ – to assist hospitals in structuring their care processes to prevent and detect patient deterio-
ration and cardiac arrest. The five rings of the chain represent ‘staff education’, ‘monitoring’, ‘recognition’,
the ‘call for help’ and the ‘response’. It is believed that a ‘chain of prevention’ has the potential to be under-
stood well by hospital clinical staff of all grades, disciplines and specialties, patients, and their families
and friends. The chain provides a structure for research to identify the importance of each of the various
components of rapid response systems.

© 2010 Elsevier Ireland Ltd. All rights reserved.

1. Introduction

The ‘chain of survival’ has proven to be useful in improving the

understanding of, and the quality of the response to, cardiac arrest,
both outside and in hospital.

1

In the 2005 European Resuscitation

Council Guidelines the importance of recognising critical illness and
preventing cardiac arrest was highlighted by their inclusion as the
first link in a new four-ring ‘chain of survival’.

2

In the in-hospital

setting, patient deterioration is often insidious and potentially pre-
ventable, with failure of recognition being a frequent problem.

3,4

However, recognising critical illness and preventing cardiac arrest
are complex tasks, each requiring the presence of several essential
steps to ensure clinical success. Failures have been reported in each
of these steps, many resulting in adverse outcomes for patients.

3,4

This article proposes the use of an additional chain for in-hospital
settings – a ‘chain of prevention’ – to assist hospitals in structuring
their care processes to prevent and detect patient deterioration and
cardiac arrest.

夽 A Spanish translated version of the summary of this article appears as Appendix

in the final online version at

doi:10.1016/j.resuscitation.2010.04.017

.

∗ Tel.: [phone]; fax: [phone].

E-mail address:

[e-mail]

.

2. The ‘chain of prevention’

The proposed ‘chain of prevention’ (

Fig. 1

) consists of five rings

linked in series. As no chain is stronger than its weakest link, weak-
ness of one or more of the components (rings) of the chain will
inevitably result in failure of the whole system. This would be man-
ifest by patient deterioration and cardiac arrest. If the components
of the chain are present and strong, the chain will work perfectly,
and this should be measurable as a reduction in the number of pre-
ventable cardiac arrests. The chain and the rationale behind it are
described below.

2.1. First ring of the chain: Education

In general, such education needs to include: how to observe

patients, including vital signs measurement and recording;
interpretation of observed signs; recognition of the signs of
deterioration; the use of an early warning score (EWS) or med-
ical emergency team (MET) calling criteria; appreciating clinical
urgency; when and how to utilise simple interventions (airway
opening, oxygen therapy, intravenous fluid administration, etc.);
knowing how to seek help from other staff; successful teamwork
and organization; knowing how to use a systematic approach to
information delivery, and end-of-life care.

Evidence supporting the role of education in preventing deterio-

ration and cardiac arrest already exists. For example, virtually all of

0300-9572/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved.
doi:

10.1016/j.resuscitation.2010.04.017

1210

G.B. Smith / Resuscitation 81 (2010) 1209–1211

Fig. 1. The chain of prevention. © Gary Smith.

the observed decrease in the hospital cardiac arrest rate in an Aus-
tralian, prospective before-and-after trial of a MET occurred before
the introduction of the MET during the period when ward staff were
being educated about, and prepared for, its implementation.

5,6

Additionally in hospitals with established rapid response teams
(RRTs), the introduction of specific, objective criteria for ward staff
to activate the RRT has been associated with improved use of the
RRTs and significant reductions in cardiac arrest rates.

7,8

Recently,

a Portuguese group concluded that the effectiveness of a rapid
response system (RRS) programme “

. . .is dependent not only on

the existence of an MET but mainly on the periodic and continued
education and training of the entire hospital staff

. . .”.

9

Suitable audit criteria that would identify whether this ring of

the chain was in place might include: the presence of a specific
education programme for the recognition and management of the
acutely ill patient in the hospital

10

; the percentage of hospital staff

successfully completing such a course per annum; and the number
of staff possessing agreed levels of competencies relating to the
deteriorating patient.

11

2.2. Second ring of the chain: Monitoring

This includes patient assessment and the measurement and

recording of patient vital signs, which may include the use of elec-
tronic monitoring devices. However, evidence suggests that vital
signs monitoring occurs infrequently and that observation sets are
often incomplete. The UK report “An Acute Problem” found that
the notes of medical patients seldom contained written requests
regarding the type and frequency of physiological observations to
be measured.

4

Pulse rate, blood pressure and temperature were

the most frequently recorded variables and breathing rate the
least.

4

Improved vital signs monitoring might be achievable using

technology, but the consequence of failing to staff clinical areas
appropriately should not be minimised. Studies of nurse staffing
levels suggest that the incidence of deterioration, cardiac arrest and
failure-to-rescue is likely to be less in areas with increased levels
of trained staff, probably due to enhanced patient surveillance.

12

Improvements in monitoring can be achieved by documenting a
vital signs monitoring plan for each patient that identifies the vari-
ables to be measured and the frequency of measurement.

13

Using

an EWS and/or a MET can also increase the frequency of vital signs
measurements.

14,15

Criteria that would identify whether this ring of the chain was in

place might include the percentage of patients who have a written
vital signs plan that identifies the variables to be measured and
dictates the frequency of measurement number of patients,

13

the

number of patients whose vital signs measurements occur with
the agreed frequency and the number of vital signs datasets that
include an agreed core dataset of vital signs parameters.

2.3. Third ring of the chain: Recognition

Recognizing patient illness can be difficult, and is a common

feature of adverse incidents.

3

Improving the tools available to

staff on general wards may help them to identify better those
patients in need of additional monitoring or intervention. The
design of vital signs charts has an important role in the detection of
deterioration,

16

but, at present, the optimal layout is unknown. The

use of colour-coded or colour-banded vital signs charts are believed
to assist in the recognition of patient deterioration, but again tech-
nology may have a future role to play. Within a given institution a
starting point for improvement could be the use of a single chart
format.

Many hospitals now also use a set of predetermined ‘calling cri-

teria’ to ‘flag’ the need to escalate monitoring or to call for more
expert help. These calling criteria, or ‘track and trigger’ systems, can
be categorized as single-parameter systems, multiple-parameter
systems, aggregate weighted scoring systems or combination sys-
tems. The aggregate weighted track and trigger systems offer a
graded escalation of care, whereas single-parameter track and trig-
ger systems provide an all-or-nothing response. The performance
of these systems is variable.

17,18

A simple criterion that would identify whether this ring of the

chain was in place might be whether the hospital used either stan-
dardized calling criteria

18

or a standardized, uniform early warning

score

17

to assist ward staff in the early recognition of patient dete-

rioration for all adult patients.

2.4. Fourth ring of the chain: Call for help

All hospitals should have a universally known and understood,

mandated, unambiguous, activation protocol for summoning a
response to a deteriorating patient. The culture of the organisation
should be such that staff are never criticised for calling. However,
data from Australia has demonstrated that, even when patients
had documented physiological MET calling criteria present, the
team is not always called.

19

In such circumstances, failures to call

may result from a lack of recognition of patient deterioration, lack
of knowledge of the escalation protocol, incorrect clinical judge-
ment, a lack of confidence in escalating or worry on the part of the
caller that they might receive criticism. Using quantifiable evidence
appears to be the most effective means for nurses to refer patients
to doctors, but the use of a standardized method of communica-
tion, such as the RSVP (Reason-Story-Vital Signs-Plan) system

20

may also improve communication about patient deterioration. In
some hospitals, the RRT can be called directly by the patient’s family
or visitors; their intimate knowledge of the patient often provides
an additional method for recognizing the subtle changes of early
deterioration.

21

One criterion that would identify whether this ring of the chain

was in place might be whether the hospital uses an unambiguous,
activation protocol for summoning a response to a deteriorating
patient, such as RSVP.

20

Spot audits of clinical notes might be used

to determine the number of times that calls for help were made
after a patient’s physiology met criteria that should trigger a call
for help.

2.5. Final ring of the chain: Response

So far this is the area of practice that has seen the greatest invest-

ment in terms of time, money and education. In many countries of
the world, hospitals have attempted to solve the problem of patient
deterioration by introducing RRTs. Although several, single-centre
studies using historical control groups have suggested a positive
impact of RRTs, others have been unable to prove a benefit.

19,22

However, having recognized that a patient is deteriorating or has
deteriorated, it makes perfect sense to escalate the patients moni-
toring status and care. In certain institutions, doing so may include
calling an RRT.

G.B. Smith / Resuscitation 81 (2010) 1209–1211

1211

Criteria that would identify whether this ring of the chain was

in place might include whether a specific response team for med-
ical crises exists in the hospital, whether a team response occurs
following a call for help and the time taken from “call for help” to
team response.

3. A better alternative?

There has been a prior attempt to develop a structure for the

components necessary to prevent and respond to deterioration.

23

In June 2005, a publication resulting from the first International
Conference on Medical Emergency Teams described the essen-
tial characteristics of rapid response systems, using the concept
similar to that of the neurological reflex arc.

23

As a minimum, it

was suggested that the system should have an afferent limb (for
event detection and response triggering) and an efferent limb (the
response to identified deterioration), although two other compo-
nents – (a) an evaluative, patient safety, and process improvement
limb and (b) a governance and administrative structure – were
described.

23

To date, the use of the afferent and efferent limb con-

cepts have not been widely adopted outside the MET community.

The use of afferent and efferent limbs seems unnecessarily com-

plex, using ‘special’ terminology most appropriate for those who
understand the function of nervous system physiology. Most vital
signs are now documented by nurse aides or assistants, who may
find this concept confusing. The beauty of using a ‘chain’ concept
is that it is simple, using common everyday language. The com-
ponents – rings and links – and the consequence of ‘breaks in the
chain’ can be easily understood and memorised by all. The proposed
‘chain of prevention’ has the potential of being better understood
by hospital clinical staff of all grades, disciplines and specialties,
patients, and their families and friends.

4. Summary

This short paper proposes the introduction of a five-ringed

‘chain of prevention’ to assist hospitals in structuring their care pro-
cesses to best prevent and detect patient deterioration and cardiac
arrest. The rings represent ‘staff education’, ‘monitoring’, ‘recogni-
tion’, the ‘call for help’ and the ‘response’. It is believed that a ‘chain
of prevention’ has the potential to be understood well by hospital
clinical staff of all grades, disciplines and specialties, patients, and
their families and friends. Suggestions for auditing the robustness
of the chain are proposed.

The chain provides a structure for research to identify the impor-

tance of each of the various components of rapid response systems.

Conflicts of interest statememt

Professor Smith is a member of the Executive Committee of

the Resuscitation Council (UK) and contributed to the 2005 Euro-
pean Resuscitation Council Guidelines for Resuscitation. He is
the Director of the Acute Life-threatening Events: Recognition
and Treatment (ALERT) course, which is run by his employers,
Portsmouth Hospitals NHS Trust. His wife hold shares in The Learn-

ing Clinic Ltd., which markets an electronic vital signs capturing
and charting system (VitalPAC). VitalPAC is a collaborative devel-
opment of The Learning Clinic Ltd. and Portsmouth Hospitals NHS
Trust.

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