BLS 740 DISPATCHER RECOGNITION OF CARDIAC ARREST – CoSTR
CONSENSUS ON SCIENCE:
For the critical outcome of “cardiac arrest recognition”, we have identified very low quality evidence
(downgraded for indirectness and imprecision) from one cluster randomized controlled trial (Weiser 2013,
883), as well as very low quality evidence (downgraded for risk of bias, indirectness and imprecision) from
eight before-after observational studies (Bohm, 2007, 256; Ropollo, 2009, 769; Tanaka, 2012, 1235;
Heward, 2004, 115; Eisenberg, 1985, 47; Vaillancourt, 2007, 877; Clawson, 2008, 257; Stipulante, 2014,
177), very low quality evidence (downgraded for risk of bias, indirectness and imprecision) from nine
prospective single-arm observational studies (Cairns, 2008; Bohm, 2007, 256; Bång, 2003, 25; Dami, 2010,
848; Hallstrom, 2003, 123; Nurmi, 2006, 463; Castrén, 2001, 265; Clarke, 1984, 1022; Bång, 1999, 175),
very low quality evidence (downgraded for risk of bias, indirectness and imprecision) from eight
retrospective single-arm observational studies (Deakin, 2010, 853; Flynn, 2006, 72; Garza, 2003, 955; Ma,
2007, 236; Lewis, 2013, 1522; Kuisma, 2005, 89; Hauf, 2003, 731; Clawson, 2012, 375) and very low quality
evidence (downgraded for risk of bias and imprecision) from one case-control study (Berdowski, 2009,
2096). A total of 17,420 patients were included in these studies.
“Cardiac arrest recognition” was reported heterogeneously across the included studies, precluding the
pooling of results. Seven observational studies reported the sensitivity of dispatch protocols to recognize
cardiac arrest (Eisenberg, 1985, 47; Cairns, 2008, 349; Deakin, 2010, 853; Flynn, 2006, 72; Garza, 2003,
955; Ma, 2007, 236 and Vaillancourt, 2007, 877); the results ranged from 38% to 96.9%; with specificity
exceeding 99% in the two studies that reported this outcome (Deakin, 2010, 853; Flynn, 2006, 72).
Recognition rates of cardiac arrest ranged from 18% to 83% where reported (Bång, 2003, 25; Nurmi, 2006,
463).
The majority of the dispatch centres included in the studies utilized scripted dispatch protocols with
questions to identify patients who are unconscious and not breathing/not breathing normally. There is
very low quality evidence (downgraded for risk of bias, indirectness and imprecision) from four beforeafter studies (Heward, 2004, 115; Eisenberg, 1985, 47; Vaillancourt, 2007, 877; Stipulante, 2014, 177) to
suggest that introducing scripted dispatch protocols or modifying existing protocols can help increase
cardiac arrest recognition. One study reported an increase in cardiac arrest recognition (Heward, 2004,
115); while three reported an increase in the rates of telephone CPR following the introduction of scripted
dispatch protocols (Eisenberg, 1985, 47; Vaillancourt, 2007, 877; Stipulante, 2014, 177). One study also
reported an increase in “high acuity” calls following a modification to the seizure protocol (Clawson, 2008,
257).
Recognition of unconsciousness with abnormal breathing is central to dispatcher recognition of cardiac
arrest. Many terms may be used by callers to describe abnormal breathing: difficulty breathing, poorly
breathing, gasping breathing, wheezing, breathing, impaired breathing (Bång, 2003, 25), occasional
breathing, barely/hardly breathing, heavy breathing, laboured or noisy breathing, sighing, strange
breathing (Berdowski, 2009, 2096). Agonal breathing was reported in approximately 30% of cases in one
study (Bohm, 2007, 256), which can make obtaining an accurate description of the patient’s breathing
pattern challenging for dispatchers. The presence of agonal breathing was mentioned as a factor
negatively affecting cardiac arrest recognition in ten studies (Bohm, 2007, 256; Bång, 2003, 25; Dami,
2010, 848; Nurmi, 2006, 463; Lewis, 2013, 1522; Hauf, 2003, 731; Bohm, 2009, 1025; Ropollo, 2009, 769;
Tanaka, 2012, 1235; Vaillancourt, 2007, 877), with one study reporting that agonal breathing was present
in 50% of non-identified cardiac arrest calls (Vaillancourt, 2007, 877). Other terms reported in the studies
that may help identify possible cardiac arrest cases include “dead”, “is dead”, “cold and stiff”, “blue”,
“grey” or “pale” (Bång, 1999, 175). The aforementioned descriptions may however be limited owing to
cultural influences and language translation limitations.
There is very low quality evidence (downgraded for serious bias concerns) from three before-after studies
to suggest that offering dispatchers additional education specifically addressing agonal breathing can
increase the rates of telephone CPR (Ropollo, 2009, 769; Tanaka, 2012, 1235) and decrease the number
of missed cases (Bohm, 2009, 1025).
There is evidence from three studies (very low quality evidence, downgraded for risk of bias, indirectness
and imprecision) that failure to recognize cardiac arrest may be associated with failure to follow scripted
protocols by not asking questions about consciousness and breathing (Castrén, 2001, 265; Hallstrom,
2003, 123; Dami, 2010, 848).
TREATMENT RECOMMENDATION:
We recommend that dispatchers determine if a patient is unconscious with abnormal breathing. If the
victim is unconscious with abnormal or absent breathing, it is reasonable to assume that the patient is in
cardiac arrest at the time of the call. (strong recommendation, very low quality of evidence)
We recommend that dispatchers be educated to identify unconsciousness with abnormal breathing. This
education should include recognition of, and significance of, agonal breathing across a range of clinical
presentations and descriptions. (strong recommendation, very low quality of evidence)
Values and preferences statement: We recognize that the evidence in support of these recommendations
comes from mainly observational studies of very low quality. Large, high-quality randomized controlled
trials addressing this question are unlikely to be conducted. We believe that the available evidence shows
consistent results favouring scripted dispatch protocols and that education including a description of the
presenting signs of cardiac arrest and populations at risk (e.g. patients presenting with seizures) enables
dispatchers to identify cardiac arrest. We recognise that dispatch protocols for a range of conditions
(including but not limited to “seizures”, “breathing problems”, “chest pains”, “falls” and “unknown
problem”) optimised to identify potential cardiac arrest without undue delay my further improve early
recognition of cardiac arrest. In making these recommendations we have placed a higher value on the
recognition of cardiac arrest by dispatchers, and a lower value on the potential harms arising from
inappropriate CPR, and the potential need for increased resources. In this situation we feel the benefits
associated with increased numbers of cardiac arrest patients receiving timely and appropriate
interventions outweigh the undesirable effects (potential for patients not in cardiac arrest to
inappropriately receive chest compressions, potential need for increased resources).