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Three Part Question

In [patients suffering Out of Hospital Cardiac Arrest (OHCA)] does [Emergency Medical Services Dispatcher Assisted CPR (DA-CPR)] improve [quality of basic life support and/or clinical outcomes]?

Clinical Scenario

A 65-year-old man is found by passers by on a riverside path. He is unresponsive and not breathing. The bystanders ring 999 but do not attempt CPR. The patient has persistent asystole, no return of spontaneous circulation, and is declared dead. Would DA-CPR, or coaching from another trained third party have increased the odds of a favourable outcome?

Search Strategy

Pubmed, Cochrane and Goggle Scholar were searched.
(((((basic life support) OR (cardiopulmonary resuscitation) OR CPR OR (out of hospital cardiac arrest))) AND (coaching OR dispatcher)) AND ((quality) OR (depth) OR (rate) OR (compression*) OR (ventilation*) OR (Return of Spontaneous Circulation) OR (ROSC) OR (Length of Stay) OR (Mortality) OR (survival) OR (recovery))

Limits: Jan1998-present.

Search Outcome

Studies concerning either DA-CPR were included. Outcomes had to include the effect on quality of CPR, as measured either using data regarding the quality of basic life support, or effect on patient outcomes. Non-English papers, conference abstracts and those which exclusively examined the identification of OHCA by dispatchers, the effect of dispatcher assistance on initiation of CPR, or were conducted exclusively in children or simulated scenarios, were not included. Out of 132 results, 32 potentially relevant titles were identified, of which 6 papers directly addressed the review question and were selected for appraisal, including one systematic review.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Bohm et al. 2011 Sweden	Systematic Review of papers on bystander CPR with or without dispatcher assistance.	Papers published between 1985 and 2009 (n=5).	Primary outcome: survival to hospital discharge.	Two studies demonstrated trends towards increased survival to discharge with dispatcher coaching (11.4% and 33%, respectively). One study showed that dispatcher coaching increased survival to discharge versus no bystander CPR at all (OR 1.45) but that spontaneous bystander CPR had the highest survival overall (21.4% vs. 15.1%). Two studies showed no difference.	Few papers met inclusion criteria No results reached statistical significance Time to initiation of DA-CPR in one study was very long (average 2m38s).
Park et al 2018 South Korea	Patients with OHCA before (n=6201) and after (n=6469) intervention.	Assessed the impact of a three part intervention consisting of (1) improved DA-CPR (2) Co-Responder Dispatch to OHCA, and (3) use of CPR feedback devices.	Primary Outcomes: ROSC, Survival to Discharge, and Neurologically Favourable survival from OHCA.	The three part intervention significantly improved all outcomes including survival to discharge (10.9% vs. 9.6%; p<0.0001) Multivariate analysis revealed that compared to no bystander CPR, DA-CPR was associated with increased ROSC (OR 1.41, 95% CI 1.20—1.66); Survival to discharge (OR 1.14 95% CI 0.97—1.14); and Neurologically favourable survival (OR 1.45 95% CI 1.18—1.77).	Positive effects determined from a multivariate analysis, but this is very complex and involves a host of assumptions Uncontrolled study Not possible to measure quality of CPR
Song et al 2014 South Korea	Adult aged 15 or over with out of hospital cardiac arrest with presumed cardiac aetiology (n=8 494)	Before and after intervention study. Assessed impact of standardised DA-CPR protocol in one city	Primary outcome: survival to discharge. Secondary outcomes: survival to discharge with a favourable neurological outcome and rates of bystander CPR.	Survival to discharge increased from 7.1% to 9.4% (OR 1.12 95% CI 1.12-1.66) post- intervention. Favourable neurological outcome increased from 2.0% to 3.5% (OR 1.69 95% CI 1.21-2.37).	Uncontrolled study High loss to follow up (n=350) Quality of CPR not assessed
Wu et al 2018 Arizona, USA	Adult (18 or older) OHCA of presumed cardiac aetiology 2011-2014 (n=2310)	Retrospective observational study.	survival to hospital discharge (primary outcome) and favourable neurological status (secondary outcome)	DA-CPR resulted in improved survival (OR 1.51 95% CI 1.04—2.18) and favourable neurological outcome (OR 1.56 95% CI 1.06—2.31) compared to no CPR. There was no difference in measured outcomes between DA-CPR and spontaneously delivered bystander CPR	Significant heterogeneity between DA-CPR and other arms of study. DA-CPR protocols varied between centres.
Takahashi et al 2018 Japan	Analysis of nation wide Ustein- Japanese database 2008-2012 (n= 37,889 cases identified)	Retrospective observational study. Compared DA-CPR to spontaneous bystander CPR.	Outcomes: rate of shockable rhythm on initial ECG, ROSC in the field. Secondary outcomes: CPC 1 or 2 at 1 month.	DA-CPR increased odds of Shockable Rhythm on arrival (OR 1.75 (95% CI 1.67-1.85), ROSC (OR 1.42 (95% CI 1.33-1.52) and neurologically favourable outcome (OR 1.67 (95% CI 1.55- 1.80) compared to no CPR. Spontaneously delivered bystander CPR showed the most favourable outcomes overall.	Assumption that cardiogenic causes of OHCA all cause shockable rhythms No standard DA-CPR protocol No assessment of CPR quality
Harjanto et al. 2016 Singapore	Adults with cardiogenic OHCA 2010-2013 (n=2968)	Before and after intervention study. Assessed impact of DA-CPR training programme in Singapore.	Primary outcomes: survival to admission, 30-day survival and good functional recovery (Glasgow Pittsburgh Overall Performance Categories 1 or 2)	Only Spontaneous bystander CPR achieved significantly better improved survival to hospital admission (OR 1..39 (95% CI 1.12-1.74)), 30 day survival (OR 2.07 (95% CI 1.41- 3.02)) and Good functional recovery (OR 2.70 (95% CI 1.65- 4.40)). DA-CPR showed trends towards increase ROSC and 30-day survival compared to no CPR but did not reach significance. Those receiving spontaneous bystander CPR had better functional recovery than the no CPR group (OR 2.70 (95% CI 1.65- 4.40))	Under- powered Potential confounders (incidental introduction of a mechanical chest compression device) No assessment of CPR Quality

Comment(s)

Five of the six identified studies suggest that DA-CPR may modestly improve the odds of both survival to discharge and favourable neurological outcome from OHCA; the remaining study was under-powered to detect a statistical effect. Two studies reported that DA-CPR was inferior to spontaneously delivered bystander CPR. Explanations for the latter may include the presence of trained responders, more rapid initiation of chest compressions, and higher quality chest compressions. A single study attempted to assess quality of DA-CPR administration, on the arrival of professional EMS, and found that this was poor. The use of national registries facilitated collection of large amounts of data in all five primary research studies included. However, studies were conducted in a range of international systems where differences in dispatch and EMS response protocols may limit external validity. No prospective studies were identified. Whilst DA-CPR has some utility as a substitute for spontaneously delivered bystander CPR, available evidence suggests there is scope to improve quality before equivalence with spontaneously delivered bystander CPR if equivalence is to be assured. Further work should identify differences between DA-CPR protocols and assess comparative effectiveness in terms of quality of CPR delivered, and clinical outcomes. This may allow for the identification and adoption of more effective protocols.

Clinical Bottom Line

Current DA-CPR strategies modestly improve the odds of favourable outcome from OHCA. However, DA-CPR may be inferior to spontaneously delivered bystander CPR. Governments and healthcare organisations should maximise opportunities to undertake face-to-face training of lay people in advance, and develop/adopt evidence based protocols which optimise outcomes from DA-CPR.

References

1. Bohm K, Vaillancourt C, Charette ML, Dunford J and Castrén M. In patients with out-of-hospital cardiac arrest, does the provision of dispatch cardiopulmonary resuscitation instructions as opposed to no instructions improve outcome: A systematic review of the lit Resuscitation 2011, Vol 82, pg 1490-1495
2. Park JH, Shin SD, Ro YS, Song KJ, Hong KJ, Kim TH, Lee EJ and Kong SY. Patients with OHCA before (n=6201) and after (n=6469) intervention. Implementation of a bundle of Utstein cardiopulmonary resuscitation programs to improve survival outcomes after out-of-hospital ca Resuscitation 2018;130,;124-132
3. Song KJ, Shin SD, Park CB, Kim JY, Kim DK, Kim CH, Ha SY, Ong MEH, Bobrow BJ, McNally B. Dispatcher-assisted bystander cardiopulmonary resuscitation in a metropolitan city: A before-after population-based study. Resuscitation 2014;85;34-41
4. Wu Z, Panczyk M, Spaite DW, Hu C, Fukushima H, Langlais B, Sutter J, Bobrow BJ. Telephone cardiopulmonary resuscitation is independently associated with improved survival and improved functional outcome after out-of-hospital cardiac arrest. Resuscitation 2018;122;135-140
5. Takahashi H, Sagisaka R, Natsume Y, Tanaka S, Takyu H, Tanaka H Does dispatcher-assisted CPR generate the same outcomes as spontaneously delivered bystander CPR in Japan? American Journal of Emergency Medicine 2018;36;384-391
6. Harjanto S, Na MXB, Hao Y, Ng YY, Doctor N, Goh ES, Leong BSH, Gan HN, Chia MYC, Tham LP, Cheah SO, Shahidah N, Ong MEH A before-after interventional trial of dispatcher-assisted cardio-pulmonary resuscitation for out-of-hospital cardiac arrests in Singapore. Resuscitation 2016;102;85-93