Table 1.

Search outcomes.

Authors, date and country	Study type, methods and outcomes (where stated)	Description of included studies/population	Key results
Bohm, Vaillancourt, Charette, Dunford, & Castrén, 2011, Sweden	Systematic review. Review of papers on bystander CPR with or without dispatcher assistance. Primary outcome: survival to hospital discharge.	Papers published between 1985 and 2009 (n = 5).	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 vs. 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.
Park et al., 2018, South Korea	Before and after intervention study. Assessed the impact of a 3-part intervention consisting of (1) improved DA-CPR, (2) co-responder dispatch to OHCA and (3) use of CPR feedback devices. Primary outcomes: return of spontaneous circulation (ROSC), survival to discharge and neurologically favourable survival from OHCA.	Patients with OHCA before (n = 6201) and after (n = 6469) intervention.	The 3-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).
Song et al., 2014, South Korea	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.	Adult aged 15 or over with out-of-hospital cardiac arrest with presumed cardiac aetiology (n = 8494).	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).
Harjanto et al., 2016, Singapore	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).	Adults with cardiogenic OHCA 2010–2013 (n = 2968).	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 increased rates of 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)).
Ro et al., 2017, South Korea	Prospective observational study using national database. Primary outcome ‘good neurological recovery’ at discharge, defined as cerebral performance category (CPC) 1 or 2. Secondary outcomes were survival to discharge and ROSC.	Adults (18 or older) OHCA of presumed cardiac cause 2012–2014 (n = 37,924).	DA-CPR resulted in increased incidence of CPC 1 or 2 versus no bystander CPR (4.8% vs. 2.1%) but spontaneously delivered bystander CPR was better (5.2%). An identical pattern was observed in relation to survival to discharge (7.3% DA-CPR vs. 8.4% SD-CPR vs. 4.8% no CPR) and ROSC (5.3% vs. 5.9% vs. 2.5%).
Wu et al., 2018, United States	Retrospective observational study. Assessed impact of DA-CPR on survival to hospital discharge (primary outcome) and favourable neurological status (secondary outcome).	Adult (18 or older) OHCA of presumed cardiac aetiology 2011–2014 (n = 2310).	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.
Takahashi et al., 2018, Japan	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.	Analysis of nationwide Utstein Japanese database 2008–2012 (n = 37,889 cases identified).	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.