For the critical outcome of survival with favorable neurologic outcome, we have identified very-low-quality evidence from 2 RCTs,(Hallstrom 2000, N190; Rea 2010, 423) 2 cohort studies,(Akahane 2012, 1410; Goto 2014, e000499) and 1 before-after study.(Tanaka 2012, 1235) The level of evidence was downgraded for risk of bias, indirectness, and imprecision. Four studies reported no benefit in neurologic outcomes.(Hallstrom 2000, N190; Rea 2010, 423) (Akahane 2012, 1410; Goto 2014, e000499) The before-after study, which included dispatcher instructions to start compression-only CPR as part of a bundle of interventions used as part of a quality improvement initiative, noted improved neurologic outcomes at 12 months (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.2–2.76).(Tanaka 2012, 1235) For the critical outcome of survival, we identified very-low-quality evidence from 3 RCTs.(Hallstrom 2000, N190; Rea 2010, 423; Svensson 2010, 434) The level of evidence was downgraded for risk of bias, indirectness, and imprecision. Meta-analysis of these trials found an absolute survival benefit of 2.4% (95% CI, 0.1%–4.9%) in favor of telephone-assisted continuous chest compressions over telephone-assisted traditional CPR (number needed to treat, 41; 95% CI, 20–1250; relative risk [RR], 1.22; 95% CI, 1.01–1.46).(Hupfl 2010, 1552)We also identified 6 before-after studies.(Eisenberg 1985, 47; Culley 1991, 362; Vaillancourt 2007, 877; Bray 2011, 1393; Tanaka 2012, 1235; Stipulante 2014, 177) One study was inconsistent with the others and found decreased survival, although it was not powered to evaluate survival outcomes.(Vaillancourt 2007, 877) One study showed a survival benefit at 1 year (population of 73 patients) from an educational program for dispatchers on continuous chest compressions and agonal breaths (adjusted OR, 1.81; 95% CI, 1.20–2.76).(Tanaka 2012, 1235) We also identified 5 cohort studies.(Bang 1999, 175; Rea 2001, 2513; Kuisma 2005, 89; Akahane 2012, 1410; Goto 2014, e000499) One study showed a survival benefit at 30 days when, after an educational program, telephone-assisted CPR was provided to a pediatric out-of-hospital cardiac arrest (OHCA) population versus not (adjusted OR, 1.46; 95% CI, 1.05–2.03).(Akahane 2012, 1410) A second cohort study in the pediatric (less than 18 years of age) population showed survival benefit at 30 days when telephone-assisted CPR was provided (adjusted OR for group not receiving CPR, 0.70; 95% CI, 0.56–0.88).(Goto 2014, e000499) For the critical outcome of ROSC, we identified very-low-quality evidence from 1 RCT(Rea 2010, 423) and 1 before-after study.(Vaillancourt 2007, 877) The studies were downgraded for indirectness and imprecision. Neither study showed a statistically significant benefit.For the important outcome of delivery of bystander CPR, we identified very-low-quality evidence from 6 before-after studies: 1 study compared 2 medical priority dispatch system versions,(Bray 2011, 1393) 3 studies compared telephone-assisted CPR versus not,(Eisenberg 1985, 47; Culley 1991, 362; Vaillancourt 2007, 877)and 2 studies(Tanaka 2012, 1235; Stipulante 2014, 177) compared various educational programs. In addition, we identified 1 cohort study.(Akahane 2012, 1410) The level of evidence was downgraded for indirectness and imprecision. All showed a strong association between telephone-assisted CPR and bystander CPR. The cohort study showed increased performed chest compressions (adjusted OR, 6.04; 95% CI, 4.72–7.72) and ventilation (adjusted OR, 3.10; 95% CI, 2.44–3.95) from telephone-assisted CPR, and an absolute increase in bystander CPR rate of 40.9% (95% CI, 36.1–45.5).(Akahane 2012, 1410) For the important outcome of time to commence CPR, we have identified very-low-quality evidence from 4 before-after studies(Eisenberg 1985, 47; Culley 1991, 362; Tanaka 2012, 1235; Stipulante 2014, 177) and 1 cohort study.(Rea 2001, 2513) The level of evidence was downgraded for risk of bias, inconsistency, indirectness, and imprecision. None of these reported a statistically significant benefit. For the important outcome of CPR parameter, assessed with initial rhythm of ventricular fibrillation (VF)/ventricular tachycardia (VT), we have identified very-low-quality evidence from 1 RCT(Svensson 2010, 434) and 1 before-after study.(Vaillancourt 2007, 877) The studies were downgraded for risk of bias, indirectness, and imprecision. Neither study showed a statistically significant benefit.