Rea 2010.
| Methods | Randomized controlled trial. | |
| Participants | Eligibility assessing when dispatcher's received call: Inclusion criteria: Participants who were recognized to be unconscious and not breathing normally by bystander willing to undertake CPR with the dispatcher's assistance Exclusion criteria: Participants with arrest due to trauma, drowning, or asphyxiation (from choking, strangulation, or suffocation), as well as participants who were under 18 years of age; and those who had 'do‐not‐resuscitate' status or were already receiving CPR Final eligibility determination after randomization: Participants who were unconscious and not breathing normally but were deemed not to be in arrest and persons who had a confirmed arrest but were found to have signs of irreversible death, in which case EMS personnel did not attempt resuscitation 1941 participants were included |
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| Interventions | Intervention group: the bystander was instructed to perform chest compressions alone, providing 50 consecutive compressions in one cycle. Control group: the bystander was instructed to perform chest compressions plus rescue breathing, with 2 initial rescue breaths followed by 15 chest compressions and subsequent cycles continuing the pattern in a ratio of 2 to 15 In both groups, with the dispatcher still on the telephone, the bystander then performed one cycle of CPR during which the dispatcher asked the bystander to count the chest compressions out loud. After the first cycle, the dispatcher could inquire about signs of life and, if warranted, encourage the bystander to continue CPR |
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| Outcomes | Survival to hospital discharge, ROSC at the end of EMS care, neurologic status at the time of hospital discharge (a favourable neurologic status was defined as a cerebral performance category of 1 or 2. (There are five Cerebral Performance Categories: category 1 represents good cerebral performance, 2 moderate cerebral disability, 3 severe cerebral disability, 4 coma or vegetative state, and 5 death) | |
| Notes | The study started before the guidelines for CPR changed the recommendation from 2 ventilations alternating with 15 compressions to 30 compressions alternating with 2 ventilations. The instructions in this study of 2 ventilations alternating with 15 compressions were maintained | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | This was not described in detail in the article |
| Allocation concealment (selection bias) | Low risk | If the caller was willing to undertake CPR with the dispatcher's assistance, a randomization envelope containing CPR instructions was opened |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Bystanders did not know that they were recruited in this study, so this would not have affected survival outcomes The EMS personnel and other physicians who gave advance therapy for the participants were not blinded and so care received following the arrival of EMS and other medical teams could have been affected by knowledge prior to treatment received |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | The review of EMS and hospital information was done without knowledge of participants' randomization status |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | In both groups, the missing data were 1.7 percent |
| Selective reporting (reporting bias) | Low risk | Main outcomes of out‐of‐hospital cardiac arrest were reported in full |
| Other bias | Low risk | We did not identify other sources of bias |