Bystander cardiopulmonary resuscitation (CPR) is one of the most important factors for survival in patients with out-of-hospital cardiac arrest (OHCA).1–8 In Korea, approximately 60% of total OHCAs are known to occur at home.9 During these cases, middle-aged and older housewives most likely become initial witnesses of the cardiac arrest and activate emergency medical service (EMS). However, current basic life support (BLS) training does not effectively target this population,10 and the expected level of skill acquisition might be overwhelming for the elderly persons because they might need more time to understand the detailed instructions of CPR training.11
For the untrained and older populations, dispatcher-assisted (DA) or telephone-assisted CPR (T-CPR) can be an alternative to traditional training and increases the likelihood and improves the quality of bystander CPR. Previous studies have demonstrated an increase in bystander CPR rate with DA-CPR, and as a result, an increasing number of communities are implementing DA-CPR to improve the outcomes associated with OHCA.12–15 Since 2012, T-CPR protocols for calls of suspected cardiac arrest have been included in 119 emergency call dispatcher centers in Korea. The rate of bystander CPR was successfully increased after the implementation of T-CPR protocols.16
However, a previous study suggested that the quality of T-CPR performed by the older persons might be insufficient to affect patient outcome.11 This is possibly because standard BLS (S-BLS) training usually does not contain the concept and protocols of T-CPR, thus making it difficult for the callers to understand and follow the instructions given by the dispatchers. In particular, it might be more challenging for the older persons to understand the instructions given by the dispatchers via the telephone for the first time without previous T-CPR training. Therefore, in parallel with the implementation of T-CPR, we have developed a telephone-BLS (T-BLS) training program called the “Home Education and Resuscitation Outcome Study,” which emphasizes T-CPR for untrained middle-aged and older housewives. The efficacy of the T-BLS training program has not been validated in previous studies. Therefore, in this study, we aimed to compare the quality of CPR performed by middle-aged and older housewives trained with the T-BLS and by those trained with S-BLS training programs in a randomized simulation trial.
Informed consent was obtained from all participants. The study was approved by the institutional review board of the investigators' hospital.
This study used a randomized controlled simulation trial and compared the quality of CPR performed by participants after receiving different BLS training programs. All recruited participants were randomized into the S-BLS or T-BLS training group. A simulation trial was conducted to measure the CPR skill level of each participant. Simulations were performed twice for each participant immediately after initial training (November 2014) and at 6-month follow-up (May 2015) without further training.
Women older than 45 years and who were primarily stay-at-home housewives without regular income were recruited from a local church community center. Participants with previous CPR training were excluded.
The S-BLS training program is a 1-hour training course based on the American Heart Association BLS provider course. It was developed by the Korea Centers for Disease Control & Prevention. The program consists of a 30-minute video-based self-instruction (VSI) training with a mannequin for each participant and a 30-minute debriefing and practice session with course instructors (video clip accessible at https://www.youtube.com/watch?v=waXpMQgubTI). The S-BLS training program focused on detailed techniques of performing high-quality chest compressions, such as the position of the rescuer's hand and body (video clip accessible at https://vimeo.com/125781926). Although there was a debriefing and practice session, there was no role-play simulating the occurrence of cardiac arrest.
The T-BLS training program is also a 1-hour training course, consisting of a 30-minute VSI training with a mannequin. However, the video included concepts and current instruction protocols of T-CPR. It also included a bystander CPR simulation with a simulated dispatcher using his/her own cell phone. After the VSI training, participants were divided into groups of two and proceeded to role-play as dispatcher and caller for 15 minutes. After this activity, a 15-minute debriefing session with the instructors was performed.
In both training courses, compression-only CPR was taught, and the importance of high-quality chest compressions with adequate depth and rate and minimization of interruptions during CPR were emphasized. The concept of T-CPR was not included in the S-BLS training program. In the S-BLS training program, knowledge regarding the recognition of cardiac arrest and methods of delivering proper chest compressions were emphasized. However, in the T-BLS training program, simple recognition and teamwork with the dispatcher were emphasized. A comparison of the two BLS training programs is shown in Table 1.
Participants were trained together according to the allocated type of training. Immediately after training session, participants were guided to a separate room for the simulation experiment one participant at a time. The other participants stayed in the waiting area where they were not able to observe the simulation experiment. At the 6-month follow-up, each participant was guided to the room for the same simulation experiment without any additional training. A mannequin simulator was located in the room for the simulation experiment.
The participants were told to consider the mannequin as a family member who collapsed in their home. The simulation scenario (Fig. 1) started with the detection of the collapsed victim on the floor by the participant. Instead of dialing 119, the national emergency hotline in Korea, the participants were instructed to dial an investigator of the study who acted as an emergency dispatcher. The investigator was located in a separate room and was therefore blinded from the randomization of the training group. The investigator's phone number was provided before the simulation and saved in the participants' cell phones for convenience of calling. The investigator responded to a call as if she were an emergency dispatcher, according to the protocol of the current emergency dispatcher system in Seoul. Telephone-assisted CPR instructions according to current dispatching protocols were given to participants regardless of training type. The investigator encouraged the participants to perform high-quality CPR by counting chest compressions with optimal speed and by giving intermittent feedback with encouragement just like a real dispatcher.
After 5 minutes from the time of the emergency call, which is the average response time of EMS ambulance in Seoul, the participants were told that EMS has arrived at the scene and the simulation ended.
Data Collection and Measurement
A Resusci Anne QCPR mannequin supported with a skill reporting system (Laerdal, Stavanger, Norway) was used in simulation. The mannequin measures the quality of chest compressions performed by participants, including chest compression depth, chest compression rate, and no-flow time. All collected data were transported wirelessly and recorded in a tablet computer. For further statistical analysis, the data were extracted and imported into Microsoft Excel spreadsheet. Cardiopulmonary resuscitation quality was measured from time of emergency call to end of simulation. All simulations performed were video recorded and reviewed for protocol violations by an independent investigator blinded from subject group assignment. Adequacy of chest compression rate and depth was defined as compression depth more than 5 cm and rate between 100 and 120 per minute according to the 2010 European Resuscitation Council and American Heart Association guideline.3,17 No-flow time was defined as more than 1.5 seconds without chest compressions.18 Total no-flow time was calculated by adding collapse-to-call time, call-to-first-compression time, and cumulative interruption time. Collapse-to-call time was measured retrospectively by video analysis by the instructor. Call-to-first-compression time and cumulative interruption time were calculated from data recorded by the simulation mannequin (Fig. 1).
The main outcome of the study is total no-flow time during simulations. Total no-flow time, collapse-to-call time, call-to-first-compression time, and cumulative interruption were compared between the two groups. Mean depth and rate of chest compressions and proportion of adequate depth and rate of chest compressions throughout the simulation were also compared.
Based on our previously conducted pilot study, to test the mean 30-second reduction in no-flow time with 80% power and significance level at 0.05, at least seven participants in each training group were needed. Continuous variables were compared with mean and standard deviation using Student t test or median with interquartile range (IQR) using Mann–Whitney U test. Categorical variables were compared using a χ2 test. Statistical analysis was performed using Stata, Version 12 (StataCorp, College Station, TX).
Twenty-four middle-aged and older full-time housewives without previous CPR training were recruited and underwent randomization. Demographics of participants according to randomized group are shown in Table 2. During initial simulation immediately after training, two participants (8.3%) who experienced mechanical failure of data transmission and storage in resuscitation mannequin and one participant (4.2%) who violated simulation protocols were excluded. Two participants (8.3%) in the S-BLS training group refused to respond at 6-month follow-up. Overall, 19 participants completed the simulation at 6-months of follow-up (8 in the S-BLS training group and 11 in the T-BLS training group) (Fig. 2).
Overall CPR performance of participants during simulation is summarized in Table 3. Median (IQR) total no-flow time during initial simulation was 79.6 (66.4–96.9) seconds for the T-BLS training group and 147.6 (122.5–184.0) seconds for the S-BLS training group (P < 0.01). At the 6-month follow-up simulation, median total no-flow time was significantly shorter in the T-BLS than in the S-BLS training group (119.0 vs. 169.0, P = 0.02).
Median cumulative interruption time and median number of interruption events at initial and at 6-month follow-up simulation were significantly shorter in the T-BLS than in the S-BLS training group (1.0 vs. 9.5, P < 0.01, and 1.0 vs. 10.5, P = 0.02, respectively).
More chest compressions were performed during simulation in the T-BLS than in the S-BLS training group. Mean proportions of chest compressions with adequate depth seemed to be lower in the T-BLS than in the S-BLS training group but were not statistically significant (12.1 vs. 23.7, P = 0.41, at initial simulation and 35.0 vs. 24.4, P = 0.87, at 6-month follow-up). There was also no significant difference in mean proportion of chest compression with adequate rate.
Improvement in quality of CPR through T-BLS training was shown in middle-aged and older housewives without previous CPR education immediately and 6 months after the training. Although the effectiveness of T-CPR in improving the rate of bystander CPR is well known by previous studies,12,13,16 provision of high-quality bystander CPR with assistance via telephone is another important issue to improve patient outcome.7 In our study, the difference in no-flow time was most prominent in cumulative interruption time during simulation. Shorter and fewer interruptions during CPR suggest higher quality of CPR performance. We developed a new public BLS training program for middle-aged and older housewives focusing on teamwork between the bystander and emergency dispatcher, and we showed its efficacy in a simulation trial.
There could be several reasons for the high-quality CPR performance observed in the T-BLS training group. One reason could be the emphasis of teamwork between the caller and dispatcher in T-BLS education. In T-BLS training, the participants were trained to understand that bystander CPR is not a process performed only by the caller in the scene but a process performed by both the caller and dispatcher and communicating with each other. Therefore, we believe that callers tend to perform uninterrupted constant CPR according to the feedback and encouragement given by the dispatcher. Continuous feedback by phone has been previously shown to help sustain the quality of bystander CPR.19 Although the same type of feedback was given to participants in both groups by the instructor who was blinded from randomization, the T-BLS training group had higher compliance with the dispatcher's feedback than the S-BLS training group, which resulted in fewer interruptions and shorter cumulative interruption time during bystander CPR. Another reason could be familiarity with protocol and process of T-CPR in participants trained with T-BLS training program. For individuals who are performing CPR through telephone instruction for the first time, it might be difficult for them to follow the instructions if they are not familiar with protocols. Therefore, familiarity to local protocols might have led to the high comprehensibility of T-CPR instructions, even though they were delivered through telephone.
Telephone-assisted CPR might be increasing confidence of laypersons in initiating and performing CPR, thus increasing CPR rates. Bystander CPR rate is known to be low when the victims are family members of bystanders.20 In a previous study,21 interviewed spouses' experiences of witnessing their partners having cardiac arrest at home demonstrated the lack of confidence in detecting the early warning signs of cardiac arrest. This lack of confidence also extended to the process of CPR. Therefore, in the T-CPR protocol, the dispatcher evaluates and decides for the callers whether the patient needs immediate initiation of BLS after they answer two key questions: (1) Is the patient conscious? and (2) Is the patient breathing normally?16 With a firm decision and instruction from the dispatcher, early initiation of BLS to patients with ambiguous symptoms of cardiac arrest can be possible, even when they are witnessed by elderly bystanders with low ability of recognizing cardiac arrest. The results of our study suggest that a tailored BLS education based on local T-CPR protocol for a specific population can be an effective strategy to improve quality of bystander CPR.
In our study, although participants in both groups generally did not produce adequate chest compression depth and rate, no-flow time was significantly shorter in the T-BLS training group than in the S-BLS training group. Although a previous simulation study reported that even elderly laypersons can successfully perform CPR with acceptable quality for 10 minutes,22 performing CPR alone for 5 minutes is challenging, especially for middle-aged and elderly bystanders, due to physical factors. In addition, for participants to have lesser interruptions during chest compressions, they have to perform a required number of chest compressions, which might be associated with rescuer fatigue. However, we believe that performing chest compressions is better than no chest compression at all. To overcome the physical barriers of middle-aged and older populations, further studies are warranted to find ways to improve the quality of chest compressions and guarantee better survival outcomes.
Our study has a few limitations. First, although the sample size was calculated based on our previously conducted pilot study, the present simulation trial had a relatively small sample size. Extrapolation to real-life practice should be carefully considered. Future studies should be planned with a larger sample size. Second, although randomization was done properly when allocating participants into each training group, the mean age was higher in the S-BLS training group, which might have biased the study results.
Middle-aged and older participants trained with the T-BLS training program showed lower no-flow time in a simulation trial of witnessed cardiac arrest. Future survival outcome analysis should be considered to measure the effect of BLS training tailored based on real dispatch protocols of the community.
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Keywords:© 2018 Society for Simulation in Healthcare
Telephone CPR; Basic life support; Cardiac arrest