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Laypersons may learn basic life support in 24 min using a personal resuscitation manikin
Resuscitation (2006) 69, 435—442
TRAINING AND EDUCATIONAL PAPER
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin夽 Dan Lou Isbye a,∗, Lars Simon Rasmussen a, Freddy Knudsen Lippert a, Søren Finnemann Rudolph a, Charlotte Vibeke Ringsted b a
Department of Anaesthesia, Section 4231, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark b Centre of Clinical Education, University of Copenhagen and Copenhagen University Hospital, Rigshospitalet, Denmark Received 24 August 2005 ; received in revised form 21 October 2005; accepted 28 October 2005 KEYWORDS Adult; Cardiac arrest; Bystander CPR; Basic life support (BLS); Manikin; Training
Summary Background: Bystander basic life support (BLS) is an important part of cardiopulmonary resuscitation (CPR) and improves outcome after out-of-hospital cardiac arrest. However, the general population has poor BLS skills. Several training initiatives could be used to improve this situation and the challenge is to find the most efficient one. Aims: To compare the efficiency of a 24 min instruction using a DVD-based selftraining BLS course combined with a simple, take-home resuscitation manikin to a conventional 6 h course for teaching BLS to laypersons. Methods: In total, 238 laypersons (age 21—55 years) without previous BLS-training were allocated into two groups: one group received 24 min of instruction using a DVD-based instruction tool on a big screen combined with a BLS self-training device, Laerdal MiniAnne manikin (MAM), before taking home the instruction material for subsequent self-training. The second group attended a conventional 6 h BLS course (6HR). After 3 months BLS skills were assessed on a Laerdal ResusciAnne manikin using the Laerdal PC Skill reporting System, and a total score was calculated. Results: There was no significant difference between groups in BLS performance using the total score. Assessment of breathing was performed significantly more often in the 6HR-group (91% versus 72%, P = 0.03). In the MAM-group, average inflation volume and chest compression depth were significantly higher (844 mL versus 524 mL, P = 0.006, and 45 mm versus 39 mm, P = 0.005). Conclusions: When assessed after 3 months, a 24 min DVD-based instruction plus subsequent self-training in BLS appears equally effective compared to a 6 h BLS course and hence is more efficient. © 2005 Elsevier Ireland Ltd. All rights reserved.
夽 A Spanish translated version of the abstract of this article appears as Appendix in the online version at 10.1016/j.resuscitation.2005.10.027. ∗ Corresponding author. Tel.: +45 35453487; fax: +45 35452950. E-mail address: [email protected] (D.L. Isbye).
0300-9572/$ — see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2005.10.027
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Introduction
Materials and methods
The initial management of cardiac arrest is based upon the concept of the ‘‘Chain of Survival’’ where each link influences survival: early access, early basic life support (BLS), early defibrillation and early advanced cardiac life support (ALS). Success of the two first links depends on several factors: where the arrest takes place, whether bystanders witness the arrest, the bystanders’ ability to recognise the arrest, to call the emergency medical service and finally to perform BLS.1 The survival rate after cardiac arrest increases when cardiac arrest takes place in a public place and is witnessed.2,3 When bystander BLS is initiated the survival rate is doubled.3,4 There is no standardised way to teach BLS to laypersons and several organisations offer courses. Such courses usually last for 4—6 h, are instructor-based, and use one or two resuscitation manikins for practicing BLS. The duration of the courses and the costs of manikins and instructors are probably factors that inhibit general dissemination of BLS training. Another problem is retention of the acquired BLS-skills after a course. McKenna and Glendon studied BLS skill retention up to 3 years after training.5 Less than 10% of the subjects performed at least 75% of the skills correctly, and it was estimated that few if any patients in cardiac arrest would benefit from the resuscitation attempts. Most probably the poor retention is explained by that fact that BLS is used infrequently and rarely refreshed. Training to a higher level of acquired skills at the end of a course and the possibility to refresh the skill improve retention over time.6 Short selfactivating courses without the use of an instructor seem to improve performance immediately after the course, but no lasting effects have been reported.7—9 Recent studies have emphasised the need for instructional methods, which can raise the level of BLS performance or reduce instructional time while preserving performance level over time.10,11 The aim of this study was to compare the efficiency of a 24 min DVD-based self-training BLS course combined with a simple, take-home resuscitation manikin to a conventional 6 h course for teaching BLS to laypersons. We hypothesised that BLS learned in 6 h would result in better skill retention after 3 months than BLS learned in 24 min.
We recruited 238 laypersons, employed in the bankand insurance business, who had not received BLS training within the last 5 years. The participants knew, before volunteering, that they would receive BLS training, but did not know that there were different courses. The participants were divided into two groups, and for practical reasons this was based on which firm they worked for. The first group received 24 min of instruction on a DVD-based resuscitation course combined with an inflatable resuscitation manikin MiniAnne (Laerdal Medical, Stavanger, Norway, Figure 1), which participants kept after the course for additional training at home, with the possibility to train relatives and friends. The training was done in four consecutive sessions using a big screen with 47—50 participants. Five facilitators were present for each session to assist the participants if technical problems arose. The second group received a 6 h instructor-based resuscitation course. This was done in four courses with 10—12 participants, using one instructor and two Ambu Man model C manikins (Ambu International, Ballerup, Denmark). Adult BLS was taught in accordance with European Resuscitation Council (ERC) Guidelines 2000 in both courses. The contents of the two courses are summarized in Table 1. After 3 months all participants were called in without notice while at work, for a 5 min skill retention assessment in a dedicated room.
Figure 1 The MiniAnne personal resuscitation manikin (Laerdal Medical, Stavanger, Norway). Around the manikin from left and clockwise: 24 min instructional DVD, instructional leaflets, 70% ethanol single use manikin wipes, cardboard mobile phone, storage box, protective kneepads, and CPR-Coach.
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin
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Table 1 Contents of the 24 min DVD developed by Laerdal Medical in cooperation with TrygFonden (Denmark) and contents of the conventional 6 h course developed by the Danish Red Cross 24 min of DVD-instruction together with MiniAnne personal resuscitation manikin 00:00 04:00 06:00 08:45 10:45 14:45 17:00 19:45 21:15 22:30 24:00
Introduction case reported by out-of-hospital cardiac arrest survivor and lay responder How to make MiniAnne ready for use Cardiac compressions—–theory and practice Ventilations—–theory and practice Combined ventilations and compressions ratio 2:15—–practice Check responsiveness, check breathing and alarming—–theory Entire BLS-algorithm—–practice CPR-Coach to get compression depth and pace correct—–practice Encouragement to use MiniAnne at home to train friends and relatives How to clean MiniAnne after use The end
Conventional 6 h instructor-based resuscitation course Part 1 (3 h) Theory—–Introduction to first aid; stop the accident and moving the injured patient; life-saving first aid; the vital oxygen-transport; state of consciousness; first aid to the unconscious but breathing patient; alarming; basic first aid; myocardial infarction; symptoms of cardiac arrest; the technique of ventilations and compressions Practice—–basic first aid Part 2 (3 h) Theory—–basic life support in the adult and child Practice—–basic life support in the adult Practice—–first aid and basic life support scenarios in the adult The program for the 6 h course is a suggestion to the instructor and it is emphasised that weight should be put on teaching practical skills.
The participants were told that an adult had collapsed in front of them while standing in a public place, with others not familiar with BLS and they were told to act as they would in a real situation. This included not explaining the procedure to the investigator who was present. The assessment was performed with the ResusciAnne manikin and the Laerdal PC-Skill Reporting System version 2.0 (Laerdal Medical, Stavanger, Norway) was used to record the overall time, time delay to first rescue breath or compression, total number of ventilations, average ventilation volume, total number of compressions, average compression depth, hand position, ventilation-compression ratio, and total ‘hands off’ time. In addition qualitative assessment was made by investigators who recorded the variables ‘checks responsiveness by talking and shaking’, ‘opens airway’, ‘checks respiration’ and ‘calls for help’. The group of investigators consisted of one nurse anaesthetist, two final year medical students, two junior physicians, and two consultant anaesthesiologists. Investigators were blinded for which type of training the participant had received. Quantitative data from Laerdal PC-Skill Reporting System version 2.0 and qual-
itative data from the investigators were registered on a form and subsequently entered into a database. To assess the overall BLS performance, points were given in a scoring system (Table 2) developed from the Cardiff test.12 Theoretically the total score could be from 12 to 52 points. The primary endpoint was the total score. Exact values of the different variables in the two groups were compared as well. Before the assessments it was decided that - calling for help should be done within the first minute; - delay was defined as the time in seconds before the first rescue breath or compression was recorded by the computer; - hand position was incorrect if one compression was in the wrong position. This was decided because it only takes one compression in the wrong place to fracture the xiphoid process of sternum; - correct ventilation—compression ratio was 2:15 ± 1; - participants unable to ventilate the manikin but who attempted a ratio of 2:15 were registered
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Table 2 Assessment of basic life support skills in laypersons 3 months after a 6 h course (6HR) or a 24 min course using a personal resuscitation manikin (MAM) Score
MAM (N = 156)
6HR (N = 36)
Checks responsiveness by talking 2: Yes 94 (60%) 1: No 62 (40%)
20 (56%) 16 (44%)
Checks responsiveness by shaking 3: Yes 102 (65%) 2: No 51 (33%) 1: Unacceptable 3 (2%)
25 (69%) 11 (31%) 0 (0%)
Opens airway—–head tilt, chin lift 5: Perfect 30 (19%) 4: Acceptable 23 (15%) 3: Attempted other 6 (4%) 2: Only one element 14 (9%) 1: No 83 (53%)
4 (11%) 7 (19%) 3 (8%) 3 (8%) 19 (53%)
Checks respiration—–see, listen and feel 2: Yes 112 (72%) 1: No 44 (28%)
32 (89%) 4 (11%)
Calls for help or dials 1-1-2 2: Yes 88 (56%) 1: No 68 (44%)
11 (31%) 25 (69%)
Total ventilations counteda 6: 31—40 19 (12%) 5: 21—30 48 (31%) 4: > 40 3 (2%) 3: 11—20 39 (25%) 2: 0—10 43 (28%) 1: Not attempted 2 (1%)
6 (18%) 9 (26%) 1 (3%) 9 (26%) 9 (26%) 0 (0%)
Average ventilation volume (mL) 7: 700—1000 31 (20%) 6: 1001—1300 25 (16%) 5: 400—699 32 (21%) 4: >1300 40 (26%) 3: 1—399 3 (2%) 2: 0 23 (15%) 1: Not attempted 2 (1%)
7 (19%) 4 (11%) 13 (36%) 2 (6%) 5 (14%) 5 (14%) 0 (0%)
a
Total compressions counted 6: 251—350 5 (3%) 5: 201—250 28 (18%) 4: >350 0 (0%) 3: 101—200 94 (61%) 2: 1—100 27 (18%) 1: Not attempted 0 (0%)
2 (6%) 4 (12%) 0(0%) 18 (53%) 10 (29%) 0 (0%)
Average compression depth (mm) 6: 40—50 61 (39%) 5: 51—55 34 (22%) 4: 24—39 43 (28%) 3: >55 9 (6%) 2: 1—24 9 (6%) 1: Not attempted 0 (0%)
12 (33%) 3 (8%) 14 (39%) 1 (3%) 6 (17%) 0 (0%)
Hand-position during compression 4: Correct 25 (16%) 3: Other wrong 41 (26%)
7 (19%) 8 (22%)
Table 2 (Continued ) Score
MAM (N = 156)
6HR (N = 36)
90 (58%) 0 (0%)
21 (58%) 0 (0%)
Ventilation/compression ratio 4: 2:15 (2:14—16) 92 (58%) 3: Other 62 (40%) 2: Compressions only 2 (1%) 1: Ventilations only 0 (0%)
17 (47%) 19 (53%) 0 (0%) 0 (0%)
Total ‘Hands Off’ time (s)a 5: 1—60 0 (0%) 4: 61—120 0 (0%) 3: 121—180 62 (40%) 2: 181—240 79 (51%) 1: 241—300 13 (8%)
0 (0%) 1 (3%) 7 (21%) 21 (62%) 5 (15%)
2: Too low 1: Not attempted
Combined Scorea,b
35 (32—38)
34 (31—38) test.12
Scoring system derived from the Cardiff In the far left column are seen the points assigned for each level of skill retained after 3 months. Frequency of each single score in the two groups is shown in middle and right column. Combined score is reported with median (25—75% range) and Mann Whitney Rank sum test is used to calculate P-value. a Due to technical difficulties two persons from each group was taken out of calculations in ‘Total ventilations, total compressions, Hands Off time and combined score’. b P = 0.41.
as such because they apparently had learned the skill for ratio; - ‘Hands Off’ time was when compressions were not being performed; - ideally BLS should be initiated within 30 s, which would give 4.5 min for ventilations and compressions. In this period an estimated 18 cycles of 2:15 could be completed and result in 36 ventilations and 270 compressions. For statistical analysis the SAS System (SAS Institute Inc., Cary, USA) was used. For continuous data, we reported a median with 25—75% range and Mann Whitney Rank sum test was used for comparison of groups. For non-continuous data we reported proportions and Chi square test was used for comparison. P-values less than 0.05 were considered statistically significant. Sample size was calculated as follows: We aimed at recognising a difference of three points in the total score as this corresponds to the difference between perfect and unacceptable performance if applied on one of the two variables ‘total number of ventilations’ and ‘total number of compressions’. The scoring system was tested in a pilot study and a S.D. of approximately seven points was found. Using a power of 90% and a significance level of 0.05 we had to include 200 participants. We estimated that
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin it was impossible to recruit this number of volunteers at the insurance company in which the project was originally planned to take place. Therefore, we recruited additional participants from a cooperating banking company. It was then decided that the MiniAnne should be distributed in the insurance company, and, for financial reasons, the smaller group of additional participants were offered the more expensive 6 h course. Subsequently the two groups became different in size and we decided on aiming to include 250 participants to compensate for this difference.
Results In total 238 responded positively to the invitation to participate. The MiniAnne manikin (MAM)-group consisted of 141 women (73%) and 53 men (27%) while the 6 h (6HR)-group consisted of 32 women (73%) and 12 men (27%). Mean age in the MAM-group was 37 years (range 22—51 years), while it was 40 years (range 21—55 years) in the 6HR-group. Fortysix participants (MAM-group 38 (20%); 6HR-group 8 (18%)) did not meet for testing after 3 months. In the MAM-group 14 of the 38 declined participation because of lack of interest. The rest just never attended although given several opportunities. In the 6HR-group we were unable to obtain any reasons for not participating. The final group consisted of 192 laypersons (Figure 2).
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Technical difficulties occurred in four instances during the assessments, which led to exclusion of the affected variables, but not of the assessment as a whole. There was no significant difference between the two groups when looking at the total score. Considering that 12—52 points could be given, the MAMgroup achieved 57.5% of the maximum score while the 6HR-group achieved 55% (Table 2). The 6HR-group performed significantly better than the MAM-group in checking for respiration (P = 0.03). The MAM-group performed significantly better than the 6HR-group in calling for help (P = 0.005). Time delay (s) to first rescue breath or compression was 33.5 (23—45) in the MAM-group, and 39.5 (29.5—46) in the 6HR-group, P = 0.15. ‘Hands Off’ time in seconds was 188.5 (170—208) in the MAM-group and 199 (181—219) in the 6HRgroup, P = 0.08. The average ventilation volume (mL) was significantly higher in the MAM-group (843.5 versus 524, P = 0.006) but the proportion of participants with an average ventilation volume between 400 and 1300 mL was not different (MAM 57% versus 6HR 66%, Table 2). Average compression depth (mm) was also significantly higher in the MAM-group (45 versus 38.5, P = 0.005), and 61% of the MAM-group had an average compression depth between 40 and 55 versus 41% in the 6HR-group, P = 0.06 (Table 2). The computer recorded a wrong hand position during compressions in more than 80% of the par-
Figure 2 Flow chart on the inclusion of participants.
440 ticipants (MAM 84%, 6HR 81%; P = 0.82) and 58% in both groups made at least one compression that was too low on the sternum.
Discussion The most important finding in this study was that there was no significant difference in the overall performance of basic life support between a 24 min course and a 6 h course. It is interesting that basic life support may be learned in a course of such short duration. If the same quality is achieved in less time, the 24 min course is more efficient basic life support training. It could be argued that a 6 h course is a rather long time for learning BLS, and in the conventional course attention is also drawn to other aspects of first aid such as treatment of the unconscious but breathing patient. However, around four of the 6 h are used for BLS theory and practice (Table 1). In the MAM-group, ‘‘hands off time’’ and time delay to first rescue breath or compression tended to be lower and in this group, average compression depth and average ventilation volume were significantly higher. Thus, hands-on skills seem to be better retained, when they are taught with a larger amount of self-activation in the learning process and the possibility to refresh skills when needed. In both groups, close to two thirds of the 5 min skill retention assessment was without compressions and subsequently without perfusion pressure. It is unknown whether the performance of the participants in reality would increase survival in out-ofhospital cardiac arrest, with both groups only scoring slightly above 50% of the maximum score. Survival increases when bystander CPR is performed, but we have no way of knowing how well these lay rescuers perform. We find it remarkable that the 6HR-group performs better than the MAM-group in one of first manoeuvres; ‘checking for respiration’. The reason for this could be that over a 6 h course, motivation for learning is high at the beginning and slowly deteriorates with time. This could result in better retention of skills learned at the beginning while skills learned later on in the course might be forgotten more easily. Against this hypothesis one could argue that the skill, ‘open airway’, is taught before the skill, ‘check respiration’, and is forgotten by more than half in both groups, thus eliminating the full effect of checking respiration. We found that the MAM-group called for help significantly more often than the 6HR-group, but this variable is difficult to evaluate in a simulation assessment where setting and environment are
D.L. Isbye et al. obviously unnatural. It is to be expected that nearly everybody would consider calling for help immediately if they encountered a person in cardiac arrest in real life. In both groups about 85% were able to ventilate during the skills assessment. This argues against not ventilating during basic life support simply on the grounds that the skill is too difficult for laypersons. We found it interesting that more than 80% of all the participants assessed used an incorrect hand position. In both groups 58% used too low a hand position, which could fracture the xiphoid process of the sternum of a patient. This finding could be due to overly sensitive sensors in the manikin, but during our pilot study we found very few using incorrect hand position. It can be discussed whether just one compression in the wrong place is enough to obtain a lower score. The groups were both instructed to identify the correct place for compression by locating the umbilicus, then moving a finger up to the xiphoid process of the sternum, then placing two fingers above the process, and finally placing the hands for compressions. This is a very complex method that is probably hard to remember. We suspect that there is room for improvement in teaching of hand position during compressions in both groups. We found that about 20% of the participants in both groups did not attend for the assessment after 3 months, even after several attempts to include as many as possible. Probably many of the participants declining the 3 months assessment felt insecure in their ability to perform BLS. We could have asked the participants in the MAM-group if they had used the manikin at home for additional training or for training family and friends. We chose not to, as the reliability of the answers could not be validated. For logistical reasons, we were unable to randomise the participants who instead were allocated into the two groups by which company they worked for. The small demographic differences between the two groups are unlikely to have influenced the results. The study design could have been stronger if inclusion criteria had been ‘never received BLS training’ instead of ‘not within the last 5 years’. Using the 5 years criteria our design could have been strengthened by including a pre-course assessment, but such an assessment would probably have increased learning during both the 24 min and the 6 h BLS courses. Using the Cardiff test as a basis for quality assessment during the assessment made the registration easy and precise as shown in earlier studies.12 Simplicity in BLS training improves the ability to remember the entire sequence but does not significantly improve BLS quality,13 which corresponds
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin well to our study when looking at the total scores, although we were able to show a few quantitative differences. Simple individual manikins can be used for teaching laypersons BLS with results just as good as conventional BLS training.14 This is comparable with our results. The MiniAnne manikin predecessor, LittleAnne (Laerdal Medical, Stavanger, Norway) has been compared to eight different small simulators and was evaluated to function most realistically for teaching of basic airway management.15 BLS training without the use of an instructor, using video self-instruction (VSI) in a 34 min course instead has been tested. VSI could produce BLS of comparable quality to that achieved by conventional training methods.10 Thirty-four minutes VSI and an inexpensive cardboard manikin, significantly improves the ability to perform BLS immediately after the course, compared to conventional BLS course.7,8 Two months later there tended to be more in the VSI group performing ventilations and compressions correctly, but there were no overall significant differences7 as in our study. The combination of 11 min VSI and an inexpensive cardboard manikin results in significantly better initial ABC assessment immediately after training and no significant differences in long-term skill retention compared to a control group9 . Recently the MiniAnne personal resuscitation manikin and a 22 min VSI have been compared with a 4 h Heartsaver course. Immediately after training the MiniAnne-group performed significantly better than an untrained control group and the MiniAnnegroup tended to demonstrate better ventilation and better overall performance than the Heartsavergroup.16 This is in accordance with our findings. The problem with too low hand position during compressions has also been shown in recent studies, varying from 41% to 69% 6 months after BLS training,17,18 which corresponds well to the 58% found in our study. Studies in which a simplified hand position (‘centre of the chest’) has been taught have not shown differences in skill acquisition or retention.19 We hope that BLS taught to groups of 50 participants using a big screen, as in this study, can increase availability to the public and thereby spread the knowledge of BLS in a population. Future research in this area could be focused on the wide spread use of short self-activating BLS courses and the effect on bystander BLS and survival rates from out-of-hospital cardiac arrest. Investigations concerning the effectiveness of this new resuscitation manikin when used at home to teach friends and relatives should also be conducted.
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Conclusions We were unable to detect any significant difference in the overall basic life support performance after 3 months in laypersons undergoing a 24 min course with a personal resuscitation manikin versus a conventional 6 h course. The level of basic life support skills after a 24 min instruction session and subsequent self-training appears equivalent to that after a 6 h course and hence is a more efficient way to teach BLS.
Conflict of interests The first author has received an unrestricted research grant from the Laerdal Foundation. Laerdal Medical has taken no part in neither designing the study, analysing data nor writing of the manuscript. None of the remaining authors have financial or personal relationships with the organizations involved in this study.
Acknowledgements The authors would like to thank communications manager Trine Heidemann, project coordinator Pia Hansen, and project assistant Karin Buch-Nielsen all from TrygFonden (Denmark) for their efforts related to coordination and blinding during data collection. Furthermore, we wish to thank nurse anaesthetist Torben Frost, medical students Christian S. Meyhoff and Søren Aalbæk, and research fellow Eske K. Aasvang for their contribution to the testing of participants. Finally, thanks to Deborah Davis for her help with editing.
References 1. Handley AJ, Monsieurs KG, Bossaert LL. European Resuscitation Council Guidelines. European Resuscitation Council Guidelines 2000 for Adult basic life support. A statement from the basic life support and Automated External Defibrillation Working Group (1) and approved by the Executive Committee of the European Resuscitation Council. Resuscitation 2001;48:199—205. 2. Litwin P, Eisenberg M, Hallstrom A, Cummins R. The location of collapse and its effect on survival from cardiac arrest. Ann Emerg Med 1987;16:787—91. 3. Herlitz J, Engdahl J, Svensson L, Angquist KA, Young M, Holmberg S. Factors associated with an increased chance of survival among patients suffering from an out-of-hospital cardiac arrest in a national perspective in Sweden. Am Heart J 2005;149:61—6.
442 4. Holmberg M, Holmberg S, Herlitz J. Effect of bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients in Sweden. Resuscitation 2000;47:59—70. 5. McKenna SP, Glendon AI. Occupational first aid training: decay in cardiopulmonary resuscitation (CPR) skill. J Occup Psychol 1985;58:109—17. 6. Patrick J. Training: Research and Practice. Academic Press Ltd; 1992. 7. Braslow A, Brennan RT, Newman MM, Bircher NG, Batcheller AM, Kaye W. CPR training without an instructor: development and evaluation of a video self-instructional system for effective performance of cardiopulmonary resuscitation. Resuscitation 1997;34:207—20. 8. Batcheller AM, Brennan RT, Braslow A, Urrutia A, Kaye W. Cardiopulmonary resuscitation performance of subjects over forty is better following half-hour video self-instruction compared to traditional 4 h classroom training. Resuscitation 2000;43:101—10. 9. Liberman M, Golberg N, Mulder D, Sampalis J. Teaching cardiopulmonary resuscitation to CEGEP students in Quebec—–a pilot project. Resuscitation 2000;47:249—57. 10. Todd KH, Heron SL, Thompson M, Dennis R, O’Connor J, Kellermann AL, Simple CPR. A randomized, controlled trial of video self-instructional training in an African American church congregation. Ann Emerg Med 1999;34:730—7. 11. Wik L, Myklebust H, Auestad BH, Steen PA. Retention of basic life support skills 6 months after training with an automated voice advisory manikin system without instructor involvement. Resuscitation 2002;52:273—9.
D.L. Isbye et al. 12. Whitfield RH, Newcombe RG, Woollard M. Reliability of the Cardiff Test of basic life support and automated external defibrillation version 3.1. Resuscitation 2003;59:291— 314. 13. Handley JA, Handley AJ. Four-step CPR—–improving skill retention. Resuscitation 1998;36:3—8. 14. Noordergraaf GJ, Van Gelder JM, Van Kesteren RG, Diets RF, Savelkoul TJ. Learning cardiopulmonary resuscitation skills: does the type of mannequin make a difference? Eur J Emerg Med 1997;4:204—9. 15. Rosenthal E, Owen H. An assessment of small simulators used to teach basic airway management. Anaesth Intensive Care 2004;32:87—92. 16. Lynch B, Einspruch EL, Nichol G, Becker LB, Aufderheide TP, Idris A. Effectiveness of a 30-min CPR self-instruction program for lay responders: a controlled randomized study. Resuscitation 2005;67:31—43. 17. Chamberlain D, Smith A, Woollard M, Colquhoun M, Handley AJ, Leaves S, Kern KB. Trials of teaching methods in basic life support (3): comparison of simulated CPR performance after first training and at 6 months, with a note on the value of re-training. Resuscitation 2002;53:179—87. 18. Woollard M, Whitfield R, Smith A, Colquhoun M, Newcombe RG, Vetteer N, Chamberlain D. Skill acquisition and retention in automated external defibrillator (AED) use and CPR by lay responders: a prospective study. Resuscitation 2004;60:17—28. 19. Handley AJ. Teaching hand placement for chest compression—–a simpler technique. Resuscitation 2002;53:29—36.
TRAINING AND EDUCATIONAL PAPER
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin夽 Dan Lou Isbye a,∗, Lars Simon Rasmussen a, Freddy Knudsen Lippert a, Søren Finnemann Rudolph a, Charlotte Vibeke Ringsted b a
Department of Anaesthesia, Section 4231, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark b Centre of Clinical Education, University of Copenhagen and Copenhagen University Hospital, Rigshospitalet, Denmark Received 24 August 2005 ; received in revised form 21 October 2005; accepted 28 October 2005 KEYWORDS Adult; Cardiac arrest; Bystander CPR; Basic life support (BLS); Manikin; Training
Summary Background: Bystander basic life support (BLS) is an important part of cardiopulmonary resuscitation (CPR) and improves outcome after out-of-hospital cardiac arrest. However, the general population has poor BLS skills. Several training initiatives could be used to improve this situation and the challenge is to find the most efficient one. Aims: To compare the efficiency of a 24 min instruction using a DVD-based selftraining BLS course combined with a simple, take-home resuscitation manikin to a conventional 6 h course for teaching BLS to laypersons. Methods: In total, 238 laypersons (age 21—55 years) without previous BLS-training were allocated into two groups: one group received 24 min of instruction using a DVD-based instruction tool on a big screen combined with a BLS self-training device, Laerdal MiniAnne manikin (MAM), before taking home the instruction material for subsequent self-training. The second group attended a conventional 6 h BLS course (6HR). After 3 months BLS skills were assessed on a Laerdal ResusciAnne manikin using the Laerdal PC Skill reporting System, and a total score was calculated. Results: There was no significant difference between groups in BLS performance using the total score. Assessment of breathing was performed significantly more often in the 6HR-group (91% versus 72%, P = 0.03). In the MAM-group, average inflation volume and chest compression depth were significantly higher (844 mL versus 524 mL, P = 0.006, and 45 mm versus 39 mm, P = 0.005). Conclusions: When assessed after 3 months, a 24 min DVD-based instruction plus subsequent self-training in BLS appears equally effective compared to a 6 h BLS course and hence is more efficient. © 2005 Elsevier Ireland Ltd. All rights reserved.
夽 A Spanish translated version of the abstract of this article appears as Appendix in the online version at 10.1016/j.resuscitation.2005.10.027. ∗ Corresponding author. Tel.: +45 35453487; fax: +45 35452950. E-mail address: [email protected] (D.L. Isbye).
0300-9572/$ — see front matter © 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2005.10.027
436
D.L. Isbye et al.
Introduction
Materials and methods
The initial management of cardiac arrest is based upon the concept of the ‘‘Chain of Survival’’ where each link influences survival: early access, early basic life support (BLS), early defibrillation and early advanced cardiac life support (ALS). Success of the two first links depends on several factors: where the arrest takes place, whether bystanders witness the arrest, the bystanders’ ability to recognise the arrest, to call the emergency medical service and finally to perform BLS.1 The survival rate after cardiac arrest increases when cardiac arrest takes place in a public place and is witnessed.2,3 When bystander BLS is initiated the survival rate is doubled.3,4 There is no standardised way to teach BLS to laypersons and several organisations offer courses. Such courses usually last for 4—6 h, are instructor-based, and use one or two resuscitation manikins for practicing BLS. The duration of the courses and the costs of manikins and instructors are probably factors that inhibit general dissemination of BLS training. Another problem is retention of the acquired BLS-skills after a course. McKenna and Glendon studied BLS skill retention up to 3 years after training.5 Less than 10% of the subjects performed at least 75% of the skills correctly, and it was estimated that few if any patients in cardiac arrest would benefit from the resuscitation attempts. Most probably the poor retention is explained by that fact that BLS is used infrequently and rarely refreshed. Training to a higher level of acquired skills at the end of a course and the possibility to refresh the skill improve retention over time.6 Short selfactivating courses without the use of an instructor seem to improve performance immediately after the course, but no lasting effects have been reported.7—9 Recent studies have emphasised the need for instructional methods, which can raise the level of BLS performance or reduce instructional time while preserving performance level over time.10,11 The aim of this study was to compare the efficiency of a 24 min DVD-based self-training BLS course combined with a simple, take-home resuscitation manikin to a conventional 6 h course for teaching BLS to laypersons. We hypothesised that BLS learned in 6 h would result in better skill retention after 3 months than BLS learned in 24 min.
We recruited 238 laypersons, employed in the bankand insurance business, who had not received BLS training within the last 5 years. The participants knew, before volunteering, that they would receive BLS training, but did not know that there were different courses. The participants were divided into two groups, and for practical reasons this was based on which firm they worked for. The first group received 24 min of instruction on a DVD-based resuscitation course combined with an inflatable resuscitation manikin MiniAnne (Laerdal Medical, Stavanger, Norway, Figure 1), which participants kept after the course for additional training at home, with the possibility to train relatives and friends. The training was done in four consecutive sessions using a big screen with 47—50 participants. Five facilitators were present for each session to assist the participants if technical problems arose. The second group received a 6 h instructor-based resuscitation course. This was done in four courses with 10—12 participants, using one instructor and two Ambu Man model C manikins (Ambu International, Ballerup, Denmark). Adult BLS was taught in accordance with European Resuscitation Council (ERC) Guidelines 2000 in both courses. The contents of the two courses are summarized in Table 1. After 3 months all participants were called in without notice while at work, for a 5 min skill retention assessment in a dedicated room.
Figure 1 The MiniAnne personal resuscitation manikin (Laerdal Medical, Stavanger, Norway). Around the manikin from left and clockwise: 24 min instructional DVD, instructional leaflets, 70% ethanol single use manikin wipes, cardboard mobile phone, storage box, protective kneepads, and CPR-Coach.
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin
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Table 1 Contents of the 24 min DVD developed by Laerdal Medical in cooperation with TrygFonden (Denmark) and contents of the conventional 6 h course developed by the Danish Red Cross 24 min of DVD-instruction together with MiniAnne personal resuscitation manikin 00:00 04:00 06:00 08:45 10:45 14:45 17:00 19:45 21:15 22:30 24:00
Introduction case reported by out-of-hospital cardiac arrest survivor and lay responder How to make MiniAnne ready for use Cardiac compressions—–theory and practice Ventilations—–theory and practice Combined ventilations and compressions ratio 2:15—–practice Check responsiveness, check breathing and alarming—–theory Entire BLS-algorithm—–practice CPR-Coach to get compression depth and pace correct—–practice Encouragement to use MiniAnne at home to train friends and relatives How to clean MiniAnne after use The end
Conventional 6 h instructor-based resuscitation course Part 1 (3 h) Theory—–Introduction to first aid; stop the accident and moving the injured patient; life-saving first aid; the vital oxygen-transport; state of consciousness; first aid to the unconscious but breathing patient; alarming; basic first aid; myocardial infarction; symptoms of cardiac arrest; the technique of ventilations and compressions Practice—–basic first aid Part 2 (3 h) Theory—–basic life support in the adult and child Practice—–basic life support in the adult Practice—–first aid and basic life support scenarios in the adult The program for the 6 h course is a suggestion to the instructor and it is emphasised that weight should be put on teaching practical skills.
The participants were told that an adult had collapsed in front of them while standing in a public place, with others not familiar with BLS and they were told to act as they would in a real situation. This included not explaining the procedure to the investigator who was present. The assessment was performed with the ResusciAnne manikin and the Laerdal PC-Skill Reporting System version 2.0 (Laerdal Medical, Stavanger, Norway) was used to record the overall time, time delay to first rescue breath or compression, total number of ventilations, average ventilation volume, total number of compressions, average compression depth, hand position, ventilation-compression ratio, and total ‘hands off’ time. In addition qualitative assessment was made by investigators who recorded the variables ‘checks responsiveness by talking and shaking’, ‘opens airway’, ‘checks respiration’ and ‘calls for help’. The group of investigators consisted of one nurse anaesthetist, two final year medical students, two junior physicians, and two consultant anaesthesiologists. Investigators were blinded for which type of training the participant had received. Quantitative data from Laerdal PC-Skill Reporting System version 2.0 and qual-
itative data from the investigators were registered on a form and subsequently entered into a database. To assess the overall BLS performance, points were given in a scoring system (Table 2) developed from the Cardiff test.12 Theoretically the total score could be from 12 to 52 points. The primary endpoint was the total score. Exact values of the different variables in the two groups were compared as well. Before the assessments it was decided that - calling for help should be done within the first minute; - delay was defined as the time in seconds before the first rescue breath or compression was recorded by the computer; - hand position was incorrect if one compression was in the wrong position. This was decided because it only takes one compression in the wrong place to fracture the xiphoid process of sternum; - correct ventilation—compression ratio was 2:15 ± 1; - participants unable to ventilate the manikin but who attempted a ratio of 2:15 were registered
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Table 2 Assessment of basic life support skills in laypersons 3 months after a 6 h course (6HR) or a 24 min course using a personal resuscitation manikin (MAM) Score
MAM (N = 156)
6HR (N = 36)
Checks responsiveness by talking 2: Yes 94 (60%) 1: No 62 (40%)
20 (56%) 16 (44%)
Checks responsiveness by shaking 3: Yes 102 (65%) 2: No 51 (33%) 1: Unacceptable 3 (2%)
25 (69%) 11 (31%) 0 (0%)
Opens airway—–head tilt, chin lift 5: Perfect 30 (19%) 4: Acceptable 23 (15%) 3: Attempted other 6 (4%) 2: Only one element 14 (9%) 1: No 83 (53%)
4 (11%) 7 (19%) 3 (8%) 3 (8%) 19 (53%)
Checks respiration—–see, listen and feel 2: Yes 112 (72%) 1: No 44 (28%)
32 (89%) 4 (11%)
Calls for help or dials 1-1-2 2: Yes 88 (56%) 1: No 68 (44%)
11 (31%) 25 (69%)
Total ventilations counteda 6: 31—40 19 (12%) 5: 21—30 48 (31%) 4: > 40 3 (2%) 3: 11—20 39 (25%) 2: 0—10 43 (28%) 1: Not attempted 2 (1%)
6 (18%) 9 (26%) 1 (3%) 9 (26%) 9 (26%) 0 (0%)
Average ventilation volume (mL) 7: 700—1000 31 (20%) 6: 1001—1300 25 (16%) 5: 400—699 32 (21%) 4: >1300 40 (26%) 3: 1—399 3 (2%) 2: 0 23 (15%) 1: Not attempted 2 (1%)
7 (19%) 4 (11%) 13 (36%) 2 (6%) 5 (14%) 5 (14%) 0 (0%)
a
Total compressions counted 6: 251—350 5 (3%) 5: 201—250 28 (18%) 4: >350 0 (0%) 3: 101—200 94 (61%) 2: 1—100 27 (18%) 1: Not attempted 0 (0%)
2 (6%) 4 (12%) 0(0%) 18 (53%) 10 (29%) 0 (0%)
Average compression depth (mm) 6: 40—50 61 (39%) 5: 51—55 34 (22%) 4: 24—39 43 (28%) 3: >55 9 (6%) 2: 1—24 9 (6%) 1: Not attempted 0 (0%)
12 (33%) 3 (8%) 14 (39%) 1 (3%) 6 (17%) 0 (0%)
Hand-position during compression 4: Correct 25 (16%) 3: Other wrong 41 (26%)
7 (19%) 8 (22%)
Table 2 (Continued ) Score
MAM (N = 156)
6HR (N = 36)
90 (58%) 0 (0%)
21 (58%) 0 (0%)
Ventilation/compression ratio 4: 2:15 (2:14—16) 92 (58%) 3: Other 62 (40%) 2: Compressions only 2 (1%) 1: Ventilations only 0 (0%)
17 (47%) 19 (53%) 0 (0%) 0 (0%)
Total ‘Hands Off’ time (s)a 5: 1—60 0 (0%) 4: 61—120 0 (0%) 3: 121—180 62 (40%) 2: 181—240 79 (51%) 1: 241—300 13 (8%)
0 (0%) 1 (3%) 7 (21%) 21 (62%) 5 (15%)
2: Too low 1: Not attempted
Combined Scorea,b
35 (32—38)
34 (31—38) test.12
Scoring system derived from the Cardiff In the far left column are seen the points assigned for each level of skill retained after 3 months. Frequency of each single score in the two groups is shown in middle and right column. Combined score is reported with median (25—75% range) and Mann Whitney Rank sum test is used to calculate P-value. a Due to technical difficulties two persons from each group was taken out of calculations in ‘Total ventilations, total compressions, Hands Off time and combined score’. b P = 0.41.
as such because they apparently had learned the skill for ratio; - ‘Hands Off’ time was when compressions were not being performed; - ideally BLS should be initiated within 30 s, which would give 4.5 min for ventilations and compressions. In this period an estimated 18 cycles of 2:15 could be completed and result in 36 ventilations and 270 compressions. For statistical analysis the SAS System (SAS Institute Inc., Cary, USA) was used. For continuous data, we reported a median with 25—75% range and Mann Whitney Rank sum test was used for comparison of groups. For non-continuous data we reported proportions and Chi square test was used for comparison. P-values less than 0.05 were considered statistically significant. Sample size was calculated as follows: We aimed at recognising a difference of three points in the total score as this corresponds to the difference between perfect and unacceptable performance if applied on one of the two variables ‘total number of ventilations’ and ‘total number of compressions’. The scoring system was tested in a pilot study and a S.D. of approximately seven points was found. Using a power of 90% and a significance level of 0.05 we had to include 200 participants. We estimated that
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin it was impossible to recruit this number of volunteers at the insurance company in which the project was originally planned to take place. Therefore, we recruited additional participants from a cooperating banking company. It was then decided that the MiniAnne should be distributed in the insurance company, and, for financial reasons, the smaller group of additional participants were offered the more expensive 6 h course. Subsequently the two groups became different in size and we decided on aiming to include 250 participants to compensate for this difference.
Results In total 238 responded positively to the invitation to participate. The MiniAnne manikin (MAM)-group consisted of 141 women (73%) and 53 men (27%) while the 6 h (6HR)-group consisted of 32 women (73%) and 12 men (27%). Mean age in the MAM-group was 37 years (range 22—51 years), while it was 40 years (range 21—55 years) in the 6HR-group. Fortysix participants (MAM-group 38 (20%); 6HR-group 8 (18%)) did not meet for testing after 3 months. In the MAM-group 14 of the 38 declined participation because of lack of interest. The rest just never attended although given several opportunities. In the 6HR-group we were unable to obtain any reasons for not participating. The final group consisted of 192 laypersons (Figure 2).
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Technical difficulties occurred in four instances during the assessments, which led to exclusion of the affected variables, but not of the assessment as a whole. There was no significant difference between the two groups when looking at the total score. Considering that 12—52 points could be given, the MAMgroup achieved 57.5% of the maximum score while the 6HR-group achieved 55% (Table 2). The 6HR-group performed significantly better than the MAM-group in checking for respiration (P = 0.03). The MAM-group performed significantly better than the 6HR-group in calling for help (P = 0.005). Time delay (s) to first rescue breath or compression was 33.5 (23—45) in the MAM-group, and 39.5 (29.5—46) in the 6HR-group, P = 0.15. ‘Hands Off’ time in seconds was 188.5 (170—208) in the MAM-group and 199 (181—219) in the 6HRgroup, P = 0.08. The average ventilation volume (mL) was significantly higher in the MAM-group (843.5 versus 524, P = 0.006) but the proportion of participants with an average ventilation volume between 400 and 1300 mL was not different (MAM 57% versus 6HR 66%, Table 2). Average compression depth (mm) was also significantly higher in the MAM-group (45 versus 38.5, P = 0.005), and 61% of the MAM-group had an average compression depth between 40 and 55 versus 41% in the 6HR-group, P = 0.06 (Table 2). The computer recorded a wrong hand position during compressions in more than 80% of the par-
Figure 2 Flow chart on the inclusion of participants.
440 ticipants (MAM 84%, 6HR 81%; P = 0.82) and 58% in both groups made at least one compression that was too low on the sternum.
Discussion The most important finding in this study was that there was no significant difference in the overall performance of basic life support between a 24 min course and a 6 h course. It is interesting that basic life support may be learned in a course of such short duration. If the same quality is achieved in less time, the 24 min course is more efficient basic life support training. It could be argued that a 6 h course is a rather long time for learning BLS, and in the conventional course attention is also drawn to other aspects of first aid such as treatment of the unconscious but breathing patient. However, around four of the 6 h are used for BLS theory and practice (Table 1). In the MAM-group, ‘‘hands off time’’ and time delay to first rescue breath or compression tended to be lower and in this group, average compression depth and average ventilation volume were significantly higher. Thus, hands-on skills seem to be better retained, when they are taught with a larger amount of self-activation in the learning process and the possibility to refresh skills when needed. In both groups, close to two thirds of the 5 min skill retention assessment was without compressions and subsequently without perfusion pressure. It is unknown whether the performance of the participants in reality would increase survival in out-ofhospital cardiac arrest, with both groups only scoring slightly above 50% of the maximum score. Survival increases when bystander CPR is performed, but we have no way of knowing how well these lay rescuers perform. We find it remarkable that the 6HR-group performs better than the MAM-group in one of first manoeuvres; ‘checking for respiration’. The reason for this could be that over a 6 h course, motivation for learning is high at the beginning and slowly deteriorates with time. This could result in better retention of skills learned at the beginning while skills learned later on in the course might be forgotten more easily. Against this hypothesis one could argue that the skill, ‘open airway’, is taught before the skill, ‘check respiration’, and is forgotten by more than half in both groups, thus eliminating the full effect of checking respiration. We found that the MAM-group called for help significantly more often than the 6HR-group, but this variable is difficult to evaluate in a simulation assessment where setting and environment are
D.L. Isbye et al. obviously unnatural. It is to be expected that nearly everybody would consider calling for help immediately if they encountered a person in cardiac arrest in real life. In both groups about 85% were able to ventilate during the skills assessment. This argues against not ventilating during basic life support simply on the grounds that the skill is too difficult for laypersons. We found it interesting that more than 80% of all the participants assessed used an incorrect hand position. In both groups 58% used too low a hand position, which could fracture the xiphoid process of the sternum of a patient. This finding could be due to overly sensitive sensors in the manikin, but during our pilot study we found very few using incorrect hand position. It can be discussed whether just one compression in the wrong place is enough to obtain a lower score. The groups were both instructed to identify the correct place for compression by locating the umbilicus, then moving a finger up to the xiphoid process of the sternum, then placing two fingers above the process, and finally placing the hands for compressions. This is a very complex method that is probably hard to remember. We suspect that there is room for improvement in teaching of hand position during compressions in both groups. We found that about 20% of the participants in both groups did not attend for the assessment after 3 months, even after several attempts to include as many as possible. Probably many of the participants declining the 3 months assessment felt insecure in their ability to perform BLS. We could have asked the participants in the MAM-group if they had used the manikin at home for additional training or for training family and friends. We chose not to, as the reliability of the answers could not be validated. For logistical reasons, we were unable to randomise the participants who instead were allocated into the two groups by which company they worked for. The small demographic differences between the two groups are unlikely to have influenced the results. The study design could have been stronger if inclusion criteria had been ‘never received BLS training’ instead of ‘not within the last 5 years’. Using the 5 years criteria our design could have been strengthened by including a pre-course assessment, but such an assessment would probably have increased learning during both the 24 min and the 6 h BLS courses. Using the Cardiff test as a basis for quality assessment during the assessment made the registration easy and precise as shown in earlier studies.12 Simplicity in BLS training improves the ability to remember the entire sequence but does not significantly improve BLS quality,13 which corresponds
Laypersons may learn basic life support in 24 min using a personal resuscitation manikin well to our study when looking at the total scores, although we were able to show a few quantitative differences. Simple individual manikins can be used for teaching laypersons BLS with results just as good as conventional BLS training.14 This is comparable with our results. The MiniAnne manikin predecessor, LittleAnne (Laerdal Medical, Stavanger, Norway) has been compared to eight different small simulators and was evaluated to function most realistically for teaching of basic airway management.15 BLS training without the use of an instructor, using video self-instruction (VSI) in a 34 min course instead has been tested. VSI could produce BLS of comparable quality to that achieved by conventional training methods.10 Thirty-four minutes VSI and an inexpensive cardboard manikin, significantly improves the ability to perform BLS immediately after the course, compared to conventional BLS course.7,8 Two months later there tended to be more in the VSI group performing ventilations and compressions correctly, but there were no overall significant differences7 as in our study. The combination of 11 min VSI and an inexpensive cardboard manikin results in significantly better initial ABC assessment immediately after training and no significant differences in long-term skill retention compared to a control group9 . Recently the MiniAnne personal resuscitation manikin and a 22 min VSI have been compared with a 4 h Heartsaver course. Immediately after training the MiniAnne-group performed significantly better than an untrained control group and the MiniAnnegroup tended to demonstrate better ventilation and better overall performance than the Heartsavergroup.16 This is in accordance with our findings. The problem with too low hand position during compressions has also been shown in recent studies, varying from 41% to 69% 6 months after BLS training,17,18 which corresponds well to the 58% found in our study. Studies in which a simplified hand position (‘centre of the chest’) has been taught have not shown differences in skill acquisition or retention.19 We hope that BLS taught to groups of 50 participants using a big screen, as in this study, can increase availability to the public and thereby spread the knowledge of BLS in a population. Future research in this area could be focused on the wide spread use of short self-activating BLS courses and the effect on bystander BLS and survival rates from out-of-hospital cardiac arrest. Investigations concerning the effectiveness of this new resuscitation manikin when used at home to teach friends and relatives should also be conducted.
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Conclusions We were unable to detect any significant difference in the overall basic life support performance after 3 months in laypersons undergoing a 24 min course with a personal resuscitation manikin versus a conventional 6 h course. The level of basic life support skills after a 24 min instruction session and subsequent self-training appears equivalent to that after a 6 h course and hence is a more efficient way to teach BLS.
Conflict of interests The first author has received an unrestricted research grant from the Laerdal Foundation. Laerdal Medical has taken no part in neither designing the study, analysing data nor writing of the manuscript. None of the remaining authors have financial or personal relationships with the organizations involved in this study.
Acknowledgements The authors would like to thank communications manager Trine Heidemann, project coordinator Pia Hansen, and project assistant Karin Buch-Nielsen all from TrygFonden (Denmark) for their efforts related to coordination and blinding during data collection. Furthermore, we wish to thank nurse anaesthetist Torben Frost, medical students Christian S. Meyhoff and Søren Aalbæk, and research fellow Eske K. Aasvang for their contribution to the testing of participants. Finally, thanks to Deborah Davis for her help with editing.
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442 4. Holmberg M, Holmberg S, Herlitz J. Effect of bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients in Sweden. Resuscitation 2000;47:59—70. 5. McKenna SP, Glendon AI. Occupational first aid training: decay in cardiopulmonary resuscitation (CPR) skill. J Occup Psychol 1985;58:109—17. 6. Patrick J. Training: Research and Practice. Academic Press Ltd; 1992. 7. Braslow A, Brennan RT, Newman MM, Bircher NG, Batcheller AM, Kaye W. CPR training without an instructor: development and evaluation of a video self-instructional system for effective performance of cardiopulmonary resuscitation. Resuscitation 1997;34:207—20. 8. Batcheller AM, Brennan RT, Braslow A, Urrutia A, Kaye W. Cardiopulmonary resuscitation performance of subjects over forty is better following half-hour video self-instruction compared to traditional 4 h classroom training. Resuscitation 2000;43:101—10. 9. Liberman M, Golberg N, Mulder D, Sampalis J. Teaching cardiopulmonary resuscitation to CEGEP students in Quebec—–a pilot project. Resuscitation 2000;47:249—57. 10. Todd KH, Heron SL, Thompson M, Dennis R, O’Connor J, Kellermann AL, Simple CPR. A randomized, controlled trial of video self-instructional training in an African American church congregation. Ann Emerg Med 1999;34:730—7. 11. Wik L, Myklebust H, Auestad BH, Steen PA. Retention of basic life support skills 6 months after training with an automated voice advisory manikin system without instructor involvement. Resuscitation 2002;52:273—9.
D.L. Isbye et al. 12. Whitfield RH, Newcombe RG, Woollard M. Reliability of the Cardiff Test of basic life support and automated external defibrillation version 3.1. Resuscitation 2003;59:291— 314. 13. Handley JA, Handley AJ. Four-step CPR—–improving skill retention. Resuscitation 1998;36:3—8. 14. Noordergraaf GJ, Van Gelder JM, Van Kesteren RG, Diets RF, Savelkoul TJ. Learning cardiopulmonary resuscitation skills: does the type of mannequin make a difference? Eur J Emerg Med 1997;4:204—9. 15. Rosenthal E, Owen H. An assessment of small simulators used to teach basic airway management. Anaesth Intensive Care 2004;32:87—92. 16. Lynch B, Einspruch EL, Nichol G, Becker LB, Aufderheide TP, Idris A. Effectiveness of a 30-min CPR self-instruction program for lay responders: a controlled randomized study. Resuscitation 2005;67:31—43. 17. Chamberlain D, Smith A, Woollard M, Colquhoun M, Handley AJ, Leaves S, Kern KB. Trials of teaching methods in basic life support (3): comparison of simulated CPR performance after first training and at 6 months, with a note on the value of re-training. Resuscitation 2002;53:179—87. 18. Woollard M, Whitfield R, Smith A, Colquhoun M, Newcombe RG, Vetteer N, Chamberlain D. Skill acquisition and retention in automated external defibrillator (AED) use and CPR by lay responders: a prospective study. Resuscitation 2004;60:17—28. 19. Handley AJ. Teaching hand placement for chest compression—–a simpler technique. Resuscitation 2002;53:29—36.