Original Contribution

Effectiveness of mouth-to-mouth ventilation after Video self-instruction training in laypersons

Hyuk J. Choi MD^a, Christopher C. Lee MD^b, Tae H. Lim MD^a,b,?, Bo S. Kang MD^a, Adam J. Singer MD^b, Mark C. Henry MD^b

^aDepartment of Emergency Medicine, Hanyang University Hospital, Seoul, Korea

^bDepartment of Emergency Medicine, Center for International Emergency Medicine, Stony Brook University Medical Center, Stony Brook, NY, USA

Received 16 January 2009; revised 1 February 2009; accepted 15 February 2009

Abstract

Background: Mouth-to-mouth ventilation is a skill taught in cardiopulmonary resuscitation training for laypersons. However, its effectiveness is questioned. Our aim was to determine the effectiveness of mouth-to-mouth ventilation training using a self-instruction CPR training video for laypersons.

Methods: Video-self-instruction CPR training was conducted with CPR Anytime (American Heart Association [AHA] & Laerdal Corporation) for laypersons who had not received CPR training during the recent 5 years. Immediately before, immediately after, and 8 weeks after the CPR training, an AHA basic life support instructor carried out a skill performance test using a standardized checklist. Also, 8 weeks after the training, a skill test concerning chest compression and mouth-to-mouth ventilation was conducted using a trained reporter.

Results: Cardiopulmonary resuscitation training of 84 laypersons was conducted. The mean performance score (from 0 to 2) for mouth-to-mouth ventilation was 0.24 right before the training,

1.58 right after the training, and 0.95 eight weeks after the training. The mean performance scores for chest compression were 0.13, 1.79, and 1.40, right before, right after, and 8 weeks after the CPR training, respectively. The rates of successful mouth-to-mouth ventilation and compression were 11.9%, and 39.1%, respectively.

Conclusions: The effectiveness and short-term retention rate of mouth-to-mouth ventilation after video self-instruction CPR training in laypersons was significantly lower than for chest compressions.

(C) 2010

Introduction

The American Heart Association (AHA) CPR guidelines in 2005 include training of laypersons in mouth-to-mouth

* Corresponding author.

E-mail address: [email protected] (T.H. Lim).

ventilation [1]. Accordingly, the skill is currently taught to laypersons through various methods. Among the training methods, video self-instruction (VSI) is widely recognized as an excellent cost-effective modality for laypersons. How- ever, mouth-to-mouth ventilation is complex, and is difficult to teach and execute; for these reasons, the rates of performance of bystander CPR are low [2-7]. Other possible

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reasons for the low rates of mouth-to-mouth ventilation include concerns with hygiene and contact with bodily fluids. With increasing recognition of the importance of uninterrupted and adequate chest compressions, questions have been raised regarding the role of mouth-to-mouth ventilation, especially for laypersons [8]. The objective of the current study was to determine the effectiveness of training laypersons in mouth-to-mouth ventilation using VSI-CPR training. The current study was not designed to determine whether mouth-to-mouth ventilation is beneficial or not.

Methods

Study design

We conducted a prospective observational study to determine the effectiveness of training in CPR using an Instructional video in laypersons. The study was approved by the institutional review board.

Study subjects

The participants of this study were 84 nonmedical personnel at an urban teaching hospital who volunteered for the VSI-CPR training program and had not received CPR training within the last 5 years. None of the volunteers were required to undergo training by their place of employment.

Interventions

Each of the participants was given a CPR Anytime (AHA & Laerdal Corporation) training kit and was asked to view the video and perform the instructed skills at the same time.

Fig. 1 Change in skill scores for mouth-to-mouth ventilation and chest compression.

Viewing of the video was not supervised by the basic life support (BLS) instructors.

Measures

We conducted chest compression and mouth-to-mouth ventilation performance tests immediately before, immedi- ately after, and 8 weeks after the CPR training. For performance test, each participant was requested to demon- strate 2 cycles of chest compression and mouth-to-mouth ventilation with a CPR training manikin (Mini Anne, AHA & Laerdal Corporation). Two AHA-certified BLS instructors recorded the participants’ actions on a standardized CPR performance checklist. The CPR checklist is composed of 2 ventilation-related and 4 compression-related items: (1) performance of 2 adequate breaths (1 second each, within 5-10 seconds); (2) correct location of CPR hand position; (3) delivery of chest compression of adequate depth (more than 23 to 30 compressions); (4) delivery of chest compressions at the correct rate (30 compressions within 23 seconds); (5)

Fig. 2 Ratios of successful ventilation and compression at 8 weeks after VSI-CPR training.

Table 1 Scores on mouth-to-mouth ventilation and chest compression skills

Skills Average number of points for skills ^a

Immediately Immediately 8 wk after before training after training training

vertical depression of the chest with dully extended elbows; and (6) delivery of 2 adequate breaths (visible chest wall rising). For each item, a correct action was given 2 points, a partially correct action was given 1 point, and an incorrect action was given 0 points. In addition, 8 weeks after the VSI-CPR training, we tested each participant’s chest compression and mouth-to-mouth ventilation skills using a CPR training manikin (Resusci Anne SkillReporter, Laerdal Corporation). The parameters measured were as follows: (1) mean tidal volume of ventilation; (2) percent of successful ventilations; (3) mean depth of chest compressions; and (4) percentage of successful chest compressions. The BLS instructors were masked to Study objectives.

Data analysis

Continuous data are summarized as means and SDs and compared with t tests. Binomial data are summarized as the percent frequency of occurrence and compared with ?2 tests. Performance of mouth-to-mouth ventilation and chest compressions at each time point were compared with the appropriate test using SPSS 15.0 software (SPSS Inc, Chicago, Ill).

Results

A total of 84 persons participated in the CPR training program and completed the tests. Among the 84 participants, 60 (71.4%) were male and 24 (28.6%) were female. The mean (SD) age of the participants was 40.1 (8.6).

Table 1 and Fig. 1 show the results on the performance tests. Before the VSI CPR training, mean scores on the 4 chest compression-related items and the 2 mouth-to-mouth ventilation-related items were 0.13 and 0.24, respectively. The mean score of the 4 items related to chest compression increased to 1.79 immediately after VSI-CPR training and decreased to 1.40 points 8 weeks after VSI-CPR training. Mean scores for mouth-to-mouth ventilation 8 weeks after VSI-CPR training decreased from 1.58 to 0.95 compared to the score immediately after VSI-CPR training. This decline in scores for mouth-to-mouth ventilation was statistically significant (P = .02), whereas the decline in scores for chest compressions was not.

On skill testing, the mean tidal volume was 1.094 mL, and only 8.4% of study subjects met the AHA BLS guideline of

500 to 600 mL. The mean percentage of successful ventilations was only 11.9%. The mean depth of chest compressions was 4.8 cm, and 16.7% of the compressions were of insufficient compression depth falling short of the AHA BLS recommended depth of 4 to 5 cm. In addition, the chest compression rate was less than 80/min in 26.2% of the study subjects, and the percentage of successful chest compressions was 39.1% (Fig. 2).

Discussion

For any Resuscitative efforts to be beneficial, they must be shown to be both effective and easy to learn. Furthermore, the skills required to perform resuscitation should be easy to maintain over time. The results of the current study indicate that how difficult it is to teach students how to perform high- quality ventilation. It also indicates that the skill of mouth-to- mouth ventilation is more easily forgotten and harder to maintain over time than chest compressions. In light of the growing doubts regarding the utility of mouth-to-mouth ventilation [9-16], our results suggest that there should be strong consideration for omitting mouth-to-mouth ventila- tion training in CPR training for laypersons when taught by instructional video. In addition, the poor rate of retention of accurate chest compressions demonstrated in this study suggests that further studies are needed to supplement such a shortcoming. Although we have shown that the particular instructional method studied was ineffective, this does not address whether the mouth-to-mouth ventilation should be taught or not.

Study limitations

Our study has several limitations. First, we measured the performance of study subjects on inanimate models. Obviously, this may not reflect performance of these skills on actual patients. Second, the study was limited to 8 weeks only. Thus, it is possible that the rate of retention may have been even lower had the study lasted longer. Finally, we only evaluated CPR skill performance and retention after VSI- CPR training. Thus, we cannot generalize our results to other methods of training.

Conclusions

The effectiveness of mouth-to-mouth ventilation after VSI CPR training in laypersons was significantly lower than for chest compressions, and the short-term retention rate was lower for mouth-to-mouth ventilation when compared to chest compression.

References

1. American Heart Association. Adult basic life support. Circulation 2005;112(suppl I):IV-19-IV-43.
2. Berg RA, Kern KB, Sanders AB, Otto CW, Hilwig RW, Ewy GA. Bystander cardiopulmonary resuscitation is ventilation necessary? Circulation 1993;88(part 1):1907-15.
3. Schneider T, Martens PR, Paschen H, et al. Multicenter, randomized, controlled trial of 150-J Biphasic shocks compared with 200- to 360-J monophasic shocks in the resuscitation of out-of-hospital cardiac arrest victims. Circulation 2000;102:1780-7.
4. Plaisance P, Lurie KG, Vicaut E, et al, for the French Active Compression-Decompression cardiopulmonary resuscitation Study Group. A comparison of standard cardiopulmonary resuscitation and active compression-decompression resuscitation for out-of-hospital cardiac arrest. N Engl J Med 1999;341:569-75.
5. Kentsch M, Schlichting H, Mathes N, et al. Out-of-hospital cardiac arrest in North-East Germany: increased resuscitation efforts and improved survival. Resuscitation 2000;43:177-83.
6. Ornato JP, Hallagan LF, McMahan SB, et al. Attitudes of BLS instructors about mouth-to-mouth resuscitation during the AIDS epidemic. Ann Emerg Med 1990;19:151-6.
7. Locke CJ, Berg RA, Sanders AB, et al. Bystander cardiopulmonary resuscitation: concerns about mouth-to-mouth contact. Arch Intern Med 1995;155:938-43.
8. Kern KB, Hilwig RW, Berg RA, Sanders AB, Ewy GA. Importance of Continuous chest compressions during cardiopulmonary resuscitation: improved outcome during a simulated single lay-rescuer scenario. Circulation 2002;105:645-9.
9. Kaye L, Rallis SF, Mancini ME, Linhares KC, Angel ML, Donovan DS, et al. The problem of poor retention of cardiopulmonary resuscitation skills may lie with the instructor not the learner or curriculum. Resuscitation 1991;21:67-87.
10. Weaver FJ, Ramirez AG, Dorfman SB, Raizner AE. Trainee’s retention of cardiopulmonary resuscitation: how quickly they forget. JAMA 1979;241:901-3.
11. Winchell SW, Safar P. Teaching and testing lay and paramedical personnel in cardiopulmonary resuscitation. Anesth Analg 1966;45: 441-9.
12. Kaye W, Mancini M. Retention of cardiopulmonary resuscitation skills by physicians, registered nurses and the general public. Crit Care Med 1986;14:620-2.
13. Martin WJ, Loomis JH, Lloyd CW. Cardiopulmonary resuscitation skills: do we expect too much? Arch Intern Med 1984;144:699-701.
14. Berg RA, Sanders AB, Kern KB, Hilwig RW, Heidenreich JW, Porter ME, et al. Adverse hemodynamic effects of interrupting chest compressions for rescue breathing during cardiopulmonary resuscita- tion for ventricular fibrillation cardiac arrest. Circulation 2001;104: 2450-70.
15. SOS-KANTO study group. Cardiopulmonary resuscitation by bystan- ders with chest compression only (SOS-KANTO): an observational study. Lancet 2007;369(9565):920-6.
16. Virkkunen I, Kujala S, Ryynanen S, Vuori A, Pettila V, Yli-Hankala A, et al. Bystander mouth-to-mouth ventilation and regurgitation during cardiopulmonary resuscitation. J Intern Med 2006;260(1):39-42.