Elsevier

Resuscitation

Volume 70, Issue 1, July 2006, Pages 117-123
Resuscitation

Training and educational paper
Comparison of mouth-to-mouth, mouth-to-mask and mouth-to-face-shield ventilation by lay persons

https://doi.org/10.1016/j.resuscitation.2005.03.024Get rights and content

Summary

Objective and methods

A prospective randomised study on 70 volunteers without previous first aid education (42 males, 28 females, mean age 17) was performed to compare mouth-to-mouth ventilation (MMV, n = 24) versus mouth-to-pocket-mask ventilation (MPV, n = 25) and mouth-to-face-shield ventilation (MFV, n = 21), and to evaluate if an instruction period of 10 min would be sufficient to teach lay persons artificial ventilation. Every volunteer performed three ventilation series using a bench model of an unprotected airway.

Results

MMV and MPV show higher mean tidal volume (TV) than MFV (values of series 3: 976 ± 454 and 868 ± 459 versus 604 ± 328 ml, P = 0.002 and P = 0.025, respectively). We found a higher inter-individual variation in TV than in previous studies (P = 0.031). The recommended TV of 700–1000 ml was reached in only 23%, most frequently with MPV (MMV 16.7%, MPV 32%, MFV 19%) but the difference was not significant (P = 0.391). However, we found a significantly higher percentage with a TV below 700 ml with MFV (MMV 33.3%, MPV 36%, MFV 66.7% P = 0.047) and a significantly higher percentage of TV exceeding 1000 ml with MMV (MMV 50%, MPV 32%, MFV 14.3%) (P = 0.039). “Stomach” inflation was highest with MMV (79.2%) followed by MPV (52%) and MFV (42.9%) (P = 0.034). We found further differences between the sexes; males produced a higher TV (P = 0.003) and a higher percentage of stomach inflation (P = 0.029).

Conclusion

MPV showed the best ventilation quality. It resulted in a more adequate TV than MMV and MFV and lower stomach inflation than MMV. Only a relatively low percentage of ventilations were within the recommended range for TV and this may be related to the short training duration. We found different performances between the sexes, a high inter-individual variation and mainly a low ventilation quality. Therefore, further studies have to focus more on teaching duration, sex differences and ventilation quality.

Introduction

Mouth-to-mouth-ventilation (MMV) is the standard technique for ventilation in Basic Life Support. MMV has been proven to be an efficient ventilation method.1, 2, 3 Nevertheless some authors have noted a lack of willingness to ventilate a patient by the mouth-to-mouth technique in witnessed respiratory arrest,4 because of concern about a potential infection.5, 6, 7 Due to these potential risks, rescuers prefer to use a barrier device during ventilation in CPR.3, 4, 8 Safer ventilation techniques for lay rescuer ventilation have been developed to overcome the problems inherent to MMV. Mouth-to-mask and mouth-to-face-shield ventilation techniques (MFV) have been introduced to encourage lay rescuers to perform artificial ventilation; their effectiveness was studied thoroughly.1, 2, 8, 9, 10, 11, 12, 13, 14 Several mouth-to-mask-ventilation devices met the criteria for adequate ventilation.1, 10, 11 On the other hand mouth-to-face shield devices failed to demonstrate the capacity to provide sufficient tidal volume (TV).9 Therefore, the ILCOR 2000 guidelines stated that “the efficacy of face shields has not been documented conclusively”, and suggested that “healthcare professionals and rescuers with a duty to respond should use face shields only as a substitute for mouth-to-mouth breathing and should use mouth-to-mask or bag-mask devices at the first opportunity”.15

So far no prospective study has been carried out on the efficiency of MMV in comparison with mouth-to-mask and MFV, provided by lay persons. Moreover, no data has been published yet, on the time needed to train lay persons sufficiently in these ventilation techniques.

Our study aimed to compare MMV with MPV and MFV, and to assess if a short period of instruction of 10 min would be sufficient to teach lay rescuers the necessary skills for proper ventilation.

Section snippets

Methods

The study was undertaken in a high school in Bruneck, Italy, at 840 m above sea level. Seventy unpaid, voluntary students (28 females, 42 males) participated having given informed, written consent. Mean age was 17.3 ± 0.7 years (range 16–20). Mean height was 178.4 ± 6.1 cm for males and 167.2 ± 6.3 cm for females. No differences in sex or age distribution was observed between the three ventilation groups (P = 0.57 Chi-Square Test). No volunteer had attended any first aid instruction before.

Before the

Results

The results of the three test series with MMV, MPV and MFV regarding TV, MV, PAP, ventilation quality and stomach inflation are given in Table 1. For TV we found overall significant differences between ventilation techniques (P = 0.029, ANOVA) and marginally significant differences for MV (P = 0.061) and PAP (P = 0.058). In TV we found that MFV had significantly lower values in three series than MMV (P = 0.002) and MPV (P = 0.025, ANOVA). Our observed pooled standard deviation (s) of the three test

Discussion

In our study we had to deal with a higher inter-individual variation in TV compared with other studies.1, 9 We suppose that this finding is related to the fact that we used non-medically trained persons in contrast to other studies, where medically trained personnel performed the ventilation tests.1, 9 Moreover, in contrast to other studies,13, 17 we used a bench model with a freely movable head (Figure 1), where candidates had to maintain a patent airway.

In spite of the observed variation we

Limitations

With a mean age of 17 years our study population was younger than in other studies, but the mean TV of 1040 ml achieved was comparable to values obtained by trained persons in other studies (1040 in1 and 1000 in9). All tests were performed on a manikin and may not reflect the situation of real CPR. In real life CPR, bystander rescuers are prone to even higher stress levels. The time between learning a ventilation technique and performing it may be months, or years, rather than hours. Moreover,

Conclusions

We infer from our data that MPV leads to best ventilation quality in bystander CPR. MPV results in a more appropriate TV than MMV and MFV and lower stomach inflation than MMV. The efficiency of ventilation with MFV was not adequate in accordance to previous publications.9 MPV seems to have substantial advantages over MMV: MPV reduces the risk of infection and should lower the barrier for a bystander to perform CPR. Additionally, PAP is moderate, resulting in less stomach inflation than with

Acknowledgements

The authors thank Alfred Niederhofer MPhil, head of the high school Realgymnasium in Bruneck, and all students who participated. We are also indebted to Michael de Zordo and the members of the Mountain Rescue Service, provided by the Alpine Club of Bruneck, for technical and logistic support. Material was provided by the South Tyrolean Mountain Rescue Service.

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    A Spanish translated version of the summary of this article appears as Appendix in the online version at doi:10.1016/j.resuscitation.2005.03.024.

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