Airway/original research
Comparison of Bag-Valve-Mask Hand-Sealing Techniques in a Simulated Model

Presented at the Society for Academic Emergency Medicine Western Regional annual meeting, February 2011, Keystone, CO; and the Society for Academic Emergency Medicine annual meeting, June 2011, Boston, MA.
https://doi.org/10.1016/j.annemergmed.2013.07.014Get rights and content

Study objective

Bag-valve-mask ventilation remains an essential component of airway management. Rescuers continue to use both traditional 1- or 2-handed mask-face sealing techniques, as well as a newer modified 2-handed technique. We compare the efficacy of 1-handed, 2-handed, and modified 2-handed bag-valve-mask technique.

Methods

In this prospective, crossover study, health care providers performed 1-handed, 2-handed, and modified 2-handed bag-valve-mask ventilation on a standardized ventilation model. Subjects performed each technique for 5 minutes, with 3 minutes’ rest between techniques. The primary outcome was expired tidal volume, defined as percentage of total possible expired tidal volume during a 5-minute bout. A specialized inline monitor measured expired tidal volume. We compared 2-handed versus modified 2-handed and 2-handed versus 1-handed techniques.

Results

We enrolled 52 subjects: 28 (54%) men, 32 (62%) with greater than or equal to 5 actual emergency bag-valve-mask situations. Median expired tidal volume percentage for 1-handed technique was 31% (95% confidence interval [CI] 17% to 51%); for 2-handed technique, 85% (95% CI 78% to 91%); and for modified 2-handed technique, 85% (95% CI 82% to 90%). Both 2-handed (median difference 47%; 95% CI 34% to 62%) and modified 2-handed technique (median difference 56%; 95% CI 29% to 65%) resulted in significantly higher median expired tidal volume percentages compared with 1-handed technique. The median expired tidal volume percentages between 2-handed and modified 2-handed techniques did not significantly differ from each other (median difference 0; 95% CI –2% to 2%).

Conclusion

In a simulated model, both 2-handed mask-face sealing techniques resulted in higher ventilatory tidal volumes than 1-handed technique. Tidal volumes from 2-handed and modified 2-handed techniques did not differ. Rescuers should perform bag-valve-mask ventilation with 2-handed techniques.

Introduction

Bag-valve-mask ventilation is an essential element of emergency airway management. Rescuers usually accomplish mask sealing against the face with 1-handed or 2-handed techniques, with the thumb and index finger wrapped in a “C” shape around the mask apex and the remaining fingers lifting the jaw.1, 2 Limited literature has shown that the 2-handed mask-face sealing technique is likely superior to the 1-handed bag-valve-mask technique.3, 4, 5, 6 However, previous studies and clinical experience suggest that mask-face sealing with the traditional 2-handed technique can be difficult in certain patients.2, 7, 8 Some clinicians use a newer modified 2-handed technique that shifts the third fingers of both hands down to the angle of the jaw to pull upward and uses the thenar eminence and thumb to apply downward force on the mask (Figure 1).9

The modified 2-handed bag-valve-mask technique could enhance the effectiveness of the 2-handed sealing technique by creating a tighter seal between the mask and face, especially for providers with small hands or weaker grip strength or for patients predicted to be difficult for bag-valve-mask ventilation.7 The efficacy of the modified 2-handed technique has not been studied.

Editor’s Capsule Summary

What is already known on this topic

Achieving a mask seal during bag-valve-mask ventilation is difficult.

What question this study addressed

Is bag-valve-mask seal best with 1-handed, 2-handed, or modified 2-handed technique?

What this study adds to our knowledge

In this controlled trial using a standardized ventilation mannequin, 2-handed mask sealing resulted in higher tidal volumes than 1-handed technique. Tidal volumes for 2-handed and modified 2-handed techniques were similar.

How this is relevant to clinical practice

Although these mannequin-based results require in vivo validation, the findings support bag-valve-mask ventilation with 2-handed mask-sealing techniques.

Our primary aim was to compare the efficacy of 2-handed and modified 2-handed bag-valve-mask mask-face sealing techniques among health care providers using a simulated ventilation model. We also compared the efficacy of each 2-handed bag-valve-mask technique to the 1-handed technique. We hypothesized that the modified 2-handed technique would provide greater expired tidal volume than the 2-handed technique. We also hypothesized that both 2-handed techniques would provide greater expired tidal volume than the 1-handed technique.

Section snippets

Study Design

In this prospective, crossover study, study participants performed 1-handed, 2-handed, and modified 2-handed bag-valve-mask technique on a simulated ventilation model. The Colorado Multiple Institutional Review Board approved this study, and written informed consent was obtained from all subjects.

We designed a semiclosed-circuit simulated model specifically for this study (Figure 2). This model consisted of a mechanical ventilator (Puritan Bennett 7200 Mechanical Ventilator; Covidien-Nellcor

Characteristics of Study Subjects

We enrolled a total of 52 subjects. The majority of subjects were attending physicians, residents, or medical students (Table 1). The subjects had a diversity of experience levels for bag-valve-mask ventilation in both emergency and difficult situations.

Main Results

All subjects completed the study protocol. Because of a failure in the Novametrix NICO device, data were missing for 1 subject during the 1-handed bag-valve-mask technique session; this observation was omitted from all comparisons involving

Limitations

We used a simulated model mimicking the bag-valve-mask ventilation of actual patients. Although our model allowed us to test our hypothesis in a highly controlled and consistent environment, it is unclear whether the same results would be achieved in a human model. Even with appropriate mask-face sealing technique, effective bag-valve-mask ventilation in practice can depend on factors not evaluated in our study, such as nasal or oral airways, head positioning, and patient facial characteristics.

Discussion

In this comparison of bag-valve-mask hand-sealing techniques in a simulated ventilation model, subjects achieved high and similar expired tidal volume with both the 2-handed and modified 2-handed techniques. Consistent with previous studies, both 2-handed techniques exhibited higher expired tidal volume percentages than the 1-handed technique.3, 4, 5, 6 An exploratory examination of subgroups showed that men were able to achieve a greater expired tidal volume percentage than women with both

References (13)

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Supervising editor: Henry E. Wang, MD, MS

Author contributions: MML conceived the study, supervised the conduct of the trial and data collection, and performed management and data analysis. DO, MML, RW, RM, AK, WB, and ED performed data collection. RW, ISD, RLB, and JSH provided statistical and data analysis advice. DO and MML drafted the article. All authors contributed substantially to the design, interpretation of data, article revision, and approved of the final article. MML takes responsibility for the paper as a whole.

Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist. Dr. Liao was supported by the Agency for Healthcare Research and Quality (AHRQ) (F32 HS018123), and Dr. Haukoos was supported by the AHRQ (K02 HS017526) and the National Institutes of Health (R01AI106057).

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