Justin Krantz Discusses Pragmatic BVM Use

Justin Krantz Discusses Pragmatic BVM Use

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I'm sure we can all remember sitting down in our first airway class wondering what that big ol’ bag looking thing was with a mask on it. What we didn’t know at the time was that piece of equipment was about to become a massive part of our care in our patients we tend to daily. So, what is a bag valve mask (BVM)?

A BVM is a piece of medical equipment we use to administer oxygen at high flow, it provides controlled ventilation, and oxygenation during spontaneous ventilation [1]. I am sure you sat there asking yourself, "What is a BVM?", well, let me tell you. It's a self-inflating resuscitation device that is made from plastic materials that re-expands after being manually collapsed [1].


These BVM's come in all sizes; according to Life in the Fast Lane (2019) we have sizes for infants (approximately 240mL), children (about 500mL), and adults (approximately 1600mL). Some BVM's have a reservoir bag at the end of it that fills up when hooked up to oxygen. The BVM hooks up to oxygen via the oxygen inlet nipple. The oxygen reservoir has two one-way valves when this oxygen reservoir is hooked up to oxygen. It allows up to 100% of oxygen to be delivered to the patient [2]. When it comes to the inlet valve, it allows room air to enter if fresh gas flow is inadequate, and an outlet valve allows for oxygen to flow out if pressure is excessive. At the "head" of the BVM, we have a standard 15mm adapter that can be used for attaching the mask or endotracheal tubes and supraglottic airways.


When it comes to  (peak end-expiratory end pressure) PEEP, some BVM's allow an attachment of a PEEP valve to the exhalation port or some have them already built-in. PEEP can be used to improve oxygenation. PEEP can increase alveolar recruitment and has been shown to prevent lung injury.

The BVM also has a built-in pop-off valve. It releases at approximately 60 cmH20.


How to Use a BVM


The first thing you want to do is to make sure you have the right BVM for the right patient. Then you want to attach the BVM to high flow oxygen (e.g., 15L/min). Make sure you have selected the proper airway adjunct (OPAs and NPAs) and place the mask over the nose and mouth. Make sure you provide an adequate tight fit if enough manpower is present use the two-handed thumbs down technique  (with an assistant bagging) in preference to the less effective one-handed E-C  grip that has been taught. We want to make sure we have airway patency. The BVM is used to deliver oxygen to a spontaneously breathing patient, or you can compress the BVM to manually ventilate the patient via the mask, endotracheal tube, or supraglottic airway.


Make sure you do deliver effective ventilations. The way you can ensure this occurs is to make is to attach a SpO2 and EtCo2 monitoring. You want to provide a breath over 1-2 seconds with adequate chest rise and fall. You should never need to squeeze the whole bag. We need to be careful with how we are ventilating because we can cause some complications with improper use of the BMV.


Here are some complications:


hyperventilating your patients due to your adrenaline lack of attention from or distractions the call.

An improper seal with the mask you may not provide appropriate ventilations.

The inability to gauge tidal volumes accurately.

And, you can cause gastric distention, the most common culprit for this is the one-handed E-C grip that is commonly used. When we cause gastric distension, these patients can tend to vomit, and now the risk of aspiration has climbed tremendously [2] [3].

Be careful there is a risk of causing barotrauma if the pop-off valve was not working appropriately and or applying to much PEEP.


It is vital to know our equipment so that we can use it to its fullest capacity. It is essential to understand what a BVM is because we shouldn't (rapid sequence inductions) RSI someone we can't ventilate. And the easiest way to ventilate someone is a BVM.


Here are some tips you can use to help ventilate your patients:


You can use the "Lower lip" technique. In this technique, you reposition the mask more superiorly to improve the BVM seal. Usually, the inferior edge of the mask sits between the lower lip and chin alveolar ridge. All you need to do is move the mask 2-3 cm more superiorly. The reason why I like this technique because the median air leak volume is very minimal when using this technique. When using the traditional BVM technique, you have an average of 400cc/ml leak vs. the lower lip face mask technique. You have an average of a 10cc/ml leak.


Use the BONES mnemonic for assessing the likelihood of the mask seal, Beard, Obese, No teeth, Elderly, Sleep apnea/snoring [5]

Use (JAWSS) as a mnemonic for the two-handed, two thumbs down technique. Jaw thrust, Airway adjuncts, Work together, Slow, and Small squeezes.


We also need to consider the position of our patients. Hyperextension of the neck, the "head tilt chin lift" for an example may help you open the airway but might not the best position for the patient, especially if they're about to get intubated. The ear of the patient should be level with the sternal notch to ensure that the place of the mouth and the larynx are in alignment. This ensures that, when the laryngoscope is used, it is easier for the person intubating to visualize the anatomy of the airway. This helps achieve the "sniffing" position. This position has also been known to help patients with large body habitus. The facial planes must be parallel with the ceiling as hyperextending the next may make the airway more challenging to visualize and to ventilate. I'm sure you may have also heard of the large Tegaderm on the beard to allow for a better mask seal, but the best mask seal is using the two-handed thumbs down technique [3].


I  firmly believe in BLS before ALS, and I hope this review of the BVM aids in managing your next patient's airway.


Justin Krantz, CCEMT-P 



References

[1]

A. Khoury, S. Hugonnot, J. Cossus, A. De Luca, T. Desmettre, S. F. Sall and G. Capellier, "From mouth-to-mouth to bag-valve-mask ventilation: Evolution and charateristics of actual devices - A review of the literature," Biomed Research Internation, vol. 2014, pp. 1-6, 2014.

[2]

ACLS Certification Institute, "What you need to know about bag-valve mask devices (BVMs)," 2020. [Online]. Available: https://acls.com/free-resources/knowledge-base/bls-articles/what-you-need-to-know-about-bag-valve-mask-devices-bvms.

[3]

J. Bucher, "Bag mask ventilation (bag valve mask, BVM)," Statpearls, 2020.

[4]

D. Saddawi-Konefka, S. L. Hung, R. M. Kacmarek and Y. Jiang, "Optimizing mask ventilation: Literature review and development of a conceptual framework," Respiratory Care, vol. 60, no. 12, pp. 1834-1840, 2015.

[5]

J. Bucher and J. Cooper, "Bag mask ventilation (Bag valve mask, BVM)," Statpearls, 2019.