Bag Valve Mask Ventilation Technique and Predictors of Difficult Mask Ventilation
Critical Care / Resuscitation, Respiratory
- BMV is an airway management technique used to provide oxygenation and ventilation. It is a critical skill required for the resuscitation and intubation of a patient.
- Effective BMV can buy time during a difficult intubation.
Predicting difficult BMV is an inexact science, and most difficult cases are unanticipated Memory device “MOANS” to assess for a potentially difficult BMV.
- Mask seal – bushy beards, crusted blood on face, disruption of lower facial continuity.
- Mallampati III or IV.
- Minimal jaw protrusion.
- Male gender.
- Obese – BMI > 30.
- Obstructing lesions – angioedema, Ludwig angina, upper airway abscesses, epiglottitis.
- Age greater than 55 – due to loss of muscle and tissue tone in upper airway.
- No teeth – inadequate mask seal, face tends to cave in.
- Neck – radiation, fixed flexion deformity.
- Obstructive Sleep apnea.
- Stiff lungs – asthma, pulmonary edema, restrictive lung disease.
Performing a proper BMV technique depends on three key steps:
- Create a patent airway with a jaw thrust by translating the mandible anteriorly.
– Once jaw thrust is achieved, you can maintain patency with airway adjuncts (OPA, NPA) unless contraindicated (see below). Airway adjuncts can be helpful for patients with a high BMI or OSA.
- Ensure adequate mask seal by lifting the mandible up towards the mask.
– Ensure proper mask size – lower border of mask cuff between groove of lower lip and chin. Upper border is placed down across nasal bridge.
– Two handed techniques are preferred. Use your preferred hand positioning (e.g. E-C grip) to lift the mandible up towards the mask.
- Adequate ventilation with the goal of visible chest rise at 10-12 breaths/min.
– Avoid aggressively squeezing the bag as it can cause gastric distension. If a manometer is available, keep airway pressure less than 20cm H2O.
Difficult BMV is most often due to a functionally obstructed airway. Troubleshoot by going through the following steps:
- Reposition head with exaggerated chin lift (if no c-spine precautions) and aggressive jaw thrust.
- Insert OPA and up to two NPAs if not already inserted.
- Perform two-person mask ventilation technique if not already done.
- Consider mask change if seal is an issue.
- Consider rescue ventilation device (LMA).
- Consider early attempt at intubation.
Oropharyngeal airways (OPA) relieve functional airway obstruction caused by the relaxation of tongue against the soft palate.
- Ensure correct sizing by placing along cheek. From the corner of the mouth, the tip should reach the angle of the mandible.
- Insert with the tip pointing up then rotate 180 degrees to avoid posterior tongue displacement.
- Not well tolerated in awake or semi-conscious patients with intact airway reflexes. Will stimulate gagging, laryngospasm, vomiting, and aspiration.
Nasopharyngeal airways (NPA) are useful for the awake or semi-conscious patient or where trismus precludes OPA insertion.
- Ensure correct sizing, the length of the airway should reach from nose tip to tragus of ear.
- Insert perpendicular to the face.
- Relative contraindication in known bleeding diathesis and cribriform plate fractures.
- Jaw thrust is the safest maneuver to open functional obstruction for patients with potential cervical spine injury. Avoid chin lift and c-spine extension for patients with c-spine precautions.
- A common pitfall with inadequate mask seal is to increase downwards pressure on the mask which increases functional airway obstruction. Bring the mandible up towards the mask instead.
- Mask seal can be difficult for edentulous patients. Seal can be improved by leaving dentures in place, packing gauze rolls into cheeks, and medial compression of soft tissues against outside margins of cuff.
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Predicting difficult BMV is difficult – Moderate quality evidence. Multiple large prospective studies.
Two-handed jaw thrust technique – Moderate quality evidence. Few randomized controlled trials showing superiority over one handed technique.
Norskov AK, Rosenstock CV, Wetterslev J, e t al. Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice-a cohort study of 1 88,064 patients registered in the Danish Anaesthesia Database. Anaesthesia 20 1 5;70:272-28 1.
Kheterpal S, Han R, Tremper KK, et al. Incidence and predictors of difficult and impossible mask ventilation. Anesthesiology. 2006; I 0 5 : 8 8 5-89 1.
Joffe AM, Hetzel S, Liew EC. A two-handed jaw-thrust technique is superior to the one-handed “EC-clamp” technique for mask ventilation in the apneic, unconscious person. Anesthesiology. 2010;113:873–875.
Racine SX, Solis A, Hamou NA, et al. Face mask ventilation in edentulous patients. A comparison of mandibular groove and lower lip placement. Anesthesiology. 2010;112:1190–1193.
OTHER RELEVANT INFORMATION
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by Emergency Care BC (formerly the BC Emergency Medicine Network) and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. Emergency Care BC is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. Emergency Care BC also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Jan 19, 2022
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