Bag-valve-mask (BVM) ventilation is the standard method for rapidly providing rescue ventilation to patients with apnea or severe ventilatory failure.
(See also Airway Establishment and Control, How To Do Head Tilt–Chin Lift and Jaw-Thrust Maneuvers, How To Insert an Oropharyngeal Airway, and How To Insert a Nasopharyngeal Airway.)
In BVM ventilation, a self-inflating bag (resuscitator bag) is attached to a nonrebreathing valve and then to a face mask that conforms to the soft tissues of the face. The opposite end of the bag is attached to an oxygen source (100% oxygen) and usually a reservoir bag. The mask is manually held tightly against the face, and squeezing the bag ventilates the patient through the nose and mouth. Unless contraindicated, airway adjuncts such as nasopharyngeal and/or oropharyngeal airways are used during BVM ventilation to assist in creating a patent airway. Positive end expiratory pressure (PEEP) valves should be used if further assistance is needed for oxygenation without contraindications to its use.
Successful BVM ventilation requires technical competence and depends on 4 things:
A patent airway
An adequate mask seal
Proper ventilation technique
PEEP valve as needed to improve oxygenation
Establishing a patent airway for BVM ventilation requires
Keeping the oropharynx clear of physical obstructions (eg, tongue, soft palate, secretions, vomitus, foreign bodies)
Proper patient positioning and manual maneuvers to relieve tongue and soft tissue obstruction of the upper airway
Airway adjuncts such as a nasopharyngeal or oropharyngeal airway to facilitate effective air exchange (see also Airway Establishment and Control)
Rapid provision of successful ventilation and oxygenation is the goal.
Indications for BVM Ventilation
Emergency ventilation for apnea, respiratory failure, or impending respiratory arrest
Pre-ventilation and/or oxygenation or interim ventilation and/or oxygenation during efforts to achieve and maintain definitive artificial airways (eg, endotracheal intubation)
Contraindications for BVM Ventilation
Absolute contraindications
There is no medical contraindication to providing ventilatory support to a patient; however, a legal contraindication (do-not-resuscitate order or specific advance directive) may be in force.
Relative contraindications
None
Complications of BVM Ventilation
If bag-valve-mask ventilation is used for a prolonged period of time or if improperly performed, air may be introduced into the stomach. If this occurs and gastric distention is noted, a nasogastric tube should be inserted to evacuate the accumulated air in the stomach.
Equipment for BVM Ventilation
Gloves, mask, gown, and eye protection (ie, universal precautions)
Oropharyngeal airways, nasopharyngeal airways, lubricating ointment
Bag-valve apparatus
PEEP valve
Variably sized ventilation face masks
Oxygen source (100% oxygen, 15 L/minute)
Nasogastric tube
Suctioning apparatus and Yankauer catheter; Magill forceps (if needed to remove easily accessible foreign bodies and patient has no gag reflex) to clear the pharynx as needed
Pulse oximeter
Capnography equipment
Additional Considerations for BVM Ventilation
Two-person bag-valve-mask (BVM) ventilation is used whenever possible. Bag-valve-mask ventilation can be done with one person or two, but two-person BVM ventilation is easier and more effective because a tight seal must be achieved and this usually requires 2 hands on the mask.
Unless contraindicated, a pharyngeal airway adjunct is used when performing BVM ventilation. An oropharyngeal airway is used unless the patient has an intact gag reflex; in such cases, a nasopharyngeal airway (nasal trumpet) is used. Bilateral nasopharyngeal airways and an oropharyngeal airway are used if necessary for ventilation.
Characteristics that predict difficult bag ventilation (and can thus help troubleshoot if ventilation is difficult) are described by the mnemonic MOANS:
M – Mask seal: Facial hair or facial trauma can interfere with creating an adequate seal.
O – Obesity/Obstruction: Obesity can be a sign of increased soft tissue in the airway and thus may cause further occlusion when the patient is obtunded. Obstruction by other soft tissues or a foreign body can also prevent adequate ventilation.
A – Age: Extremes of age can predict who may be difficult to ventilate using a BVM due to anatomical changes.
N – No teeth. Performing BVM on a patient without teeth is usually ineffective; a supraglottic airway may be indicated.
S – Snoring: Snoring respirations can indicate that soft tissue, usually the tongue, is occluding the airway and that repositioning (eg, head-tilt, chin-lift. jaw thrust) is required.
A positive end expiratory pressure (PEEP) valve may be used during BVM to improve oxygenation. PEEP can increase alveolar recruitment and thus oxygenation if oxygenation is compromised even with 100% oxygen due to atelectasis. PEEP has also been shown to prevent lung injury. However, PEEP should be used cautiously in patients who are hypotensive or pre-load dependent because it reduces venous return.
Relevant Anatomy for BVM Ventilation
Aligning the external auditory canal with the sternal notch may help open the upper airway to maximize air exchange and establishes the best position to view the airway if endotracheal intubation becomes necessary.
The degree of head elevation that best aligns the ear and sternal notch varies (eg, none in children with a large occiput, a large degree in obese patients).
Positioning for BVM Ventilation
The sniffing position—only in the absence of cervical spine injury
Position the patient supine on the stretcher.
Align the upper airway for optimal air passage by placing the patient into a proper sniffing position. Proper sniffing position aligns the external auditory canal with the sternal notch. To achieve the sniffing position, folded towels or other materials may need to be placed under the head, neck, or shoulders, so that the neck is flexed on the body and the head is extended on the neck. In obese patients, many folded towels or a commercial ramp device may be needed to sufficiently elevate the shoulders and neck. In children, padding is usually needed behind the shoulders to accommodate the enlarged occiput.
Head and neck positioning to open the airway: Sniffing position
A: The head is flat on the stretcher; the airway is constricted. B: The ear and sternal notch are aligned, with the face parallel to the ceiling (in the sniffing position), opening the airway. Adapted from Levitan RM, Kinkle WC: The Airway Cam Pocket Guide to Intubation, ed. 2. Wayne (PA), Airway Cam Technologies, 2007. |
If there is concern for cervical spine injury:
Position the patient supine or at a slight incline on the stretcher.
Position yourself at the head of the stretcher.
Avoid moving the neck and, if possible, use only the jaw-thrust maneuver or chin lift without head tilt to manually facilitate opening of the upper airway.
Step-by-Step Description of BVM Ventilation
Insert an oropharyngeal airway (unless the patient has a gag reflex) or one to two nasopharyngeal airways prior to bag-valve-mask (BVM) ventilation.
Select a mask that fits over the mouth and nose but spares the eyes.
Do two-person BVM ventilation if possible. (NOTE: The accompanying video presents the one-person technique first.)
Use waveform capnometry to monitor end tidal CO2 levels to assess adequacy of ventilations.
Two-person mask technique
In the two-person technique, the more experienced operator handles the mask, because maintaining a proper mask seal is the most difficult task. The second operator squeezes the bag.
Stand at the head of the stretcher and have the second operator stand to the side.
Using both hands, hold the mask between your thumbs and index fingers placed on either side of the connector stem.
Making sure not to place your hands or the mask on the patient’s eyes, first place the nasal portion of the mask over the nose high enough to cover the bridge without air leaks. Next, lower the mask over the chin and allow it to seal along the 2 malar eminences. Cover the bridge of the nose, the 2 malar eminences, and the patient's lower lip by the mask to achieve a proper seal. Stretching the internal portion of the mask before placing it over the nose and mouth can help create a tighter seal.
Traditional hand placement is the "C-E" grip, placing the middle, ring, and little fingers (the "E") under the mandible and pulling the mandible upward, while the thumbs and index fingers create a "C" and then press down against the mask.
An alternative, often preferred, method (1, 2) can be used in which the thenar eminences (muscles at the base of the thumb) hold the mask to the face. Place the thenar eminences (the base of the thumbs in the palm) along each lateral edge of the mask. Then lower the mask onto the face and place the other 4 fingers under the mandible. Press the mask to the face with the thenar eminences while pulling the mandible upward with the fingers. Head tilt may be applied concurrently. This technique is easier to perform; allows the use of stronger hand muscles to maintain a proper seal, minimizing fatigue; and enables 4 fingers rather than 3 to lift the mandible (accomplishing chin lift and jaw thrust).
If using the traditional hand placement, provide a head tilt–chin lift maneuver by pulling up on the mask and patient’s face with your middle, ring, and little fingers while holding the mask onto the patient’s face, to further open the airway. If your hands are large enough, place your little fingers behind the mandibular rami to do a jaw-thrust maneuver. This re-positioning helps to direct air into the trachea rather than into the esophagus and prevents gastric distention.
Be sure to pull up only on the bony parts of the mandible, because pressure to the soft tissues of the neck or under the chin may obstruct the airway.
Once a proper seal is achieved, have the second operator attach the bag to the mask and begin ventilation.
One-person mask technique
Using one hand, hold the mask, with your thumb and index finger wrapped around the connector stem of the mask. Most operators use their nondominant hand to grasp the mask, but either hand can be used as long as a good mask seal can be maintained.
Making sure not to place your hand or the mask on the patient’s eyes, first place the nasal portion of the mask over the nose, and then lower the body over the patient’s mouth. The bridge of the nose, the 2 malar eminences, and the mandibular alveolar ridge must be covered by the mask in order to achieve a proper seal.
Now extend your middle, ring, and little fingers underneath the patient’s mandible, and pull it upward into the mask. This maneuver is similar to that of the head tilt–chin lift technique and further opens the airway.
While maintaining this upward traction on the mandible, press the mask downward onto the face to attain a tight mask seal. If your hand is large enough, place your little finger behind the mandibular ramus to do a jaw-thrust maneuver to further open the airway.
Be sure to pull up only on the bony parts of the mandible, because pressure to the soft tissues of the neck or under the chin may obstruct the airway.
Once a proper seal is achieved, use your other hand to begin ventilation.
Bag ventilation and oxygenation
For each breath, steadily and smoothly squeeze the bag to deliver a tidal volume of 6 to 7 mL/kg (or about 500 mL for an average size adult) over 1 second, and then release the bag to allow it to reinflate. If using a 1000-mL volume bag, squeeze only halfway to obtain the correct tidal volume.
In cardiac arrest cases, do not exceed 8 to 10 breaths per minute (ie, one complete breath every 6 to 7.5 seconds).
Observe for proper chest rise during ventilations; in practice, you can use a tidal volume just large enough to cause the chest to rise.
Monitor the patient, checking breath sounds and, if possible, end-tidal carbon dioxide and pulse oximeter. (Pulse oximetry may not be useful during cardiac arrest due to poor peripheral perfusion.) Assess if adequate ventilation is continuous and sustainable or is requiring too much physical effort. If available, use waveform capnography, an excellent indicator of mask seal and proper ventilation.
If oxygenation is inadequate despite proper form and use of 100% oxygen, attach a positive end expiratory pressure (PEEP) valve to recruit more alveoli for gas exchange. Set the PEEP valve initially at 5 and increase as needed to improve oxygen saturation. However, avoid PEEP in hypotensive patients.
If ventilation or oxygenation is still not adequate, prepare for other airway maneuvers such as a supraglottic airway or endotracheal intubation.
Aftercare for BVM Ventilation
If a patient becomes more conscious or a gag reflex returns while doing BVM ventilation with an oropharyngeal airway in place, remove the oropharyngeal airway and provide continued treatment as appropriate. A nasopharyngeal airway may be better tolerated.
If endotracheal intubation is necessary, ventilate using maximum FiO2 through a non-rebreather mask for 3 to 5 minutes before inserting the tube if feasible; if this is not feasible because intubation must proceed immediately, pre-oxygenate the patient by giving 5 to 8 vital capacity breaths using a PEEP valve.
Warnings and Common Errors for BVM Ventilation
Do not place your hands or the mask on the patient’s eyes. Doing so may damage the eyes or cause a vagal reaction.
Tips and Tricks for BVM Ventilation
Neither excessive force nor rapid insufflation should be used to ventilate; doing so increases gastric distention, compromising ventilation.
A nasogastric tube is inserted to help decompress the stomach when possible.
References
1. Soleimanpour M, Rahmani F, Ala A, et al: Comparison of four techniques on facility of two-hand bag-valve-mask (BVM) ventilation: E-C, thenar eminence, thenar eminence (dominant hand)-E-C (non-dominant hand) and thenar eminence (non-dominant hand) - E-C (dominant hand). J Cardiovasc Thorac Res 8(4):147-151, 2016. doi:10.15171/jcvtr.2016.30
2. Otten D, Liao MM, Wolken R, et al: Comparison of bag-valve-mask hand-sealing techniques in a simulated model. Ann Emerg Med 63(1):6-12.e3, 2014. doi:10.1016/j.annemergmed.2013.07.014
More Information
The following is a English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Jarvis JL, Gonzales J, Johns D, et al: Implementation of a clinical bundle to reduce out-of-hospital peri-intubation hypoxia. Ann Emerg Med 72(3):272-279.e1, 2018. doi.org/10.1016/j.annemergmed.2018.01.044.
