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One of the most likely procedures to save a patient's life that a provider can learn is bag-mask ventilation. Patients in respiratory distress who are resuscitated prior to progressing to cardiovascular arrest have much higher chances of survival. This need for assisted ventilation usually arises from either poor respiratory effort (opioid overdose, sedation, brain injury, asthma, etc.) or airway obstruction (soft tissue obstruction, secretions, etc.). After identifying the acute need for assisted ventilation immediate use of bag-mask ventilation is usually indicated.
In any patient with suspected c-spine injury, immediate immobilization of their spine is indicated. Bag-mask ventilation can still be performed with a c-collar in place as can a jaw-thrust. However, movement of the head into optimal positioning (head tilt, chin lift) is not possible and may make ventilation more difficult. Patients expected to require bag-mask ventilation for an extend period of time should undergo endotracheal intubation.
Optimizing airway positioning assists the effectiveness of both the patient's own ability to breath and with bag-mask ventilation. Adults may benefit from support behind their occiput to bring their airway into a strait line position. Infants have large occiputs and anterior airways and benefit from support behind their shoulders allowing their occiput to fall back and their chin to be tilted up (hyperextension should be avoided however). Young children fall in-between these two anatomical situations and are best ventilated flat with their airways midline. In patients where c-spine injury is NOT a concern, a head tilt - chin lift maneuver can help lift the tongue from the posterior pharynx and improve ventilation. A jaw thrust can be used even in c-spine patients and also improves airway patency.
Oropharyngeal (OPA) and nasopharyngeal (NPA) airway devices may be helpful during bag mask ventilation to remove or bypass obstruction of the airway by the soft tissues of the pharynx. OPAs should only be used in unconscious or deeply sedated patients as they may cause an awake patient to gag and vomit. They need to be properly sized to the angle of the jaw and when inserted care should be made not to push the tongue deeper into the pharynx. NPAs (nasal trumpets) can be used in awake patients and patients who have clenched their jaw. They also need to be sized to the mandible and require lubrication. Patients with severe mid-face or basilar skull fractures should likely not have a NPA.
There are two common bag types available to most providers: flow-inflating or self-inflating bags. Flow-inflating bags required a continuous air pressure source to fill and are generally more difficult to use and less preferred for resuscitation. Self-inflating bags conversely are easier to use and have been found to deliver less oxygen at higher ventilation rates. They also do not require an oxygen source and thus are more mobile. Until a provider is adequately experienced with a flow-inflating bag, a self-inflating bag should be used in most cases.
Bag-mask ventilation can be performed by one or more providers. The American Heart Association teaches the "E-C clamp technique" if only one provider is present. In this technique the provider places the mask with the narrow part resting on the bridge of the nose. Then with one hand, the provider grips the mask with the webbing between their thumb and first finger resting on top of the mask. The other three fingers are placed along the mandible allowing for a chin lift (in patients with no risk for c-spine injury) and jaw thrust. The mask should fit tightly to the face with no air leak.
If two airway providers are available then the two handed technique can be used. This method has been shown to provide better airway seal, decreased provider fatigue and increase total effectiveness of ventilation (greater minute ventilation and tidal volumes). This technique is similar to the one-handed method, but allows one provider to place both hands on the mask and grips on the mandible while the other provider can focus on delivering the breaths via the bag.
In both techniques the provider holding the mandible should take care to avoid compressing the soft tissue of the neck as this may lead to worsening airway obstruction.
Chest rise is often the best first indicator of adequate ventilation of a patient via bag-mask techniques. The provider can then titrate the volume required by assessing for adequate chest rise with each breath remembering that lower tidal volumes may be sufficient in patients with reduced cardiac output (i.e. CPR) and that larger tidal volumes and ventilation rates increase intrathorasic pressure thereby decreasing coronary/cerebral perfusion pressures.
Ventilation rates are usually adequate at 8 - 10 breaths/min for infants, children and adults with greater than 12 breaths/min rarely needed. Providing these breaths slowly (long inspiration time) allows the full tidal volume to be provided with low pressures and reducing the amount of gastric distention.