Of all the fundamental skills employed by EMS, few are more crucial than the ability to ventilate a patient.
When a patient can’t breathe, the bag-valve mask (BVM) enables rescuers operating within almost any environment or situation to deliver lifesaving oxygen to the patient’s lungs.
Provided there is adequate gas exchange at the alveolar level and adequate circulation to the tissues, artificial ventilation via the BVM in the hands of a skilled practitioner can keep a patient alive indefinitely.
Performed incorrectly, however, BVM ventilation can accelerate hypoxia and exacerbate the airway obstruction that naturally occurs during profoundly depressed levels of consciousness. This can result in serious injury or death.
A properly sized mask should cover the nares and mouth without gaps.
Here’s a quick walk-through on how to achieve the most beneficial outcome from this basic, yet critically important skill.
1. Recognize the need to ventilate a patient, and do so immediately. Hypoventilation occurs when the rate of spontaneous ventilations falls below 8 per minute or when the tidal volume falls below approximately 300 cc per breath. In either case, assisted ventilations become necessary. Although apnea or hypoventilation may be corrected when the cause is reversed (e.g., administration of naloxone in recognized narcotic overdoses), artificial ventilation is necessary in these instances to prevent hypoxia/anoxia and subsequent ischemic injury to the brain during the intervals between cause recognition, medication administration and the onset of therapeutic effect.
2. Position the patient, position the airway and maintain the proper airway position. Lay the patient supine. If a stretcher is available, position the patient on it quickly, with the patient ideally elevated to the rescuer’s mid-abdomen. In any circumstance, adequate space must be available for rescuers to move freely and comfortably around the patient, including enough area at the head for a rescuer to kneel or stand. The patient shouldn’t be crowded or obstructed by equipment or other obstacles.
A rescuer should be positioned at the crown of the patient’s head, facing toward the patient’s feet. The rescuer’s thumbs should be placed on each of the patient’s cheeks, parallel with the midline of the body. Three or four fingers from each of the rescuers hands should be placed behind or on the angle of the jaw, and the jaw should be firmly thrust straight forward, pushing the chin toward the ceiling or sky. This will lift the posterior aspect of the tongue off the back of the oropharynx, thereby creating an open airway. For patients in which trauma isn’t suspected, the head may be tilted back slightly to further open the airway. Maintain this position throughout the duration of the resuscitation effort.
3. Assist positioning with an adjunct. A properly-sized nasopharyngeal airway (NPA) adjunct should be placed in a patient with a gag reflex, or an oropharnygeal (OPA) in patients without a gag reflex. This will assist in keeping the tongue from falling onto the back of the throat and obstructing the airway.
4. Select a properly sized mask. When placed on the patient’s face, a properly sized mask will completely cover the nares and mouth without any gaps between the mask and face. The mask shouldn’t spill over the sides of the face because air may escape during ventilation.
5. Seal the mask to the face. The rescuer positioning the airway should take the mask, place the apex of the narrow portion on the bridge of the nose and seal the mask to the patient’s face by positioning the rescuer’s thumbs on each side of the mask above the cheeks while continuing to thrust the jaw forward, bringing the jaw into the mask. This effectively seals the mask to the face and maintains a patent airway.
6. Ventilate the patient. While the rescuer positioned at the crown of the patient’s head maintains airway position and mask seal with two hands, a second rescuer should encircle the bag with two hands and provide steady, regular ventilations at a volume of approximately 800 cc (adult). The ventilation should last approximately one second and be provided every five seconds for a target rate of 10 ventilations per minute. Both rescuers should watch the chest for adequate rise, and a third rescuer should periodically auscultate the lungs to ensure adequate ventilation. Provide high-flow supplemental oxygen, if available, to the reservoir bag. Pulse oximetry and capnography should be also utilized, if available.
A nasopharyngeal airway helps ensure an open airway during BVM use.
The proper size nasopharyngeal airway should be gauged by the distance from the nare to the ear lobe.
Common BVM Pitfalls
Here are a few things to avoid:
1. Not properly positioning the airway. Failing to open the airway, or not maintaining an open airway once it has been positioned doesn’t allow air into the lungs.
2. Pushing the mask into the face. Pushing the mask down on the face, instead of lifting the jaw into the mask, pushes the tongue against the back of the throat and obstructs the airway. Together with the mask on the face, this practice suffocates, rather than ventilates, the patient.
3. Not maintaining an effective seal. BVM ventilation is recognized as a two-rescuer skill. Only rescuers with exceptionally large hands can effectively maintain an open airway, displace the jaw into the mask and maintain a proper mask seal with a single hand. For most rescuers, two hands are needed on the mask to accomplish all of these tasks simultaneously
4. Over-ventilating and hyperventilating. Giving too much volume or going too fast could push air into the stomach, resulting in gastric insufflation. This could lead to vomiting and subsequent airway obstruction or aspiration.
Although artificial ventilation is taught to us early and frequently reinforced throughout our EMS careers, proper BVM technique is an art that must be practiced regularly to ensure it remains second nature for anyone called upon to perform this critical intervention.
Monthly hands-on, scenario-based drills using the techniques described here should be practiced with your crew to guarantee you’re able to effectively work together to build the foundation for a successful resuscitation outcome. This small investment of time can mean a lifetime for your patients.