Overview of Bag-Valve-Mask Ventilation
Using a bag valve mask to help a person breathe is an important skill for anyone who works in emergency healthcare. It can take time and practice to learn how to do it correctly, particularly since it’s often used in urgent, high-pressure situations. Properly positioning the patient is crucial to making sure the procedure works the way it should.
One of the challenges can be that a person’s tongue can block their airway by falling to the back of their throat. Certain movements like tilting the head, lifting the chin, or thrusting the jaw can help keep the airway open. These actions can help the patient assume a “sniffing” position, with their neck bent forward and their chest bone (sternal notch) and jaw bone (angle of the mandible) aligned. This position not only helps to keep the airway open, but it also provides a better view of the opening to the windpipe (glottis) and the vocal cords, which can make it easier to insert a breathing tube (endotracheal intubation) on the first attempt.
Devices like an oropharyngeal (a curved plastic device inserted in the mouth) or nasopharyngeal (a flexible tube inserted in the nose) may be used to help maintain an open airway. The bag valve mask itself often includes a one-way valve or pressure valve, and requires an oxygen supply to deliver adequate oxygen to the patient.
Anatomy and Physiology of Bag-Valve-Mask Ventilation
Understanding the structure of our throat and mouth is critical for comprehending the challenges associated with a medical procedure called bag-valve-mask ventilation. Sometimes, the specific structure of a person’s throat can make the procedure more difficult.
Doctors have developed ways to predict which patients may face these difficulties. They use short terms, like MOANS and BONES, to remember the common factors that might cause issues. MOANS stands for Mask seal (trouble sealing the mask on the face), Obesity, Age (particularly older people), No teeth, Stiffness. BONES stands for Beard, Obesity, No teeth, Elderly, Sleep apnea or snoring. If you have any of these factors, you might have a difficult time with the procedeure and doctors may need to use a specific breathing tool to increase your chances of easy breathing.
Studies have confirmed that beards, obesity, lack of teeth, snoring, older age, and a jaw that can’t protrude much can all make it more challenging to ventilate a patient. For those who have dentures, leaving them in can help achieve a better mask seal. If a significant beard or facial hair is present, a water-soluble lubricant can be used to help create a better seal.
Why do People Need Bag-Valve-Mask Ventilation
If you have too much carbon dioxide in your blood (hypercapnic respiratory failure) or too little oxygen in your blood (hypoxic respiratory failure), you might need help with your breathing. This might also be needed if you stop breathing completely (apnea) or if you’re not alert enough to keep your airway open (altered mental status). This kind of help is often provided with a bag valve mask (BVM), which is a device that can push air into your lungs. It’s often used during operations as well, for patients who are under anesthesia.
When a Person Should Avoid Bag-Valve-Mask Ventilation
There might be certain health issues that can prevent doctors from safely carrying out some medical procedures. These issues include:
An upper airway blockage: This means that something is completely blocking the passage of air in the upper part of the respiratory system, making it hard to breathe.
An increased risk of pulling food or liquid into the lungs after paralysis and induction: This is when there’s a higher chance of substances going down the wrong pipe and getting into the lungs after a person has been paralyzed and induced, possibly as part of a medical treatment.
Equipment used for Bag-Valve-Mask Ventilation
The necessary tools for this procedure include a bag valve mask, which is a device used to help breathing; an oxygen source that provides the necessary gas for life-support; oxygen tubing which is a pipe used to transport the oxygen from the source to the patient; a PEEP valve that helps keep the airways open; and simple airway aids, such as an oropharyngeal airway and nasopharyngeal airway which are tubes inserted into the throat to maintain an open airway.
Who is needed to perform Bag-Valve-Mask Ventilation?
In simple terms, using a bag valve mask to help a patient breathe usually only needs one healthcare provider. This provider will hold the mask to the patient’s face. There can be a second helper, who squeezes the bag to push air into the patient’s lungs while the first person focuses on keeping the mask in place. This teamwork helps make sure the patient is getting enough oxygen.
Preparing for Bag-Valve-Mask Ventilation
When a patient is unable to breathe properly, healthcare providers may use a device known as an oropharyngeal airway. This device is inserted into a patient’s throat to push the tongue forward and keep the airway open, especially when the patient is lying on their back. However, this device should not be used if the patient has a gag reflex, a bodily function that makes you feel like you need to vomit.
Another device, a nasopharyngeal airway, can be used to help a patient breathe. This device is inserted into a patient’s nose and gets to the back of their throat, especially if the patient has a large tongue or an obstruction that makes breathing difficult. This device should not be used in patients with facial injuries, as it might harm the brain cavity. The device must be inserted carefully to reach the back part of the patient’s throat.
The healthcare provider usually positions themselves at the patient’s head during this process and makes sure they have a secure seal over the patient’s face. The seal over the face should prevent any air from escaping and is usually achieved by pressing the mask firmly over the patient’s nose and mouth.
In some cases, a second person might be involved, with one person creating the secure seal while the other person presses a bag to deliver air to the patient. Proper positioning can make it easier to provide air to the patient. For instance, having the patient’s head in line with their chest can improve airflow. It’s also helpful to use an appropriately sized mask – one that’s larger than needed might form a good seal, but a smaller one can cause air to leak out.
How is Bag-Valve-Mask Ventilation performed
An adult Bag Valve Mask (BVM), which is a device used to help a person breathe, filled with oxygen supplied at a minimum of 15 liters per minute, can deliver as much as 1.5 liters of oxygen with each breath. When using this device, it’s important to be careful and only provide as much breath as it takes to recognize a rise in the person’s chest. This is to lower the chance of blowing too much air into the stomach – a situation that could lead to vomiting – and prevent damage to the lungs from over-inflation.
Possible Complications of Bag-Valve-Mask Ventilation
The potential problems that can occur from this procedure include barotrauma and gastric insufflation. Barotrauma is a condition caused by too much air pressure in the lungs, causing them to overinflate. Gastric insufflation, on the other hand, is when air gets into the stomach, which may cause a person to vomit. In turn, this could lead to aspiration, a situation where the vomit is inhaled back into the lungs.
What Else Should I Know About Bag-Valve-Mask Ventilation?
Cricoid pressure is a technique originally used during procedures like mask ventilation and placing a breathing tube. The idea behind it was to block the food pipe to prevent stomach contents from coming back up and being inhaled into the lungs. However, recently it has not been consistently shown to improve patient outcomes. Some evidence suggests that it shifts the food pipe instead of blocking it, and it may not fully block the food pipe depending on how much force is used. Other studies have found that it can make it harder to see the windpipe when placing a breathing tube.
Bag-valve-mask (BVM) ventilation, a method to help someone breathe, can be improved by the use of a positive end-expiratory pressure (PEEP) valve. This device, which can be adjusted to apply varying pressure, helps to improve oxygen levels before a breathing tube is inserted for those patients who can’t be sufficiently pre-oxygenated by standard methods. However, the pressure should not exceed 20 cm H2O as it can cause the lower part of the food pipe to open, leading to inflation of the stomach and vomiting.
To avoid the stomach from expanding with air, a technique applying a small amount of pressure and volume can be used.
Some BVM devices can have a filter added to them to trap harmful particles. However, these devices may not be totally reliable, and wearing personal protective equipment is recommended whenever dealing with a patient.
In addition, some BVM models can have an end-tidal monitor or a container for aerosol medications added to them, increasing their usefulness. However, if the device doesn’t fit the face properly, the information from the monitor will be inaccurate and the aerosol medication could escape.
